Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103008904/fr1421sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270103008904/fr1421Isup2.hkl |
CCDC reference: 214376
The ligand 1,2-bis(2-pyridyl)ethyne was prepared according to the method described by Teitei et al. (1972). A methanol solution (5 ml) of Cd(NO3)2·4H2O (30.8 mg, 0.1 mmol) was slowly added to a methylene chloride (5 ml) solution of 2,2'-dpa (18.2 mg, 0.1 mmol). After one week, the yellow–orange solution was slowly evaporated (at room temperature over a period of two weeks) to saturation. Large yellow block-like crystals grew at the bottom of the test tube after 2 d.
H atoms attached to C atoms were idealized and treated as riding [C—H = 0.95 A and Uiso(H) = 1.2 Uiso(C)]. Water H atoms were located in a Fourier map and refined freely.
Data collection: SMART-NT (Bruker, 1999); cell refinement: SAINT-Plus-NT (Bruker, 1999); data reduction: SAINT-Plus-NT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: ATOMS (Dowty, 2001) & SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.
[Cd2(NO3)4(C12H8N2)2(H2O)2] | F(000) = 1712 |
Mr = 869.28 | Dx = 1.916 Mg m−3 |
Orthorhombic, Pbcn | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2n 2ab | Cell parameters from 5750 reflections |
a = 19.910 (3) Å | θ = 2.6–26.4° |
b = 7.8559 (8) Å | µ = 1.50 mm−1 |
c = 19.263 (2) Å | T = 173 K |
V = 3013.0 (6) Å3 | Block, yellow |
Z = 4 | 0.48 × 0.44 × 0.32 mm |
Bruker SMART APEX CCD diffractometer | 3074 independent reflections |
Radiation source: fine-focus sealed tube | 2697 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.019 |
ω scans | θmax = 26.4°, θmin = 2.1° |
Absorption correction: multi-scan (SADABS; Bruker, 1999) | h = −24→14 |
Tmin = 0.515, Tmax = 0.647 | k = −8→9 |
14574 measured reflections | l = −21→24 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: geom & difmap |
R[F2 > 2σ(F2)] = 0.019 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.052 | w = 1/[σ2(Fo2) + (0.0321P)2 + 0.0456P] where P = (Fo2 + 2Fc2)/3 |
S = 1.06 | (Δ/σ)max = 0.001 |
3074 reflections | Δρmax = 0.40 e Å−3 |
234 parameters | Δρmin = −0.43 e Å−3 |
0 restraints | Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.00294 (13) |
[Cd2(NO3)4(C12H8N2)2(H2O)2] | V = 3013.0 (6) Å3 |
Mr = 869.28 | Z = 4 |
Orthorhombic, Pbcn | Mo Kα radiation |
a = 19.910 (3) Å | µ = 1.50 mm−1 |
b = 7.8559 (8) Å | T = 173 K |
c = 19.263 (2) Å | 0.48 × 0.44 × 0.32 mm |
Bruker SMART APEX CCD diffractometer | 3074 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 1999) | 2697 reflections with I > 2σ(I) |
Tmin = 0.515, Tmax = 0.647 | Rint = 0.019 |
14574 measured reflections |
R[F2 > 2σ(F2)] = 0.019 | 0 restraints |
wR(F2) = 0.052 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.06 | Δρmax = 0.40 e Å−3 |
3074 reflections | Δρmin = −0.43 e Å−3 |
234 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 | ||
Cd | 0.375080 (7) | 0.233543 (16) | 0.158156 (6) | 0.01963 (7) | |
C1 | 0.49270 (11) | 0.2478 (2) | 0.04658 (11) | 0.0280 (4) | |
H1 | 0.4611 | 0.1816 | 0.0214 | 0.042 (6)* | |
C2 | 0.55109 (10) | 0.2989 (3) | 0.01329 (11) | 0.0336 (5) | |
H2 | 0.5595 | 0.2671 | −0.0335 | 0.038 (6)* | |
C3 | 0.59648 (10) | 0.3964 (3) | 0.04948 (11) | 0.0349 (5) | |
H3 | 0.6366 | 0.4344 | 0.0277 | 0.035 (6)* | |
C4 | 0.58330 (10) | 0.4388 (2) | 0.11790 (10) | 0.0295 (4) | |
H4 | 0.6143 | 0.5055 | 0.1437 | 0.033 (6)* | |
C5 | 0.52409 (9) | 0.3821 (2) | 0.14806 (9) | 0.0220 (4) | |
C6 | 0.50804 (9) | 0.4105 (2) | 0.21998 (9) | 0.0223 (4) | |
C7 | 0.30083 (9) | 0.1170 (2) | 0.29482 (10) | 0.0262 (4) | |
H7 | 0.2668 | 0.1805 | 0.2719 | 0.031 (5)* | |
C8 | 0.28641 (10) | 0.0447 (3) | 0.35847 (11) | 0.0336 (5) | |
H8 | 0.2432 | 0.0582 | 0.3787 | 0.042 (6)* | |
C9 | 0.33526 (11) | −0.0469 (3) | 0.39227 (10) | 0.0356 (5) | |
H9 | 0.3263 | −0.0974 | 0.4361 | 0.032 (5)* | |
C10 | 0.39732 (11) | −0.0646 (2) | 0.36167 (10) | 0.0299 (4) | |
H10 | 0.4318 | −0.1277 | 0.3841 | 0.030 (5)* | |
C11 | 0.40889 (9) | 0.0107 (2) | 0.29768 (9) | 0.0219 (4) | |
C12 | 0.47307 (8) | −0.0023 (2) | 0.26376 (9) | 0.0232 (4) | |
N1 | 0.47884 (8) | 0.28748 (18) | 0.11247 (8) | 0.0218 (3) | |
N2 | 0.36103 (7) | 0.10118 (18) | 0.26397 (8) | 0.0211 (3) | |
N3 | 0.27536 (9) | 0.3079 (2) | 0.05851 (9) | 0.0318 (4) | |
N4 | 0.35745 (8) | 0.58649 (19) | 0.19734 (8) | 0.0244 (3) | |
O1 | 0.33331 (7) | 0.28351 (16) | 0.03544 (7) | 0.0313 (3) | |
O2 | 0.26403 (7) | 0.27369 (17) | 0.12142 (8) | 0.0336 (3) | |
O3 | 0.23002 (8) | 0.3656 (2) | 0.02124 (8) | 0.0511 (4) | |
O4 | 0.37963 (7) | 0.5586 (2) | 0.13786 (8) | 0.0338 (3) | |
O5 | 0.33949 (7) | 0.46129 (16) | 0.23400 (7) | 0.0314 (3) | |
O6 | 0.35314 (8) | 0.73257 (15) | 0.22109 (8) | 0.0320 (3) | |
O1W | 0.37703 (8) | −0.03747 (18) | 0.11165 (9) | 0.0290 (3) | |
H1W | 0.3742 (14) | −0.104 (4) | 0.1440 (17) | 0.065 (11)* | |
H2W | 0.3468 (13) | −0.055 (3) | 0.0848 (14) | 0.051 (8)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cd | 0.02036 (10) | 0.01888 (9) | 0.01966 (10) | −0.00015 (5) | 0.00178 (5) | 0.00147 (4) |
C1 | 0.0291 (11) | 0.0315 (11) | 0.0234 (10) | 0.0039 (8) | 0.0009 (8) | −0.0013 (7) |
C2 | 0.0353 (12) | 0.0412 (12) | 0.0243 (11) | 0.0069 (9) | 0.0089 (9) | 0.0034 (9) |
C3 | 0.0276 (11) | 0.0422 (12) | 0.0348 (12) | 0.0014 (9) | 0.0107 (9) | 0.0114 (9) |
C4 | 0.0256 (10) | 0.0308 (10) | 0.0322 (11) | −0.0046 (8) | 0.0026 (8) | 0.0058 (8) |
C5 | 0.0223 (9) | 0.0201 (9) | 0.0235 (9) | 0.0028 (7) | 0.0014 (7) | 0.0041 (7) |
C6 | 0.0192 (9) | 0.0191 (9) | 0.0285 (9) | −0.0008 (7) | −0.0012 (7) | 0.0008 (7) |
C7 | 0.0234 (10) | 0.0270 (9) | 0.0282 (10) | −0.0035 (7) | 0.0014 (8) | −0.0011 (7) |
C8 | 0.0306 (11) | 0.0397 (12) | 0.0303 (11) | −0.0050 (9) | 0.0085 (9) | 0.0001 (9) |
C9 | 0.0482 (13) | 0.0373 (11) | 0.0214 (10) | −0.0062 (10) | 0.0065 (9) | 0.0055 (8) |
C10 | 0.0372 (11) | 0.0280 (10) | 0.0247 (10) | −0.0003 (9) | −0.0046 (9) | 0.0038 (8) |
C11 | 0.0254 (10) | 0.0174 (8) | 0.0228 (9) | −0.0027 (7) | −0.0016 (8) | −0.0013 (6) |
C12 | 0.0275 (10) | 0.0169 (8) | 0.0251 (10) | −0.0004 (7) | −0.0049 (7) | 0.0009 (7) |
N1 | 0.0207 (8) | 0.0219 (8) | 0.0227 (8) | 0.0019 (6) | 0.0035 (6) | 0.0020 (6) |
N2 | 0.0231 (8) | 0.0182 (7) | 0.0220 (8) | −0.0025 (6) | 0.0012 (6) | −0.0002 (6) |
N3 | 0.0349 (10) | 0.0348 (9) | 0.0258 (9) | 0.0048 (8) | −0.0041 (7) | −0.0030 (7) |
N4 | 0.0242 (8) | 0.0193 (8) | 0.0296 (9) | 0.0015 (6) | −0.0043 (7) | −0.0005 (6) |
O1 | 0.0307 (8) | 0.0341 (7) | 0.0290 (8) | 0.0013 (6) | 0.0028 (6) | −0.0024 (6) |
O2 | 0.0281 (8) | 0.0504 (9) | 0.0223 (8) | 0.0045 (6) | −0.0014 (6) | 0.0046 (6) |
O3 | 0.0459 (10) | 0.0779 (12) | 0.0297 (8) | 0.0245 (9) | −0.0111 (7) | 0.0043 (8) |
O4 | 0.0375 (9) | 0.0317 (8) | 0.0321 (8) | 0.0046 (6) | 0.0080 (6) | −0.0044 (6) |
O5 | 0.0349 (8) | 0.0214 (7) | 0.0380 (8) | −0.0015 (6) | −0.0006 (6) | 0.0061 (6) |
O6 | 0.0431 (9) | 0.0193 (7) | 0.0337 (8) | −0.0011 (6) | 0.0004 (7) | −0.0067 (5) |
O1W | 0.0364 (9) | 0.0214 (7) | 0.0292 (8) | −0.0033 (6) | 0.0018 (7) | −0.0007 (6) |
Cd—N1 | 2.2852 (15) | C7—C8 | 1.381 (3) |
Cd—N2 | 2.3052 (15) | C7—H7 | 0.9500 |
Cd—O1W | 2.3102 (14) | C8—C9 | 1.374 (3) |
Cd—O2 | 2.3429 (15) | C8—H8 | 0.9500 |
Cd—O5 | 2.4162 (14) | C9—C10 | 1.376 (3) |
Cd—O1 | 2.5364 (14) | C9—H9 | 0.9500 |
Cd—O4 | 2.5848 (16) | C10—C11 | 1.387 (3) |
Cd—Cdi | 6.1045 (6) | C10—H10 | 0.9500 |
C1—N1 | 1.336 (3) | C11—N2 | 1.355 (2) |
C1—C2 | 1.387 (3) | C11—C12 | 1.439 (2) |
C1—H1 | 0.9500 | C11—O6ii | 2.861 (2) |
C2—C3 | 1.375 (3) | C12—C12i | 1.196 (3) |
C2—H2 | 0.9500 | N3—O3 | 1.239 (2) |
C3—C4 | 1.384 (3) | N3—O1 | 1.251 (2) |
C3—H3 | 0.9500 | N3—O2 | 1.262 (2) |
C4—C5 | 1.388 (3) | N4—O6 | 1.2383 (18) |
C4—H4 | 0.9500 | N4—O4 | 1.247 (2) |
C5—N1 | 1.354 (2) | N4—O5 | 1.2625 (19) |
C5—C6 | 1.439 (2) | O1W—H1W | 0.81 (3) |
C6—C6i | 1.200 (4) | O1W—H2W | 0.81 (3) |
C7—N2 | 1.344 (2) | ||
N1—Cd—N2 | 122.27 (5) | C6i—C6—C5 | 170.74 (11) |
N1—Cd—O1W | 90.36 (5) | C6i—C6—C12i | 86.48 (5) |
N2—Cd—O1W | 85.94 (5) | C5—C6—C12i | 85.01 (10) |
N1—Cd—O2 | 135.39 (6) | C6i—C6—C12 | 73.04 (5) |
N2—Cd—O2 | 102.31 (5) | C5—C6—C12 | 97.78 (11) |
O1W—Cd—O2 | 91.31 (5) | N2—C7—C8 | 122.68 (18) |
N1—Cd—O5 | 111.14 (5) | N2—C7—H7 | 118.7 |
N2—Cd—O5 | 76.34 (5) | C8—C7—H7 | 118.7 |
O1W—Cd—O5 | 157.20 (5) | C9—C8—C7 | 119.27 (18) |
O2—Cd—O5 | 78.82 (5) | C9—C8—H8 | 120.4 |
N1—Cd—O1 | 84.77 (5) | C7—C8—H8 | 120.4 |
N2—Cd—O1 | 148.65 (5) | C8—C9—C10 | 119.04 (18) |
O1W—Cd—O1 | 77.69 (5) | C8—C9—H9 | 120.5 |
O2—Cd—O1 | 52.28 (5) | C10—C9—H9 | 120.5 |
O5—Cd—O1 | 110.66 (4) | C9—C10—C11 | 119.14 (18) |
N1—Cd—O4 | 74.15 (5) | C9—C10—H10 | 120.4 |
N2—Cd—O4 | 125.71 (5) | C11—C10—H10 | 120.4 |
O1W—Cd—O4 | 148.34 (5) | N2—C11—C10 | 122.22 (17) |
O2—Cd—O4 | 81.63 (5) | N2—C11—C12 | 116.38 (16) |
O5—Cd—O4 | 50.97 (5) | C10—C11—C12 | 121.40 (17) |
O1—Cd—O4 | 73.60 (5) | C12i—C12—C11 | 175.85 (11) |
N1—Cd—Cdi | 59.11 (4) | C12i—C12—C6 | 73.05 (5) |
N2—Cd—Cdi | 65.57 (4) | C11—C12—C6 | 103.02 (11) |
O1W—Cd—Cdi | 102.18 (4) | C1—N1—C5 | 118.14 (16) |
O2—Cd—Cdi | 160.75 (4) | C1—N1—Cd | 120.62 (13) |
O5—Cd—Cdi | 83.60 (3) | C5—N1—Cd | 120.55 (12) |
O1—Cd—Cdi | 143.84 (3) | C7—N2—C11 | 117.65 (15) |
O4—Cd—Cdi | 93.39 (3) | C7—N2—Cd | 117.24 (12) |
N1—C1—C2 | 123.03 (19) | C11—N2—Cd | 125.11 (12) |
N1—C1—H1 | 118.5 | O3—N3—O1 | 121.47 (17) |
C2—C1—H1 | 118.5 | O3—N3—O2 | 120.26 (17) |
C3—C2—C1 | 118.53 (19) | O1—N3—O2 | 118.27 (16) |
C3—C2—H2 | 120.7 | O6—N4—O4 | 121.79 (15) |
C1—C2—H2 | 120.7 | O6—N4—O5 | 119.72 (16) |
C2—C3—C4 | 119.49 (18) | O4—N4—O5 | 118.50 (15) |
C2—C3—H3 | 120.3 | N3—O1—Cd | 89.72 (10) |
C4—C3—H3 | 120.3 | N3—O2—Cd | 98.62 (11) |
C3—C4—C5 | 118.84 (18) | N4—O4—Cd | 91.28 (10) |
C3—C4—H4 | 120.6 | N4—O5—Cd | 98.95 (11) |
C5—C4—H4 | 120.6 | Cd—O1W—H1W | 107 (2) |
N1—C5—C4 | 121.96 (17) | Cd—O1W—H2W | 113.4 (19) |
N1—C5—C6 | 115.14 (15) | H1W—O1W—H2W | 109 (3) |
C4—C5—C6 | 122.81 (17) | ||
N1—C1—C2—C3 | −0.8 (3) | O2—Cd—N2—C7 | −19.60 (13) |
C1—C2—C3—C4 | 0.9 (3) | O5—Cd—N2—C7 | 55.49 (12) |
C2—C3—C4—C5 | −0.4 (3) | O1—Cd—N2—C7 | −51.89 (17) |
C3—C4—C5—N1 | −0.3 (3) | O4—Cd—N2—C7 | 68.87 (14) |
C3—C4—C5—C6 | 175.97 (17) | Cdi—Cd—N2—C7 | 144.60 (13) |
N1—C5—C6—C12i | 65.01 (14) | N1—Cd—N2—C11 | −17.08 (15) |
C4—C5—C6—C12i | −111.51 (17) | O1W—Cd—N2—C11 | 70.78 (14) |
N1—C5—C6—C12 | 49.03 (16) | O2—Cd—N2—C11 | 161.24 (13) |
C4—C5—C6—C12 | −127.49 (16) | O5—Cd—N2—C11 | −123.67 (14) |
N2—C7—C8—C9 | 0.2 (3) | O1—Cd—N2—C11 | 128.95 (13) |
C7—C8—C9—C10 | −0.1 (3) | O4—Cd—N2—C11 | −110.29 (13) |
C8—C9—C10—C11 | 0.1 (3) | Cdi—Cd—N2—C11 | −34.57 (12) |
C9—C10—C11—N2 | −0.2 (3) | O3—N3—O1—Cd | 169.19 (18) |
C9—C10—C11—C12 | 179.33 (18) | O2—N3—O1—Cd | −10.07 (16) |
N2—C11—C12—C6 | 49.04 (16) | N1—Cd—O1—N3 | −161.03 (11) |
C10—C11—C12—C6 | −130.49 (16) | N2—Cd—O1—N3 | 47.30 (14) |
C6i—C6—C12—C12i | −129.4 (2) | O1W—Cd—O1—N3 | 107.45 (11) |
C5—C6—C12—C12i | 51.8 (2) | O2—Cd—O1—N3 | 6.02 (10) |
C6i—C6—C12—C11 | 49.20 (19) | O5—Cd—O1—N3 | −50.38 (11) |
C5—C6—C12—C11 | −129.57 (14) | O4—Cd—O1—N3 | −86.03 (10) |
C12i—C6—C12—C11 | 178.6 (3) | Cdi—Cd—O1—N3 | −158.67 (8) |
C2—C1—N1—C5 | 0.1 (3) | O3—N3—O2—Cd | −168.23 (16) |
C2—C1—N1—Cd | 170.62 (14) | O1—N3—O2—Cd | 11.04 (17) |
C4—C5—N1—C1 | 0.5 (3) | N1—Cd—O2—N3 | 12.51 (14) |
C6—C5—N1—C1 | −176.09 (15) | N2—Cd—O2—N3 | −165.47 (10) |
C4—C5—N1—Cd | −170.08 (13) | O1W—Cd—O2—N3 | −79.34 (11) |
C6—C5—N1—Cd | 13.4 (2) | O5—Cd—O2—N3 | 121.37 (11) |
N2—Cd—N1—C1 | 132.13 (13) | O1—Cd—O2—N3 | −6.03 (10) |
O1W—Cd—N1—C1 | 46.71 (14) | O4—Cd—O2—N3 | 69.67 (11) |
O2—Cd—N1—C1 | −45.52 (16) | Cdi—Cd—O2—N3 | 145.77 (10) |
O5—Cd—N1—C1 | −141.04 (12) | O6—N4—O4—Cd | 174.16 (15) |
O1—Cd—N1—C1 | −30.89 (13) | O5—N4—O4—Cd | −5.37 (16) |
O4—Cd—N1—C1 | −105.30 (14) | N1—Cd—O4—N4 | −132.30 (11) |
Cdi—Cd—N1—C1 | 150.72 (14) | N2—Cd—O4—N4 | −13.65 (12) |
N2—Cd—N1—C5 | −57.56 (14) | O1W—Cd—O4—N4 | 164.31 (11) |
O1W—Cd—N1—C5 | −142.98 (13) | O2—Cd—O4—N4 | 85.53 (10) |
O2—Cd—N1—C5 | 124.78 (13) | O5—Cd—O4—N4 | 3.17 (9) |
O5—Cd—N1—C5 | 29.27 (14) | O1—Cd—O4—N4 | 138.57 (11) |
O1—Cd—N1—C5 | 139.41 (13) | Cdi—Cd—O4—N4 | −75.77 (10) |
O4—Cd—N1—C5 | 65.01 (13) | O6—N4—O5—Cd | −173.72 (14) |
Cdi—Cd—N1—C5 | −38.97 (12) | O4—N4—O5—Cd | 5.82 (17) |
C8—C7—N2—C11 | −0.3 (3) | N1—Cd—O5—N4 | 43.16 (11) |
C8—C7—N2—Cd | −179.50 (15) | N2—Cd—O5—N4 | 162.83 (11) |
C10—C11—N2—C7 | 0.3 (3) | O1W—Cd—O5—N4 | −157.20 (14) |
C12—C11—N2—C7 | −179.28 (15) | O2—Cd—O5—N4 | −91.40 (11) |
C10—C11—N2—Cd | 179.41 (13) | O1—Cd—O5—N4 | −49.21 (11) |
C12—C11—N2—Cd | −0.1 (2) | O4—Cd—O5—N4 | −3.17 (9) |
N1—Cd—N2—C7 | 162.08 (12) | Cdi—Cd—O5—N4 | 96.48 (10) |
O1W—Cd—N2—C7 | −110.06 (13) |
Symmetry codes: (i) −x+1, y, −z+1/2; (ii) x, y−1, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1W···O6ii | 0.81 (3) | 2.01 (3) | 2.817 (2) | 172 (3) |
O1W—H2W···O3iii | 0.81 (3) | 2.06 (3) | 2.856 (2) | 172 (3) |
Symmetry codes: (ii) x, y−1, z; (iii) −x+1/2, y−1/2, z. |
Experimental details
Crystal data | |
Chemical formula | [Cd2(NO3)4(C12H8N2)2(H2O)2] |
Mr | 869.28 |
Crystal system, space group | Orthorhombic, Pbcn |
Temperature (K) | 173 |
a, b, c (Å) | 19.910 (3), 7.8559 (8), 19.263 (2) |
V (Å3) | 3013.0 (6) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 1.50 |
Crystal size (mm) | 0.48 × 0.44 × 0.32 |
Data collection | |
Diffractometer | Bruker SMART APEX CCD diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 1999) |
Tmin, Tmax | 0.515, 0.647 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 14574, 3074, 2697 |
Rint | 0.019 |
(sin θ/λ)max (Å−1) | 0.626 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.019, 0.052, 1.06 |
No. of reflections | 3074 |
No. of parameters | 234 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.40, −0.43 |
Computer programs: SMART-NT (Bruker, 1999), SAINT-Plus-NT (Bruker, 1999), SAINT-Plus-NT, SHELXS97 (Sheldrick, 1997a), SHELXL97 (Sheldrick, 1997a), ATOMS (Dowty, 2001) & SHELXTL (Sheldrick, 1997b), SHELXTL.
Cd—N1 | 2.2852 (15) | Cd—O5 | 2.4162 (14) |
Cd—N2 | 2.3052 (15) | Cd—O1 | 2.5364 (14) |
Cd—O1W | 2.3102 (14) | Cd—O4 | 2.5848 (16) |
Cd—O2 | 2.3429 (15) | ||
N1—Cd—N2 | 122.27 (5) | N2—Cd—O1 | 148.65 (5) |
N1—Cd—O1W | 90.36 (5) | O1W—Cd—O1 | 77.69 (5) |
N2—Cd—O1W | 85.94 (5) | O5—Cd—O1 | 110.66 (4) |
N1—Cd—O2 | 135.39 (6) | N1—Cd—O4 | 74.15 (5) |
N2—Cd—O2 | 102.31 (5) | N2—Cd—O4 | 125.71 (5) |
O1W—Cd—O2 | 91.31 (5) | O1W—Cd—O4 | 148.34 (5) |
N1—Cd—O5 | 111.14 (5) | O2—Cd—O4 | 81.63 (5) |
N2—Cd—O5 | 76.34 (5) | O1—Cd—O4 | 73.60 (5) |
O1W—Cd—O5 | 157.20 (5) | C6i—C6—C5 | 170.74 (11) |
O2—Cd—O5 | 78.82 (5) | C12i—C12—C11 | 175.85 (11) |
N1—Cd—O1 | 84.77 (5) |
Symmetry code: (i) −x+1, y, −z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
O1W—H1W···O6ii | 0.81 (3) | 2.01 (3) | 2.817 (2) | 172 (3) |
O1W—H2W···O3iii | 0.81 (3) | 2.06 (3) | 2.856 (2) | 172 (3) |
Symmetry codes: (ii) x, y−1, z; (iii) −x+1/2, y−1/2, z. |
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Dipyridylacetylene ligands have been used by several groups for the construction of structurally diverse coordination networks (Bosch & Barnes, 2001; Carlucci et al., 1998, 1999a,b; Dong et al., 1999a,b) and as supramolecular synthons (Zaman et al., 2000). Most efforts have employed the 4,4'-dipyridyl species, with comparatively fewer 3,3'- and 2,2'-dipyridyl studies. As part of an exploration of the structural effect of the 2,2'-, 3,3'- and 4,4'-positional orientation of the N atoms in dipyridylacetylene ligands, we report here the structure of [Cd(2,2'-dpa)(H2O)(NO3)2]2, (I), the product of the reaction of 2,2'-dipyridylacetylene [systematic name 1,2-bis(2-pyridyl)ethyne, hereafter 2,2'-dpa) with Cd(NO3)2·4H2O.
Slow evaporation of a 1:1 C d(NO3)2·4H2O/2,2'-dpa mixture from a 1:1 methylene chloride/methanol solvent system deposited plentiful yellow block crystals of (I) after 2 d. The asymmetric unit of the dinuclear title complex consists of half of two independent 2,2'-dpa ligands, two nitrate ions and a coordinated water molecule. The heptacoordinate Cd environment is irregular, but can be described as a distorted trigonal bipyramid (Figure 1) with two additional long Cd—O bonds. The equatorial sites contain two pyridyl N atoms from two ligands and atom O2, with the axial sites occupied by the coordinated water molecule and atom O5. Atoms O1 and O4 complete the coordination sphere at distances greater than 2.5 Å. The nitrate anions are thus intermediate between monodentate and bidentate (the distances and angles around Cd are given in Table 1).
The complex lies on a C2 axis passing through the mid-point of the acetylene units of both ligands (C6—C6i and C12—C12i). Each 2,2'-dpa ligand bridges two equivalent cadmium centers [Cd···Cd = 6.1045 (6) Å], and the ligands arch across one another to create an infinite zigzag cycle molecular geometry (Fig. 1). The ligands crisscross each other in projection along [010], with interligand Cacetylene—Cacetylene distances of 3.422 (2) Å (C6—C12) and 3.280 (2) (C6—C12i) Å [symmetry code: (i) = 1 − x, y, 1/2 − z], the latter indicating a possible alkyne–alkyne interaction (C···C van der Waals sum = 3.40 Å).
Both independent ligands in (I) are significantly distorted as as result of the geometric requirements of bridging two metal centers into a cyclic system. The acetylene units of the ligands show a more pronounced deviation from linearity [C11—C12—C12i = 175.8 (1)° and C5—C6—C6i = 170.7 (1)°), than observed previously (Neenan et al., 1996). Additionally, the pyridyl rings in each independent ligand are rotated with respect to one another by identical values of 67.2 (1) °, whereas in all other published accounts this ligand tends strongly toward planarity, with maximum dihedral angles between pyridyl ring planes of less than 5° (Neenan et al., 1996; Zaman et al., 2000).
Intermolecular O—H···O hydrogen bonding (Table 2) between water atoms H1W and H2W and uncoordinated nitrate atoms O6 and O3, respectively, serves to link the complexes into sheets parallel to the crystallographic ab plane (Fig. 2). All available hydrogen-bonding donor and acceptor atoms are utilized in the crystal, either in coordination to the Cd center or in the O—H···O network. The hydrogen- bonded layers then stack along [001] with no obvious interactions except of the van der Waals type.
Interestingly, an unusually short C—O contact of 2.861 (2) Å, involving atom C11 of a pyridyl ring (adjacent to N2) and the nitrate donor O6 from a neighboring molecule (symmetry code: x, y − 1, z) is present in the crystal structure. Though quite short (C—O van der Waals sum = 3.3 Å), this interaction is most likely a by-product of the strong O1W—H1W···O6 hydrogen bond mentioned above.
The 'zigzag loop' geometry of the title complex represents the third distinct structural motif obtained from the M(NO3)2/2,2'-dpa system (M = transition metal), after the unusual non-cyclic Cu2(NO3)2(µ-2,2'-dpa)(2,2'-dpa)2 zigzag complex and the infinite one-dimensional zigzag chain [Co(NO3)2(2,2'-dpa)] polymer, both reported by Neenan et al. (1996). Besides demonstrating the structural unpredictability of this ligand, these results show how the 2,2'-position of the pyridyl N atoms necessarily results in zigzag motifs rather than more orthogonal systems. For example, the reported 4,4'-dpa coordination network structures tend to adopt ladder, brick-wall, 'parquet' and more complex structural motifs, with N—M—N angles near 90°. Also, there is increased steric difficulty in coordinating more than two 2,2'-dpa ligands around a metal center due to the 'bending back' of the ligand toward the metal and therefore toward any other coordinated ligands, instead of stretching outward as with 4,4'-dpa. However, higher 2,2'-dpa ligand coordination and increased structure dimensionality might be more likely with a non-coordinating anion.