The title dinuclear CuII complex, [Cu2(C7H8NO2)2(C7H9NO2)2](CH3COO)2, has been synthesized by the reaction of Cu(CH3COO)2·H2O with pdmH2 (pdmH2 is pyridine-2,6-diyldimethanol) in the presence of tetrabutylammonium hydroxide. The title complex contains a centrosymmetric Cu2O2 core and each CuII atom has distorted octahedral geometry. Molecular [Cu2(pdmH)2(pdmH2)]2+ cations are connected by hydrogen bonds involving the CH3COO− anions, forming one-dimensional chains along the a axis.
Supporting information
CCDC reference: 217122
To a green solution of Cu(CH3COO)2·H2O (0.3254 g, 1.63 mmol) in acetonitrile (30 ml), pdmH2 (0.56 g, 4 mmol) was added. The reaction mixture was stirred continuously, and then a solution of n-Bu4NOH (0.4 ml, 1.0 mol) in methanol was added dropwise, causing the color of the solution to change to bright blue. The solution was stirred for 4 h, then filtered and concentrated under reduced pressure. The resulting green solution was treated with hexane to afford a crystalline solid. Recrystallization from dichloromethane–hexane solution gave single crystals suitable for X-ray analysis. Analysis found: C 48.7, H 5.09, N 7.14%; C32H40Cu2N4O12 requires: C 48.1, H 5.04, N 7.00%.
All H atoms were introduced at calculated positions as riding atoms, with bond lengths of 0.93 (CH), 0.96 (CH3) and 0.82 Å (OH) and displacement parameters equal to 1.2 (CH and OH) or 1.5 (CH3) times that of the parent atom.
Data collection: MACH3 (Nonius, 1996); cell refinement: CELDIM (Nonius, 1996); data reduction: XCAD4 (Harms & Wocadlo, 1995); 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, 1999).
Crystal data top
[Cu2(C7H8NO2)2(C7H9NO2)2](C2H3O2)2 | F(000) = 828 |
Mr = 799.76 | Dx = 1.590 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 25 reflections |
a = 10.252 (1) Å | θ = 19.9–31.3° |
b = 12.1310 (7) Å | µ = 1.34 mm−1 |
c = 14.2226 (8) Å | T = 296 K |
β = 109.150 (5)° | Plate, green |
V = 1671.0 (2) Å3 | 0.25 × 0.20 × 0.11 mm |
Z = 2 | |
Data collection top
Enraf–Nonius CAD4 diffractometer | 2427 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.045 |
Graphite monochromator | θmax = 25.0°, θmin = 2.2° |
θ/2θ scans | h = −12→11 |
Absorption correction: ϕ-scan (PSISCANS; North et al., 1968) | k = 0→14 |
Tmin = 0.761, Tmax = 0.883 | l = 0→16 |
3061 measured reflections | 3 standard reflections every 200 reflections |
2938 independent reflections | intensity decay: none |
Refinement top
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)] = 0.033 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.096 | H-atom parameters constrained |
S = 1.07 | w = 1/[σ2(Fo2) + (0.0497P)2 + 1.3695P] where P = (Fo2 + 2Fc2)/3 |
2938 reflections | (Δ/σ)max < 0.001 |
227 parameters | Δρmax = 0.34 e Å−3 |
0 restraints | Δρmin = −0.39 e Å−3 |
Crystal data top
[Cu2(C7H8NO2)2(C7H9NO2)2](C2H3O2)2 | V = 1671.0 (2) Å3 |
Mr = 799.76 | Z = 2 |
Monoclinic, P21/n | Mo Kα radiation |
a = 10.252 (1) Å | µ = 1.34 mm−1 |
b = 12.1310 (7) Å | T = 296 K |
c = 14.2226 (8) Å | 0.25 × 0.20 × 0.11 mm |
β = 109.150 (5)° | |
Data collection top
Enraf–Nonius CAD4 diffractometer | 2427 reflections with I > 2σ(I) |
Absorption correction: ϕ-scan (PSISCANS; North et al., 1968) | Rint = 0.045 |
Tmin = 0.761, Tmax = 0.883 | 3 standard reflections every 200 reflections |
3061 measured reflections | intensity decay: none |
2938 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.033 | 0 restraints |
wR(F2) = 0.096 | H-atom parameters constrained |
S = 1.07 | Δρmax = 0.34 e Å−3 |
2938 reflections | Δρmin = −0.39 e Å−3 |
227 parameters | |
Special details top
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 (Å2) top | x | y | z | Uiso*/Ueq | |
Cu1 | 0.12725 (4) | 0.06953 (3) | 0.01222 (2) | 0.03014 (13) | |
N1 | 0.2848 (2) | 0.1092 (2) | 0.13593 (17) | 0.0301 (5) | |
N2 | 0.1721 (2) | 0.1286 (2) | −0.11208 (17) | 0.0317 (5) | |
O1 | 0.2989 (3) | −0.06113 (19) | 0.01535 (17) | 0.0479 (6) | |
H51 | 0.2726 | −0.1254 | 0.0103 | 0.058* | |
O2 | 0.0749 (2) | 0.2476 (2) | 0.05630 (16) | 0.0435 (6) | |
H52 | −0.0068 | 0.2633 | 0.0440 | 0.052* | |
O3 | −0.0311 (2) | 0.0142 (2) | −0.08976 (14) | 0.0412 (5) | |
O4 | 0.3993 (3) | 0.3664 (2) | −0.0467 (2) | 0.0552 (7) | |
H54 | 0.4584 | 0.3571 | −0.0733 | 0.066* | |
C1 | 0.3950 (3) | 0.0425 (3) | 0.1678 (2) | 0.0356 (7) | |
C2 | 0.4949 (4) | 0.0578 (3) | 0.2603 (3) | 0.0483 (9) | |
H2 | 0.5707 | 0.0109 | 0.2815 | 0.058* | |
C3 | 0.4809 (4) | 0.1428 (3) | 0.3202 (2) | 0.0498 (9) | |
H3 | 0.5462 | 0.1531 | 0.3827 | 0.060* | |
C4 | 0.3698 (3) | 0.2121 (3) | 0.2868 (2) | 0.0410 (8) | |
H4 | 0.3598 | 0.2712 | 0.3256 | 0.049* | |
C5 | 0.2722 (3) | 0.1928 (2) | 0.1939 (2) | 0.0325 (6) | |
C6 | 0.4126 (4) | −0.0490 (3) | 0.1018 (3) | 0.0485 (9) | |
H6A | 0.4941 | −0.0345 | 0.0834 | 0.058* | |
H6B | 0.4276 | −0.1176 | 0.1388 | 0.058* | |
C7 | 0.1464 (3) | 0.2655 (3) | 0.1581 (2) | 0.0410 (8) | |
H7A | 0.0856 | 0.2500 | 0.1963 | 0.049* | |
H7B | 0.1742 | 0.3421 | 0.1685 | 0.049* | |
C8 | 0.0922 (3) | 0.0758 (3) | −0.1937 (2) | 0.0379 (7) | |
C9 | 0.0992 (4) | 0.0977 (3) | −0.2883 (2) | 0.0518 (9) | |
H9 | 0.0433 | 0.0601 | −0.3440 | 0.062* | |
C10 | 0.1909 (4) | 0.1763 (4) | −0.2969 (3) | 0.0586 (10) | |
H10 | 0.1977 | 0.1927 | −0.3590 | 0.070* | |
C11 | 0.2719 (4) | 0.2304 (3) | −0.2145 (3) | 0.0489 (9) | |
H11 | 0.3334 | 0.2842 | −0.2204 | 0.059* | |
C12 | 0.2624 (3) | 0.2051 (3) | −0.1220 (2) | 0.0347 (7) | |
C13 | −0.0081 (4) | −0.0065 (3) | −0.1791 (2) | 0.0473 (9) | |
H13A | −0.0945 | −0.0017 | −0.2337 | 0.057* | |
H13B | 0.0285 | −0.0804 | −0.1783 | 0.057* | |
C14 | 0.3485 (3) | 0.2634 (3) | −0.0290 (2) | 0.0423 (8) | |
H14A | 0.2932 | 0.2740 | 0.0141 | 0.051* | |
H14B | 0.4260 | 0.2166 | 0.0061 | 0.051* | |
C15 | 0.7356 (3) | 0.3387 (3) | −0.0439 (2) | 0.0391 (7) | |
C16 | 0.7937 (4) | 0.4523 (3) | −0.0255 (3) | 0.0593 (10) | |
H16A | 0.7842 | 0.4873 | −0.0880 | 0.089* | |
H16B | 0.8897 | 0.4485 | 0.0137 | 0.089* | |
H16C | 0.7448 | 0.4941 | 0.0095 | 0.089* | |
O5 | 0.8080 (2) | 0.2609 (2) | 0.00571 (18) | 0.0466 (6) | |
O6 | 0.6187 (2) | 0.3253 (2) | −0.10525 (19) | 0.0561 (7) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cu1 | 0.0313 (2) | 0.0350 (2) | 0.02149 (19) | −0.00561 (16) | 0.00519 (14) | −0.00086 (15) |
N1 | 0.0312 (13) | 0.0322 (13) | 0.0257 (12) | −0.0046 (11) | 0.0075 (10) | −0.0001 (10) |
N2 | 0.0329 (13) | 0.0358 (14) | 0.0274 (12) | 0.0047 (11) | 0.0110 (10) | 0.0024 (11) |
O1 | 0.0580 (15) | 0.0382 (13) | 0.0407 (13) | 0.0062 (11) | 0.0066 (11) | −0.0033 (10) |
O2 | 0.0386 (12) | 0.0558 (15) | 0.0341 (12) | 0.0096 (11) | 0.0093 (10) | −0.0002 (10) |
O3 | 0.0449 (12) | 0.0550 (14) | 0.0211 (10) | −0.0175 (11) | 0.0073 (9) | −0.0028 (10) |
O4 | 0.0607 (16) | 0.0444 (14) | 0.0710 (17) | −0.0090 (12) | 0.0360 (14) | −0.0033 (13) |
C1 | 0.0311 (15) | 0.0391 (17) | 0.0330 (16) | −0.0044 (13) | 0.0056 (12) | 0.0042 (13) |
C2 | 0.0373 (18) | 0.058 (2) | 0.0408 (19) | −0.0013 (16) | 0.0003 (14) | 0.0059 (17) |
C3 | 0.0435 (19) | 0.064 (2) | 0.0312 (17) | −0.0178 (18) | −0.0024 (14) | 0.0030 (17) |
C4 | 0.0477 (19) | 0.0468 (19) | 0.0266 (15) | −0.0151 (16) | 0.0096 (14) | −0.0061 (14) |
C5 | 0.0359 (16) | 0.0333 (16) | 0.0296 (15) | −0.0099 (13) | 0.0128 (12) | −0.0002 (12) |
C6 | 0.0406 (18) | 0.046 (2) | 0.050 (2) | 0.0051 (15) | 0.0029 (15) | −0.0026 (16) |
C7 | 0.0488 (19) | 0.0374 (18) | 0.0333 (16) | −0.0034 (15) | 0.0085 (14) | −0.0079 (14) |
C8 | 0.0461 (18) | 0.0413 (18) | 0.0279 (15) | 0.0023 (15) | 0.0144 (13) | −0.0007 (13) |
C9 | 0.064 (2) | 0.068 (3) | 0.0259 (16) | −0.0087 (19) | 0.0174 (16) | −0.0037 (16) |
C10 | 0.070 (3) | 0.078 (3) | 0.038 (2) | 0.000 (2) | 0.0322 (19) | 0.0087 (19) |
C11 | 0.051 (2) | 0.059 (2) | 0.0446 (19) | −0.0023 (18) | 0.0263 (16) | 0.0084 (17) |
C12 | 0.0338 (15) | 0.0385 (17) | 0.0346 (16) | 0.0053 (13) | 0.0150 (13) | 0.0050 (13) |
C13 | 0.059 (2) | 0.055 (2) | 0.0287 (16) | −0.0155 (18) | 0.0148 (15) | −0.0080 (15) |
C14 | 0.0389 (18) | 0.0459 (19) | 0.0447 (19) | −0.0055 (15) | 0.0172 (15) | 0.0030 (15) |
C15 | 0.0348 (17) | 0.050 (2) | 0.0370 (17) | 0.0079 (15) | 0.0185 (14) | −0.0022 (15) |
C16 | 0.063 (3) | 0.045 (2) | 0.065 (3) | −0.0003 (18) | 0.016 (2) | −0.0053 (18) |
O5 | 0.0427 (13) | 0.0450 (14) | 0.0505 (14) | 0.0032 (11) | 0.0128 (11) | 0.0034 (11) |
O6 | 0.0366 (13) | 0.0680 (18) | 0.0581 (16) | 0.0016 (12) | 0.0078 (12) | −0.0018 (13) |
Geometric parameters (Å, º) top
Cu1—O3 | 1.909 (2) | C4—C5 | 1.391 (4) |
Cu1—O3i | 1.983 (2) | C4—H4 | 0.9300 |
Cu1—N1 | 2.018 (2) | C5—C7 | 1.506 (4) |
Cu1—N2 | 2.094 (2) | C6—H6A | 0.9700 |
Cu1—O1 | 2.358 (2) | C6—H6B | 0.9700 |
Cu1—O2 | 2.360 (2) | C7—H7A | 0.9700 |
Cu1—Cu1i | 3.0298 (7) | C7—H7B | 0.9700 |
N1—C5 | 1.340 (4) | C8—C9 | 1.396 (4) |
N1—C1 | 1.341 (4) | C8—C13 | 1.496 (5) |
N2—C8 | 1.343 (4) | C9—C10 | 1.372 (5) |
N2—C12 | 1.351 (4) | C9—H9 | 0.9300 |
O1—C6 | 1.397 (4) | C10—C11 | 1.361 (5) |
O1—O5ii | 2.636 (3) | C10—H10 | 0.9300 |
O1—H51 | 0.8200 | C11—C12 | 1.385 (5) |
O2—C7 | 1.408 (4) | C11—H11 | 0.9300 |
O2—O5iii | 2.596 (3) | C12—C14 | 1.504 (4) |
O2—H52 | 0.8200 | C13—H13A | 0.9700 |
O3—C13 | 1.389 (4) | C13—H13B | 0.9700 |
O3—Cu1i | 1.983 (2) | C14—H14A | 0.9700 |
O4—C14 | 1.408 (4) | C14—H14B | 0.9700 |
O4—O6 | 2.689 (4) | C15—O6 | 1.240 (4) |
O4—H54 | 0.8200 | C15—O5 | 1.264 (4) |
C1—C2 | 1.390 (4) | C15—C16 | 1.489 (5) |
C1—C6 | 1.502 (5) | C16—H16A | 0.9600 |
C2—C3 | 1.375 (5) | C16—H16B | 0.9600 |
C2—H2 | 0.9300 | C16—H16C | 0.9600 |
C3—C4 | 1.369 (5) | O6—H54 | 1.8839 |
C3—H3 | 0.9300 | | |
| | | |
O3—Cu1—O3i | 77.79 (9) | C5—C4—H4 | 120.5 |
O3—Cu1—N1 | 169.80 (9) | N1—C5—C4 | 121.8 (3) |
O3i—Cu1—N1 | 92.23 (9) | N1—C5—C7 | 118.7 (3) |
O3—Cu1—N2 | 81.17 (9) | C4—C5—C7 | 119.5 (3) |
O3i—Cu1—N2 | 158.71 (9) | O1—C6—C1 | 113.0 (3) |
N1—Cu1—N2 | 108.7 (1) | O1—C6—H6A | 109.0 |
O3—Cu1—O1 | 102.8 (1) | C1—C6—H6A | 109.0 |
O3i—Cu1—O1 | 98.6 (1) | O1—C6—H6B | 109.0 |
N1—Cu1—O1 | 76.39 (9) | C1—C6—H6B | 109.0 |
N2—Cu1—O1 | 82.91 (9) | H6A—C6—H6B | 107.8 |
O3—Cu1—O2 | 108.24 (9) | O2—C7—C5 | 110.9 (3) |
O3i—Cu1—O2 | 97.08 (9) | O2—C7—H7A | 109.5 |
N1—Cu1—O2 | 74.75 (9) | C5—C7—H7A | 109.5 |
N2—Cu1—O2 | 92.48 (9) | O2—C7—H7B | 109.5 |
O1—Cu1—O2 | 147.54 (8) | C5—C7—H7B | 109.5 |
O3—Cu1—Cu1i | 39.77 (6) | H7A—C7—H7B | 108.0 |
O3i—Cu1—Cu1i | 38.02 (6) | N2—C8—C9 | 122.2 (3) |
N1—Cu1—Cu1i | 130.22 (7) | N2—C8—C13 | 116.7 (3) |
N2—Cu1—Cu1i | 120.87 (7) | C9—C8—C13 | 121.1 (3) |
O1—Cu1—Cu1i | 103.72 (6) | C10—C9—C8 | 118.1 (3) |
O2—Cu1—Cu1i | 106.13 (6) | C10—C9—H9 | 121.0 |
C5—N1—C1 | 119.3 (3) | C8—C9—H9 | 121.0 |
C5—N1—Cu1 | 120.4 (2) | C11—C10—C9 | 120.1 (3) |
C1—N1—Cu1 | 119.7 (2) | C11—C10—H10 | 120.0 |
C8—N2—C12 | 118.8 (3) | C9—C10—H10 | 120.0 |
C8—N2—Cu1 | 109.1 (2) | C10—C11—C12 | 119.8 (3) |
C12—N2—Cu1 | 132.2 (2) | C10—C11—H11 | 120.1 |
C6—O1—Cu1 | 110.35 (19) | C12—C11—H11 | 120.1 |
C6—O1—O5ii | 113.1 (2) | N2—C12—C11 | 121.0 (3) |
Cu1—O1—O5ii | 109.62 (11) | N2—C12—C14 | 117.1 (3) |
C6—O1—H51 | 109.5 | C11—C12—C14 | 121.9 (3) |
Cu1—O1—H51 | 114.5 | O3—C13—C8 | 109.7 (3) |
O5ii—O1—H51 | 5.0 | O3—C13—H13A | 109.7 |
C7—O2—Cu1 | 109.09 (18) | C8—C13—H13A | 109.7 |
C7—O2—O5iii | 114.9 (2) | O3—C13—H13B | 109.7 |
Cu1—O2—O5iii | 107.11 (10) | C8—C13—H13B | 109.7 |
C7—O2—H52 | 109.5 | H13A—C13—H13B | 108.2 |
Cu1—O2—H52 | 117.5 | O4—C14—C12 | 113.8 (3) |
O5iii—O2—H52 | 10.4 | O4—C14—H14A | 108.8 |
C13—O3—Cu1 | 113.64 (19) | C12—C14—H14A | 108.8 |
C13—O3—Cu1i | 132.9 (2) | O4—C14—H14B | 108.8 |
Cu1—O3—Cu1i | 102.21 (9) | C12—C14—H14B | 108.8 |
C14—O4—O6 | 106.7 (2) | H14A—C14—H14B | 107.7 |
C14—O4—H54 | 109.5 | O6—C15—O5 | 123.4 (3) |
O6—O4—H54 | 9.0 | O6—C15—C16 | 118.9 (3) |
N1—C1—C2 | 121.1 (3) | O5—C15—C16 | 117.7 (3) |
N1—C1—C6 | 119.7 (3) | C15—C16—H16A | 109.5 |
C2—C1—C6 | 119.2 (3) | C15—C16—H16B | 109.5 |
C3—C2—C1 | 119.5 (3) | H16A—C16—H16B | 109.5 |
C3—C2—H2 | 120.2 | C15—C16—H16C | 109.5 |
C1—C2—H2 | 120.2 | H16A—C16—H16C | 109.5 |
C4—C3—C2 | 119.3 (3) | H16B—C16—H16C | 109.5 |
C4—C3—H3 | 120.3 | C15—O6—H54 | 121.4 |
C2—C3—H3 | 120.3 | C15—O6—O4 | 118.1 (2) |
C3—C4—C5 | 118.9 (3) | H54—O6—O4 | 3.9 |
C3—C4—H4 | 120.5 | | |
Symmetry codes: (i) −x, −y, −z; (ii) −x+1, −y, −z; (iii) x−1, y, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H51···O5ii | 0.82 | 1.82 | 2.636 (4) | 173 |
O2—H52···O5iii | 0.82 | 1.80 | 2.596 (4) | 165 |
O4—H54···O6 | 0.82 | 1.88 | 2.689 (4) | 167 |
Symmetry codes: (ii) −x+1, −y, −z; (iii) x−1, y, z. |
Experimental details
Crystal data |
Chemical formula | [Cu2(C7H8NO2)2(C7H9NO2)2](C2H3O2)2 |
Mr | 799.76 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 296 |
a, b, c (Å) | 10.252 (1), 12.1310 (7), 14.2226 (8) |
β (°) | 109.150 (5) |
V (Å3) | 1671.0 (2) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 1.34 |
Crystal size (mm) | 0.25 × 0.20 × 0.11 |
|
Data collection |
Diffractometer | Enraf–Nonius CAD4 diffractometer |
Absorption correction | ϕ-scan (PSISCANS; North et al., 1968) |
Tmin, Tmax | 0.761, 0.883 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3061, 2938, 2427 |
Rint | 0.045 |
(sin θ/λ)max (Å−1) | 0.594 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.033, 0.096, 1.07 |
No. of reflections | 2938 |
No. of parameters | 227 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.34, −0.39 |
Selected geometric parameters (Å, º) topCu1—O3 | 1.909 (2) | Cu1—O1 | 2.358 (2) |
Cu1—O3i | 1.983 (2) | Cu1—O2 | 2.360 (2) |
Cu1—N1 | 2.018 (2) | Cu1—Cu1i | 3.0298 (7) |
Cu1—N2 | 2.094 (2) | | |
| | | |
O3—Cu1—O3i | 77.79 (9) | N1—Cu1—O1 | 76.39 (9) |
O3—Cu1—N1 | 169.80 (9) | N2—Cu1—O1 | 82.91 (9) |
O3i—Cu1—N1 | 92.23 (9) | O3—Cu1—O2 | 108.24 (9) |
O3—Cu1—N2 | 81.17 (9) | O3i—Cu1—O2 | 97.08 (9) |
O3i—Cu1—N2 | 158.71 (9) | N1—Cu1—O2 | 74.75 (9) |
N1—Cu1—N2 | 108.7 (1) | N2—Cu1—O2 | 92.48 (9) |
O3—Cu1—O1 | 102.8 (1) | O1—Cu1—O2 | 147.54 (8) |
O3i—Cu1—O1 | 98.6 (1) | Cu1—O3—Cu1i | 102.21 (9) |
Symmetry code: (i) −x, −y, −z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O1—H51···O5ii | 0.82 | 1.821 | 2.636 (4) | 173 |
O2—H52···O5iii | 0.82 | 1.796 | 2.596 (4) | 165 |
O4—H54···O6 | 0.82 | 1.884 | 2.689 (4) | 167 |
Symmetry codes: (ii) −x+1, −y, −z; (iii) x−1, y, z. |
The 2,6-pyridyldimethanolate ligand functions as a bridge through its two O atoms to afford polynuclear metal complexes (Boskovic et al., 2002; Yoo et al., 2000). Our main strategy is to synthesize polynuclear copper complexes using N,O-donor hydroxyalkylpyridyl ligands, because these cluster complexes act as model complexes for active centers of many metalloenzymes (Agnus, 1988) and as supramolecular building blocks for promising magnetic materials (Del Sesto et al., 2000). Less attention has been given to copper complexes based on N,O-donor hydroxyalkylpyridyl ligands. Few mononuclear (Andac et al., 2002; Koman et al., 2000) and dinunclear complexes (Cheng et al., 2002) have been reported. Herein, we report the synthesis and X-ray structure of a new dinuclear CuII complex, [Cu2(pdmH)2(pdmH2)2](CH3COO)2, (I), from the reaction of Cu(acetate)2·H2O and pdmH2 (pdmH2 is pyridine-2.6-diyldimethanol) in the presence of tetrabutylammonium hydroxide.
The complex cation of the title compound comprises a [CuII2(µ2-O)2] core, in which the two µ2-O atoms belong to the bridging pdmH− ligand. As shown in Fig. 1, each CuII atom is coordinated by neutral pdmH2 as a terminal tridentate ligand and anionic pdmH− as a bridging bidentate ligand. The crystallographic inversion center is located in the middle of the [Cu2O2] rhombus. In the planar [Cu2O2] unit, the Cu—Cu separation and Cu—O—Cu angle are comparable with other known alkoxo-bridged [Cu2O2] complexes (Berti et al., 2003; Cheng et al., 2002; Graham et al., 2001). Each Cu atom has a highly distorted octahedral geometry (see Table 1), with acute µ-O—Cu—µ-O and N—Cu—O angles in the [Cu(pdmH2)] unit, which are similar to those found in other known distorted-octahedral CuO4N2 cores containing the pdmH2 ligand (Andac et al., 2002; Koman et al., 2000). The axial Cu1—O1 [2.358 (2) Å] and Cu1—O2 [2.360 (2) Å] distances are substantially longer than the equatorial Cu—O and Cu—N distances [1.909 (2)–2.094 (2) Å], which indicates severe Jahn–Teller distortion, despite the presumably restraining effects of the chelate rings. The equatorial distances are similar to the corresponding distances in the tetragonally elongated octahedral complex [Cu(C5H5NO)6](NO3)2·2H2O (Wood et al., 1984), while the axial Cu—O bond distances are shorter than the bond lengths of 2.478 (2) Å found in [Cu(C5H5NO)6](NO3)2·2H2O and 2.548 Å found in [Cu(3,2,3-tet)(ClO4)]n [3,2,3-tet is N,N'-bis(3-aminopropyl)ethylenediamine; Kwak et al., 2001], in which axial coordination ligands have no geometrical constraints. The O1—Cu1—O1' angle [147.54 (8) °] is significantly reduced from 180°.
It is hard to estimate quantitatively the elongation of the axial Cu—O bond that results from the Jahn–Teller effect and from geometrical restraints of the chelate ring. However, it is certain that there is conflict between stabilization from the Jahn–Teller effect and the chelate geometrical requirements, because the nature of the chelate ring tends to restrict the distortion of a complex (Huheey, 1983). Bond parameters of (I) are not different from those of various CuL2 compounds with the CuO4N2 chromophore (L = chelate ligand; Koman et al., 2000) and CuII compounds containing the pdmH fragment (Atkinson et al., 2000), whereas [Cu(pdmH2)2]2+ exhibits a Jahn–Teller contraction effect (Andac et al., 2002).
The adjacent dinuclear copper complex units are associated via hydrogen bonds between the hydroxide groups of the 2,6-pyridinedimethanol ligands and the acetate anions, as illustrated in Fig. 2 and Table 2. There is one carboxylate anion in the asymmetric unit. Carboxylate atom O5 interacts with two hydroxide H atoms of adjacent pdmH2 ligands, while atom O6 interacts with the H atom on the hydroxide O4 atom of pdmH−, resulting in one-dimensional linear chains running parallel to the a axis.