Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104031178/jz1676sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270104031178/jz1676Isup2.hkl |
CCDC reference: 268077
HP was dissolved in aqueous ammonia and refluxed for 2 h. Upon complete dissolution of the solid, the solvent was evaporated under vacuum to dryness. The residue was redissolved in methanol, and copper(II) acetate in methanol at a 2:1 molar ratio was added with vigorous stirring at 333 K. After stirring at this temperature for 2 h, the mixture was filtered and the deep-blue filtrate was left to stand, allowing slow evaporation of the solvent at room temperature. Finally, blue crystals of (I) were obtained by repeated recrystallization from acetonitrile at room temperature. Analysis calculated for C12H12CuN2O8: C 38.36, H 3.22, N 7.46%; found: C 38.40, H 3.32, N 7.47%. IR (KBr pellet, cm−1): 3420 (b), 3093 (m), 2792 (sh), 2597 (sh), 1666 (s), 1617.(versus), 1575 (s), 1394 (s), 1319 (versus), 1253 (s), 1149 (m), 1070 (w), 1018 (m), 827 (s), 746 (s), 554 (m), 431 (m). EPR (77.0 K): g1 = 2.26, g2 = 2.07 and g3 = 2.01.
The three aromatic H atoms were refined using a riding model [with C—H = 0.93 Å and Uiso(H) = 1.2Ueq(C)]. The O-bound H atoms were refined freely.
Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-RED (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1998).
Fig. 1. The title compound (I), with displacement ellipsoids shown at the 40% probability level. | |
Fig. 2. A packing diagram for (I). Hydrogen bonds are indicated by dashed lines. |
[Cu(C6H4NO3)2(H2O)2] | Z = 1 |
Mr = 375.78 | F(000) = 191 |
Triclinic, P1 | Dx = 1.830 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 6.1036 (8) Å | Cell parameters from 7424 reflections |
b = 7.2946 (11) Å | θ = 2.4–27.2° |
c = 8.5571 (13) Å | µ = 1.65 mm−1 |
α = 99.605 (12)° | T = 296 K |
β = 92.776 (12)° | Prism, blue |
γ = 113.758 (11)° | 0.24 × 0.18 × 0.14 mm |
V = 340.98 (9) Å3 |
Stoe IPDS-II diffractometer | 1341 independent reflections |
Radiation source: fine-focus sealed tube | 1190 reflections with I > 2σ(I) |
Plane graphite monochromator | Rint = 0.057 |
Detector resolution: 6.67 pixels mm-1 | θmax = 26.0°, θmin = 2.4° |
rotation method scans | h = −7→7 |
Absorption correction: integration (X-RED; Stoe & Cie, 2002) | k = −8→8 |
Tmin = 0.726, Tmax = 0.826 | l = −10→10 |
5001 measured reflections |
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)] = 0.029 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.071 | H atoms treated by a mixture of independent and constrained refinement |
S = 0.99 | w = 1/[σ2(Fo2) + (0.0439P)2] where P = (Fo2 + 2Fc2)/3 |
1341 reflections | (Δ/σ)max < 0.001 |
118 parameters | Δρmax = 0.38 e Å−3 |
0 restraints | Δρmin = −0.35 e Å−3 |
[Cu(C6H4NO3)2(H2O)2] | γ = 113.758 (11)° |
Mr = 375.78 | V = 340.98 (9) Å3 |
Triclinic, P1 | Z = 1 |
a = 6.1036 (8) Å | Mo Kα radiation |
b = 7.2946 (11) Å | µ = 1.65 mm−1 |
c = 8.5571 (13) Å | T = 296 K |
α = 99.605 (12)° | 0.24 × 0.18 × 0.14 mm |
β = 92.776 (12)° |
Stoe IPDS-II diffractometer | 1341 independent reflections |
Absorption correction: integration (X-RED; Stoe & Cie, 2002) | 1190 reflections with I > 2σ(I) |
Tmin = 0.726, Tmax = 0.826 | Rint = 0.057 |
5001 measured reflections |
R[F2 > 2σ(F2)] = 0.029 | 0 restraints |
wR(F2) = 0.071 | H atoms treated by a mixture of independent and constrained refinement |
S = 0.99 | Δρmax = 0.38 e Å−3 |
1341 reflections | Δρmin = −0.35 e Å−3 |
118 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 | ||
C1 | 0.7474 (4) | 0.7411 (3) | 0.2894 (3) | 0.0343 (5) | |
C2 | 0.8042 (5) | 0.8426 (4) | 0.1671 (3) | 0.0444 (6) | |
H2 | 0.9631 | 0.9288 | 0.1607 | 0.053* | |
C3 | 0.6181 (5) | 0.8143 (4) | 0.0516 (3) | 0.0485 (6) | |
H3 | 0.6518 | 0.8828 | −0.0327 | 0.058* | |
C4 | 0.3873 (5) | 0.6863 (4) | 0.0628 (3) | 0.0450 (6) | |
H4 | 0.2620 | 0.6656 | −0.0139 | 0.054* | |
C5 | 0.3411 (4) | 0.5863 (4) | 0.1911 (3) | 0.0366 (5) | |
C7 | 0.9332 (4) | 0.7592 (3) | 0.4209 (3) | 0.0360 (5) | |
N1 | 0.5188 (3) | 0.6149 (3) | 0.3029 (2) | 0.0332 (4) | |
O1 | 0.8470 (3) | 0.6545 (3) | 0.5285 (2) | 0.0425 (4) | |
O2 | 1.1468 (3) | 0.8652 (3) | 0.4215 (2) | 0.0470 (4) | |
O3 | 0.1154 (3) | 0.4588 (3) | 0.1990 (2) | 0.0488 (4) | |
O4 | 0.4596 (4) | 0.8038 (3) | 0.6540 (2) | 0.0494 (5) | |
Cu1 | 0.5000 | 0.5000 | 0.5000 | 0.03532 (16) | |
H1A | 0.361 (7) | 0.810 (6) | 0.598 (5) | 0.089 (15)* | |
H1B | 0.572 (6) | 0.893 (5) | 0.645 (4) | 0.058 (10)* | |
H3A | 0.112 (5) | 0.418 (4) | 0.277 (3) | 0.035 (7)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0315 (11) | 0.0350 (12) | 0.0364 (11) | 0.0144 (10) | 0.0047 (9) | 0.0061 (9) |
C2 | 0.0403 (13) | 0.0443 (13) | 0.0478 (14) | 0.0130 (11) | 0.0113 (11) | 0.0177 (11) |
C3 | 0.0562 (16) | 0.0535 (15) | 0.0413 (13) | 0.0230 (13) | 0.0123 (12) | 0.0221 (11) |
C4 | 0.0484 (14) | 0.0532 (14) | 0.0361 (12) | 0.0240 (12) | −0.0020 (10) | 0.0112 (10) |
C5 | 0.0349 (12) | 0.0387 (12) | 0.0350 (11) | 0.0156 (10) | −0.0004 (9) | 0.0051 (9) |
C7 | 0.0293 (11) | 0.0343 (11) | 0.0431 (12) | 0.0129 (10) | 0.0042 (9) | 0.0053 (9) |
N1 | 0.0294 (9) | 0.0345 (9) | 0.0337 (9) | 0.0120 (8) | 0.0017 (7) | 0.0061 (7) |
O1 | 0.0291 (8) | 0.0486 (9) | 0.0453 (9) | 0.0095 (7) | −0.0007 (7) | 0.0165 (7) |
O2 | 0.0295 (9) | 0.0473 (10) | 0.0598 (11) | 0.0098 (8) | 0.0060 (8) | 0.0156 (8) |
O3 | 0.0335 (9) | 0.0597 (11) | 0.0448 (10) | 0.0098 (8) | −0.0061 (7) | 0.0173 (9) |
O4 | 0.0474 (11) | 0.0452 (11) | 0.0539 (11) | 0.0157 (10) | 0.0072 (10) | 0.0149 (9) |
Cu1 | 0.0246 (2) | 0.0405 (3) | 0.0360 (2) | 0.00662 (17) | 0.00005 (15) | 0.01435 (16) |
C1—N1 | 1.351 (3) | C7—O2 | 1.218 (3) |
C1—C2 | 1.360 (3) | C7—O1 | 1.290 (3) |
C1—C7 | 1.509 (3) | N1—Cu1 | 1.9931 (18) |
C2—C3 | 1.393 (4) | O1—Cu1 | 1.9364 (16) |
C2—H2 | 0.9300 | O3—H3A | 0.78 (3) |
C3—C4 | 1.360 (4) | O4—Cu1 | 2.491 (2) |
C3—H3 | 0.9300 | O4—H1A | 0.77 (4) |
C4—C5 | 1.396 (3) | O4—H1B | 0.75 (4) |
C4—H4 | 0.9300 | Cu1—O1i | 1.9364 (16) |
C5—O3 | 1.328 (3) | Cu1—N1i | 1.9931 (18) |
C5—N1 | 1.336 (3) | ||
N1—C1—C2 | 122.6 (2) | C5—N1—C1 | 118.94 (19) |
N1—C1—C7 | 114.29 (19) | C5—N1—Cu1 | 129.17 (15) |
C2—C1—C7 | 123.1 (2) | C1—N1—Cu1 | 111.88 (14) |
C1—C2—C3 | 118.4 (2) | C7—O1—Cu1 | 115.89 (14) |
C1—C2—H2 | 120.8 | C5—O3—H3A | 108.5 (19) |
C3—C2—H2 | 120.8 | Cu1—O4—H1A | 101 (3) |
C4—C3—C2 | 119.8 (2) | Cu1—O4—H1B | 105 (2) |
C4—C3—H3 | 120.1 | H1A—O4—H1B | 104 (4) |
C2—C3—H3 | 120.1 | O1i—Cu1—O1 | 180.0 |
C3—C4—C5 | 119.1 (2) | O1i—Cu1—N1 | 96.91 (7) |
C3—C4—H4 | 120.5 | O1—Cu1—N1 | 83.09 (7) |
C5—C4—H4 | 120.5 | O1i—Cu1—N1i | 83.09 (7) |
O3—C5—N1 | 120.3 (2) | O1—Cu1—N1i | 96.91 (7) |
O3—C5—C4 | 118.4 (2) | N1—Cu1—N1i | 180.000 (1) |
N1—C5—C4 | 121.3 (2) | O1i—Cu1—O4 | 90.57 (8) |
O2—C7—O1 | 124.2 (2) | O1—Cu1—O4 | 89.43 (8) |
O2—C7—C1 | 121.0 (2) | N1—Cu1—O4 | 89.99 (7) |
O1—C7—C1 | 114.81 (19) | N1i—Cu1—O4 | 90.01 (7) |
N1—C1—C2—C3 | −0.1 (4) | C7—C1—N1—C5 | −179.13 (18) |
C7—C1—C2—C3 | 179.9 (2) | C2—C1—N1—Cu1 | −177.92 (18) |
C1—C2—C3—C4 | −0.5 (4) | C7—C1—N1—Cu1 | 2.1 (2) |
C2—C3—C4—C5 | 0.4 (4) | O2—C7—O1—Cu1 | 179.65 (18) |
C3—C4—C5—O3 | −178.8 (2) | C1—C7—O1—Cu1 | −0.7 (2) |
C3—C4—C5—N1 | 0.3 (4) | C7—O1—Cu1—N1 | 1.47 (16) |
N1—C1—C7—O2 | 178.7 (2) | C7—O1—Cu1—N1i | −178.53 (16) |
C2—C1—C7—O2 | −1.3 (3) | C7—O1—Cu1—O4 | −88.59 (16) |
N1—C1—C7—O1 | −1.0 (3) | C5—N1—Cu1—O1i | −0.6 (2) |
C2—C1—C7—O1 | 179.0 (2) | C1—N1—Cu1—O1i | 178.04 (14) |
O3—C5—N1—C1 | 178.17 (19) | C5—N1—Cu1—O1 | 179.4 (2) |
C4—C5—N1—C1 | −1.0 (3) | C1—N1—Cu1—O1 | −1.96 (14) |
O3—C5—N1—Cu1 | −3.3 (3) | C5—N1—Cu1—O4 | −91.1 (2) |
C4—C5—N1—Cu1 | 177.56 (16) | C1—N1—Cu1—O4 | 87.47 (15) |
C2—C1—N1—C5 | 0.9 (3) |
Symmetry code: (i) −x+1, −y+1, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3A···O1i | 0.78 (3) | 1.86 (3) | 2.631 (2) | 172 (3) |
O4—H1A···O2ii | 0.77 (4) | 2.14 (4) | 2.902 (3) | 168 (4) |
O4—H1B···O2iii | 0.75 (4) | 2.09 (4) | 2.831 (3) | 169 (4) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x−1, y, z; (iii) −x+2, −y+2, −z+1. |
Experimental details
Crystal data | |
Chemical formula | [Cu(C6H4NO3)2(H2O)2] |
Mr | 375.78 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 296 |
a, b, c (Å) | 6.1036 (8), 7.2946 (11), 8.5571 (13) |
α, β, γ (°) | 99.605 (12), 92.776 (12), 113.758 (11) |
V (Å3) | 340.98 (9) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 1.65 |
Crystal size (mm) | 0.24 × 0.18 × 0.14 |
Data collection | |
Diffractometer | Stoe IPDS-II diffractometer |
Absorption correction | Integration (X-RED; Stoe & Cie, 2002) |
Tmin, Tmax | 0.726, 0.826 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 5001, 1341, 1190 |
Rint | 0.057 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.029, 0.071, 0.99 |
No. of reflections | 1341 |
No. of parameters | 118 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.38, −0.35 |
Computer programs: X-AREA (Stoe & Cie, 2002), X-AREA, X-RED (Stoe & Cie, 2002), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1998).
C5—O3 | 1.328 (3) | N1—Cu1 | 1.9931 (18) |
C7—O2 | 1.218 (3) | O1—Cu1 | 1.9364 (16) |
C7—O1 | 1.290 (3) | O4—Cu1 | 2.491 (2) |
O3—C5—N1 | 120.3 (2) | O1—Cu1—N1 | 83.09 (7) |
O2—C7—O1 | 124.2 (2) | O1i—Cu1—O4 | 90.57 (8) |
O2—C7—C1 | 121.0 (2) | O1—Cu1—O4 | 89.43 (8) |
O1—C7—C1 | 114.81 (19) | N1—Cu1—O4 | 89.99 (7) |
N1—C1—C7—O2 | 178.7 (2) | N1—C1—C7—O1 | −1.0 (3) |
Symmetry code: (i) −x+1, −y+1, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
O3—H3A···O1i | 0.78 (3) | 1.86 (3) | 2.631 (2) | 172 (3) |
O4—H1A···O2ii | 0.77 (4) | 2.14 (4) | 2.902 (3) | 168 (4) |
O4—H1B···O2iii | 0.75 (4) | 2.09 (4) | 2.831 (3) | 169 (4) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x−1, y, z; (iii) −x+2, −y+2, −z+1. |
Copper complexes play an important role in catalyzing enzymatic activity, and much attention has been paid to copper complexes of organic acids because of their special biocatalytic functions (Hong et al., 2002). Recently, considerable attention has been paid to the complexes of hydroxypicolinates, which pose structural ambiguities since they display a number of possible bonding modes (Constantino et al., 1994; Gatto et al., 1998). It is well known that the incorporation of carboxylic acid groups into coordination compounds gives interesting supramolecular architectures (Puddephatt et al., 2002). The 6-hydroxypicolinate ligand (HP) is a potential chelate with interesting possibilities, exhibiting either N,O-chelation (through the pyridine N atom and the carboxylate group, forming a five-membered chelate ring) (Nogueira et al., 2000) or N,O,O-chelation (through the pyridine N atom and the carboxylate group, and further through the deprotonated hydroxy group as a bridging ligand). The latter coordination mode was reported for [Mn2(µ-O)(C6H3NO3)2(py)4]·H2O by Takayoshi et al. (2004). Owing to the inherent coordination and hydrogen-bonding donor/acceptor functionalities, this dimanganese complex formed a three-dimensional structure. To the best of our knowledge, the crystal structures of no metal complexes with the HP ligand, other than those with dimanganese (see above), have been reported to date, although there are several crystal structures of complexes with analogous ligands, the 2-, 3- and 4-hydroxy derivatives (Nogueira et al., 2000). We report here our efforts to establish the preferred coordination mode of HP to copper(II) in the structure of the title compound, (I).
An ORTEP-3 (Farrugia, 1997) view of (I) and a packing diagram are shown in Figs. 1 and 2, respectively and selected bond lengths and angles are shown in Table 1. Compound (I) displays a distorted octahedral coordination geometry, with the metal ion at a centre of inversion. The two bidentate ligands are necessarily trans to one another, and coordinate to the central metal ion through the pyridine N atoms and the carboxylate O atoms, to form a five-membered ring in the equatorial plane. Two O atoms of the aqua ligands complete the octahedron at the axial positions.
The coordination bond length in the axial direction [Cu1—O4 = 2.491 (2) Å] is longer than those in the equatorial plane [Cu1—O1 1.9364 (16) Å and Cu1—N1 1.9931 (18) Å]. Similar behavior is found for the complex trans-bis(5-n-butylpyridine-2-carboxylato-κ2N,O)-bis(methanol-KO)copper(II), in which the bond lengths in the equatorial plane are 2.596 (3) and 1.952 (2) Å, respectively (Okabe et al., 2002), and for hydrated bis(pyridine-2-carboxylato)copper(II) [2.752 (2) and 1.940 (2) Å, respectively; Faure et al., 1973]. These long bonds in the axial direction, compared with those in the equatorial plane, are usually observed in copper complexes of octahedral coordination geometry and are usually explained by a Jahn–Teller effect. This agrees with the EPR spectrum of the title compound, which resembles those of the analogously distorted octhahedral CuII complexes (Hathaway et al., 1970).
As shown in Table 1, the Cu1—O1 distance is slightly shorter than the Cu1—N1 distance. This effect is usually observed for the metal complexes of analogous compounds, such as bis(µ-6-hydroxypicolinato)-µ-oxo-bis[dipyridinemanganese(III)] monohydrate [Mn1—O2eq = 1.939 (2) Å and Mn1—N1 = 2.094 (2) Å; Takayoshi et al., 2004], 5-n-butylpyridine-2-carboxylate-copper(II) [Cu—Oeq = 1.952 (2) Å and Cu—N = 1.977 (2) Å; Okabe et al., 2002] and trans-bis(isoquinoline-3-carboxylato-κ2N,O)bis(methanol-κO) copper(II) [Cu—Oeq = 1.963 (2) Å and Cu—N 1.979 (2) Å; Okabe et al., 2004]. In the title compound, the angles around the Cu atom are slightly distorted from ideal octahedral [O1—Cu1—N1 = 83.07 (7)°]. Similar bond angles are observed in some related metal complexes, such as trans-bis(isoquinoline-3-carboxylato-κ2N,O)bis(methanol-κO)copper(II) [O—Cu—N = 83.77 (7)°; Okabe et al., 2004] and trans-diaqua-bis-(3-hydroxypicolinato)zinc(II) [O—Zn—N = 79.3 (1)°; Bombi et al., 2004].
The molecular packing of (I) is shown in Fig. 2. The intramolecular hydrogen bonds, O3—H3A···O1i (Table 2) between carbonyl and the hydroxy groups of the bidenate ligands reinforce the planarity of the equatorial groupings. The water molecules coordinated to the Cu atom in the apical position participate in two hydrogen bonds, O4—H1A···O2ii and O4—H1B···O2iii, which link the layers to form a three-dimensional structure (Fig. 2).