Hexaaqua­cobalt(II) and hexa­aqua­nickel(II) bis­([mu]-pyridine-2,6-dicarboxyl­ato)bis­[(pyridine-2,6-dicarboxyl­ato)bismuthate(III)] dihydrate

The title complexes, hexa­aqua­cobalt(II) bis­([mu]-pyridine-2,6-dicarboxyl­ato)bis­[(pyridine-2,6-dicarboxyl­ato)bismuthate(III)] dihydrate, [Co(H₂O)₆][Bi₂(C₇H₄NO₄)₄]·2H₂O, (I), and hexa­aqua­nickel(II) bis­([mu]-pyridine-2,6-dicarboxyl­ato)bis[(pyridine-2,6-dicarboxyl­ato)bismuthate(III)] dihydrate, [Ni(H₂O)₆][Bi₂(C₇H₄NO₄)₄]·2H₂O, (II), are isomorphous and crystallize in the triclinic space group P. The transition metal ions are located on the inversion centre and adopt slightly distorted MO₆ (M = Co or Ni) octa­hedral geometries. Two [Bi(pydc)₂]^- units (pydc is pyridine-2,6-dicarboxyl­ate) are linked via bridging carboxyl­ate groups into centrosymmetric [Bi₂(pydc)₄]^2- dianions. The crystal packing reveals that the [M(H₂O)₆]²⁺ cations, [Bi₂(pydc)₄]^2- anions and solvent water mol­ecules form multiple hydrogen bonds to generate a supra­molecular three-dimensional network. The formation of secondary Bi...O bonds between adjacent [Bi₂(pydc)₄]^2- dimers provides an additional supra­molecular synthon that directs and facilitates the crystal packing of both (I) and (II).

S1. Comment

Compounds of bismuth(III) with aminopolycarboxylate ligands have been of interest over the past few decades, mainly due to their high stability in aqueous solutions and their rich structural chemistry (Stavila et al., 2006). The bismuth(III) centre is highly acidic and can achieve coordination numbers as high as 10 (Briand & Burford, 2000; Stavila et al., 2006). Pyridine-2,6-dicarboxylic acid (H₂pydc) is a versatile chelating ligand and its metal complexes have been intensively explored in the context of their biological activity (Hwang et al., 2003) and rich coordination chemistry (Serezhkin et al., 2009). Bismuth(III) is known to form stable chelate complexes with H₂pydc (or its anions), and several crystal structures have been reported to date (Agbabozorg et al., 2008; Ranjbar et al., 2003, 2001; Sheshmani et al., 2005). In these structures, H₂pydc acts as an O,N,O-donor ligand to the metal ion to form five-membered metallocycles. This high coordination capacity, coupled with the ability to link to metal centres in a variety of bridging modes, makes aminopolycarboxylate ligands attractive for the assembly of mixed-metal complexes. Previously, we have described several transition metal–bismuth complexes based on ethylenediaminetetraacetate and nitrilotriacetate ligands (Bachman et al., 2003; Stavila et al., 2000, 2002, 2003; Stavila, Gulea, Shova et al. 2004; Stavila, Gulea, Popa et al., 2004). Here, we report the crystal structures of the first transition metal–bismuth pyridine-2,6-dicarboxylates, namely hexaaquacobalt(II) bis(µ-pyridine-2,6-dicarboxylato)bis[(pyridine-2,6-dicarboxylato)bismuthate(III)] dihydrate, (I), and hexaaquanickel(II) bis(µ-pyridine-2,6-dicarboxylato)bis[(pyridine-2,6-dicarboxylato)bismuthate(III)] dihydrate, (II).

Compounds (I) and (II) were obtained under slightly acidic reaction conditions by dissolution of freshly prepared cobalt(II) or nickel(II) hydroxycarbonates in a saturated solution of Bi(Hpydc)(pydc). Both compounds crystallize in the triclinic system (space group P1) and they are essentially isomorphous. The transition metal rests on the inversion centre and is coordinated to six water molecules in a slightly distorted octahedral coordination geometry with typical Co—O and Ni—O distances (Fig. 1, Table 1) (Guo et al., 2008; Morzyk-Ociepa, 2007). The primary coordination environment of Bi^III includes seven donor atoms, six from two tridentate pydc^2- ligands and one bridging O atom from an adjacent symmetry-related complex. The pydc^2- ligand is coordinated to the Bi^III centre in a conventional O,N,O-tridentate fashion via the N atom and two O atoms, one from each of the two carboxylate groups. Atom Bi1 and its symmetry counterpart constitute the anionic part of the molecule, forming a [Bi₂(pydc)₄]^2- dimer (Fig. 1).

The bridging carboxylate group C11—O11—O12 in (I) and (II) displays a monoatomic bidentate η⁰:η²:µ₂-type coordination, which represents the most common bridging motif in structurally characterized Bi^III complexes with dipicolinate ligands (Stavila et al., 2006). According to the nomenclature proposed by Serezhkin et al. (2009), the coordination type of the bridging aminocarboxylate ligand in (I) and (II) can be represented as T¹⁰¹, indicating that one pydc^2- ion acts as a tridentate ligand towards one Bi^III atom and as a monodentate ligand towards the other. This type of coordination of the pydc^2- ligand is also found in complexes of Tl^I, Pb^II and some lanthanides (Serezhkin et al., 2009). The non-bridging pydc^2- group has a coordination of type T⁰⁰¹, which represents the most frequent coordination mode in dipicolinate complexes and is typically adopted by the bis(pydc^2-) complexes of the first- and second-row transition metals. The crystal structures of other Bi^III complexes with H₂pydc acid exhibit similar coordination features. The dimeric structure of [Bi(Hpydc)(pydc)(dmso)]₂ (Zevaco et al., 1992) (dmso is dimethylsulfoxide) displays octa-coordinated Bi^III atoms surrounded by six donor atoms from the H_npydc^(2-n)- ions, a bridging O atom from an adjacent complex and one O atom from a dmso molecule. [{BiCl(H₂O)(pydc)}₂]_n (Ranjbar et al., 2001) contains only one pydc^2- group per Bi^III atom, with an additional Cl^- ligand to complete a pentagonal–bipyramidal environment. In [pydaH]₂[Bi₂(pydc)₄(H₂O)₂]·4H₂O (Ranjbar et al., 2003) (pyda is pyridine-2,6-diamine) and (phenH)₂[Bi₂(pydc)₄(H₂O)₂]·5H₂O (Sheshmani et al., 2005) (phen is 1,10-phenanthroline), the Bi^III centres are coordinated by two pydc^2- ions, a bridging carboxylate O atom and a water molecule. Interestingly enough, no Bi^III–H₂O bonds were found in [creatH]₂[Bi₂(pydc)₄]·4H₂O (Agbabozorg et al., 2008) (creatH = creatinine, 2-amino-1-methyl-5H-imidazol-4-one). We have recently synthesized and determined the crystal structures of two bismuth(III) dipicolinate complexes with thiourea and thiosemicarbazide (Stavila et al., 2009), [Bi₆(pydc)₈(Hpydc)₂(tu)₈] and [Bi₂(pydc)₃(tsc)(H₂O)₂]·H₂O (tu is thiourea and tsc is thiosemicarbazide), which contain Bi—S bonds. In [Bi₆(pydc)₈(Hpydc)₂(tu)₈], there are three independent Bi^III atoms connected by means of bridging carboxylate groups into hexanuclear Bi₆ units, while [Bi₂(pydc)₃(tsc)(H₂O)₂]·H₂O is a coordination polymer generated by bridging carboxylate groups.

The Bi···Bi distances in the [Bi(pydc)₂]₂^2- dimers here are 4.225 (4) and 4.220 (4) Å for (I) and (II), respectively, which is somewhat shorter than the sum of the van der Waals radii (4.8 Å; Standard reference?). The transition metal and Bi^III atoms in (I) and (II) are separated by 6.394 (5) and 6.381 (4) Å, respectively. The interatomic distances and bond angles in (I) and (II) are statistically about the same (Table 1). The Bi—N distances found in the [Bi₂(pydc)₄]^2- dimer correlate well with those in other structurally characterized Bi^III complexes with pydc^2- ligands (Stavila et al., 2006). The Bi—O distances are asymmetric, with the longest distance being to the bridging atom O11 [2.682 (3) and 2.687 (3) for (I) and (II), respectively], which is situated closer to the adjacent Bi^III atom of the dimer at 2.492 (3) and 2.505 (2) Å, respectively.

The extended three-dimensional structure of (I) and (II) shows layers of anions alternating with layers of cations along the b axis. Each anion layer contains dimeric [Bi₂(pydc)₄]^2- complexes joined into chains by secondary Bi···O24ⁱⁱ bonds [3.121 (4) and 3.084 (3) Å for (I) and (II), respectively; symmetry code: (ii) -x, -y - 1, -z]. The layers are held together by a network of nearly linear O—H···O hydrogen bonds with medium to long O···O separations (Fig. 2, Table 2). The H atoms of all water molecules in the structure are involved in hydrogen bonds with the O atoms of other water molecules or carboxylate O atoms. The hydrogen bonds, secondary Bi—O bonds and electrostatic interactions between the cations and anions are the major packing forces that stabilize the crystal structures of compounds (I) and (II).

Related literature

For related literature, see: Agbabozorg et al. (2008); Bachman et al. (2003); Briand & Burford (2000); Guo et al. (2008); Hwang et al. (2003); Morzyk-Ociepa (2007); Ranjbar et al. (2001, 2003); Serezhkin et al. (2009); Sheshmani et al. (2005); Stavila et al. (2000, 2002, 2003, 2006, 2009); Stavila, Gulea, Popa, Shova, Merbach, Simonov & Lipkowski (2004); Stavila, Gulea, Shova, Simonov, Petrenko, Lipkowski, Riblet & Helm (2004); Zevaco et al. (1992).

S2. Experimental

Pyridine-2,6-dicarboxylic acid and all other reactants were obtained commercially. Bismuth(III) oxide (466 mg, 1.0 mmol) and pyridine-2,6-dicarboxylic acid (668 mg, 4.0 mmol) were stirred at reflux in water (Volume?) until the dissolution of most of the oxide. The filtered solution was reacted with freshly prepared cobalt(II) or nickel(II) basic carbonate, obtained upon reaction of aqueous solutions of the transition metal nitrates with excess sodium carbonate. The solutions of the Co^II–Bi^III and Ni^II–Bi^III compounds were filtered and allowed to stand for crystallization at ambient temperature. Light-pink crystals of (I) and light-green crystals of (II) were obtained after 3–4 weeks.

S3. Refinement

C-bound H atoms were located in calculated positions and constrained to ride on their parent atoms, with C—H = 0.93 Å and U_iso(H) = 1.2U_eq(C). Water H atoms were found in a difference Fourier map and included in the refinement with the restraints O—H = 0.84 (1) Å and H···H >= 1.33 (1) Å, and with U_iso(H) = 1.2U_eq(O).

Computing details

For both compounds, data collection: XSCANS (Bruker, 1997); cell refinement: XSCANS (Bruker, 1997); data reduction: SHELXTL (Sheldrick, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of (I), showing the atom-labelling scheme. Displacement ellipsoids are drawn at the 40% probability level. [Symmetry code: (A) -x + 1, -y + 1, -z + 1.] The molecular structure of (II) is available in the Supplementary material.
	Fig. 2. The network formed by hydrogen-bonding interactions (dashed lines) in (I). The aromatic H atoms have been omitted for clarity. The network in (II) is similar?

(I) hexaaquacobalt(II) bis(µ-pyridine-2,6-dicarboxylato)bis[(pyridine-2,6- dicarboxylato)bismuthate(III)] dihydrate

Crystal data

[Co(H2O)6][Bi2(C7H4NO4)4]·2H2O	Z = 1
Mr = 1281.43	F(000) = 609
Triclinic, P1	Dx = 2.385 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.2966 (15) Å	Cell parameters from 9400 reflections
b = 11.184 (2) Å	θ = 2.8–28.7°
c = 12.004 (2) Å	µ = 10.40 mm^−1
α = 112.99 (3)°	T = 293 K
β = 90.67 (3)°	Plate, light-pink
γ = 97.44 (3)°	0.21 × 0.16 × 0.11 mm
V = 892.1 (3) Å^3

Data collection

Bruker CCD 1000 area-detector diffractometer	4176 independent reflections
Radiation source: fine-focus sealed tube	3914 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.035
ω scans	θmax = 28.5°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −9→9
Tmin = 0.219, Tmax = 0.394	k = −14→14
10685 measured reflections	l = −15→15

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)] = 0.024	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.063	H atoms treated by a mixture of independent and constrained refinement
S = 1.07	w = 1/[σ^2(Fo^2) + (0.0304P)^2 + 1.1642P] where P = (Fo^2 + 2Fc^2)/3
4176 reflections	(Δ/σ)max = 0.001
292 parameters	Δρmax = 1.10 e Å^−3
12 restraints	Δρmin = −1.73 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq
Bi1	0.389333 (19)	0.311936 (13)	0.371001 (12)	0.02241 (6)
N1	0.3445 (5)	0.2102 (3)	0.5221 (3)	0.0242 (7)
N2	0.5785 (5)	0.2340 (3)	0.2057 (3)	0.0234 (7)
O11	0.4431 (5)	0.4703 (3)	0.6070 (3)	0.0318 (7)
O12	0.4744 (5)	0.4851 (3)	0.7978 (3)	0.0353 (7)
O13	0.3068 (5)	0.0871 (3)	0.2822 (3)	0.0331 (7)
O14	0.2018 (6)	−0.1019 (3)	0.2943 (3)	0.0454 (9)
O21	0.2421 (4)	0.2833 (3)	0.1716 (3)	0.0288 (6)
O22	0.2624 (5)	0.2020 (4)	−0.0287 (3)	0.0467 (9)
O23	0.6765 (4)	0.2977 (3)	0.4349 (3)	0.0325 (7)
O24	0.9639 (5)	0.2571 (4)	0.3941 (3)	0.0455 (9)
C11	0.4371 (6)	0.4224 (4)	0.6881 (4)	0.0269 (8)
C12	0.3773 (6)	0.2763 (4)	0.6420 (4)	0.0253 (8)
C13	0.3537 (7)	0.2131 (4)	0.7204 (4)	0.0319 (9)
H13A	0.3811	0.2596	0.8033	0.038*
C14	0.2895 (8)	0.0816 (5)	0.6751 (4)	0.0428 (12)
H14A	0.2685	0.0384	0.7271	0.051*
C15	0.2561 (8)	0.0134 (5)	0.5511 (4)	0.0387 (11)
H15A	0.2141	−0.0763	0.5183	0.046*
C16	0.2866 (6)	0.0815 (4)	0.4770 (4)	0.0272 (8)
C17	0.2610 (6)	0.0155 (4)	0.3405 (4)	0.0280 (8)
C21	0.3229 (6)	0.2311 (4)	0.0764 (4)	0.0288 (9)
C22	0.5142 (6)	0.2002 (4)	0.0925 (4)	0.0259 (8)
C23	0.6174 (6)	0.1385 (4)	−0.0042 (4)	0.0305 (9)
H23A	0.5724	0.1174	−0.0834	0.037*
C24	0.7881 (6)	0.1089 (4)	0.0187 (4)	0.0331 (9)
H24A	0.8581	0.0655	−0.0451	0.040*
C25	0.8540 (6)	0.1445 (4)	0.1380 (4)	0.0304 (9)
H25A	0.9681	0.1250	0.1556	0.036*
C26	0.7457 (6)	0.2100 (4)	0.2303 (4)	0.0263 (8)
C27	0.8038 (6)	0.2583 (4)	0.3617 (4)	0.0304 (9)
Co1	0.0000	0.5000	0.0000	0.02622 (16)
O1	−0.2898 (5)	0.4621 (4)	−0.0162 (3)	0.0439 (8)
H1A	−0.359 (6)	0.463 (6)	0.039 (3)	0.053*
H1B	−0.356 (6)	0.471 (6)	−0.069 (4)	0.053*
O2	−0.0030 (5)	0.5428 (3)	−0.1541 (3)	0.0376 (7)
H2A	−0.022 (7)	0.478 (3)	−0.221 (3)	0.045*
H2B	−0.071 (6)	0.596 (4)	−0.159 (4)	0.045*
O3	−0.0090 (5)	0.6937 (3)	0.1035 (3)	0.0387 (8)
H3A	−0.077 (6)	0.730 (4)	0.074 (5)	0.046*
H3B	0.066 (6)	0.756 (3)	0.153 (4)	0.046*
O4	−0.0665 (17)	0.3260 (6)	0.6517 (5)	0.146 (4)
H4A	−0.077 (19)	0.250 (5)	0.652 (10)	0.176*
H4B	−0.058 (19)	0.315 (11)	0.579 (3)	0.176*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Bi1	0.03055 (9)	0.02192 (8)	0.01466 (8)	0.00454 (5)	0.00155 (5)	0.00691 (6)
N1	0.0319 (17)	0.0214 (16)	0.0178 (16)	0.0038 (13)	0.0022 (13)	0.0061 (13)
N2	0.0285 (16)	0.0241 (16)	0.0196 (16)	0.0038 (12)	0.0016 (13)	0.0106 (13)
O11	0.0517 (19)	0.0236 (14)	0.0202 (14)	0.0036 (13)	0.0044 (13)	0.0091 (12)
O12	0.0520 (19)	0.0312 (16)	0.0185 (15)	0.0001 (14)	0.0000 (13)	0.0071 (13)
O13	0.0528 (19)	0.0251 (15)	0.0174 (14)	0.0006 (13)	0.0037 (13)	0.0057 (12)
O14	0.073 (3)	0.0279 (17)	0.0243 (17)	−0.0103 (16)	−0.0036 (16)	0.0042 (14)
O21	0.0298 (14)	0.0358 (16)	0.0219 (14)	0.0076 (12)	0.0035 (11)	0.0117 (12)
O22	0.056 (2)	0.066 (2)	0.0207 (16)	0.0290 (19)	−0.0018 (15)	0.0140 (17)
O23	0.0341 (16)	0.0446 (18)	0.0195 (14)	0.0073 (13)	−0.0027 (12)	0.0129 (13)
O24	0.0348 (17)	0.069 (3)	0.0341 (19)	0.0090 (16)	−0.0046 (14)	0.0222 (18)
C11	0.031 (2)	0.027 (2)	0.022 (2)	0.0053 (15)	0.0054 (16)	0.0086 (16)
C12	0.0298 (19)	0.029 (2)	0.0170 (18)	0.0028 (15)	0.0035 (15)	0.0097 (16)
C13	0.049 (3)	0.030 (2)	0.0178 (19)	0.0012 (18)	0.0002 (17)	0.0115 (17)
C14	0.074 (4)	0.034 (2)	0.023 (2)	−0.002 (2)	0.003 (2)	0.017 (2)
C15	0.066 (3)	0.023 (2)	0.024 (2)	−0.005 (2)	−0.002 (2)	0.0093 (18)
C16	0.035 (2)	0.0236 (19)	0.0190 (19)	0.0002 (15)	−0.0008 (16)	0.0056 (16)
C17	0.037 (2)	0.025 (2)	0.0194 (19)	0.0007 (16)	−0.0006 (16)	0.0082 (16)
C21	0.037 (2)	0.029 (2)	0.024 (2)	0.0082 (17)	−0.0002 (16)	0.0131 (17)
C22	0.033 (2)	0.0246 (19)	0.023 (2)	0.0047 (15)	0.0003 (16)	0.0119 (16)
C23	0.044 (2)	0.029 (2)	0.0180 (19)	0.0067 (17)	0.0054 (17)	0.0081 (16)
C24	0.036 (2)	0.029 (2)	0.030 (2)	0.0059 (17)	0.0120 (18)	0.0062 (18)
C25	0.026 (2)	0.032 (2)	0.032 (2)	0.0052 (16)	0.0058 (17)	0.0110 (18)
C26	0.030 (2)	0.0255 (19)	0.025 (2)	0.0051 (15)	0.0033 (16)	0.0121 (17)
C27	0.034 (2)	0.032 (2)	0.029 (2)	0.0017 (17)	−0.0024 (17)	0.0165 (18)
Co1	0.0294 (4)	0.0281 (4)	0.0203 (4)	0.0072 (3)	−0.0014 (3)	0.0079 (3)
O1	0.0298 (16)	0.069 (3)	0.0351 (19)	0.0098 (16)	0.0007 (14)	0.0227 (19)
O2	0.055 (2)	0.0348 (18)	0.0242 (16)	0.0111 (15)	−0.0012 (14)	0.0119 (14)
O3	0.049 (2)	0.0292 (16)	0.0310 (18)	0.0143 (14)	−0.0128 (14)	0.0023 (14)
O4	0.343 (12)	0.050 (3)	0.031 (3)	−0.008 (5)	−0.044 (5)	0.013 (2)

Geometric parameters (Å, º)

Bi1—O23	2.269 (3)	C15—C16	1.382 (6)
Bi1—O13	2.307 (3)	C15—H15A	0.9300
Bi1—N2	2.372 (3)	C16—C17	1.508 (6)
Bi1—O11^i	2.493 (3)	C21—C22	1.508 (6)
Bi1—N1	2.494 (3)	C22—C23	1.386 (6)
Bi1—O21	2.498 (3)	C23—C24	1.380 (7)
Bi1—O11	2.682 (3)	C23—H23A	0.9300
N1—C16	1.331 (5)	C24—C25	1.389 (7)
N1—C12	1.338 (5)	C24—H24A	0.9300
N2—C22	1.323 (5)	C25—C26	1.387 (6)
N2—C26	1.337 (5)	C25—H25A	0.9300
O11—C11	1.281 (5)	C26—C27	1.490 (6)
O11—Bi1^i	2.493 (3)	Co1—O3^ii	2.044 (3)
O12—C11	1.233 (5)	Co1—O3	2.044 (3)
O13—C17	1.272 (5)	Co1—O2^ii	2.084 (3)
O14—C17	1.223 (5)	Co1—O2	2.084 (3)
O21—C21	1.256 (5)	Co1—O1^ii	2.094 (3)
O22—C21	1.234 (5)	Co1—O1	2.094 (3)
O23—C27	1.285 (5)	O1—H1A	0.836 (10)
O24—C27	1.230 (5)	O1—H1B	0.835 (10)
C11—C12	1.507 (6)	O2—H2A	0.836 (10)
C12—C13	1.381 (6)	O2—H2B	0.837 (10)
C13—C14	1.367 (7)	O3—H3A	0.839 (10)
C13—H13A	0.9300	O3—H3B	0.841 (10)
C14—C15	1.383 (7)	O4—H4A	0.840 (10)
C14—H14A	0.9300	O4—H4B	0.839 (10)
O23—Bi1—O13	93.19 (12)	C15—C16—C17	122.7 (4)
O23—Bi1—N2	68.79 (11)	O14—C17—O13	125.0 (4)
O13—Bi1—N2	73.57 (12)	O14—C17—C16	118.3 (4)
O23—Bi1—O11^i	79.71 (12)	O13—C17—C16	116.7 (4)
O13—Bi1—O11^i	156.24 (11)	O22—C21—O21	127.0 (4)
N2—Bi1—O11^i	82.74 (11)	O22—C21—C22	116.5 (4)
O23—Bi1—N1	73.56 (11)	O21—C21—C22	116.5 (4)
O13—Bi1—N1	67.02 (11)	N2—C22—C23	121.1 (4)
N2—Bi1—N1	122.67 (11)	N2—C22—C21	115.9 (4)
O11^i—Bi1—N1	130.55 (11)	C23—C22—C21	123.0 (4)
O23—Bi1—O21	134.27 (10)	C24—C23—C22	119.1 (4)
O13—Bi1—O21	78.84 (11)	C24—C23—H23A	120.5
N2—Bi1—O21	65.75 (11)	C22—C23—H23A	120.5
O11^i—Bi1—O21	89.88 (11)	C23—C24—C25	119.3 (4)
N1—Bi1—O21	137.88 (11)	C23—C24—H24A	120.4
O23—Bi1—O11	72.66 (11)	C25—C24—H24A	120.4
O13—Bi1—O11	129.08 (10)	C26—C25—C24	118.5 (4)
N2—Bi1—O11	136.25 (11)	C26—C25—H25A	120.8
O11^i—Bi1—O11	70.63 (11)	C24—C25—H25A	120.8
N1—Bi1—O11	62.07 (10)	N2—C26—C25	121.1 (4)
O21—Bi1—O11	144.46 (10)	N2—C26—C27	115.1 (4)
C16—N1—C12	119.8 (4)	C25—C26—C27	123.7 (4)
C16—N1—Bi1	116.0 (3)	O24—C27—O23	124.1 (4)
C12—N1—Bi1	124.2 (3)	O24—C27—C26	120.3 (4)
C22—N2—C26	120.9 (4)	O23—C27—C26	115.6 (4)
C22—N2—Bi1	121.7 (3)	O3^ii—Co1—O3	180.0 (3)
C26—N2—Bi1	116.9 (3)	O3^ii—Co1—O2^ii	88.90 (14)
C11—O11—Bi1^i	126.3 (3)	O3—Co1—O2^ii	91.10 (14)
C11—O11—Bi1	120.5 (3)	O3^ii—Co1—O2	91.10 (14)
Bi1^i—O11—Bi1	109.37 (11)	O3—Co1—O2	88.90 (14)
C17—O13—Bi1	124.3 (3)	O2^ii—Co1—O2	180.00 (17)
C21—O21—Bi1	119.5 (3)	O3^ii—Co1—O1^ii	90.42 (16)
C27—O23—Bi1	122.6 (3)	O3—Co1—O1^ii	89.58 (16)
O12—C11—O11	125.7 (4)	O2^ii—Co1—O1^ii	89.79 (15)
O12—C11—C12	118.9 (4)	O2—Co1—O1^ii	90.21 (15)
O11—C11—C12	115.4 (4)	O3^ii—Co1—O1	89.58 (16)
N1—C12—C13	121.1 (4)	O3—Co1—O1	90.42 (16)
N1—C12—C11	117.4 (4)	O2^ii—Co1—O1	90.21 (15)
C13—C12—C11	121.4 (4)	O2—Co1—O1	89.79 (15)
C14—C13—C12	119.4 (4)	O1^ii—Co1—O1	180.0
C14—C13—H13A	120.3	Co1—O1—H1A	126 (4)
C12—C13—H13A	120.3	Co1—O1—H1B	124 (3)
C13—C14—C15	119.3 (4)	H1A—O1—H1B	105.9 (17)
C13—C14—H14A	120.3	Co1—O2—H2A	116 (4)
C15—C14—H14A	120.3	Co1—O2—H2B	119 (4)
C16—C15—C14	118.6 (4)	H2A—O2—H2B	105.6 (17)
C16—C15—H15A	120.7	Co1—O3—H3A	115 (3)
C14—C15—H15A	120.7	Co1—O3—H3B	135 (3)
N1—C16—C15	121.7 (4)	H3A—O3—H3B	104.3 (16)
N1—C16—C17	115.6 (4)	H4A—O4—H4B	105.0 (17)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···O12^iii	0.84 (1)	2.04 (2)	2.848 (5)	163 (6)
O1—H1B···O12^iv	0.84 (1)	2.08 (1)	2.913 (5)	177 (6)
O2—H2A···O4^v	0.84 (1)	1.78 (1)	2.607 (6)	171 (6)
O2—H2B···O21^ii	0.84 (1)	2.00 (1)	2.839 (5)	178 (5)
O3—H3A···O22^ii	0.84 (1)	1.81 (2)	2.631 (5)	167 (6)
O3—H3B···O14^vi	0.84 (1)	1.96 (2)	2.785 (5)	167 (6)
O4—H4A···O14^vii	0.84 (1)	2.11 (6)	2.885 (7)	153 (12)
O4—H4B···O24^viii	0.84 (1)	2.07 (2)	2.898 (7)	171 (11)

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

(II) hexaaquacobalt(II) bis(µ-pyridine-2,6-dicarboxylato)bis[(pyridine-2,6- dicarboxylato)nickelate(III)] dihydrate

Crystal data

[Ni(H2O)6][Bi2(C7H4NO4)4]·2H2O	Z = 1
Mr = 1281.21	F(000) = 610
Triclinic, P1	Dx = 2.388 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.2615 (15) Å	Cell parameters from 8595 reflections
b = 11.210 (2) Å	θ = 2.8–28.3°
c = 12.014 (2) Å	µ = 10.48 mm^−1
α = 112.96 (3)°	T = 293 K
β = 90.79 (3)°	Plate, light-green
γ = 97.33 (3)°	0.17 × 0.14 × 0.12 mm
V = 891.0 (3) Å^3

Data collection

Bruker CCD 1000 area-detector diffractometer	4214 independent reflections
Radiation source: fine-focus sealed tube	3837 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.030
ω scans	θmax = 28.3°, θmin = 1.9°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −9→9
Tmin = 0.269, Tmax = 0.366	k = −14→14
10920 measured reflections	l = −15→15

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)] = 0.021	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.050	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0218P)^2 + 0.3727P] where P = (Fo^2 + 2Fc^2)/3
4214 reflections	(Δ/σ)max = 0.001
292 parameters	Δρmax = 1.06 e Å^−3
12 restraints	Δρmin = −0.85 e Å^−3

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

Refinement. Refinement of F² against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F², conventional R-factors R are based on F, with F set to zero for negative F². The threshold expression of F² > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq
Bi1	0.388113 (17)	0.312794 (11)	0.371459 (11)	0.02065 (5)
N1	0.3443 (4)	0.2100 (3)	0.5218 (3)	0.0220 (6)
N2	0.5790 (4)	0.2347 (3)	0.2063 (3)	0.0203 (6)
O11	0.4418 (4)	0.4700 (2)	0.6081 (2)	0.0299 (6)
O12	0.4719 (4)	0.4843 (3)	0.7984 (2)	0.0341 (6)
O13	0.3067 (4)	0.0883 (2)	0.2805 (2)	0.0316 (6)
O14	0.2033 (5)	−0.1015 (3)	0.2917 (3)	0.0442 (8)
O21	0.2411 (3)	0.2857 (2)	0.1712 (2)	0.0269 (5)
O22	0.2625 (4)	0.2032 (3)	−0.0288 (3)	0.0465 (8)
O23	0.6780 (4)	0.2988 (3)	0.4358 (2)	0.0311 (6)
O24	0.9667 (4)	0.2579 (3)	0.3959 (3)	0.0431 (7)
C11	0.4356 (5)	0.4221 (3)	0.6886 (3)	0.0232 (7)
C12	0.3764 (5)	0.2756 (3)	0.6416 (3)	0.0231 (7)
C13	0.3529 (6)	0.2119 (4)	0.7198 (3)	0.0319 (8)
H13A	0.3797	0.2577	0.8028	0.038*
C14	0.2898 (7)	0.0810 (4)	0.6733 (4)	0.0428 (11)
H14A	0.2699	0.0373	0.7248	0.051*
C15	0.2553 (6)	0.0131 (4)	0.5498 (4)	0.0380 (10)
H15A	0.2125	−0.0763	0.5171	0.046*
C16	0.2860 (5)	0.0812 (3)	0.4756 (3)	0.0248 (7)
C17	0.2612 (5)	0.0158 (4)	0.3397 (3)	0.0278 (8)
C21	0.3233 (5)	0.2324 (4)	0.0757 (3)	0.0257 (7)
C22	0.5159 (5)	0.2006 (3)	0.0925 (3)	0.0221 (7)
C23	0.6191 (6)	0.1392 (4)	−0.0034 (3)	0.0293 (8)
H23A	0.5747	0.1186	−0.0827	0.035*
C24	0.7902 (5)	0.1090 (4)	0.0206 (3)	0.0312 (8)
H24A	0.8606	0.0651	−0.0427	0.037*
C25	0.8557 (5)	0.1447 (4)	0.1398 (4)	0.0285 (8)
H25A	0.9699	0.1247	0.1577	0.034*
C26	0.7483 (5)	0.2104 (3)	0.2310 (3)	0.0220 (7)
C27	0.8054 (5)	0.2587 (4)	0.3627 (3)	0.0267 (8)
Ni1	0.0000	0.5000	0.0000	0.02368 (13)
O1	−0.2866 (4)	0.4586 (3)	−0.0175 (3)	0.0400 (7)
H1A	−0.345 (5)	0.467 (5)	0.043 (2)	0.048*
H1B	−0.358 (5)	0.470 (5)	−0.066 (3)	0.048*
O2	0.0047 (4)	0.5436 (3)	−0.1505 (2)	0.0341 (6)
H2A	−0.030 (5)	0.476 (2)	−0.213 (3)	0.041*
H2B	−0.072 (5)	0.594 (3)	−0.149 (4)	0.041*
O3	−0.0126 (4)	0.6901 (3)	0.1053 (3)	0.0363 (7)
H3A	−0.083 (4)	0.731 (3)	0.082 (4)	0.044*
H3B	0.079 (4)	0.745 (3)	0.142 (4)	0.044*
O4	−0.0812 (13)	0.3289 (4)	0.6558 (4)	0.144 (3)
H4A	−0.080 (15)	0.251 (3)	0.646 (8)	0.173*
H4B	−0.067 (14)	0.332 (8)	0.588 (4)	0.173*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Bi1	0.02727 (7)	0.02004 (7)	0.01416 (7)	0.00388 (5)	0.00127 (5)	0.00609 (5)
N1	0.0271 (15)	0.0231 (14)	0.0161 (14)	0.0029 (12)	0.0014 (11)	0.0084 (12)
N2	0.0248 (14)	0.0184 (13)	0.0178 (14)	0.0024 (11)	0.0016 (11)	0.0074 (11)
O11	0.0475 (16)	0.0214 (12)	0.0191 (13)	0.0008 (11)	0.0042 (11)	0.0075 (10)
O12	0.0497 (17)	0.0287 (14)	0.0189 (13)	0.0003 (12)	0.0004 (12)	0.0057 (11)
O13	0.0497 (17)	0.0237 (13)	0.0187 (13)	0.0008 (12)	0.0047 (11)	0.0067 (11)
O14	0.072 (2)	0.0229 (14)	0.0285 (15)	−0.0125 (14)	−0.0055 (14)	0.0062 (12)
O21	0.0273 (13)	0.0330 (14)	0.0226 (13)	0.0071 (10)	0.0022 (10)	0.0123 (11)
O22	0.0536 (18)	0.066 (2)	0.0228 (15)	0.0286 (16)	−0.0023 (13)	0.0152 (15)
O23	0.0325 (14)	0.0416 (15)	0.0189 (13)	0.0071 (12)	0.0004 (11)	0.0112 (12)
O24	0.0299 (15)	0.064 (2)	0.0345 (17)	0.0088 (14)	−0.0063 (12)	0.0184 (15)
C11	0.0268 (17)	0.0269 (18)	0.0171 (17)	0.0048 (14)	0.0037 (13)	0.0097 (14)
C12	0.0286 (17)	0.0256 (17)	0.0157 (16)	0.0020 (14)	0.0024 (13)	0.0092 (14)
C13	0.048 (2)	0.030 (2)	0.0167 (17)	0.0006 (17)	0.0026 (16)	0.0098 (15)
C14	0.071 (3)	0.034 (2)	0.028 (2)	−0.003 (2)	0.002 (2)	0.0196 (19)
C15	0.060 (3)	0.0222 (19)	0.030 (2)	−0.0047 (18)	0.0011 (19)	0.0115 (17)
C16	0.0313 (18)	0.0220 (17)	0.0200 (17)	0.0005 (14)	0.0006 (14)	0.0081 (14)
C17	0.0336 (19)	0.0252 (18)	0.0220 (18)	0.0013 (15)	0.0029 (15)	0.0074 (15)
C21	0.0321 (18)	0.0259 (18)	0.0221 (18)	0.0061 (14)	−0.0014 (15)	0.0123 (15)
C22	0.0305 (18)	0.0191 (16)	0.0163 (16)	0.0023 (13)	0.0026 (13)	0.0069 (13)
C23	0.042 (2)	0.0289 (19)	0.0149 (17)	0.0047 (16)	0.0045 (15)	0.0068 (15)
C24	0.036 (2)	0.0277 (19)	0.0255 (19)	0.0064 (16)	0.0119 (16)	0.0049 (16)
C25	0.0277 (18)	0.0259 (18)	0.032 (2)	0.0050 (15)	0.0035 (15)	0.0111 (16)
C26	0.0235 (16)	0.0193 (16)	0.0231 (18)	0.0006 (13)	0.0018 (13)	0.0088 (14)
C27	0.0316 (19)	0.0274 (18)	0.0228 (18)	0.0035 (15)	−0.0005 (15)	0.0120 (15)
Ni1	0.0257 (3)	0.0256 (3)	0.0189 (3)	0.0061 (2)	−0.0012 (2)	0.0073 (3)
O1	0.0290 (14)	0.064 (2)	0.0296 (16)	0.0088 (14)	0.0014 (12)	0.0212 (15)
O2	0.0460 (17)	0.0341 (15)	0.0225 (14)	0.0121 (13)	−0.0003 (12)	0.0098 (12)
O3	0.0440 (16)	0.0268 (14)	0.0314 (16)	0.0103 (12)	−0.0123 (13)	0.0032 (12)
O4	0.333 (9)	0.051 (3)	0.034 (2)	−0.008 (4)	−0.058 (4)	0.013 (2)

Geometric parameters (Å, º)

Bi1—O23	2.277 (3)	C15—C16	1.385 (5)
Bi1—O13	2.310 (3)	C15—H15A	0.9300
Bi1—N2	2.378 (3)	C16—C17	1.503 (5)
Bi1—N1	2.497 (3)	C21—C22	1.517 (5)
Bi1—O11^i	2.504 (3)	C22—C23	1.379 (5)
Bi1—O21	2.510 (3)	C23—C24	1.384 (6)
Bi1—O11	2.688 (3)	C23—H23A	0.9300
N1—C16	1.337 (4)	C24—C25	1.386 (5)
N1—C12	1.337 (4)	C24—H24A	0.9300
N2—C22	1.325 (4)	C25—C26	1.375 (5)
N2—C26	1.346 (4)	C25—H25A	0.9300
O11—C11	1.275 (4)	C26—C27	1.492 (5)
O11—Bi1^i	2.504 (3)	Ni1—O3^ii	2.024 (3)
O12—C11	1.234 (4)	Ni1—O3	2.024 (3)
O13—C17	1.289 (4)	Ni1—O2^ii	2.049 (3)
O14—C17	1.225 (4)	Ni1—O2	2.049 (3)
O21—C21	1.266 (4)	Ni1—O1	2.063 (3)
O22—C21	1.227 (4)	Ni1—O1^ii	2.063 (3)
O23—C27	1.285 (4)	O1—H1A	0.832 (10)
O24—C27	1.235 (4)	O1—H1B	0.835 (10)
C11—C12	1.514 (5)	O2—H2A	0.839 (10)
C12—C13	1.386 (5)	O2—H2B	0.838 (10)
C13—C14	1.363 (6)	O3—H3A	0.839 (10)
C13—H13A	0.9300	O3—H3B	0.835 (10)
C14—C15	1.380 (6)	O4—H4A	0.835 (10)
C14—H14A	0.9300	O4—H4B	0.837 (10)
O23—Bi1—O13	93.28 (10)	C15—C16—C17	122.8 (3)
O23—Bi1—N2	68.68 (9)	O14—C17—O13	123.9 (4)
O13—Bi1—N2	72.91 (10)	O14—C17—C16	119.2 (3)
O23—Bi1—N1	73.46 (10)	O13—C17—C16	116.9 (3)
O13—Bi1—N1	67.39 (9)	O22—C21—O21	126.7 (3)
N2—Bi1—N1	122.22 (9)	O22—C21—C22	116.8 (3)
O23—Bi1—O11^i	79.49 (10)	O21—C21—C22	116.5 (3)
O13—Bi1—O11^i	155.11 (9)	N2—C22—C23	121.7 (3)
N2—Bi1—O11^i	82.30 (9)	N2—C22—C21	115.5 (3)
N1—Bi1—O11^i	131.06 (9)	C23—C22—C21	122.8 (3)
O23—Bi1—O21	134.06 (9)	C22—C23—C24	118.6 (3)
O13—Bi1—O21	78.75 (9)	C22—C23—H23A	120.7
N2—Bi1—O21	65.72 (9)	C24—C23—H23A	120.7
N1—Bi1—O21	138.26 (9)	C23—C24—C25	119.5 (3)
O11^i—Bi1—O21	89.20 (9)	C23—C24—H24A	120.3
O23—Bi1—O11	72.58 (9)	C25—C24—H24A	120.3
O13—Bi1—O11	129.42 (9)	C26—C25—C24	118.6 (3)
N2—Bi1—O11	136.28 (9)	C26—C25—H25A	120.7
N1—Bi1—O11	62.04 (8)	C24—C25—H25A	120.7
O11^i—Bi1—O11	71.33 (9)	N2—C26—C25	121.3 (3)
O21—Bi1—O11	144.48 (8)	N2—C26—C27	114.6 (3)
C16—N1—C12	120.1 (3)	C25—C26—C27	124.1 (3)
C16—N1—Bi1	115.8 (2)	O24—C27—O23	123.8 (3)
C12—N1—Bi1	124.1 (2)	O24—C27—C26	120.1 (3)
C22—N2—C26	120.2 (3)	O23—C27—C26	116.1 (3)
C22—N2—Bi1	122.2 (2)	O3^ii—Ni1—O3	180.0 (2)
C26—N2—Bi1	117.1 (2)	O3^ii—Ni1—O2^ii	89.91 (12)
C11—O11—Bi1^i	126.7 (2)	O3—Ni1—O2^ii	90.09 (12)
C11—O11—Bi1	120.7 (2)	O3^ii—Ni1—O2	90.09 (12)
Bi1^i—O11—Bi1	108.67 (9)	O3—Ni1—O2	89.91 (12)
C17—O13—Bi1	123.6 (2)	O2^ii—Ni1—O2	180.00 (14)
C21—O21—Bi1	119.2 (2)	O3^ii—Ni1—O1	89.10 (13)
C27—O23—Bi1	122.6 (2)	O3—Ni1—O1	90.90 (13)
O12—C11—O11	125.9 (3)	O2^ii—Ni1—O1	88.32 (12)
O12—C11—C12	118.8 (3)	O2—Ni1—O1	91.68 (12)
O11—C11—C12	115.3 (3)	O3^ii—Ni1—O1^ii	90.90 (13)
N1—C12—C13	121.1 (3)	O3—Ni1—O1^ii	89.10 (13)
N1—C12—C11	117.6 (3)	O2^ii—Ni1—O1^ii	91.68 (12)
C13—C12—C11	121.3 (3)	O2—Ni1—O1^ii	88.32 (12)
C14—C13—C12	118.9 (4)	O1—Ni1—O1^ii	180.0
C14—C13—H13A	120.5	Ni1—O1—H1A	120 (3)
C12—C13—H13A	120.5	Ni1—O1—H1B	127 (3)
C13—C14—C15	120.1 (4)	H1A—O1—H1B	106.1 (16)
C13—C14—H14A	119.9	Ni1—O2—H2A	110 (3)
C15—C14—H14A	119.9	Ni1—O2—H2B	112 (3)
C14—C15—C16	118.4 (4)	H2A—O2—H2B	104.6 (16)
C14—C15—H15A	120.8	Ni1—O3—H3A	119 (3)
C16—C15—H15A	120.8	Ni1—O3—H3B	125 (3)
N1—C16—C15	121.2 (3)	H3A—O3—H3B	105.1 (16)
N1—C16—C17	115.9 (3)	H4A—O4—H4B	105.8 (17)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1A···O12^iii	0.83 (1)	2.03 (1)	2.856 (4)	172 (5)
O1—H1B···O12^iv	0.84 (1)	2.10 (1)	2.927 (4)	174 (4)
O2—H2A···O4^v	0.84 (1)	1.77 (1)	2.608 (5)	175 (4)
O2—H2B···O21^ii	0.84 (1)	2.02 (1)	2.852 (4)	170 (4)
O3—H3A···O22^ii	0.84 (1)	1.80 (1)	2.634 (4)	170 (4)
O3—H3B···O14^vi	0.84 (1)	2.04 (3)	2.796 (4)	151 (4)
O4—H4A···O14^vii	0.84 (1)	2.19 (6)	2.895 (6)	142 (8)
O4—H4B···O24^viii	0.84 (1)	2.15 (4)	2.944 (6)	157 (8)

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