Cationic, neutral and anionic metal(II) complexes derived from 4-oxo-4H-­pyran-2,6-dicarboxylic acid (chelidonic acid)

The structures of five metal complexes containing the 4-oxo-4H-pyran-2,6-dicarboxyl­ate dianion illustrate the remarkable coordinating versatility of this ligand and the great structural diversity of its complexes. In tetra­aqua­beryllium 4-oxo-4H-pyran-2,6-dicarboxyl­ate, [Be(H₂O)₄](C₇H₂O₆), (I), the ions are linked by eight independent O—H...O hydrogen bonds to form a three-dimensional hydrogen-bonded framework structure. Each of the ions in hydrazinium(2+) diaqua­(4-oxo-4H-­pyran-2,6-dicarboxyl­ato)calcate, (N₂H₆)[Ca(C₇H₂O₆)₂(H₂O)₂], (II), lies on a twofold rotation axis in the space group P2/c; the anions form hydrogen-bonded sheets which are linked into a three-dimensional framework by the cations. In bis­(μ-4-oxo-4H-pyran-2,6-dicarboxyl­ato)bis­[tetraaquamanganese(II)] tetra­hydrate, [Mn₂(C₇H₂O₆)₂(H₂O)₈]·4H₂O, (III), the metal ions and the organic ligands form a cyclic centrosymmetric Mn₂(C₇H₂O₆)₂ unit, and these units are linked into a complex three-dimensional framework structure containing 12 independent O—H...O hydrogen bonds. There are two independent Cu^II ions in tetra­aqua­(4-oxo-4H-pyran-2,6-dicarboxyl­ato)­copper(II), [Cu(C₇H₂O₆)(H₂O)₄], (IV), and both lie on centres of inversion in the space group P; the metal ions and the organic ligands form a one-dimensional coordination polymer, and the polymer chains are linked into a three-dimensional framework containing eight independent O—H...O hydrogen bonds. Diaqua­(4-oxo-4H-pyran-2,6-dicarboxyl­ato)cadmium monohydrate, [Cd(C₇H₂O₆)(H₂O)₂]·H₂O, (V), forms a three-dimensional coordination polymer in which the organic ligand is coordinated to four different Cd sites, and this polymer is inter­woven with a complex three-dimensional framework built from O—H...O hydrogen bonds.

S1. Comment

4-Oxo-4H-pyran-2,6-dicarboxylic acid (chelidonic acid), (A), is one of the constituents of the greater celandine Chelidonium majus, which exhibits a wide range of therapeutic properties (Chevallier, 1996). It is also an inhibitor of dihydrodipicolinate synthase, a key enzyme in the biosynthesis of lysine via the diaminopimelate pathway (Borthwick et al., 1995). A pK_a of about 2.4 for both carboxyl groups (Miyamoto & Brochmann-Hanssen, 1962) makes it a very effective chelating agent at physiological pH. However, while a number of metal complexes formed by the closely-related 4-oxo-1,4-dihydropyridine-2,6-dicarboxylic acid (chelidamic acid), (B), have been structurally characterized (Devereux et al., 2002; Burnett et al., 2003; Zhou et al., 2004; Cui et al., 2006; Gao et al., 2006), very few complexes derived from 4-oxo-4H-pyran-2,6-dicarboxylic acid have been structurally characterized. In pentaaqua(4-oxo-4H-pyran-2,6-dicarboxylato)copper(II) monohydrate, the organic ligand is coordinated to the Cu via the ketonic O atom only and the coordination polyhedron around Cu is completed by five water ligands. The carboxylate groups do not coordinate to Cu, but they participate in a complex hydrogen-bonding scheme which generates a three-dimensional framework structure (Manojlović-Muir et al., 1999). In the dicyclohexylammonium salt of tributyl(4-oxo-4H-pyran-2,6-dicarboxylato)stannate(IV), the 4-oxo-4H-pyran-2,6-dicarboxylato dianion acts as a bridging ligand, via two different carboxylate groups, between planar tributyltin(IV) units, so forming a chain polymer (Ng et al., 2000).

With this in mind, we report here the molecular and supramolecular structures of five metal complexes derived from 4-oxo-4H-pyran-2,6-dicarboxylic acid, namely tetraaquaberyllium 4-oxo-4H-pyran-2,6-dicarboxylate, (I), hydrazinium(2+) diaqua(4-oxo-4H-pyran-2,6-dicarboxylato)calcate, (II), tetraaqua(4-oxo-4H-pyran-2,6-dicarboxylato)manganese(II) dihydrate, (III), tetraaqua(4-oxo-4H-pyran-2,6-dicarboxylato)copper(II), (IV), and diaqua(4-oxo-4H-pyran-2,6-dicarboxylato)cadmium monohydrate, (V). Complexes (I), (III) and (V) were prepared straightforwardly by the reactions, in aqueous solution, of 4-oxo-4H-pyran-2,6-dicarboxylic acid with beryllium sulfate tetrahydrate, manganese(II) acetate and cadmium nitrate, respectively. Complex (IV) was similarly prepared using basic copper carbonate. Attempts to prepare the simple hydrazinium salt by a similar type of reaction consistently yielded only polycrystalline material when conducted in doubly distilled water, but the same procedure in singly distilled water unexpectedly gave the anionic complex, (II), where the calcium component has presumably arisen from the water employed. Attempts to isolate crystals of this material from solutions containing hydrazine, calcium nitrate and 4-oxo-4H-pyran-2,6-dicarboxylic acid have been uniformly unsuccessful: polycrystalline samples of (II) have been readily obtained in this manner, in yields of around 65–70%, but no crystals suitable for single-crystal X-ray diffraction have been obtained by this route.

In each of compounds (I)–(V), the organic component is present in dianionic form, C₇H₂O₆^2-. This entity occurs as isolated ions in compound (I), which is a hydrated salt in which the metal is present as a simple aqua ion, thus [Be(H₂O)₄]²⁺·C₇H₂O₆^2- (Fig. 1). In each of the coordination compounds (II)–(V), the 4-oxo-4H-pyran-2,6-dicarboxylate anion acts as a ligand towards the metal, and the coordination complexes are neutral in the cases of compounds (III)–(V) and anionic in compound (II). Compound (II) contains isolated mononuclear anions (Fig. 2), compound (III) contains isolated dimers which are neutral and centrosymmetric (Fig. 3), while both (IV) and (V) (Figs. 4 and 5) form coordination polymers, which are one-dimensional in the case of (IV) and three-dimensional in the case of (V). In all compounds, there is an extensive series of hydrogen bonds which link the metal-containing species. We note in particular here the contrast between the coordination polymer formed in the tetrahydrate, (IV), and the isolated mononuclear complexes formed in the corresponding hexahydrate (Manojlović-Muir et al., 1999).

In compound (II), the 4-oxo-4H-pyran-2,6-dicarboxylate anion acts as a tridentate ligand to the Ca²⁺ cation, coordinating via a pair of carboxylate O atoms and also via the ring O atom (Fig. 2). In each of compounds (III) and (IV), the organic anion acts as a bidentate ligand bridging a pair of metal centres. However, in the Mn complex, (III), the anion utilizes two O atoms from a single carboxylate group acting as donor to a pair of symmetry-related Mn^II cations, and the resulting aggregate is centrosymmetric (Fig. 3). By contrast, in the Cu complex, (IV), the anion utilizes one O atom from each carboxylate group as donors to two independent Cu^II cations, each of which lies on a centre of inversion (Fig. 4). Finally, in the Cd complex, (V), the organic ligand utilizes three carboxylate O atoms and the ketonic O atom as donors to four different Cd atoms (Fig. 5).

The bond lengths within the organic ligands are remarkably constant across the series (I)–(V). The C—O distances in the carboxylate groups are fully consistent with complete ionization in every case. The metal—O distances present only a few unexpected values. In the Ca complex, (II), the distance to the ring O atom [2.6231 (12) Å] is significantly longer than the distances [2.4002 (13) and 2.4314 (13) Å] to the adjacent carboxylate O atoms, purely for geometric reasons. In the Cd complex, (V), the Cd—O(carboxylate) distances range from 2.242 (3) to 2.3284 (19) Å, with the distances to the water O atoms both within this range, but the distance to the ketonic O atom is significantly longer, at 2.419 (3) Å. The most striking distances occur for the Cu^II complex, (IV), where the six-coordination of the two independent Cu^II cations is subject to Jahn–Teller distortion giving, for both ions, the typical (4 + 2) coordination having local D_4h (4/mmm) point symmtry, with the two axial distances significantly longer than the four equatorial distances. However, for atom Cu1, the two axial sites are occupied by a pair of water molecules, while for atom Cu2, these sites are occupied by a pair of carboxylate ligands (Table 4).

The supramolecular structures of compounds (I)–(V) are all three-dimensional. In compounds (I)–(III), the three-dimensional frameworks are all built entirely from hydrogen bonds. Compound (IV) forms a one-dimensional polymer chain, and these chains are linked into a three-dimensional structure by hydrogen bonds, while compound (V) consists of the three-dimensional coordination polymer interwoven with a three-dimensional hydrogen-bonded framework.

Within the selected asymmetric unit of the hydrated salt, (I) (Fig. 1), the cation is linked to the anion by two nearly linear O—H···O hydrogen bonds (Table 1), where both acceptors are in the same carboxylate group. Ion pairs of this type are linked by six further O—H···O hydrogen bonds into a three-dimensional framework structure, whose formation is readily analysed in terms of simple sub-structures. The cation at (x, y, z) acts as hydrogen-bond donor via atom O11 to atom O61 in the anion at (1/2 - x, 1/2 + y, 3/2 - z), via atom O13 to atoms O21 and O61 in the anion at (3/2 - x, 1/2 + y, 3/2 - z), and via atom O14 to atom O62 in the anion at (1 + x, 1 + y, z), resulting in the formation of a complex sheet parallel to (001) generated by the 2₁ screw axes at z = 3/4 (Fig. 6). Successive (001) sheets are linked by two further hydrogen bonds. The cation at (x, y, z) is linked via atoms O12 and O14, respectively, to atoms O4 in the anions at (2 - x, 1 - y, 1 - z) and (1 - x, 1 - y, 1 - z), both of which lie in the (001) sheet generated by the 2₁ screw axes at y = 1/4. These two interactions together form a chain of alternating R⁴₄(18) (Bernstein et al., 1995) and R⁴₄(22) rings (Fig. 7), whose propagation by the space group thus links each (001) sheet to the two adjacent sheets. Hence, all of the component ions are linked into a single three-dimensional structure.

In the salt (II), N₂H₆²⁺·[Ca(C₇H₂O₆)₂(H₂O)₂]^2-, the Ca atom forms part of an isolated anion, which lies across a twofold rotation axis in space group P2/c. The hydrazinium cation likewise lies across a twofold axis. A combination of O—H···O and N—H···O hydrogen bonds (Table 2) links the component ions into a three-dimensional framework, but it is possible to identify a two-dimensional sub-structure built from anions only. The water atoms O2 at (x, y, z) and (1 - x, y, 1/2 - z) are components of the reference anion across the axis (1/2, y, 1/4). These two atoms act as hydrogen-bond donors via atom H2A to the ketonic atoms O4 at (1 - x, 2 - y, -z) and (x, 2 - y, 1/2 + z), respectively, which lie in the anions across (1/2, -y, 1/4) and (1/2, -y, 3/4), respectively. Similarly, the water atoms O2 at (x, y, z) and (1 - x, y, 1/2 - z) act as hydrogen-bond donors via atom H2B to the carboxylate atoms O22 at (-1 + x, y, z) and (2 - x, y, 1/2 - z), which form parts of the anions across (-1/2, y, 1/4) and (3/2, y, 1/4), respectively. Propagation of these two hydrogen bonds by translation, rotation and inversion then generates a sheet of anions lying parallel to (010) and containing three types of ring (Fig. 8). A single sheet of this type passes through each unit cell. The hydrazinium cations lie within one of the larger rings, and each cation forms six N—H···O hydrogen bonds, four of which (involving atoms H3A and H3B) lie within the reference (010) sheet, while the other two, involving atom H3C, serve to link the reference sheet to the two adjacent sheets, so linking all of the ions into a single three-dimensional framework.

The 4-oxo-4H-pyran-2,6-dicarboxylate ligand in the Mn^II complex, (III), acts as a bridging ligand between two symmetrically related metal centres, thereby forming a cyclic centrosymmetric aggregate containing an R²₄(8) (Starbuck et al., 1999) ring (Fig. 3), located for the sake of convenience across (1/2, 1/2, 1/2). The four water molecules coordinated to the metal form three internal O—H···O hydrogen bonds, one to a carboxylate O atom and the other two to the uncoordinated water molecules. In addition, the non-coordinated water atom O15 at (x, y, z) forms an internal hydrogen bond to the coordinated water atom O12 at (1 - x, 1 - y, 1 - z). In each dimeric aggregate, therefore, there are 16 O—H bonds available for the formation of hydrogen bonds between the aggregates (Table 3), and these link the metal complexes into a three-dimensional framework structure of considerable complexity. However, the three-dimensional nature of the supramolecular structure can be readily demonstrated using just four of the independent hydrogen bonds between the aggregates, which give rise to three simple one-dimensional sub-structures. In the first of these sub-structures, water atom O12 at (x, y, z) acts as hydrogen-bond donor, via atom H12A, to ketonic atom O4 at (x, y, -1 + z), so generating by translation a molecular ladder running parallel to the [001] direction, in which the uprights are formed by an antiparallel pair of C(8) chains, while the rungs of the ladder contain the R²₄(8) rings (Fig. 9). In addition, atom O12 at (x, y, z) also acts as donor to atom O4 at (1 - x, 2 - y, 1 - z), this time via atom H12B, and propagation of this interaction by inversion generates a chain of fused rings running parallel to the [010] direction (Fig. 10). Finally, water atoms O13 and O14 at (x, y, z) act as donors to, respectively, carboxylate atoms O61 and O62 at (-1 + x, 1 + y, -1 + z), so generating by translation a chain of fused rings running parallel to the [111] direction (Fig. 11). The combination of these [001], [010] and [111] chains suffices to generate a three-dimensional framework, whose structure is rendered considerably more complex by further hydrogen bonds involving both coordinated and non-coordinated water molecules (Table 3).

The two independent Cu^II ions in compound (IV) both lie on centres of inversion in space group P1, selected as those at (0, 0, 1/2) for Cu1 and (1/2, 0, 0) for Cu2. The 4-oxo-4H-pyran-2,6-dicarboxylate ligand lies in a general position, bridging the two Cu ions via a pair of carboxylate O atoms (Fig. 4). The action of the two independent inversion centres then generates a coordination polymer chain of alternating cations and anions, running parallel to the [101] direction (Fig. 12). The role of the 4-oxo-4H-pyran-2,6-dicarboxylate ligand in (IV) is thus similar to that in the polymer formed with tributyltin(IV) units (Ng et al., 2000), although in that instance the coordination polymer is anionic, whereas in (IV) it is neutral.

The coordination polymer chains are linked into a complex three-dimensional framework by no fewer than eight independent O—H···O hydrogen bonds (Table 5), but the three-dimensional nature of the supramolecular structure can most simply be demonstrated in terms of two one-dimensional hydrogen-bonded sub-structures involving just three of the hydrogen bonds. In the first of these sub-structures, water atom O1B at (x, y, z) acts as hydrogen-bond donor, via atom H12B, to ketonic atom O4 at (x, -1 + y, z), and propagation of this interaction by translation and inversion generates a chain of spiro-fused R⁴₆(18) rings running parallel to the [010] direction (Fig. 13). In the second hydrogen-bonded sub-structure, water atoms O2A and O2B at (x, y, z) act as donors to, respectively, atoms O62 and O61 at (-1 + x, y, z). Propagation of these interactions by translation and inversion then generates a complex chain of R⁴₄(8) and R⁴₆(8) rings running parallel to the [100] direction (Fig. 14). The combination of these [100], [010] and [101] chains is sufficient to generate a three-dimensional framework, with further complexity generated by the remaining hydrogen bonds.

Compound (V) is a coordination compound, [Cd(C₇H₂O₆)(H₂O)₂]·H₂O (Fig. 5), in which the Cd centre is coordinated by two water molecules, occupying cis sites, and four O atoms, one of them a ketonic O atom and three of them from carboxylate groups, which themselves form parts of four different anionic ligands. The six-coordination of the Cd ion is markedly distorted from regular octahedral. The third water molecule is not coordinated to the Cd ion, but instead forms hydrogen bonds to O atoms in three different anions via one two-centre O—H···O interaction and one three-centre O—H···(O)₂ interaction (Table 6).

The Cd cations and the anions together form a three-dimensional coordination polymer, whose formation is very easily analysed in terms of two simple sub-structures, namely a two-dimensional sub-structure involving only carboxylate coordination and a one-dimensional sub-structure based on the coordination of the ketonic O atom to the Cd ion. The reference Cd ion at (x, y, z) is coordinated not only by atom O21 at (x, y, z), but also by atoms O61 and O62 in the anions at (x, 1 + y, z) and (-1 + x, 1 + y, z), respectively, and these interactions together generate a sheet parallel to (001) which takes the form of a (4,4) net (Batten & Robson, 1998) (Fig. 15). In the second sub-structure, the reference Cd ion is coordinated by ketonic atom O4 in the anion at (-1 + x, y, -1 + z), so forming a C(7) chain (Starbuck et al., 1999) running parallel to the [101] direction (Fig. 16). The combination of these [101] chains and (001) sheets suffices to generate a single three-dimensional coordination polymer.

In addition, the polymer framework is reinforced by an extensive series of hydrogen bonds (Table 6). These individually form chains parallel to [100], [010], [101], [201], [011] and [111], and their combination thereby forms a very complex three-dimensional hydrogen-bonded framework interwoven with the coordination polymer framework.

The range of the structures reported here, together with those reported previously (Manojlović-Muir et al., 1999, Ng et al., 2000), indicates the remarkably versatile coordination behaviour of the 4-oxo-4H-pyran-2,6-dicarboxylate dianion, which has led here to the characterization of cationic, neutral and anionic complexes, encompassing finite coordination species, both mononuclear and binuclear, as well as one- and three-dimensional coordination polymers.

Related literature

For related literature, see: Batten & Robson (1998); Bernstein et al. (1995); Borthwick et al. (1995); Burnett et al. (2003); Chevallier (1996); Cui et al. (2006); Devereux et al. (2002); Flack (1983); Gao et al. (2006); Manojlović-Muir, Muir, Campbell, McKendrick & Robins (1999); Miyamoto & Brochmann-Hanssen (1962); Ng et al. (2000); Starbuck et al. (1999); Zhou et al. (2004).

S2. Experimental

For the synthesis of compound (I), equimolar quantities (1 mmol of each component) of beryllium sulfate tetrahydrate and 4-oxo-4H-pyran-2,6-dicarboxylic acid were dissolved in doubly distilled water (20 ml). Slow evaporation at ambient temperature yielded, after 19 d, pale-yellow prismatic crystals of (I) (yield 94%). Analysis for (I), found: C 32.0, H 3.8%; C₇H₁₀BeO₁₀ requires: C 31.9, H 3.8%.

Compound (II) was unexpectedly obtained from the reaction between equimolar quantities (1 mmol of each component) of hydrazine hydrate and 4-oxo-4H-pyran-2,6-dicarboxylic acid in singly distilled water, followed by slow evaporation. Analysis for (II), found: C 36.0, H 2.9, N 5.8%; C₁₄H₈CaN₂O₁₄ requires: C 35.4, H 3.0, N 5.9%; IR (KBr, ν, cm^-1): 3460, 3299, 3064, 1616, 1402, 1349, 1109.

For the synthesis of compound (III), a solution of manganese(II) acetate (1 mmol in 5 ml of water) was added to a solution of 4-oxo-4H-pyran-2,6-dicarboxylic acid (1 mmol in 15 ml of water). Slow evaporation at ambient temperature gave, after 12 d, yellow rhomboid crystals of (III) (yield 53%). Analysis for (III), found: C 26.0, H 3.0%; C₇H₁₄MnO₁₂ requires: C 24.4, H 4.1%.

Compound (IV) was prepared by the portionwise addition of basic copper(II) carbonate (1 mmol, as a solid) to a hot (ca 350 K) solution of 4-oxo-4H-pyran-2,6-dicarboxylic acid (2 mmol in 40 ml of water). The solution was filtered hot and then allowed to cool to ambient temperature, when slow evaporation gave pale-green crystals of (IV) after 12 d (yield 80%). Analysis for (IV), found: C 26.1, H 3.2%; C₇H₁₀CuO₁₀ requires: C 26.5, H 3.2%.

For the synthesis of compound (V), aqueous solutions of cadmium nitrate (1 mmol in 5 ml of water) and 4-oxo-4H-pyran-2,6-dicarboxylic acid (1 mmol in 15 ml of water) were mixed at ambient temperature. Subsequent slow evaporation at ambient temperature yielded, after 8 d, pale-yellow rhomboid crystals of (V) (yield 79%). Analysis for (V), found: C 24.4, H 2.1%; C₇H₈CdO₉ requires: C 24.15, H 2.3%.

In every case, the crystals were collected by filtration and then washed with ice-cold water (ca 5 ml) prior to analysis.

S3. Refinement

For compound (I), the space group P2₁/n was uniquely assigned from the systematic absences. For compound (II), the systematic absences permitted Pc and P2/c as possible space groups; P2/c was selected, and confirmed by the successful structure analysis. Crystals of compounds (III)–(V) are all triclinic. The space group P1 was selected for compounds (III) and (IV), and P1 was selected for compound (V), and these selections were all confirmed by the subsequent structure analyses. All H atoms were located in difference maps and then treated as riding atoms. H atoms bonded to C atoms were placed in calculated positions, with C—H = 0.95 Å, and with U_iso(H) = 1.2U_eq(C). H atoms bonded to N or O atoms were permitted to ride at the locations deduced from the difference maps, giving N—H = 0.88–0.96 Å and O—H = 0.82–0.94 Å, with U_iso(H) = 1.2U_eq(N) or 1.5U_eq(O). The correct absolute configuration of the structure of compound (V) in the crystal selected for data collection was established by means of the Flack parameter (Flack, 1983).

Computing details

For all compounds, data collection: COLLECT (Nonius, 1999); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: OSCAIL (McArdle, 2003) and SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: OSCAIL and SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).

Figures

	Fig. 1. The independent ionic components of compound (I), showing the atom-numbering scheme and the two hydrogen bonds (dashed lines) within the selected asymmetric unit. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii.
	Fig. 2. The independent ionic components of compound (II), showing the atom-labelling scheme and the hydrogen bond (dashed line) between the ions in the selected asymmetric unit. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii. Atoms labelled with the suffix a or b are at the symmetry positions (1 - x, y, 1/2 - z) and (-x, y, 1/2 - z), respectively.
	Fig. 3. The dimeric aggregate in compound (III) and the two independent non-coordinated water molecules, showing the atom-labelling scheme and the hydrogen bonds (dashed lines) within the selected asymmetric unit. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii. Atoms labelled with the suffix a are at the symmetry position (1 - x, 1 - y, 1 - z).
	Fig. 4. The independent components of compound (IV), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii. Atoms labelled with the suffix a or b are at the symmetry positions (-x, -y, 1 - z) and (1 - x, -y, -z), respectively.
	Fig. 5. The independent components of compound (V), showing the atom-labelling scheme, the hydrogen bond (dashed line) within the selected asymmetric unit and the distorted octahedral coordination of the Cd atom. Displacement ellipsoids are drawn at the 30% probability level and H atoms are shown as small spheres of arbitrary radii. Atoms labelled with the suffix a, b or d are at the symmetry positions (-1 + x, y, -1 + z), (-1 + x, 1 + y, z) and (x, 1 + y, z), respectively.
	Fig. 6. A stereoview of part of the crystal structure of compound (I), showing the formation of a hydrogen-bonded sheet parallel to (001). For the sake of clarity, H atoms bonded to C atoms have been omitted.
	Fig. 7. A stereoview of part of the crystal structure of compound (I), showing the formation of the hydrogen-bonded chain of rings which links adjacent (001) sheets. For the sake of clarity, H atoms bonded to C atoms have been omitted.
	Fig. 8. A stereoview of part of the crystal structure of compound (II), showing the formation of a hydrogen-bonded sheet of anions. For the sake of clarity, the cations and H atoms bonded to C atoms have been omitted.
	Fig. 9. A stereoview of part of the crystal structure of compound (III), showing the formation of a hydrogen-bonded molecular ladder along [001]. For the sake of clarity, non-coordinated water molecules and H atoms bonded to C atoms have been omitted.
	Fig. 10. A stereoview of part of the crystal structure of compound (III), showing the formation of a hydrogen-bonded chain of fused rings along [010]. For the sake of clarity, non-coordinated water molecules and H atoms bonded to C atoms have been omitted.
	Fig. 11. A stereoview of part of the crystal structure of compound (III), showing the formation of a hydrogen-bonded chain of fused rings along [111]. For the sake of clarity, non-coordinated water molecules and H atoms bonded to C atoms have been omitted.
	Fig. 12. Part of the crystal structure of compound (IV), showing the formation of a chain of alternating cations and anions along [101]. For the sake of clarity, the water molecules and H atoms bonded to C atoms have all been omitted. O atoms marked with an asterisk (*), a hash (#), a dollar sign ($) or an ampersand (&) are at the symmetry positions (-x, -y, 1 - z), (1 - x, -y, -z), (1 + x, y, -1 + z) and (-1 + x, y, 1 + z), respectively. Atoms Cu1# and Cu1& are at ((1, 0, -1/2) and (-1, 0, 3/2), respectively, and atoms Cu2* and Cu2$ are at (-1/2, 0, 1) and (3/2, 0, 01), respectively.
	Fig. 13. A stereoview of part of the crystal structure of compound (IV), showing the formation of a hydrogen-bonded chain of spiro-fused rings along [010]. For the sake of clarity, atom Cu2, three of the water molecules, and H atoms bonded to C atoms, have been omitted.
	Fig. 14. A stereoview of part of the crystal structure of compound (IV), showing the formation of a hydrogen-bonded chain of fused rings along [100]. For the sake of clarity, atom Cu1, two of the water molecules, and H atoms bonded to C atoms, have been omitted.
	Fig. 15. A stereoview of part of the crystal structure of compound (V), showing the formation of a coordination polymer sheet parallel to (001). For the sake of clarity, the water molecules and H atoms bonded to C atoms have been omitted.
	Fig. 16. Part of the crystal structure of compound (V), showing the formation of a coordination polymer chain along [101]. For the sake of clarity, the water molecules and H atoms bonded to C atoms have been omitted. Atoms marked with an asterisk (*) or a hash (#) are at the symmetry positions (-1 + x, y, -1 + z) and (1 + x, y, 1 + z), respectively.

(I) tetraaquaberyllium 4-oxo-4H-pyran-2,6-dicarboxylate

Crystal data

[Be(H2O)4](C7H2O6)	F(000) = 544
Mr = 263.16	Dx = 1.594 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yn	Cell parameters from 2504 reflections
a = 5.4331 (2) Å	θ = 3.7–27.5°
b = 10.6173 (4) Å	µ = 0.15 mm^−1
c = 19.1890 (5) Å	T = 120 K
β = 97.771 (2)°	Block, colourless
V = 1096.75 (6) Å^3	0.28 × 0.24 × 0.11 mm
Z = 4

Data collection

Bruker Nonius KappaCCD area-detector diffractometer	2504 independent reflections
Radiation source: Bruker Nonius FR591 rotating anode	2180 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.034
Detector resolution: 9.091 pixels mm^-1	θmax = 27.5°, θmin = 3.7°
ϕ and ω scans	h = −7→7
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	k = −13→13
Tmin = 0.968, Tmax = 0.984	l = −24→24
11511 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.118	H-atom parameters constrained
S = 1.15	w = 1/[σ^2(Fo^2) + (0.0538P)^2 + 0.5571P] where P = (Fo^2 + 2Fc^2)/3
2504 reflections	(Δ/σ)max < 0.001
163 parameters	Δρmax = 0.37 e Å^−3
0 restraints	Δρmin = −0.34 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Be1	0.9267 (4)	0.82639 (19)	0.70311 (10)	0.0159 (4)
O11	0.7690 (2)	0.72233 (11)	0.73958 (6)	0.0207 (3)
O12	1.0599 (2)	0.74678 (11)	0.64721 (6)	0.0232 (3)
O13	1.1337 (2)	0.89899 (10)	0.75675 (5)	0.0166 (2)
O14	0.7441 (2)	0.93860 (11)	0.66807 (6)	0.0181 (3)
O1	0.40311 (19)	0.33307 (10)	0.60011 (5)	0.0150 (2)
C2	0.5898 (3)	0.38121 (14)	0.56826 (7)	0.0135 (3)
C21	0.7056 (3)	0.49728 (14)	0.60615 (8)	0.0158 (3)
O21	0.6151 (2)	0.53141 (11)	0.65993 (6)	0.0219 (3)
O22	0.8768 (2)	0.54817 (11)	0.57978 (6)	0.0226 (3)
C3	0.6627 (3)	0.33029 (14)	0.51029 (8)	0.0141 (3)
C4	0.5414 (3)	0.21854 (14)	0.47974 (7)	0.0147 (3)
O4	0.6024 (2)	0.16676 (11)	0.42565 (6)	0.0187 (3)
C5	0.3443 (3)	0.16948 (15)	0.51547 (8)	0.0150 (3)
C6	0.2847 (3)	0.22814 (14)	0.57311 (8)	0.0136 (3)
C61	0.0816 (3)	0.18509 (15)	0.61493 (8)	0.0146 (3)
O61	0.0470 (2)	0.24956 (11)	0.66770 (6)	0.0185 (3)
O62	−0.0342 (2)	0.08964 (11)	0.59166 (6)	0.0202 (3)
H11A	0.7154	0.6595	0.7130	0.031*
H11B	0.6794	0.7367	0.7775	0.031*
H12A	0.9988	0.6801	0.6256	0.035*
H12B	1.1678	0.7810	0.6217	0.035*
H13A	1.0664	0.9449	0.7874	0.025*
H13B	1.2387	0.8536	0.7864	0.025*
H14A	0.6244	0.9146	0.6343	0.027*
H14B	0.8245	0.9979	0.6391	0.027*
H3	0.7938	0.3678	0.4895	0.017*
H5	0.2568	0.0959	0.4983	0.018*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Be1	0.0188 (9)	0.0161 (9)	0.0141 (8)	−0.0038 (7)	0.0062 (7)	−0.0015 (7)
O11	0.0274 (6)	0.0155 (6)	0.0223 (6)	−0.0064 (5)	0.0145 (5)	−0.0056 (4)
O12	0.0284 (6)	0.0202 (6)	0.0248 (6)	−0.0122 (5)	0.0169 (5)	−0.0102 (5)
O13	0.0183 (5)	0.0173 (6)	0.0144 (5)	0.0013 (4)	0.0034 (4)	−0.0018 (4)
O14	0.0183 (5)	0.0186 (6)	0.0170 (5)	−0.0056 (4)	0.0013 (4)	0.0009 (4)
O1	0.0164 (5)	0.0148 (5)	0.0149 (5)	−0.0041 (4)	0.0064 (4)	−0.0021 (4)
C2	0.0126 (7)	0.0140 (7)	0.0141 (7)	−0.0021 (5)	0.0020 (5)	0.0026 (6)
C21	0.0193 (7)	0.0135 (7)	0.0150 (7)	−0.0014 (6)	0.0032 (6)	−0.0003 (6)
O21	0.0304 (6)	0.0180 (6)	0.0198 (6)	−0.0085 (5)	0.0127 (5)	−0.0058 (4)
O22	0.0254 (6)	0.0205 (6)	0.0241 (6)	−0.0109 (5)	0.0116 (5)	−0.0065 (5)
C3	0.0140 (7)	0.0148 (7)	0.0139 (7)	−0.0030 (5)	0.0030 (5)	0.0017 (5)
C4	0.0145 (7)	0.0170 (7)	0.0127 (7)	−0.0007 (6)	0.0027 (5)	0.0002 (6)
O4	0.0188 (6)	0.0220 (6)	0.0166 (5)	−0.0063 (4)	0.0073 (4)	−0.0064 (4)
C5	0.0146 (7)	0.0155 (7)	0.0153 (7)	−0.0036 (6)	0.0033 (5)	−0.0003 (6)
C6	0.0134 (7)	0.0124 (7)	0.0152 (7)	−0.0022 (5)	0.0022 (5)	0.0017 (5)
C61	0.0135 (7)	0.0166 (7)	0.0140 (7)	0.0000 (5)	0.0033 (5)	0.0033 (5)
O61	0.0178 (5)	0.0218 (6)	0.0174 (5)	−0.0033 (4)	0.0072 (4)	−0.0021 (4)
O62	0.0205 (6)	0.0201 (6)	0.0210 (6)	−0.0079 (5)	0.0065 (4)	−0.0003 (4)

Geometric parameters (Å, º)

Be1—O12	1.612 (2)	C2—C3	1.344 (2)
Be1—O13	1.614 (2)	C2—C21	1.523 (2)
Be1—O11	1.614 (2)	C21—O22	1.2413 (18)
Be1—O14	1.636 (2)	C21—O21	1.2549 (18)
O11—H11A	0.8652	C3—C4	1.443 (2)
O11—H11B	0.9418	C3—H3	0.95
O12—H12A	0.8635	C4—O4	1.2579 (18)
O12—H12B	0.8908	C4—C5	1.445 (2)
O13—H13A	0.8802	C5—C6	1.347 (2)
O13—H13B	0.8906	C5—H5	0.95
O14—H14A	0.8911	C6—C61	1.520 (2)
O14—H14B	0.9810	C61—O62	1.2437 (19)
O1—C2	1.3535 (17)	C61—O61	1.2572 (19)
O1—C6	1.3540 (18)
O12—Be1—O13	109.76 (13)	C3—C2—C21	124.90 (13)
O12—Be1—O11	104.00 (13)	O1—C2—C21	112.10 (12)
O13—Be1—O11	114.53 (13)	O22—C21—O21	127.43 (14)
O12—Be1—O14	114.22 (13)	O22—C21—C2	116.19 (13)
O13—Be1—O14	104.24 (12)	O21—C21—C2	116.37 (13)
O11—Be1—O14	110.41 (13)	C2—C3—C4	119.86 (13)
Be1—O11—H11A	115.4	C2—C3—H3	120.1
Be1—O11—H11B	125.8	C4—C3—H3	120.1
H11A—O11—H11B	114.3	O4—C4—C3	122.54 (13)
Be1—O12—H12A	124.9	O4—C4—C5	121.93 (14)
Be1—O12—H12B	122.7	C3—C4—C5	115.53 (13)
H12A—O12—H12B	108.0	C6—C5—C4	119.95 (14)
Be1—O13—H13A	111.9	C6—C5—H5	120.0
Be1—O13—H13B	118.6	C4—C5—H5	120.0
H13A—O13—H13B	99.3	C5—C6—O1	122.70 (13)
Be1—O14—H14A	115.7	C5—C6—C61	124.55 (13)
Be1—O14—H14B	114.1	O1—C6—C61	112.75 (12)
H14A—O14—H14B	96.2	O62—C61—O61	127.53 (14)
C2—O1—C6	118.96 (12)	O62—C61—C6	115.08 (13)
C3—C2—O1	123.00 (13)	O61—C61—C6	117.38 (13)
C6—O1—C2—C3	0.6 (2)	O4—C4—C5—C6	−179.82 (14)
C6—O1—C2—C21	−178.87 (12)	C3—C4—C5—C6	0.2 (2)
C3—C2—C21—O22	1.3 (2)	C4—C5—C6—O1	−0.2 (2)
O1—C2—C21—O22	−179.20 (13)	C4—C5—C6—C61	−179.90 (13)
C3—C2—C21—O21	−179.51 (14)	C2—O1—C6—C5	−0.2 (2)
O1—C2—C21—O21	−0.02 (19)	C2—O1—C6—C61	179.50 (12)
O1—C2—C3—C4	−0.6 (2)	C5—C6—C61—O62	−1.0 (2)
C21—C2—C3—C4	178.87 (13)	O1—C6—C61—O62	179.29 (12)
C2—C3—C4—O4	−179.82 (14)	C5—C6—C61—O61	−179.98 (14)
C2—C3—C4—C5	0.1 (2)	O1—C6—C61—O61	0.28 (19)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O11—H11A···O21	0.86	1.74	2.6073 (16)	179
O11—H11B···O61^i	0.94	1.73	2.6501 (16)	165
O12—H12A···O22	0.86	1.74	2.6003 (16)	178
O12—H12B···O4^ii	0.89	1.73	2.6187 (16)	174
O13—H13A···O21^iii	0.88	1.76	2.6353 (15)	171
O13—H13B···O61^iii	0.89	1.75	2.6360 (15)	170
O14—H14A···O4^iv	0.89	1.79	2.6672 (16)	168
O14—H14B···O62^v	0.98	1.60	2.5788 (16)	177

Symmetry codes: (i) −x+1/2, y+1/2, −z+3/2; (ii) −x+2, −y+1, −z+1; (iii) −x+3/2, y+1/2, −z+3/2; (iv) −x+1, −y+1, −z+1; (v) x+1, y+1, z.

(II) hydrazinium(2+) diaqua(4-oxo-4H-pyran-2,6-dicarboxylato)calcate

Crystal data

(N2H6)[Ca(C7H2O6)2(H2O)2]	F(000) = 488
Mr = 474.35	Dx = 1.843 Mg m^−3
Monoclinic, P2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2yc	Cell parameters from 1953 reflections
a = 6.4669 (2) Å	θ = 3.1–27.5°
b = 7.0797 (3) Å	µ = 0.46 mm^−1
c = 18.8278 (6) Å	T = 120 K
β = 97.372 (2)°	Lath, yellow
V = 854.88 (5) Å^3	0.26 × 0.18 × 0.08 mm
Z = 2

Data collection

Bruker Nonius KappaCCD area-detector diffractometer	1953 independent reflections
Radiation source: Bruker Nonius FR591 rotating anode	1876 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.030
Detector resolution: 9.091 pixels mm^-1	θmax = 27.5°, θmin = 3.1°
ϕ and ω scans	h = −8→7
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	k = −9→9
Tmin = 0.909, Tmax = 0.964	l = −24→24
9031 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.116	H-atom parameters constrained
S = 1.20	w = 1/[σ^2(Fo^2) + (0.060P)^2 + 0.7277P] where P = (Fo^2 + 2Fc^2)/3
1953 reflections	(Δ/σ)max < 0.001
141 parameters	Δρmax = 0.68 e Å^−3
0 restraints	Δρmin = −0.54 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Ca1	0.5000	0.85706 (7)	0.2500	0.01039 (17)
O1	0.51583 (19)	0.74693 (18)	0.11779 (6)	0.0101 (3)
C2	0.6593 (3)	0.8198 (2)	0.07852 (9)	0.0096 (3)
C21	0.8291 (3)	0.9236 (3)	0.12590 (9)	0.0118 (3)
O21	0.7934 (2)	0.95232 (19)	0.18942 (7)	0.0138 (3)
O22	0.9825 (2)	0.9765 (2)	0.09744 (7)	0.0162 (3)
C3	0.6390 (3)	0.8098 (2)	0.00668 (9)	0.0108 (3)
C4	0.4521 (3)	0.7278 (2)	−0.03265 (9)	0.0102 (3)
O4	0.4236 (2)	0.71664 (19)	−0.09930 (6)	0.0133 (3)
C5	0.3012 (3)	0.6570 (2)	0.01138 (9)	0.0103 (4)
C6	0.3415 (3)	0.6643 (2)	0.08294 (9)	0.0093 (3)
C61	0.2130 (3)	0.5782 (2)	0.13619 (9)	0.0102 (3)
O61	0.2756 (2)	0.60581 (19)	0.20161 (7)	0.0133 (3)
O62	0.0588 (2)	0.4825 (2)	0.11096 (7)	0.0153 (3)
N3	0.0905 (2)	0.3231 (2)	0.27702 (8)	0.0130 (3)
O2	0.3223 (2)	1.09917 (19)	0.18032 (7)	0.0129 (3)
H3	0.7468	0.8562	−0.0184	0.013*
H5	0.1731	0.6053	−0.0105	0.012*
H3A	0.1982	0.3794	0.2623	0.016*
H3B	0.0510	0.3660	0.3218	0.016*
H3C	0.1300	0.2046	0.2777	0.016*
H2A	0.3847	1.1675	0.1538	0.019*
H2B	0.2118	1.0582	0.1500	0.019*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ca1	0.0120 (3)	0.0114 (3)	0.0075 (3)	0.000	0.00036 (18)	0.000
O1	0.0094 (6)	0.0130 (6)	0.0082 (5)	−0.0044 (5)	0.0020 (4)	−0.0016 (4)
C2	0.0099 (8)	0.0087 (7)	0.0109 (8)	−0.0014 (6)	0.0038 (6)	−0.0007 (6)
C21	0.0121 (8)	0.0119 (8)	0.0110 (8)	−0.0009 (6)	0.0006 (6)	−0.0010 (6)
O21	0.0151 (6)	0.0161 (7)	0.0104 (6)	−0.0034 (5)	0.0022 (5)	−0.0025 (5)
O22	0.0124 (6)	0.0222 (7)	0.0144 (6)	−0.0066 (5)	0.0035 (5)	−0.0025 (5)
C3	0.0119 (8)	0.0107 (8)	0.0104 (8)	−0.0009 (6)	0.0032 (6)	−0.0004 (6)
C4	0.0129 (8)	0.0083 (7)	0.0093 (8)	0.0010 (6)	0.0013 (6)	0.0004 (6)
O4	0.0165 (6)	0.0164 (7)	0.0072 (6)	−0.0016 (5)	0.0017 (5)	0.0008 (5)
C5	0.0097 (8)	0.0110 (8)	0.0102 (8)	−0.0009 (6)	0.0011 (6)	0.0002 (6)
C6	0.0077 (7)	0.0093 (8)	0.0112 (8)	−0.0016 (6)	0.0020 (6)	−0.0008 (6)
C61	0.0105 (7)	0.0112 (8)	0.0093 (8)	−0.0017 (6)	0.0027 (6)	0.0007 (6)
O61	0.0147 (6)	0.0174 (7)	0.0078 (6)	−0.0057 (5)	0.0013 (5)	−0.0008 (5)
O62	0.0141 (6)	0.0213 (7)	0.0104 (6)	−0.0093 (5)	0.0003 (5)	0.0007 (5)
N3	0.0146 (8)	0.0144 (7)	0.0099 (7)	0.0019 (6)	0.0012 (6)	−0.0005 (6)
O2	0.0129 (6)	0.0158 (6)	0.0102 (6)	−0.0005 (5)	0.0017 (5)	0.0034 (5)

Geometric parameters (Å, º)

Ca1—O2^i	2.3649 (13)	C3—H3	0.95
Ca1—O2	2.3649 (13)	C4—O4	1.247 (2)
Ca1—O61	2.4002 (13)	C4—C5	1.449 (2)
Ca1—O61^i	2.4002 (13)	C5—C6	1.340 (2)
Ca1—O21	2.4314 (13)	C5—H5	0.95
Ca1—O21^i	2.4314 (13)	C6—C61	1.510 (2)
Ca1—O1	2.6230 (12)	C61—O62	1.248 (2)
Ca1—O1^i	2.6231 (12)	C61—O61	1.261 (2)
O1—C2	1.360 (2)	N3—N3^ii	1.449 (3)
O1—C6	1.362 (2)	N3—H3A	0.8774
C2—C3	1.344 (2)	N3—H3B	0.9617
C2—C21	1.513 (2)	N3—H3C	0.8768
C21—O22	1.244 (2)	O2—H2A	0.8356
C21—O21	1.263 (2)	O2—H2B	0.9040
C3—C4	1.455 (2)
O2^i—Ca1—O2	87.09 (7)	C3—C2—C21	126.06 (16)
O2^i—Ca1—O61	167.11 (4)	O1—C2—C21	110.97 (14)
O2—Ca1—O61	95.71 (5)	O22—C21—O21	127.74 (17)
O2^i—Ca1—O61^i	95.71 (5)	O22—C21—C2	116.78 (15)
O2—Ca1—O61^i	167.11 (4)	O21—C21—C2	115.42 (15)
O61—Ca1—O61^i	84.35 (7)	C21—O21—Ca1	130.38 (11)
O2^i—Ca1—O21	72.92 (4)	C2—C3—C4	120.05 (16)
O2—Ca1—O21	83.78 (5)	C2—C3—H3	120.0
O61—Ca1—O21	119.85 (4)	C4—C3—H3	120.0
O61^i—Ca1—O21	85.03 (5)	O4—C4—C5	122.03 (16)
O2^i—Ca1—O21^i	83.78 (4)	O4—C4—C3	122.91 (16)
O2—Ca1—O21^i	72.92 (4)	C5—C4—C3	115.05 (15)
O61—Ca1—O21^i	85.03 (5)	C6—C5—C4	120.23 (15)
O61^i—Ca1—O21^i	119.85 (4)	C6—C5—H5	119.9
O21—Ca1—O21^i	147.79 (7)	C4—C5—H5	119.9
O2^i—Ca1—O1	131.80 (4)	C5—C6—O1	122.90 (15)
O2—Ca1—O1	76.37 (4)	C5—C6—C61	126.81 (15)
O61—Ca1—O1	60.97 (4)	O1—C6—C61	110.23 (14)
O61^i—Ca1—O1	92.56 (4)	O62—C61—O61	126.62 (16)
O21—Ca1—O1	60.62 (4)	O62—C61—C6	116.57 (15)
O21^i—Ca1—O1	130.95 (4)	O61—C61—C6	116.78 (15)
O2^i—Ca1—O1^i	76.37 (4)	C61—O61—Ca1	126.03 (11)
O2—Ca1—O1^i	131.80 (4)	N3^ii—N3—H3A	112.4
O61—Ca1—O1^i	92.56 (4)	N3^ii—N3—H3B	109.6
O61^i—Ca1—O1^i	60.97 (4)	H3A—N3—H3B	116.3
O21—Ca1—O1^i	130.95 (4)	N3^ii—N3—H3C	102.6
O21^i—Ca1—O1^i	60.62 (4)	H3A—N3—H3C	101.4
O1—Ca1—O1^i	145.42 (6)	H3B—N3—H3C	113.5
C2—O1—C6	118.79 (13)	Ca1—O2—H2A	120.9
C2—O1—Ca1	121.03 (10)	Ca1—O2—H2B	114.0
C6—O1—Ca1	117.02 (10)	H2A—O2—H2B	102.2
C3—C2—O1	122.80 (15)
O2^i—Ca1—O1—C2	7.11 (14)	O21^i—Ca1—O21—C21	−117.74 (16)
O2—Ca1—O1—C2	80.44 (12)	O1—Ca1—O21—C21	3.43 (14)
O61—Ca1—O1—C2	−174.98 (13)	O1^i—Ca1—O21—C21	143.11 (14)
O61^i—Ca1—O1—C2	−92.88 (12)	O1—C2—C3—C4	3.6 (3)
O21—Ca1—O1—C2	−10.04 (11)	C21—C2—C3—C4	−171.27 (16)
O21^i—Ca1—O1—C2	132.81 (12)	C2—C3—C4—O4	179.16 (16)
O1^i—Ca1—O1—C2	−130.62 (12)	C2—C3—C4—C5	−1.6 (2)
O2^i—Ca1—O1—C6	−152.55 (10)	O4—C4—C5—C6	177.13 (17)
O2—Ca1—O1—C6	−79.22 (11)	C3—C4—C5—C6	−2.1 (2)
O61—Ca1—O1—C6	25.36 (11)	C4—C5—C6—O1	4.2 (3)
O61^i—Ca1—O1—C6	107.46 (11)	C4—C5—C6—C61	−172.81 (16)
O21—Ca1—O1—C6	−169.71 (13)	C2—O1—C6—C5	−2.3 (2)
O21^i—Ca1—O1—C6	−26.85 (13)	Ca1—O1—C6—C5	157.79 (14)
O1^i—Ca1—O1—C6	69.72 (11)	C2—O1—C6—C61	175.08 (14)
C6—O1—C2—C3	−1.7 (2)	Ca1—O1—C6—C61	−24.78 (17)
Ca1—O1—C2—C3	−160.98 (13)	C5—C6—C61—O62	3.8 (3)
C6—O1—C2—C21	173.86 (14)	O1—C6—C61—O62	−173.46 (15)
Ca1—O1—C2—C21	14.55 (18)	C5—C6—C61—O61	−178.12 (17)
C3—C2—C21—O22	−13.2 (3)	O1—C6—C61—O61	4.6 (2)
O1—C2—C21—O22	171.45 (16)	O62—C61—O61—Ca1	−160.20 (14)
C3—C2—C21—O21	164.21 (18)	C6—C61—O61—Ca1	22.0 (2)
O1—C2—C21—O21	−11.1 (2)	O2^i—Ca1—O61—C61	147.9 (2)
O22—C21—O21—Ca1	179.72 (14)	O2—Ca1—O61—C61	45.89 (15)
C2—C21—O21—Ca1	2.6 (2)	O61^i—Ca1—O61—C61	−121.16 (16)
O2^i—Ca1—O21—C21	−163.27 (16)	O21—Ca1—O61—C61	−40.20 (16)
O2—Ca1—O21—C21	−74.41 (16)	O21^i—Ca1—O61—C61	118.13 (15)
O61—Ca1—O21—C21	18.62 (17)	O1—Ca1—O61—C61	−25.06 (13)
O61^i—Ca1—O21—C21	99.19 (16)	O1^i—Ca1—O61—C61	178.34 (14)

Symmetry codes: (i) −x+1, y, −z+1/2; (ii) −x, y, −z+1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2A···O4^iii	0.84	1.89	2.7149 (18)	167
O2—H2B···O22^iv	0.90	1.77	2.6717 (19)	175
N3—H3A···O61	0.88	2.07	2.8091 (19)	142
N3—H3B···O62^ii	0.96	1.74	2.679 (2)	166
N3—H3C···O21^v	0.88	1.93	2.781 (2)	162

Symmetry codes: (ii) −x, y, −z+1/2; (iii) −x+1, −y+2, −z; (iv) x−1, y, z; (v) −x+1, y−1, −z+1/2.

(III) bis(µ-4-oxo-4H-pyran-2,6-dicarboxylato)bis[tetraaquamanganese(II)] tetrahydrate

Crystal data

[Mn2(C7H2O6)2(H2O)8]·4H2O	Z = 1
Mr = 690.24	F(000) = 354
Triclinic, P1	Dx = 1.809 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.4343 (2) Å	Cell parameters from 2877 reflections
b = 10.1176 (3) Å	θ = 1.0–27.5°
c = 10.2290 (3) Å	µ = 1.11 mm^−1
α = 61.935 (2)°	T = 120 K
β = 78.219 (3)°	Block, colourless
γ = 69.061 (2)°	0.47 × 0.21 × 0.10 mm
V = 633.49 (3) Å^3

Data collection

Bruker Nonius KappaCCD area-detector diffractometer	2914 independent reflections
Radiation source: Bruker Nonius FR591 rotating anode	2423 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.037
Detector resolution: 9.091 pixels mm^-1	θmax = 27.6°, θmin = 2.3°
ϕ and ω scans	h = −9→9
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	k = −13→13
Tmin = 0.625, Tmax = 0.898	l = −13→13
14668 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.030	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.074	H-atom parameters constrained
S = 1.08	w = 1/[σ^2(Fo^2) + (0.0298P)^2 + 0.4478P] where P = (Fo^2 + 2Fc^2)/3
2914 reflections	(Δ/σ)max = 0.001
181 parameters	Δρmax = 0.45 e Å^−3
0 restraints	Δρmin = −0.40 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Mn1	0.31863 (4)	0.76085 (3)	0.36918 (3)	0.01098 (9)
O11	0.10413 (19)	0.67707 (15)	0.54233 (14)	0.0155 (3)
O12	0.54328 (18)	0.84672 (14)	0.20661 (14)	0.0137 (3)
O13	0.11232 (19)	0.85552 (15)	0.19602 (14)	0.0152 (3)
O14	0.20426 (19)	0.98191 (15)	0.37900 (15)	0.0180 (3)
O1	0.72562 (18)	0.44480 (14)	0.87582 (14)	0.0115 (3)
C2	0.6253 (2)	0.5879 (2)	0.77498 (19)	0.0104 (4)
C21	0.5665 (3)	0.5768 (2)	0.6477 (2)	0.0115 (4)
O21	0.5760 (2)	0.44477 (15)	0.66593 (15)	0.0170 (3)
O22	0.50595 (18)	0.70582 (14)	0.53764 (14)	0.0132 (3)
C3	0.5743 (3)	0.7197 (2)	0.7926 (2)	0.0119 (4)
C4	0.6237 (3)	0.7147 (2)	0.9248 (2)	0.0122 (4)
O4	0.5717 (2)	0.83307 (15)	0.94879 (14)	0.0169 (3)
C5	0.7341 (3)	0.5617 (2)	1.0273 (2)	0.0119 (4)
C6	0.7787 (2)	0.4361 (2)	0.99952 (19)	0.0106 (4)
C61	0.8887 (3)	0.2688 (2)	1.1021 (2)	0.0127 (4)
O61	0.9128 (2)	0.16511 (15)	1.06153 (15)	0.0195 (3)
O62	0.9432 (2)	0.25253 (15)	1.21799 (15)	0.0175 (3)
O15	0.1088 (2)	0.37608 (17)	0.67361 (18)	0.0278 (4)
O16	0.2782 (2)	1.07386 (16)	0.57159 (15)	0.0194 (3)
H11A	0.1093	0.5831	0.5852	0.023*
H11B	0.0938	0.6922	0.6165	0.023*
H12A	0.5532	0.8347	0.1195	0.021*
H12B	0.5191	0.9417	0.1794	0.021*
H13A	0.0422	0.9589	0.1591	0.023*
H13B	0.1467	0.8283	0.1240	0.023*
H14A	0.2359	1.0063	0.4429	0.027*
H14B	0.1232	1.0706	0.3228	0.027*
H3	0.5055	0.8167	0.7181	0.014*
H5	0.7755	0.5497	1.1152	0.014*
H15A	0.2212	0.3116	0.7036	0.042*
H15B	0.0224	0.3184	0.7118	0.042*
H16A	0.3508	1.1363	0.5416	0.029*
H16B	0.1565	1.1533	0.5581	0.029*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Mn1	0.01369 (15)	0.00878 (15)	0.01055 (15)	−0.00173 (11)	−0.00393 (10)	−0.00411 (11)
O11	0.0219 (7)	0.0143 (7)	0.0123 (7)	−0.0071 (5)	0.0002 (5)	−0.0067 (6)
O12	0.0210 (7)	0.0091 (6)	0.0109 (6)	−0.0039 (5)	−0.0016 (5)	−0.0042 (5)
O13	0.0190 (7)	0.0120 (6)	0.0135 (7)	0.0005 (5)	−0.0067 (5)	−0.0061 (5)
O14	0.0242 (7)	0.0103 (6)	0.0188 (7)	0.0037 (6)	−0.0113 (6)	−0.0082 (6)
O1	0.0143 (6)	0.0092 (6)	0.0103 (6)	−0.0010 (5)	−0.0046 (5)	−0.0039 (5)
C2	0.0097 (8)	0.0084 (8)	0.0102 (8)	−0.0012 (7)	−0.0023 (7)	−0.0020 (7)
C21	0.0111 (8)	0.0115 (9)	0.0112 (9)	−0.0012 (7)	−0.0025 (7)	−0.0053 (7)
O21	0.0266 (8)	0.0096 (6)	0.0168 (7)	−0.0017 (6)	−0.0078 (6)	−0.0074 (6)
O22	0.0169 (7)	0.0111 (6)	0.0111 (6)	−0.0032 (5)	−0.0060 (5)	−0.0031 (5)
C3	0.0132 (9)	0.0104 (9)	0.0098 (9)	−0.0025 (7)	−0.0026 (7)	−0.0024 (7)
C4	0.0148 (9)	0.0109 (9)	0.0117 (9)	−0.0055 (7)	0.0002 (7)	−0.0046 (7)
O4	0.0277 (8)	0.0107 (6)	0.0129 (7)	−0.0039 (6)	−0.0038 (6)	−0.0059 (5)
C5	0.0142 (9)	0.0122 (9)	0.0097 (9)	−0.0042 (7)	−0.0011 (7)	−0.0046 (7)
C6	0.0107 (8)	0.0128 (9)	0.0073 (8)	−0.0036 (7)	−0.0018 (7)	−0.0030 (7)
C61	0.0139 (9)	0.0104 (9)	0.0108 (9)	−0.0003 (7)	−0.0022 (7)	−0.0039 (7)
O61	0.0285 (8)	0.0111 (6)	0.0167 (7)	0.0017 (6)	−0.0100 (6)	−0.0063 (6)
O62	0.0233 (7)	0.0139 (7)	0.0141 (7)	0.0006 (5)	−0.0091 (6)	−0.0064 (6)
O15	0.0189 (8)	0.0178 (7)	0.0398 (9)	−0.0065 (6)	−0.0054 (7)	−0.0048 (7)
O16	0.0222 (7)	0.0176 (7)	0.0219 (7)	−0.0079 (6)	−0.0024 (6)	−0.0093 (6)

Geometric parameters (Å, º)

Mn1—O21^i	2.1199 (13)	C2—C21	1.517 (2)
Mn1—O14	2.1337 (13)	C21—O21	1.237 (2)
Mn1—O22	2.1775 (12)	C21—O22	1.256 (2)
Mn1—O11	2.1905 (13)	O21—Mn1^i	2.1199 (13)
Mn1—O12	2.2030 (13)	C3—C4	1.447 (2)
Mn1—O13	2.2068 (13)	C3—H3	0.95
O11—H11A	0.8286	C4—O4	1.246 (2)
O11—H11B	0.8254	C4—C5	1.444 (2)
O12—H12A	0.9395	C5—C6	1.343 (3)
O12—H12B	0.8240	C5—H5	0.95
O13—H13A	0.9097	C6—C61	1.525 (2)
O13—H13B	0.8645	C61—O61	1.245 (2)
O14—H14A	0.8941	C61—O62	1.249 (2)
O14—H14B	0.8765	O15—H15A	0.8632
O1—C6	1.356 (2)	O15—H15B	0.9256
O1—C2	1.361 (2)	O16—H16A	0.8823
C2—C3	1.338 (3)	O16—H16B	0.9536
O21^i—Mn1—O14	173.56 (5)	C6—O1—C2	118.14 (14)
O21^i—Mn1—O22	102.25 (5)	C3—C2—O1	123.42 (16)
O14—Mn1—O22	83.30 (5)	C3—C2—C21	124.58 (16)
O21^i—Mn1—O11	94.50 (5)	O1—C2—C21	111.85 (14)
O14—Mn1—O11	88.72 (5)	O21—C21—O22	127.61 (17)
O22—Mn1—O11	90.12 (5)	O21—C21—C2	117.13 (15)
O21^i—Mn1—O12	87.64 (5)	O22—C21—C2	115.19 (15)
O14—Mn1—O12	89.50 (5)	C21—O21—Mn1^i	156.82 (13)
O22—Mn1—O12	86.04 (5)	C21—O22—Mn1	127.91 (11)
O11—Mn1—O12	175.93 (5)	C2—C3—C4	120.14 (16)
O21^i—Mn1—O13	86.92 (5)	C2—C3—H3	119.9
O14—Mn1—O13	87.46 (5)	C4—C3—H3	119.9
O22—Mn1—O13	170.70 (5)	O4—C4—C5	122.98 (16)
O11—Mn1—O13	90.69 (5)	O4—C4—C3	122.24 (16)
O12—Mn1—O13	92.89 (5)	C5—C4—C3	114.77 (15)
Mn1—O11—H11A	121.7	C6—C5—C4	120.63 (16)
Mn1—O11—H11B	117.0	C6—C5—H5	119.7
H11A—O11—H11B	98.1	C4—C5—H5	119.7
Mn1—O12—H12A	114.3	C5—C6—O1	122.86 (16)
Mn1—O12—H12B	109.9	C5—C6—C61	124.97 (16)
H12A—O12—H12B	105.5	O1—C6—C61	112.16 (15)
Mn1—O13—H13A	119.3	O61—C61—O62	127.79 (17)
Mn1—O13—H13B	118.9	O61—C61—C6	116.70 (16)
H13A—O13—H13B	108.6	O62—C61—C6	115.50 (16)
Mn1—O14—H14A	126.0	H15A—O15—H15B	107.3
Mn1—O14—H14B	131.2	H16A—O16—H16B	97.1
H14A—O14—H14B	102.7
C6—O1—C2—C3	−0.9 (3)	O1—C2—C3—C4	−0.7 (3)
C6—O1—C2—C21	−176.66 (15)	C21—C2—C3—C4	174.50 (17)
C3—C2—C21—O21	−160.11 (18)	C2—C3—C4—O4	−176.72 (17)
O1—C2—C21—O21	15.6 (2)	C2—C3—C4—C5	2.1 (3)
C3—C2—C21—O22	17.1 (3)	O4—C4—C5—C6	176.80 (18)
O1—C2—C21—O22	−167.24 (15)	C3—C4—C5—C6	−2.0 (3)
O22—C21—O21—Mn1^i	71.4 (4)	C4—C5—C6—O1	0.5 (3)
C2—C21—O21—Mn1^i	−111.9 (3)	C4—C5—C6—C61	−177.98 (16)
O21—C21—O22—Mn1	20.1 (3)	C2—O1—C6—C5	1.0 (3)
C2—C21—O22—Mn1	−156.77 (12)	C2—O1—C6—C61	179.68 (14)
O21^i—Mn1—O22—C21	−39.88 (15)	C5—C6—C61—O61	177.81 (18)
O14—Mn1—O22—C21	143.45 (15)	O1—C6—C61—O61	−0.8 (2)
O11—Mn1—O22—C21	54.75 (15)	C5—C6—C61—O62	−1.8 (3)
O12—Mn1—O22—C21	−126.59 (15)	O1—C6—C61—O62	179.55 (16)

Symmetry code: (i) −x+1, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O11—H11A···O15	0.83	1.85	2.6784 (19)	176
O11—H11B···O62^ii	0.83	1.96	2.7846 (18)	175
O12—H12A···O4^iii	0.94	1.73	2.6670 (18)	174
O12—H12B···O4^iv	0.82	1.95	2.7356 (18)	158
O13—H13A···O61^v	0.91	1.81	2.7133 (18)	172
O13—H13B···O61^i	0.86	2.00	2.7866 (18)	151
O14—H14A···O16	0.89	1.86	2.7532 (19)	174
O14—H14B···O62^v	0.88	1.82	2.6908 (18)	176
O15—H15A···O12^i	0.86	1.93	2.7930 (19)	173
O15—H15B···O13^vi	0.93	2.07	2.9814 (19)	166
O16—H16A···O22^iv	0.88	2.00	2.8765 (19)	175
O16—H16B···O11^vii	0.95	2.13	3.0423 (19)	160

Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y+1, −z+2; (iii) x, y, z−1; (iv) −x+1, −y+2, −z+1; (v) x−1, y+1, z−1; (vi) −x, −y+1, −z+1; (vii) −x, −y+2, −z+1.

(IV) tetraaqua(4-oxo-4H-pyran-2,6-dicarboxylato)copper(II)

Crystal data

[Cu(C7H2O6)(H2O)4]	Z = 2
Mr = 317.70	F(000) = 322
Triclinic, P1	Dx = 2.086 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 4.9593 (6) Å	Cell parameters from 2264 reflections
b = 9.8973 (14) Å	θ = 3.0–27.7°
c = 10.4697 (12) Å	µ = 2.21 mm^−1
α = 94.237 (9)°	T = 120 K
β = 94.955 (9)°	Block, green
γ = 97.353 (6)°	0.12 × 0.12 × 0.10 mm
V = 505.88 (11) Å^3

Data collection

Bruker Nonius KappaCCD area-detector diffractometer	2264 independent reflections
Radiation source: Bruker Nonius FR591 rotating anode	2043 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.034
Detector resolution: 9.091 pixels mm^-1	θmax = 27.7°, θmin = 3.0°
ϕ and ω scans	h = −6→6
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	k = −12→12
Tmin = 0.777, Tmax = 0.809	l = −13→13
6400 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.052	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.156	H-atom parameters constrained
S = 1.12	w = 1/[σ^2(Fo^2) + (0.0763P)^2 + 2.2295P] where P = (Fo^2 + 2Fc^2)/3
2264 reflections	(Δ/σ)max < 0.001
167 parameters	Δρmax = 1.42 e Å^−3
0 restraints	Δρmin = −1.42 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cu1	0.0000	0.0000	0.5000	0.0106 (2)
O1A	0.2978 (6)	−0.0275 (3)	0.6286 (3)	0.0144 (6)
O1B	0.1358 (8)	−0.1487 (3)	0.3266 (4)	0.0238 (8)
Cu2	0.5000	0.0000	0.0000	0.0108 (2)
O2A	0.3739 (7)	0.1700 (3)	−0.0507 (3)	0.0175 (7)
O2B	0.2379 (6)	−0.0106 (3)	0.1229 (3)	0.0179 (7)
O1	0.5368 (6)	0.2869 (3)	0.2755 (3)	0.0132 (6)
C2	0.3774 (8)	0.3563 (4)	0.3476 (4)	0.0119 (8)
C21	0.2055 (9)	0.2683 (4)	0.4303 (4)	0.0143 (8)
O21	0.2528 (6)	0.1442 (3)	0.4337 (3)	0.0140 (6)
O22	0.0323 (8)	0.3231 (4)	0.4846 (4)	0.0273 (8)
C3	0.3702 (9)	0.4924 (4)	0.3446 (4)	0.0150 (8)
C4	0.5389 (10)	0.5700 (4)	0.2643 (5)	0.0172 (9)
O4	0.5466 (9)	0.6975 (4)	0.2634 (4)	0.0292 (9)
C5	0.7043 (9)	0.4922 (5)	0.1875 (5)	0.0167 (9)
C6	0.6990 (8)	0.3571 (4)	0.1981 (4)	0.0122 (8)
C61	0.8765 (8)	0.2673 (4)	0.1289 (4)	0.0119 (8)
O61	0.8556 (6)	0.1442 (3)	0.1577 (3)	0.0149 (6)
O62	1.0274 (7)	0.3210 (3)	0.0545 (3)	0.0179 (7)
H11A	0.4442	−0.0615	0.6064	0.022*
H12A	0.2531	−0.0696	0.6963	0.022*
H11B	−0.0203	−0.2028	0.3091	0.036*
H12B	0.2808	−0.1903	0.3401	0.036*
H21A	0.2306	0.2025	−0.0229	0.026*
H22A	0.4215	0.2072	−0.1206	0.026*
H21B	0.1092	0.0428	0.1254	0.027*
H22B	0.1985	−0.0713	0.1781	0.027*
H3	0.2527	0.5364	0.3959	0.018*
H5	0.8165	0.5364	0.1296	0.020*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0075 (3)	0.0116 (4)	0.0133 (4)	0.0006 (3)	0.0033 (3)	0.0042 (3)
O1A	0.0110 (13)	0.0164 (15)	0.0167 (15)	0.0024 (11)	0.0022 (11)	0.0058 (12)
O1B	0.0273 (18)	0.0173 (16)	0.029 (2)	0.0019 (14)	0.0126 (15)	0.0036 (14)
Cu2	0.0090 (3)	0.0124 (4)	0.0123 (4)	0.0028 (3)	0.0042 (3)	0.0032 (3)
O2A	0.0182 (15)	0.0187 (16)	0.0192 (17)	0.0081 (12)	0.0096 (13)	0.0070 (13)
O2B	0.0155 (15)	0.0210 (16)	0.0211 (17)	0.0093 (13)	0.0078 (12)	0.0098 (13)
O1	0.0124 (14)	0.0129 (14)	0.0153 (15)	0.0026 (11)	0.0056 (12)	0.0010 (12)
C2	0.0120 (18)	0.015 (2)	0.0095 (19)	0.0011 (15)	0.0035 (15)	0.0017 (15)
C21	0.0140 (19)	0.014 (2)	0.015 (2)	−0.0009 (15)	0.0058 (16)	0.0019 (16)
O21	0.0123 (13)	0.0136 (14)	0.0172 (16)	0.0022 (11)	0.0039 (11)	0.0047 (12)
O22	0.0300 (19)	0.0164 (16)	0.041 (2)	0.0063 (14)	0.0256 (17)	0.0076 (15)
C3	0.0152 (19)	0.016 (2)	0.015 (2)	0.0053 (16)	0.0036 (16)	0.0017 (16)
C4	0.023 (2)	0.0099 (19)	0.020 (2)	0.0034 (16)	0.0066 (18)	0.0036 (16)
O4	0.050 (2)	0.0136 (16)	0.029 (2)	0.0093 (16)	0.0218 (18)	0.0053 (14)
C5	0.019 (2)	0.016 (2)	0.016 (2)	0.0031 (17)	0.0083 (17)	0.0033 (17)
C6	0.0113 (18)	0.014 (2)	0.012 (2)	0.0017 (15)	0.0036 (15)	0.0027 (15)
C61	0.0100 (18)	0.016 (2)	0.010 (2)	0.0041 (15)	0.0015 (15)	−0.0009 (15)
O61	0.0150 (14)	0.0150 (15)	0.0164 (16)	0.0034 (12)	0.0069 (12)	0.0042 (12)
O62	0.0205 (16)	0.0170 (16)	0.0190 (17)	0.0048 (12)	0.0122 (13)	0.0047 (12)

Geometric parameters (Å, º)

Cu1—O1A	1.970 (3)	O2B—H21B	0.8801
Cu1—O1A^i	1.970 (3)	O2B—H22B	0.88
Cu1—O21	1.982 (3)	O1—C2	1.353 (5)
Cu1—O21^i	1.982 (3)	O1—C6	1.357 (5)
Cu1—O1B	2.447 (4)	C2—C3	1.355 (6)
Cu1—O1B^i	2.447 (4)	C2—C21	1.511 (6)
O1A—H11A	0.8797	C21—O22	1.230 (6)
O1A—H12A	0.8794	C21—O21	1.282 (5)
O1B—H11B	0.88	C3—C4	1.432 (6)
O1B—H12B	0.8798	C3—H3	0.95
Cu2—O2A^ii	1.961 (3)	C4—O4	1.258 (6)
Cu2—O2A	1.961 (3)	C4—C5	1.449 (6)
Cu2—O2B	1.906 (3)	C5—C6	1.346 (6)
Cu2—O2B^ii	1.906 (3)	C5—H5	0.95
Cu2—O61	2.525 (3)	C6—C61	1.518 (6)
Cu2—O61^ii	2.525 (3)	C61—O62	1.228 (6)
O2A—H21A	0.88	C61—O61	1.271 (5)
O2A—H22A	0.8801
O1A—Cu1—O1A^i	180.0	O1—C2—C3	122.9 (4)
O1A—Cu1—O21	88.68 (13)	O1—C2—C21	114.1 (4)
O1A^i—Cu1—O21	91.32 (13)	C3—C2—C21	123.0 (4)
O1A—Cu1—O21^i	91.32 (13)	O22—C21—O21	127.4 (4)
O1A^i—Cu1—O21^i	88.68 (13)	O22—C21—C2	116.3 (4)
O21—Cu1—O21^i	180.00 (13)	O21—C21—C2	116.3 (4)
Cu1—O1A—H11A	121.8	C21—O21—Cu1	123.0 (3)
Cu1—O1A—H12A	117.6	C2—C3—C4	120.2 (4)
H11A—O1A—H12A	104.6	C2—C3—H3	119.9
H11B—O1B—H12B	115.4	C4—C3—H3	119.9
O2B—Cu2—O2B^ii	180.0 (3)	O4—C4—C3	122.0 (4)
O2B—Cu2—O2A^ii	91.08 (13)	O4—C4—C5	122.7 (4)
O2B^ii—Cu2—O2A^ii	88.92 (13)	C3—C4—C5	115.3 (4)
O2B—Cu2—O2A	88.92 (13)	C6—C5—C4	120.0 (4)
O2B^ii—Cu2—O2A	91.08 (13)	C6—C5—H5	120.0
O2A^ii—Cu2—O2A	180.00 (19)	C4—C5—H5	120.0
Cu2—O2A—H21A	124.2	C5—C6—O1	123.0 (4)
Cu2—O2A—H22A	122.0	C5—C6—C61	124.5 (4)
H21A—O2A—H22A	111.2	O1—C6—C61	112.4 (3)
Cu2—O2B—H21B	122.9	O62—C61—O61	127.3 (4)
Cu2—O2B—H22B	131.3	O62—C61—C6	117.4 (4)
H21B—O2B—H22B	105.2	O61—C61—C6	115.3 (4)
C2—O1—C6	118.5 (3)
C6—O1—C2—C3	0.9 (6)	C2—C3—C4—O4	−176.8 (5)
C6—O1—C2—C21	−179.9 (4)	C2—C3—C4—C5	1.6 (7)
O1—C2—C21—O22	−171.0 (4)	O4—C4—C5—C6	176.2 (5)
C3—C2—C21—O22	8.2 (7)	C3—C4—C5—C6	−2.2 (7)
O1—C2—C21—O21	7.6 (6)	C4—C5—C6—O1	2.3 (7)
C3—C2—C21—O21	−173.2 (4)	C4—C5—C6—C61	−176.0 (4)
O22—C21—O21—Cu1	13.4 (7)	C2—O1—C6—C5	−1.5 (6)
C2—C21—O21—Cu1	−165.0 (3)	C2—O1—C6—C61	176.9 (3)
O1A—Cu1—O21—C21	−121.0 (3)	C5—C6—C61—O62	−2.9 (6)
O1A^i—Cu1—O21—C21	59.0 (3)	O1—C6—C61—O62	178.7 (4)
O1—C2—C3—C4	−1.0 (7)	C5—C6—C61—O61	175.4 (4)
C21—C2—C3—C4	179.8 (4)	O1—C6—C61—O61	−3.0 (5)

Symmetry codes: (i) −x, −y, −z+1; (ii) −x+1, −y, −z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1A—H11A···O21^iii	0.88	1.86	2.743 (4)	176
O1A—H12A···O61^iii	0.88	1.84	2.715 (4)	175
O1B—H11B···O4^iv	0.88	2.24	3.110 (6)	169
O1B—H12B···O4^v	0.88	2.01	2.790 (5)	147
O2A—H21A···O62^vi	0.88	1.83	2.672 (4)	160
O2A—H22A···O4^vii	0.88	1.83	2.699 (5)	168
O2B—H21B···O61^vi	0.88	1.75	2.618 (4)	170
O2B—H22B···O1B	0.88	1.82	2.666 (5)	162

Symmetry codes: (iii) −x+1, −y, −z+1; (iv) x−1, y−1, z; (v) x, y−1, z; (vi) x−1, y, z; (vii) −x+1, −y+1, −z.

(V) diaqua(4-oxo-4H-pyran-2,6-dicarboxylato)cadmium monohydrate

Crystal data

[Cd(C7H2O6)(H2O)2]·H2O	Z = 1
Mr = 348.53	F(000) = 170
Triclinic, P1	Dx = 2.434 Mg m^−3
Hall symbol: P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.3262 (2) Å	Cell parameters from 2108 reflections
b = 6.2885 (2) Å	θ = 3.6–27.7°
c = 8.1008 (3) Å	µ = 2.34 mm^−1
α = 97.733 (2)°	T = 120 K
β = 105.0554 (17)°	Block, colourless
γ = 110.4356 (18)°	0.10 × 0.04 × 0.04 mm
V = 237.80 (2) Å^3

Data collection

Bruker Nonius KappaCCD area-detector diffractometer	2108 independent reflections
Radiation source: Bruker Nonius FR591 rotating anode	2108 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.050
Detector resolution: 9.091 pixels mm^-1	θmax = 27.7°, θmin = 3.6°
ϕ and ω scans	h = −6→6
Absorption correction: multi-scan (SADABS; Sheldrick, 2003)	k = −8→8
Tmin = 0.781, Tmax = 0.912	l = −10→10
7006 measured reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.018	H-atom parameters constrained
wR(F^2) = 0.042	w = 1/[σ^2(Fo^2) + (0.0114P)^2 + 0.0048P] where P = (Fo^2 + 2Fc^2)/3
S = 1.15	(Δ/σ)max = 0.001
2108 reflections	Δρmax = 0.58 e Å^−3
136 parameters	Δρmin = −0.98 e Å^−3
3 restraints	Absolute structure: Flack (1983), with 1003 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.002 (17)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cd1	0.00000 (1)	0.50000 (1)	0.00000 (1)	0.00988 (6)
O11	−0.0137 (5)	0.7926 (4)	−0.1443 (3)	0.0143 (4)
O12	−0.4494 (4)	0.2331 (4)	−0.1384 (3)	0.0162 (4)
O13	0.4510 (7)	0.7778 (6)	0.6771 (4)	0.0165 (7)
O1	0.5050 (4)	0.0405 (3)	0.2331 (3)	0.0096 (3)
C2	0.5019 (10)	0.2251 (8)	0.3401 (6)	0.0097 (5)
C21	0.2943 (6)	0.3182 (5)	0.2507 (4)	0.0104 (5)
O21	0.1374 (5)	0.2152 (4)	0.0927 (3)	0.0116 (4)
O22	0.2975 (4)	0.4995 (4)	0.3360 (3)	0.0142 (4)
C3	0.6760 (6)	0.3164 (5)	0.5079 (4)	0.0099 (4)
C4	0.8828 (6)	0.2263 (5)	0.5826 (4)	0.0096 (3)
O4	1.0493 (6)	0.3090 (5)	0.7377 (4)	0.0131 (6)
C5	0.8833 (6)	0.0358 (5)	0.4631 (4)	0.0097 (5)
C6	0.6983 (6)	−0.0471 (5)	0.2967 (4)	0.0099 (4)
C61	0.6863 (6)	−0.2438 (5)	0.1608 (4)	0.0097 (5)
O61	0.4763 (4)	−0.3306 (4)	0.0227 (3)	0.0120 (4)
O62	0.8958 (6)	−0.2957 (5)	0.2016 (4)	0.0138 (6)
H11A	−0.1770	0.7758	−0.1936	0.021*
H11B	0.0595	0.9165	−0.0687	0.021*
H12A	−0.4789	0.0975	−0.1811	0.024*
H12B	−0.6066	0.2366	−0.1597	0.024*
H13A	0.3396	0.7017	0.7217	0.025*
H13B	0.3841	0.7135	0.5714	0.025*
H3	0.6629	0.4427	0.5788	0.012*
H5	1.0148	−0.0323	0.5015	0.012*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cd1	0.01116 (9)	0.01089 (9)	0.00812 (9)	0.00639 (6)	0.00209 (6)	0.00079 (6)
O11	0.0189 (11)	0.0092 (10)	0.0119 (11)	0.0060 (8)	0.0013 (9)	−0.0003 (8)
O12	0.0101 (9)	0.0134 (10)	0.0216 (12)	0.0053 (8)	0.0018 (9)	−0.0019 (9)
O13	0.0201 (15)	0.0155 (12)	0.0102 (13)	0.0035 (11)	0.0059 (10)	−0.0002 (10)
O1	0.0103 (7)	0.0103 (8)	0.0068 (8)	0.0053 (6)	0.0002 (6)	−0.0006 (6)
C2	0.0106 (10)	0.0105 (11)	0.0102 (11)	0.0069 (8)	0.0036 (8)	0.0020 (9)
C21	0.0110 (12)	0.0092 (13)	0.0103 (13)	0.0046 (10)	0.0018 (10)	0.0025 (10)
O21	0.0134 (10)	0.0124 (10)	0.0085 (10)	0.0080 (8)	−0.0004 (8)	0.0012 (8)
O22	0.0159 (10)	0.0151 (11)	0.0138 (11)	0.0105 (8)	0.0036 (8)	0.0015 (8)
C3	0.0108 (9)	0.0093 (10)	0.0103 (10)	0.0056 (8)	0.0033 (8)	0.0010 (8)
C4	0.0103 (7)	0.0103 (8)	0.0068 (8)	0.0053 (6)	0.0002 (6)	−0.0006 (6)
O4	0.0120 (12)	0.0147 (12)	0.0095 (14)	0.0077 (10)	−0.0014 (11)	−0.0034 (11)
C5	0.0106 (10)	0.0105 (11)	0.0102 (11)	0.0069 (8)	0.0036 (8)	0.0020 (9)
C6	0.0108 (9)	0.0093 (10)	0.0103 (10)	0.0056 (8)	0.0033 (8)	0.0010 (8)
C61	0.0129 (13)	0.0093 (13)	0.0074 (13)	0.0052 (11)	0.0037 (11)	0.0007 (10)
O61	0.0099 (9)	0.0137 (10)	0.0077 (10)	0.0031 (8)	0.0002 (8)	−0.0021 (8)
O62	0.0127 (13)	0.0177 (13)	0.0104 (15)	0.0096 (10)	0.0002 (11)	−0.0010 (11)

Geometric parameters (Å, º)

Cd1—O62^i	2.242 (3)	C2—C3	1.341 (6)
Cd1—O12	2.258 (2)	C2—C21	1.497 (6)
Cd1—O21	2.302 (2)	C21—O22	1.243 (4)
Cd1—O11	2.320 (2)	C21—O21	1.265 (4)
Cd1—O61^ii	2.3284 (19)	C3—C4	1.443 (4)
Cd1—O4^iii	2.419 (3)	C3—H3	0.95
O11—H11A	0.82	C4—O4	1.249 (4)
O11—H11B	0.82	C4—C5	1.436 (4)
O12—H12A	0.82	C5—C6	1.350 (4)
O12—H12B	0.82	C5—H5	0.95
O13—H13A	0.82	C6—C61	1.512 (4)
O13—H13B	0.82	C61—O62	1.246 (4)
O1—C6	1.351 (3)	C61—O61	1.249 (4)
O1—C2	1.360 (5)
O62^i—Cd1—O12	95.60 (9)	C3—C2—C21	124.2 (4)
O62^i—Cd1—O21	113.93 (9)	O1—C2—C21	113.5 (4)
O12—Cd1—O21	90.83 (8)	O22—C21—O21	124.4 (3)
O62^i—Cd1—O11	83.99 (9)	O22—C21—C2	117.0 (3)
O12—Cd1—O11	99.26 (8)	O21—C21—C2	118.6 (3)
O21—Cd1—O11	158.60 (7)	C21—O21—Cd1	102.03 (17)
O62^i—Cd1—O61^ii	112.34 (9)	C2—C3—C4	121.2 (3)
O12—Cd1—O61^ii	151.83 (7)	C2—C3—H3	119.4
O21—Cd1—O61^ii	81.34 (8)	C4—C3—H3	119.4
O11—Cd1—O61^ii	80.92 (8)	O4—C4—C5	122.9 (3)
O62^i—Cd1—O4^iii	167.51 (8)	O4—C4—C3	122.7 (3)
O12—Cd1—O4^iii	79.30 (9)	C5—C4—C3	114.4 (2)
O21—Cd1—O4^iii	77.76 (9)	C4—O4—Cd1^iv	131.0 (2)
O11—Cd1—O4^iii	85.59 (9)	C6—C5—C4	120.5 (3)
O61^ii—Cd1—O4^iii	72.61 (9)	C6—C5—H5	119.8
Cd1—O11—H11A	111.7	C4—C5—H5	119.8
Cd1—O11—H11B	107.2	C5—C6—O1	123.1 (3)
H11A—O11—H11B	106.1	C5—C6—C61	124.3 (3)
Cd1—O12—H12A	120.0	O1—C6—C61	112.7 (2)
Cd1—O12—H12B	134.7	O62—C61—O61	128.1 (3)
H12A—O12—H12B	105.3	O62—C61—C6	114.3 (3)
H13A—O13—H13B	105.7	O61—C61—C6	117.7 (2)
C6—O1—C2	118.5 (3)	C61—O61—Cd1^v	127.30 (17)
C3—C2—O1	122.3 (4)	C61—O62—Cd1^vi	121.8 (2)
C6—O1—C2—C3	−2.7 (6)	C5—C4—O4—Cd1^iv	−151.7 (2)
C6—O1—C2—C21	175.5 (3)	C3—C4—O4—Cd1^iv	29.1 (5)
C3—C2—C21—O22	4.2 (6)	O4—C4—C5—C6	179.9 (3)
O1—C2—C21—O22	−173.9 (3)	C3—C4—C5—C6	−0.8 (4)
C3—C2—C21—O21	−178.8 (4)	C4—C5—C6—O1	−0.2 (4)
O1—C2—C21—O21	3.0 (5)	C4—C5—C6—C61	178.9 (2)
O22—C21—O21—Cd1	16.8 (3)	C2—O1—C6—C5	1.9 (5)
C2—C21—O21—Cd1	−159.9 (3)	C2—O1—C6—C61	−177.3 (3)
O62^i—Cd1—O21—C21	−40.9 (2)	C5—C6—C61—O62	−13.3 (4)
O12—Cd1—O21—C21	−137.45 (18)	O1—C6—C61—O62	165.9 (3)
O11—Cd1—O21—C21	104.0 (3)	C5—C6—C61—O61	168.0 (3)
O61^ii—Cd1—O21—C21	69.73 (18)	O1—C6—C61—O61	−12.8 (4)
O4^iii—Cd1—O21—C21	143.69 (19)	O62—C61—O61—Cd1^v	124.3 (3)
O1—C2—C3—C4	1.7 (6)	C6—C61—O61—Cd1^v	−57.2 (3)
C21—C2—C3—C4	−176.3 (3)	O61—C61—O62—Cd1^vi	16.7 (5)
C2—C3—C4—O4	179.3 (4)	C6—C61—O62—Cd1^vi	−161.86 (19)
C2—C3—C4—C5	0.1 (4)

Symmetry codes: (i) x−1, y+1, z; (ii) x, y+1, z; (iii) x−1, y, z−1; (iv) x+1, y, z+1; (v) x, y−1, z; (vi) x+1, y−1, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O11—H11A···O13^iii	0.82	1.99	2.805 (4)	172
O11—H11B···O21^ii	0.82	1.98	2.780 (3)	165
O12—H12A···O13^vii	0.82	2.03	2.844 (4)	171
O12—H12B···O4^viii	0.82	2.04	2.827 (3)	162
O13—H13A···O61^ix	0.82	2.42	2.950 (4)	124
O13—H13A···O4^x	0.82	2.46	3.169 (5)	146
O13—H13B···O22	0.82	2.02	2.809 (4)	162

Symmetry codes: (ii) x, y+1, z; (iii) x−1, y, z−1; (vii) x−1, y−1, z−1; (viii) x−2, y, z−1; (ix) x, y+1, z+1; (x) x−1, y, z.