A new polymorph of bis­[2,6-bis­(1H-benzimidazol-2-yl-κN³)pyridinido-κN]zinc(II)

The title compound, [Zn(C₁₉H₁₂N₅)₂], crystallizes in the tetra­gonal space group P4₃2₁2, with the monomer residing on a twofold axis. The imidazole N-bound H atoms are disordered over the two positions, with refined occupancies of 0.59 (3) and 0.41 (3). The strong similarities to, and slight differences from, a reported P4₂2₁2 polymorph which has a 50% smaller unit-cell volume [Harvey, Baggio, Muñoz & Baggio (2003). Acta Cryst. C59, m283–m285], to which the present structure bears a group–subgroup relationship, are discussed.

An anisaldehyde sodium bis­ulfite derivative: poly[[μ₄-(hy­droxy)(4-meth­oxy­phenyl)methane­sulfonato]­sodium]

The title complex, [Na(C₈H₉O₅S)]_n, is polymeric and consists of broad layers parallel to (100) made up of an inner hydro­philic core of Na⁺ cations and polar SO₃C(OH)– groups, padded on both sides by two hydro­phobic layers of pendant meth­oxy­phenyl groups. The Na⁺ cations in the inner core are six-coordinated into highly distorted NaO₆ octa­hedra by four symmetry-related (hy­droxy)(4-meth­oxy­phenyl)methane­sul­fon­ate anions, leading to a tightly woven two-dimensional structure. While there are some hydrogen bonds providing inter­planar cohesion, inter­actions between adjacent layers are weak hydro­phobic ones. The present compound appears to be the first reported structure containing the (hy­droxy)(4-meth­oxy­phenyl)methane­sulfonate ligand.

3,5-Dimethyl-4-[(E)-(2-nitro­phenyl)diazenyl]-1-(2,3,4,5,6-penta­fluoro­phenyl)-1H-pyrazole

The title compound, C₁₇H₁₀F₅N₅O₂, is described and com­pared with its 4-nitro­phenyl isomer [Bustos, Sánchez, Schott, Alvarez-Thon & Fuentealba (2007). Acta Cryst. E63, o1138–o1139]. The title mol­ecule presents its nitro group split into two rotationally disordered components, which in conjunction with the rotation of the `unclamped' rings constitute the main mol­ecular differences. Packing is directed by a head-to-tail type `I' C—F...F—C inter­action, generating double-chain strips running along [100]. These substructures are inter­linked by a variety of weak F...F, O...F, F...π and O...π inter­actions.

Aripiprazole salts. III. Bis(aripipra­zolium) oxalate-oxalic acid (1/1)

The asymmetric unit of the title salt [systematic name: bis­(4-(2,3-dichloro­phen­yl)-1-{4-[(2-oxo-1,2,3,4-tetra­hydro­quinolin-7-yl)­oxy]but­yl}piperazin-1-ium) oxalate-oxalic acid (1/1)], 2C₂₃H₂₈Cl₂N₃O₂⁺·C₂O₄^2-·C₂H₂O₄, consists of one protonated aripiprazole unit (HArip⁺), half an oxalate dianion and half an oxalic acid mol­ecule, the latter two lying on inversion centres. The conformation of the HArip⁺ cation differs from that in other reported salts and resembles more the conformation of neutral Arip units in reported polymorphs and solvates. The inter­molecular inter­action linking HArip⁺ cations is also similar to those in reported Arip compounds crystallizing in the space group P, with head-to-head N-H...O hydrogen bonds generating centrosymmetric dimers, which are further organized into planar ribbons parallel to (01). The oxalate anions and oxalic acid mol­ecules form hydrogen-bonded chains running along [010], which `pierce' the planar ribbons, inter­acting with them through a number of stronger N-H...O and weaker C-H...O hydrogen bonds, forming a three-dimensional network.

Relative influence of noncovalent inter­actions on the melting points of a homologous series of 1,2-dibromo-4,5-dialk­oxy­benzenes

Crystal structures are presented for two members of the homologous series of 1,2-dibromo-4,5-di­alk­oxy­benzenes, viz. those with decyl­oxy and hexa­decyl­oxy substituents, namely 1,2-dibromo-4,5-bis(decyl­oxy)­benzene, C₂₆H₄₄Br₂O₂, (II), and 1,2-dibromo-4,5-bis(hexa­decyl­oxy)­benzene, C₃₈H₆₈Br₂O₂, (III). The relative influences which halogen bonding, [pi]-[pi] stacking and van der Waals inter­actions have on these structures are analysed and the results compared with those already found for the lightest homologue, 1,2-dibromo-4,5-dimeth­oxy­benzene, (I) [Cukiernik, Zelcer, Garland & Baggio (2008). Acta Cryst. C64, o604-o608]. The results confirm that the prevalent inter­actions stabilizing the structures of (II) and (III) are van der Waals contacts between the aliphatic chains. In the case of (II), weak halogen C-Br...(Br-C)' inter­actions are also present and contribute to the stability of the structure. In the case of (III), van der Waals inter­actions between the aliphatic chains are almost exclusive, weaker C-Br...[pi] inter­actions being the only additional inter­actions detected. The results are in line with commonly accepted models concerning trends in crystal stability along a homologous series (as measured by their melting points), but the earlier report for n = 1, and the present report for n = 10 and 16, are among the few providing single-crystal information validating the hypothesis.

A polymeric cobalt(II) complex derived from citric acid (H₄cit) and 2,6-diamino­purine (dap): {[Co₄(cit)₂(dap)₄(H₂O)₄]·6.35H₂O}_n

Poly[[tetraaquadi-μ₄-citrato-tetrakis(2,6-diaminopurine)tetra­cobalt(II)] 6.35-hydrate], {[Co₄(C₆H₄O₇)₂(C₅H₆N₆)₄(H₂O)₄]·6.35H₂O}_n, presents three different types of Co^II cations in the asymmetric unit, two of them lying on symmetry elements (one on an inversion centre and the other on a twofold axis). The main fragment is further composed of one fully deprotonated citrate (cit) tetraanion, two 2,6-diamino­purine (dap) mol­ecules and two aqua ligands. The structure is completed by a mixture of fully occupied and disordered solvent water mol­ecules. The two independent dap ligands are neutral and the cit tetra­anion provides for charge balance, compensating the 4+ cationic charge. There are two well defined coordination geometries in the structure. The simplest is mononuclear, with the Co^II cation arranged in a regular centrosymmetric octa­hedral array, coordinated by two aqua ligands, two dap ligands and two O atoms from the β-carboxyl­ate groups of the bridging cit tetra­anions. The second, more complex, group is trinuclear, bis­ected by a twofold axis, with the metal centres coordinated by two cit tetra­anions through their α- and β-carboxyl­ate and α-hy­droxy groups, and by two dap ligands bridging through one of their pyridine and one of their imidazole N atoms. The resulting coordination geometry around each metal centre is distorted octa­hedral. Both groups are linked alternately to each other, defining parallel chains along [201], laterally inter­leaved and well connected via hydrogen bonding to form a strongly coupled three-dimensional network. The compound presents a novel μ₄-κ⁵O:O,O′:O′,O′′,O′′′:O′′′′ mode of coordination of the cit tetraanion.

Tetra­aqua­(4,4'-dimethyl-2,2'-bipyridine-[kappa]²N,N')nickel(II) sulfate monohydrate: a simple molecule with an extremely complex hydrogen-bonding scheme

The title ionic compound, [Ni(C₁₂H₁₂N₂)(H₂O)₄]SO₄·H₂O, is composed of an Ni^II cation coordinated by a chelating 4,4'-di­methyl-2,2'-bipyridine ligand via its two N atoms [mean Ni-N = 2.056 (2) Å] and by four aqua ligands [mean Ni-O = 2.073 (9) Å], the net charge being balanced by an external sulfate anion. The whole structure is stabilized by a solvent water mol­ecule. Even though the individual constituents are rather featureless, they generate an extremely complex supra­molecular structure consisting of a central hydrogen-bonded two-dimensional hydro­philic nucleus made up of complex cations, sulfate anions and coordinated and solvent water mol­ecules, with pendant hydro­phobic 4,4'-dimethyl-2,2'-bipyridine ligands which inter­act laterally with their neighbours via [pi]-[pi] inter­actions. The structure is compared with closely related analogues in the literature.

Two complexes derived from the reaction of M₃(CO)₁₂ clusters (M = Ru, Os) with the 9-(triphenyl­phosphonio)­fluoren­ide ylide: tricarbonyl[9-(tri­phenyl­phosphonio)fluorenyl­idene]­ruthenium and nona­carbonyl-μ₃-fluorenyl­idene-μ₂-hydrido-triangulo-triosmium(III)

Tricarbon­yl[9-(triphenyl­phospho­nio)fluorenyl­idene]ruthenium, [Ru(C₃₁H₂₁P)(CO)₃], (I), is mononuclear, consisting of a single Ru centre, to which three carbonyl units and a chelating μ₃-9-(triphenyl­phospho­nio)fluorenide ylide bind to generate a distorted octa­hedral RuC₆ core. Nonacarbonyl-μ₃-fluorenyl­idene-μ₂-hydrido-triangulo-triosmium(III), [Os₃H(C₁₃H₇)(CO)₉], (II), is trinuclear and presents a triangular triosmium core, nine carbonyl ligands and one fluorenyl­idene ligand. Two of the Os^III centres present a highly distorted hexa­coordinated Os(Os₂C₄) core and are in turn bridged by a hydride ligand. The remaining Os^III cation is octa­coordinated, with an Os(Os₂C₆) nucleus. The crystal structures of both compounds are the result of nondirectional forces, much resembling the packing of weakly inter­acting quasi-spherical units, viz. the mol­ecules themselves in (I) and centrosymmetric π–π-bonded dimers in (II).

Two solvatomorphic forms of a copper complex formulated as Cu(L¹)(ClO₄)₂·1.2H₂O and Cu(L¹)(ClO₄)₂, where L¹ is 3,10-C-meso-3,5,7,7,10,12,14,14-octa­methyl-1,4,8,11-tetra­aza­cyclo­tetra­decane

Two copper complex solvatomorphs, namely (3,10-C-meso-3,5,7,7,10,12,14,14-octa­methyl-1,4,8,11-tetra­aza­cyclo­tetradecane)bis­(perchlorato-[kappa]O)copper(II) 1.2-hydrate, [Cu(ClO₄)₂(C₁₈H₄₀N₄)]·1.2H₂O, (I), and (3,10-C-meso-3,5,7,7,10,12,14,14-octa­methyl-1,4,8,11-tetra­aza­cyclo­tetradecane)bis­(perchlor­ato-[kappa]O)copper(II), [Cu(ClO₄)₂(C₁₈H₄₀N₄)], (II), are described and compared with each other and with a third, already reported, anhydrous diastereomer, denoted (III). Both compounds present very similar centrosymmetic coordination environments, with the Cu^II cation lying on an inversion centre in a distorted 4+2 octa­hedral environment, defined by the macrocyclic N₄ group in the equatorial sites and two perchlorate groups in trans-axial positions [one of the perchlorate ligands in (I) is partially disordered]. The most significant difference in mol­ecular shape is seen in the orientation of the perchlorate anions, and the influence of this on the intra­molecular hydrogen bonding is discussed. The (partially) hydrated state of (I) favours the formation of chains along [011], while the anhydrous character of (II) and (III) promotes loosely bound structures with low packing indices.

Two isomorphous transition metal complexes displaying a coordinated tetra­thio­nate unit: bis­(4,4′-dimethyl-2,2′-bi­pyridine-κ²N,N′)(tetra­thio­nato-κ²S,S′)cadmium(II) di­methyl­formamide disolvate and the zinc(II) analogue

The isomorphous title compounds, [Tr(S₄O₆)(C₁₂H₁₂N₂)₂]·2C₃H₇NO (Tr = Cd^II and Zn^II), consist of metal centres to which one tetra­thio­nate and two 4,4′-dimethyl-2,2′-bi­pyridine chelating ligands bind. The structures are completed by two symmetry-related di­methyl­formamide solvent mol­ecules. Each metal-centred complex is bis­ected by a twofold axis running through the metal centre and halving the chelating tetra­thio­nate dianion through the central S—S bond. The ancillary symmetry-related 4,4′-dimethyl-2,2′-bi­pyridine lig­ands act as chelates. This results in a distorted six-coordinate geometry, with similar Tr—O/N distances but central angles differing substanti­ally from 90 and 180°. Both ligands are basically featureless from a geometric point of view, with torsion angles in both coordinated tetra­thio­nate groups suggesting a trend linking metal size (covalent radius) and ligand `openness'. Packing is directed by (C—H)_aromatic...O bridges and π–π offset stacked inter­actions defining chains along [001], further linked by weaker (C—H)_methyl...O bridges, some of them mediated by the di­methyl­formamide solvent mol­ecules.

(E)-Ethyl 3-(3,4-di­hydroxy­phen­yl)prop-2-enoate: a natural polymorph extracted from Aristotelia chilensis (Maqui)

The natural title compound, C₁₁H₁₂O₄, extracted from the Chilean native tree Aristotelia chilensis (Maqui), is a polymorph of the synthetic E form reported by Xia, Hu & Rao [Acta Cryst. (2004), E60, o913-o914]. Both rotational conformers are identical from a metrical point of view, and only differ in the orientation of the 3,4-dihydroxyphenyl ring with respect to the rest of the molecule, which leads to completely different crystal structure arrangements and packing efficiencies. The reasons behind both reside in the different hydrogen-bonding inter­actions.

The supra­molecular structure of a cadmium complex with the new functionalized terpyridine ligand 4'-[4-(pyrimidin-5-yl)phen­yl]-2,2':6',2''-terpyridine (L1): aqua­(L1-[kappa]³N,N',N'')(nitrato-[kappa]²O,O')(nitrato-[kappa]O)cadmium(II) dihydrate

The coordinating properties of the novel ligand 4'-[4-(pyrimidin-5-yl)phenyl]-2,2':6',2''-terpyridine were tested by reacting it with cadmium(II) nitrate. The resulting title complex presents a supramolecular motif dominated by a significant number of [pi]-[pi] interactions involving all the aromatic rings.

Three transition-metal complexes with the macrocyclic ligand meso-5,7,7,12,14,14-hexa­methyl-1,4,8,11-tetra­aza­cyclotetra­decane (L): [Cu(ClO₄)₂(L)], [Zn(NO₃)₂(L)] and [CuCl(L)(H₂O)]Cl

The three title transition-metal complexes display a distorted 4+2 octahedral environment for the cation, with the macrocycle defining the base. The effect of the different axial ligands in the intra- and intermolecular hydrogen bonding is discussed.

Dimers linked by type-I C—F...F—C contacts in (Z)-3-methyl-4-[2-(4-methyl­phenyl)hydrazinyl­idene]-1-(penta­fluoro­phenyl)-1H-pyrazol-5(4H)-one

In the title compound, there are two independent mol­ecules forming hydrogen- and π-bonded dimeric entities with a noticeable noncrystallographic C₂ symmetry. Dimers are linked by medium-strength type-I C—F...F—C inter­actions, forming elongated tetra­mers.

A dense hydrogen-bonding network and an unusually large packing index in tri­aqua­tris­(2,4-dioxo-1,2,3,4-tetra­hydro­pyrimidine-5-carboxyl­ato)neodymium(III) trihydrate

In a mononuclear Nd^III complex, three chelating 2,4-dioxo-1,2,3,4-tetra­hydro­pyrimidine-5-carboxyl­ate ligands and three aqua ligands build up a distorted monocapped square anti­prism around the cation. A complex hydrogen-bonding network results in a densely packed structure (packing index = 77.7%)

A polymorphic form of 4,4-dimethyl-8-methyl­ene-3-aza­bicyclo­[3.3.1]non-2-en-2-yl 3-indolyl ketone, an indole alkaloid extracted from Aristotelia chilensis (maqui)

A polymorphic form of the title indole alkaloid was extracted from Aristotelia chilensis. Its crystal structure is described and compared with a previously reported polymorph.