Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807053603/bg2115sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807053603/bg2115Isup2.hkl |
CCDC reference: 667245
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (C-C) = 0.004 Å
- Disorder in main residue
- R factor = 0.041
- wR factor = 0.105
- Data-to-parameter ratio = 11.5
checkCIF/PLATON results
No syntax errors found
Alert level C PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ .... ? PLAT154_ALERT_1_C The su's on the Cell Angles are Equal (x 10000) 300 Deg. PLAT301_ALERT_3_C Main Residue Disorder ......................... 17.00 Perc. PLAT720_ALERT_4_C Number of Unusual/Non-Standard Label(s) ........ 8
Alert level G PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature 293 K PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature . 293 K PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints ....... 48
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 4 ALERT level C = Check and explain 3 ALERT level G = General alerts; check 4 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 2 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion 0 ALERT type 5 Informative message, check
See Fan et al. (2007); He et al. (2007); Okabe, Muranishi & Wada (2002) for the copper(II), cobalt(II) and iron(III) derivatives, respectively, and Okabe, Wada & Muranishi (2002) for the cadmium derivative.
Nickel chloride (0.26 g, 20 mmol) and fusaric acid (0.36 g, 20 mmol) were dissolved in a small volume of hot water; aqueous sodium hydroxide (30 mmol) was added to a pH of 7. Crystals suitable for x-ray diffraction appeared from the solution after a few days.
The butyl group is disordered over two positions in the β-, γ- and δ-carbon atoms, and was refined with a distance restraint of C—C 1.54 (1) Å; the vibration of the disordered atoms was restrained to be nearly isotropic. The occupation refined to a 681 (8):319 (8) ratio. The water H-atoms were located in a difference Fourier map, and were refined with distance restraints of O—H 0.85 (3) and H···H 1.39 (3) Å. The carbon-bound H atoms were treated as riding, (C—H: 0.93–0.97 Å). The displacement factors of all H atoms were tied to those of their hosts through a factor of 1.2–1.5
5-Butyl-pyridyl-2-carboxylic acid (fusaric acid), unlike the parent unsubstituted carboxylic acid that affords a large number of N,O-chelated metal derivates, forms only three metal carboxylates that have been characterized by crystallography (Fan et al., 2007; He et al., 2007). The aquacadmium derivative (Okabe, Wada & Muranishi, 2002) has two chelating carboxylate groups. The sixth coordination site is taken up by a carboxyl oxygen atom from an adjacent molecule; the water and carboxyl oxygen atoms are cis to each other. The copper derivative has two coordinated methanol molecules whereas the iron(III) derivative is a tris-chelated compound; (Okabe, Muranishi & Wada, 2002). The metal atom in the title nickel(II) derivative (I) (Fig. 1) lies on an inversion center, and presents two coordinated water molecules in the octahedral environment, the remaining sites being occupied by two chelating alky-substituted 2-pyridylcarboxylate groups (Table 1); the coordinated water and the lattice water molecules engage in hydrogen bonding (Table 2) with the carboxyl group to furnish a two-dimensional network motif parallel to (001) (Fig. 2).
See Fan et al. (2007); He et al. (2007); Okabe, Muranishi & Wada (2002) for the copper(II), cobalt(II) and iron(III) derivatives, respectively, and Okabe, Wada & Muranishi (2002) for the cadmium derivative.
Data collection: SMART (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2007).
[Ni(C10H13NO2)2(H2O)2]·2H2O | Z = 1 |
Mr = 487.19 | F(000) = 258 |
Triclinic, P1 | Dx = 1.414 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 5.2217 (10) Å | Cell parameters from 1053 reflections |
b = 9.9614 (17) Å | θ = 3.6–24.8° |
c = 11.5070 (19) Å | µ = 0.90 mm−1 |
α = 79.378 (3)° | T = 293 K |
β = 79.191 (3)° | Block, green |
γ = 80.152 (3)° | 0.16 × 0.15 × 0.09 mm |
V = 572.05 (17) Å3 |
Bruker APEX area-detector diffractometer | 2022 independent reflections |
Radiation source: fine-focus sealed tube | 1747 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.027 |
φ and ω scans | θmax = 25.2°, θmin = 3.0° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −6→6 |
Tmin = 0.870, Tmax = 0.924 | k = −11→11 |
3673 measured reflections | l = −13→13 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.041 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.105 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.06 | w = 1/[σ2(Fo2) + (0.0598P)2 + 0.0105P] where P = (Fo2 + 2Fc2)/3 |
2022 reflections | (Δ/σ)max < 0.001 |
176 parameters | Δρmax = 0.43 e Å−3 |
48 restraints | Δρmin = −0.45 e Å−3 |
[Ni(C10H13NO2)2(H2O)2]·2H2O | γ = 80.152 (3)° |
Mr = 487.19 | V = 572.05 (17) Å3 |
Triclinic, P1 | Z = 1 |
a = 5.2217 (10) Å | Mo Kα radiation |
b = 9.9614 (17) Å | µ = 0.90 mm−1 |
c = 11.5070 (19) Å | T = 293 K |
α = 79.378 (3)° | 0.16 × 0.15 × 0.09 mm |
β = 79.191 (3)° |
Bruker APEX area-detector diffractometer | 2022 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 1747 reflections with I > 2σ(I) |
Tmin = 0.870, Tmax = 0.924 | Rint = 0.027 |
3673 measured reflections |
R[F2 > 2σ(F2)] = 0.041 | 48 restraints |
wR(F2) = 0.105 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.06 | Δρmax = 0.43 e Å−3 |
2022 reflections | Δρmin = −0.45 e Å−3 |
176 parameters |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Ni1 | 0.5000 | 0.5000 | 0.5000 | 0.02811 (19) | |
O2 | 0.2417 (4) | 0.1359 (2) | 0.5223 (2) | 0.0458 (6) | |
O1 | 0.2861 (4) | 0.35853 (18) | 0.47295 (17) | 0.0322 (5) | |
O1W | 0.8216 (4) | 0.41784 (19) | 0.38023 (19) | 0.0356 (5) | |
N1 | 0.5972 (4) | 0.3419 (2) | 0.6331 (2) | 0.0294 (5) | |
C2 | 0.5090 (5) | 0.2248 (3) | 0.6261 (2) | 0.0299 (6) | |
C3 | 0.5740 (6) | 0.1037 (3) | 0.6988 (3) | 0.0392 (7) | |
H3 | 0.5154 | 0.0233 | 0.6909 | 0.047* | |
C4 | 0.7286 (7) | 0.1028 (3) | 0.7844 (3) | 0.0441 (8) | |
H4 | 0.7744 | 0.0210 | 0.8346 | 0.053* | |
C5 | 0.8152 (5) | 0.2221 (3) | 0.7959 (3) | 0.0358 (7) | |
C6 | 0.7457 (6) | 0.3387 (3) | 0.7170 (3) | 0.0355 (7) | |
H6 | 0.8052 | 0.4199 | 0.7222 | 0.043* | |
C1 | 0.3318 (5) | 0.2391 (3) | 0.5330 (3) | 0.0303 (6) | |
C7 | 0.9731 (6) | 0.2290 (4) | 0.8915 (3) | 0.0506 (9) | |
H7A | 1.1202 | 0.2786 | 0.8553 | 0.061* | |
H7B | 1.0445 | 0.1361 | 0.9237 | 0.061* | |
O2W | 0.8816 (5) | 0.1367 (2) | 0.3708 (2) | 0.0498 (6) | |
H1W1 | 0.785 (7) | 0.345 (2) | 0.363 (3) | 0.075* | |
H2W1 | 0.814 (7) | 0.063 (2) | 0.392 (3) | 0.075* | |
H1W2 | 0.963 (5) | 0.400 (3) | 0.410 (3) | 0.075* | |
H2W2 | 0.995 (6) | 0.137 (3) | 0.415 (3) | 0.075* | |
C8 | 0.8110 (11) | 0.3002 (6) | 0.9948 (4) | 0.0532 (17) | 0.681 (8) |
H8A | 0.9281 | 0.3142 | 1.0463 | 0.064* | 0.681 (8) |
H8B | 0.7260 | 0.3900 | 0.9622 | 0.064* | 0.681 (8) |
C9 | 0.6039 (12) | 0.2166 (7) | 1.0683 (5) | 0.0642 (19) | 0.681 (8) |
H9A | 0.6881 | 0.1277 | 1.1032 | 0.077* | 0.681 (8) |
H9B | 0.4881 | 0.2007 | 1.0170 | 0.077* | 0.681 (8) |
C10 | 0.442 (3) | 0.2930 (18) | 1.1683 (11) | 0.070 (3) | 0.681 (8) |
H10A | 0.3120 | 0.2386 | 1.2144 | 0.105* | 0.681 (8) |
H10B | 0.3564 | 0.3802 | 1.1336 | 0.105* | 0.681 (8) |
H10C | 0.5568 | 0.3079 | 1.2194 | 0.105* | 0.681 (8) |
C8' | 0.8037 (19) | 0.2008 (11) | 1.0182 (8) | 0.048 (3) | 0.319 (8) |
H8'1 | 0.7264 | 0.1173 | 1.0250 | 0.058* | 0.319 (8) |
H8'2 | 0.9166 | 0.1861 | 1.0787 | 0.058* | 0.319 (8) |
C9' | 0.584 (2) | 0.3203 (12) | 1.0417 (10) | 0.053 (4) | 0.319 (8) |
H9'1 | 0.4832 | 0.3413 | 0.9764 | 0.064* | 0.319 (8) |
H9'2 | 0.6628 | 0.4014 | 1.0430 | 0.064* | 0.319 (8) |
C10' | 0.397 (8) | 0.289 (4) | 1.161 (2) | 0.070 (3) | 0.319 (8) |
H10D | 0.2659 | 0.3676 | 1.1716 | 0.105* | 0.319 (8) |
H10E | 0.4956 | 0.2680 | 1.2258 | 0.105* | 0.319 (8) |
H10F | 0.3125 | 0.2110 | 1.1587 | 0.105* | 0.319 (8) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ni1 | 0.0258 (3) | 0.0260 (3) | 0.0334 (3) | −0.00582 (19) | −0.0074 (2) | −0.0022 (2) |
O2 | 0.0487 (14) | 0.0328 (11) | 0.0626 (15) | −0.0153 (10) | −0.0209 (12) | −0.0037 (10) |
O1 | 0.0299 (11) | 0.0282 (10) | 0.0399 (12) | −0.0061 (8) | −0.0122 (9) | −0.0003 (9) |
O1W | 0.0306 (11) | 0.0353 (11) | 0.0419 (12) | −0.0047 (9) | −0.0078 (9) | −0.0070 (10) |
N1 | 0.0265 (12) | 0.0287 (12) | 0.0334 (13) | −0.0058 (9) | −0.0047 (10) | −0.0048 (10) |
C2 | 0.0242 (14) | 0.0299 (15) | 0.0334 (16) | −0.0036 (11) | 0.0003 (12) | −0.0047 (12) |
C3 | 0.0421 (18) | 0.0279 (15) | 0.0462 (19) | −0.0066 (13) | −0.0093 (15) | 0.0010 (13) |
C4 | 0.049 (2) | 0.0360 (17) | 0.0428 (19) | 0.0013 (14) | −0.0125 (15) | 0.0050 (14) |
C5 | 0.0256 (15) | 0.0441 (17) | 0.0349 (16) | 0.0004 (12) | −0.0045 (12) | −0.0044 (13) |
C6 | 0.0331 (16) | 0.0393 (17) | 0.0353 (17) | −0.0086 (13) | −0.0044 (13) | −0.0068 (13) |
C1 | 0.0234 (14) | 0.0321 (15) | 0.0366 (16) | −0.0063 (11) | −0.0027 (12) | −0.0084 (13) |
C7 | 0.041 (2) | 0.069 (2) | 0.0423 (19) | −0.0061 (16) | −0.0145 (16) | −0.0036 (17) |
O2W | 0.0513 (15) | 0.0373 (13) | 0.0634 (16) | −0.0082 (10) | −0.0165 (12) | −0.0059 (11) |
C8 | 0.060 (4) | 0.062 (4) | 0.044 (3) | −0.012 (3) | −0.021 (3) | −0.010 (3) |
C9 | 0.072 (4) | 0.059 (4) | 0.057 (4) | −0.005 (3) | −0.005 (3) | −0.009 (3) |
C10 | 0.074 (6) | 0.080 (3) | 0.056 (3) | −0.006 (3) | −0.008 (3) | −0.015 (2) |
C8' | 0.048 (6) | 0.051 (6) | 0.044 (6) | 0.003 (5) | −0.016 (5) | −0.007 (5) |
C9' | 0.058 (7) | 0.050 (7) | 0.046 (6) | 0.008 (5) | −0.009 (5) | −0.005 (5) |
C10' | 0.074 (6) | 0.080 (3) | 0.056 (3) | −0.006 (3) | −0.008 (3) | −0.015 (2) |
Ni1—O1 | 2.0398 (18) | C7—H7A | 0.9700 |
Ni1—O1i | 2.0398 (18) | C7—H7B | 0.9700 |
Ni1—N1i | 2.053 (2) | O2W—H2W1 | 0.85 (3) |
Ni1—N1 | 2.053 (2) | O2W—H2W2 | 0.85 (3) |
Ni1—O1W | 2.113 (2) | C8—C9 | 1.511 (7) |
Ni1—O1Wi | 2.113 (2) | C8—H8A | 0.9700 |
O2—C1 | 1.236 (3) | C8—H8B | 0.9700 |
O1—C1 | 1.269 (3) | C9—C10 | 1.534 (9) |
O1W—H1W1 | 0.85 (3) | C9—H9A | 0.9700 |
O1W—H1W2 | 0.85 (3) | C9—H9B | 0.9700 |
N1—C6 | 1.339 (4) | C10—H10A | 0.9600 |
N1—C2 | 1.347 (3) | C10—H10B | 0.9600 |
C2—C3 | 1.365 (4) | C10—H10C | 0.9600 |
C2—C1 | 1.515 (4) | C8'—C9' | 1.528 (9) |
C3—C4 | 1.383 (4) | C8'—H8'1 | 0.9700 |
C3—H3 | 0.9300 | C8'—H8'2 | 0.9700 |
C4—C5 | 1.378 (4) | C9'—C10' | 1.541 (10) |
C4—H4 | 0.9300 | C9'—H9'1 | 0.9700 |
C5—C6 | 1.377 (4) | C9'—H9'2 | 0.9700 |
C5—C7 | 1.512 (4) | C10'—H10D | 0.9600 |
C6—H6 | 0.9300 | C10'—H10E | 0.9600 |
C7—C8 | 1.536 (5) | C10'—H10F | 0.9600 |
O1—Ni1—O1i | 180.00 (10) | C8—C7—H7A | 108.9 |
O1—Ni1—N1i | 99.56 (8) | C8'—C7—H7A | 136.8 |
O1i—Ni1—N1i | 80.44 (8) | C5—C7—H7B | 108.9 |
O1—Ni1—N1 | 80.44 (8) | C8—C7—H7B | 108.9 |
O1i—Ni1—N1 | 99.56 (8) | H7A—C7—H7B | 107.7 |
N1i—Ni1—N1 | 180.000 (1) | H2W1—O2W—H2W2 | 109.2 (17) |
O1—Ni1—O1W | 89.28 (8) | C9—C8—C7 | 112.1 (5) |
O1i—Ni1—O1W | 90.72 (8) | C9—C8—H8A | 109.2 |
N1i—Ni1—O1W | 90.35 (8) | C7—C8—H8A | 109.2 |
N1—Ni1—O1W | 89.65 (8) | C9—C8—H8B | 109.2 |
O1—Ni1—O1Wi | 90.72 (8) | C7—C8—H8B | 109.2 |
O1i—Ni1—O1Wi | 89.28 (8) | H8A—C8—H8B | 107.9 |
N1i—Ni1—O1Wi | 89.65 (8) | C8—C9—C10 | 110.4 (7) |
N1—Ni1—O1Wi | 90.35 (8) | C8—C9—H9A | 109.6 |
O1W—Ni1—O1Wi | 180.000 (1) | C10—C9—H9A | 109.6 |
C1—O1—Ni1 | 115.02 (17) | C8—C9—H9B | 109.6 |
Ni1—O1W—H1W1 | 108 (3) | C10—C9—H9B | 109.6 |
Ni1—O1W—H1W2 | 112 (3) | H9A—C9—H9B | 108.1 |
H1W1—O1W—H1W2 | 110.0 (17) | C9—C10—H10A | 109.5 |
C6—N1—C2 | 118.2 (2) | C9—C10—H10B | 109.5 |
C6—N1—Ni1 | 129.16 (19) | H10A—C10—H10B | 109.5 |
C2—N1—Ni1 | 112.47 (18) | C9—C10—H10C | 109.5 |
N1—C2—C3 | 121.9 (3) | H10A—C10—H10C | 109.5 |
N1—C2—C1 | 114.8 (2) | H10B—C10—H10C | 109.5 |
C3—C2—C1 | 123.3 (3) | C9'—C8'—C7 | 112.1 (8) |
C2—C3—C4 | 118.9 (3) | C9'—C8'—H8'1 | 109.2 |
C2—C3—H3 | 120.6 | C7—C8'—H8'1 | 109.2 |
C4—C3—H3 | 120.6 | C9'—C8'—H8'2 | 109.2 |
C5—C4—C3 | 120.4 (3) | C7—C8'—H8'2 | 109.2 |
C5—C4—H4 | 119.8 | H8'1—C8'—H8'2 | 107.9 |
C3—C4—H4 | 119.8 | C8'—C9'—C10' | 113.0 (18) |
C6—C5—C4 | 116.8 (3) | C8'—C9'—H9'1 | 109.0 |
C6—C5—C7 | 120.3 (3) | C10'—C9'—H9'1 | 109.0 |
C4—C5—C7 | 122.8 (3) | C8'—C9'—H9'2 | 109.0 |
N1—C6—C5 | 123.7 (3) | C10'—C9'—H9'2 | 109.0 |
N1—C6—H6 | 118.1 | H9'1—C9'—H9'2 | 107.8 |
C5—C6—H6 | 118.1 | C9'—C10'—H10D | 109.5 |
O2—C1—O1 | 125.4 (3) | C9'—C10'—H10E | 109.5 |
O2—C1—C2 | 118.3 (2) | H10D—C10'—H10E | 109.5 |
O1—C1—C2 | 116.3 (2) | C9'—C10'—H10F | 109.5 |
C5—C7—C8 | 113.2 (3) | H10D—C10'—H10F | 109.5 |
C5—C7—C8' | 110.1 (5) | H10E—C10'—H10F | 109.5 |
C5—C7—H7A | 108.9 |
Symmetry code: (i) −x+1, −y+1, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1W1···O2W | 0.85 (3) | 2.04 (2) | 2.784 (3) | 147 (3) |
O1W—H1W2···O1ii | 0.85 (3) | 1.92 (2) | 2.760 (3) | 179 (4) |
O2W—H2W2···O2ii | 0.85 (3) | 1.94 (2) | 2.792 (3) | 177 (4) |
O2W—H2W1···O2iii | 0.85 (3) | 2.08 (2) | 2.893 (3) | 160 (3) |
Symmetry codes: (ii) x+1, y, z; (iii) −x+1, −y, −z+1. |
Experimental details
Crystal data | |
Chemical formula | [Ni(C10H13NO2)2(H2O)2]·2H2O |
Mr | 487.19 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 293 |
a, b, c (Å) | 5.2217 (10), 9.9614 (17), 11.5070 (19) |
α, β, γ (°) | 79.378 (3), 79.191 (3), 80.152 (3) |
V (Å3) | 572.05 (17) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 0.90 |
Crystal size (mm) | 0.16 × 0.15 × 0.09 |
Data collection | |
Diffractometer | Bruker APEX area-detector |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.870, 0.924 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3673, 2022, 1747 |
Rint | 0.027 |
(sin θ/λ)max (Å−1) | 0.599 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.105, 1.06 |
No. of reflections | 2022 |
No. of parameters | 176 |
No. of restraints | 48 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.43, −0.45 |
Computer programs: SMART (Bruker, 2004), SAINT (Bruker, 2004), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), X-SEED (Barbour, 2001), publCIF (Westrip, 2007).
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1W1···O2W | 0.85 (3) | 2.04 (2) | 2.784 (3) | 147 (3) |
O1W—H1W2···O1i | 0.85 (3) | 1.92 (2) | 2.760 (3) | 179 (4) |
O2W—H2W2···O2i | 0.85 (3) | 1.94 (2) | 2.792 (3) | 177 (4) |
O2W—H2W1···O2ii | 0.85 (3) | 2.08 (2) | 2.893 (3) | 160 (3) |
Symmetry codes: (i) x+1, y, z; (ii) −x+1, −y, −z+1. |
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5-Butyl-pyridyl-2-carboxylic acid (fusaric acid), unlike the parent unsubstituted carboxylic acid that affords a large number of N,O-chelated metal derivates, forms only three metal carboxylates that have been characterized by crystallography (Fan et al., 2007; He et al., 2007). The aquacadmium derivative (Okabe, Wada & Muranishi, 2002) has two chelating carboxylate groups. The sixth coordination site is taken up by a carboxyl oxygen atom from an adjacent molecule; the water and carboxyl oxygen atoms are cis to each other. The copper derivative has two coordinated methanol molecules whereas the iron(III) derivative is a tris-chelated compound; (Okabe, Muranishi & Wada, 2002). The metal atom in the title nickel(II) derivative (I) (Fig. 1) lies on an inversion center, and presents two coordinated water molecules in the octahedral environment, the remaining sites being occupied by two chelating alky-substituted 2-pyridylcarboxylate groups (Table 1); the coordinated water and the lattice water molecules engage in hydrogen bonding (Table 2) with the carboxyl group to furnish a two-dimensional network motif parallel to (001) (Fig. 2).