Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100004984/ln1104sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270100004984/ln1104Isup2.hkl |
CCDC reference: 147622
A 4 ml e thanol solution containing hydrated phenanthroline (C12H8N2·H2O, 59.5 mg, 0.30 mmol) and a 4 ml e thanol solution of Cu(CH3COO)2·H2O (59.9 mg, 0.30 mmol) were mixed and stirred for 5 min, then a 2 ml aqueous solution of NaN(CN)2 (26.7 mg, 0.30 mmol) was added to the above solution and stirred for another 5 min. The clear blue solution was filtered. Blue block-shaped crystals were obtained after slow evaporation of the filtrate for one week. Yield 22%. Analysis calculated for C16H8Cu1N8: C 51.13, H 2.15, N 29.82, Cu 16.91%; found: C 51.39, H 2.24, N 29.81, Cu 19.5% (by ICP).
Data collection: KappaCCD Software (Nonius, 1998); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: HKL DENZO (Otwinowski & Minor, 1997) and maXus (Mackay et al., 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 1998); software used to prepare material for publication: SHELXL97.
[Cu(C2N3)2(C12H8N2)] | F(000) = 756 |
Mr = 375.84 | Dx = 1.607 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
a = 9.8389 (3) Å | Cell parameters from 27425 reflections |
b = 11.2975 (5) Å | θ = 3.4–27.8° |
c = 14.2340 (5) Å | µ = 1.42 mm−1 |
β = 100.988 (2)° | T = 293 K |
V = 1553.17 (10) Å3 | Block, blue |
Z = 4 | 0.25 × 0.22 × 0.13 mm |
NONIUS KappaCCD diffractometer | 3682 independent reflections |
Radiation source: fine-focus sealed tube | 2489 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.066 |
Detector resolution: 0.76 pixels mm-1 | θmax = 27.8°, θmin = 3.4° |
CCD scans | h = −12→12 |
Absorption correction: empirical (using intensity measurements) (Blessing, 1995, 1997) | k = −14→14 |
Tmin = 0.766, Tmax = 0.831 | l = −18→18 |
27425 measured reflections |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.044 | H-atom parameters constrained |
wR(F2) = 0.120 | w = 1/[σ2(Fo2) + (0.0616P)2 + 0.6068P] where P = (Fo2 + 2Fc2)/3 |
S = 1.02 | (Δ/σ)max = 0.001 |
3682 reflections | Δρmax = 0.70 e Å−3 |
227 parameters | Δρmin = −0.45 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0046 (10) |
[Cu(C2N3)2(C12H8N2)] | V = 1553.17 (10) Å3 |
Mr = 375.84 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 9.8389 (3) Å | µ = 1.42 mm−1 |
b = 11.2975 (5) Å | T = 293 K |
c = 14.2340 (5) Å | 0.25 × 0.22 × 0.13 mm |
β = 100.988 (2)° |
NONIUS KappaCCD diffractometer | 3682 independent reflections |
Absorption correction: empirical (using intensity measurements) (Blessing, 1995, 1997) | 2489 reflections with I > 2σ(I) |
Tmin = 0.766, Tmax = 0.831 | Rint = 0.066 |
27425 measured reflections |
R[F2 > 2σ(F2)] = 0.044 | 0 restraints |
wR(F2) = 0.120 | H-atom parameters constrained |
S = 1.02 | Δρmax = 0.70 e Å−3 |
3682 reflections | Δρmin = −0.45 e Å−3 |
227 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 | ||
Cu1 | 0.65279 (3) | 0.88099 (3) | 0.23482 (2) | 0.04640 (16) | |
N1 | 0.8339 (2) | 0.8175 (2) | 0.30654 (16) | 0.0440 (6) | |
N2 | 0.7457 (2) | 1.0372 (2) | 0.27649 (16) | 0.0424 (5) | |
N3 | 0.4915 (3) | 0.9589 (3) | 0.1574 (2) | 0.0660 (8) | |
N4 | 0.2656 (4) | 0.9883 (4) | 0.0594 (3) | 0.1085 (15) | |
N5 | 0.1923 (3) | 1.0955 (3) | −0.0882 (2) | 0.0797 (10) | |
N6 | 0.5982 (3) | 0.7260 (3) | 0.17018 (19) | 0.0607 (7) | |
N7 | 0.4735 (3) | 0.6528 (3) | 0.0174 (2) | 0.0723 (9) | |
N8 | 0.5514 (3) | 0.6451 (3) | −0.1349 (2) | 0.0641 (8) | |
C1 | 0.8713 (4) | 0.7064 (3) | 0.3242 (2) | 0.0566 (8) | |
H1 | 0.8097 | 0.6462 | 0.3007 | 0.068* | |
C2 | 1.0020 (4) | 0.6771 (3) | 0.3778 (3) | 0.0656 (10) | |
H2 | 1.0252 | 0.5980 | 0.3901 | 0.079* | |
C3 | 1.0940 (4) | 0.7622 (4) | 0.4117 (2) | 0.0618 (9) | |
H3 | 1.1810 | 0.7421 | 0.4461 | 0.074* | |
C4 | 1.0580 (3) | 0.8816 (3) | 0.3948 (2) | 0.0505 (7) | |
C5 | 1.1442 (3) | 0.9807 (4) | 0.4284 (2) | 0.0602 (9) | |
H4 | 1.2334 | 0.9671 | 0.4622 | 0.072* | |
C6 | 1.1002 (3) | 1.0926 (3) | 0.4126 (2) | 0.0586 (9) | |
H5 | 1.1595 | 1.1546 | 0.4356 | 0.070* | |
C7 | 0.9627 (3) | 1.1188 (3) | 0.3608 (2) | 0.0494 (7) | |
C8 | 0.9081 (3) | 1.2329 (3) | 0.3442 (2) | 0.0575 (8) | |
H6 | 0.9612 | 1.2987 | 0.3667 | 0.069* | |
C9 | 0.7753 (3) | 1.2463 (3) | 0.2945 (2) | 0.0585 (8) | |
H7 | 0.7375 | 1.3215 | 0.2827 | 0.070* | |
C10 | 0.6970 (3) | 1.1464 (3) | 0.2616 (2) | 0.0497 (7) | |
H8 | 0.6071 | 1.1568 | 0.2278 | 0.060* | |
C11 | 0.8780 (3) | 1.0230 (3) | 0.32609 (18) | 0.0410 (6) | |
C12 | 0.9248 (3) | 0.9045 (3) | 0.34204 (19) | 0.0436 (7) | |
C13 | 0.3921 (4) | 0.9791 (4) | 0.1070 (3) | 0.0672 (10) | |
C14 | 0.2380 (3) | 1.0522 (3) | −0.0205 (2) | 0.0526 (7) | |
C15 | 0.5443 (3) | 0.6926 (3) | 0.0962 (2) | 0.0499 (7) | |
C16 | 0.5220 (3) | 0.6508 (3) | −0.0616 (2) | 0.0491 (7) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cu1 | 0.0411 (2) | 0.0560 (3) | 0.0371 (2) | −0.00175 (16) | −0.00538 (14) | 0.00008 (16) |
N1 | 0.0471 (13) | 0.0492 (15) | 0.0337 (12) | 0.0022 (11) | 0.0027 (10) | 0.0024 (10) |
N2 | 0.0342 (11) | 0.0546 (15) | 0.0370 (12) | 0.0036 (10) | 0.0029 (9) | 0.0000 (11) |
N3 | 0.0482 (15) | 0.082 (2) | 0.0589 (17) | 0.0008 (14) | −0.0137 (13) | 0.0101 (15) |
N4 | 0.061 (2) | 0.145 (4) | 0.107 (3) | −0.005 (2) | −0.016 (2) | 0.062 (3) |
N5 | 0.070 (2) | 0.103 (3) | 0.063 (2) | 0.0228 (19) | 0.0040 (17) | 0.0251 (19) |
N6 | 0.0563 (16) | 0.0763 (19) | 0.0493 (16) | −0.0129 (15) | 0.0093 (13) | −0.0142 (14) |
N7 | 0.0556 (16) | 0.116 (3) | 0.0474 (16) | −0.0330 (17) | 0.0150 (13) | −0.0251 (16) |
N8 | 0.0638 (18) | 0.085 (2) | 0.0436 (16) | −0.0002 (15) | 0.0113 (14) | −0.0025 (14) |
C1 | 0.064 (2) | 0.057 (2) | 0.0470 (17) | 0.0070 (16) | 0.0063 (15) | 0.0031 (15) |
C2 | 0.075 (2) | 0.067 (2) | 0.055 (2) | 0.028 (2) | 0.0121 (18) | 0.0145 (18) |
C3 | 0.0525 (18) | 0.085 (3) | 0.0463 (18) | 0.0250 (19) | 0.0052 (15) | 0.0079 (17) |
C4 | 0.0389 (14) | 0.076 (2) | 0.0355 (14) | 0.0133 (15) | 0.0047 (12) | 0.0019 (14) |
C5 | 0.0330 (14) | 0.098 (3) | 0.0466 (17) | 0.0033 (17) | −0.0015 (13) | −0.0023 (18) |
C6 | 0.0380 (15) | 0.083 (3) | 0.0529 (19) | −0.0088 (16) | 0.0039 (14) | −0.0069 (17) |
C7 | 0.0439 (15) | 0.067 (2) | 0.0380 (15) | −0.0063 (15) | 0.0091 (12) | −0.0066 (14) |
C8 | 0.0600 (19) | 0.056 (2) | 0.0587 (19) | −0.0103 (16) | 0.0169 (16) | −0.0110 (16) |
C9 | 0.061 (2) | 0.055 (2) | 0.061 (2) | 0.0048 (16) | 0.0154 (16) | −0.0041 (16) |
C10 | 0.0429 (15) | 0.058 (2) | 0.0479 (16) | 0.0081 (14) | 0.0075 (13) | 0.0018 (14) |
C11 | 0.0342 (13) | 0.0554 (17) | 0.0324 (13) | 0.0028 (12) | 0.0040 (11) | −0.0023 (12) |
C12 | 0.0370 (13) | 0.0631 (19) | 0.0292 (13) | 0.0064 (13) | 0.0026 (11) | 0.0018 (12) |
C13 | 0.0536 (19) | 0.087 (3) | 0.056 (2) | 0.0086 (18) | −0.0035 (17) | 0.0087 (19) |
C14 | 0.0434 (15) | 0.060 (2) | 0.0502 (18) | 0.0049 (14) | −0.0029 (14) | 0.0026 (16) |
C15 | 0.0412 (15) | 0.062 (2) | 0.0488 (18) | −0.0106 (14) | 0.0137 (14) | −0.0068 (15) |
C16 | 0.0415 (15) | 0.0595 (19) | 0.0446 (17) | −0.0061 (13) | 0.0036 (13) | −0.0055 (14) |
Cu1—N3 | 1.959 (3) | N7—C16 | 1.303 (4) |
Cu1—N6 | 2.003 (3) | N8—C16 | 1.136 (4) |
Cu1—N1 | 2.010 (2) | N8—Cu1iii | 2.286 (3) |
Cu1—N2 | 2.024 (2) | C1—C2 | 1.404 (5) |
Cu1—N8i | 2.286 (3) | C2—C3 | 1.345 (5) |
Cu1—N5ii | 2.821 (3) | C3—C4 | 1.403 (5) |
N1—C1 | 1.318 (4) | C4—C12 | 1.404 (4) |
N1—C12 | 1.360 (4) | C4—C5 | 1.431 (5) |
N2—C10 | 1.325 (4) | C5—C6 | 1.342 (5) |
N2—C11 | 1.367 (3) | C6—C7 | 1.443 (4) |
N3—C13 | 1.121 (4) | C7—C11 | 1.398 (4) |
N4—C13 | 1.303 (5) | C7—C8 | 1.399 (5) |
N4—C14 | 1.331 (5) | C8—C9 | 1.371 (5) |
N5—C14 | 1.098 (4) | C9—C10 | 1.396 (5) |
N6—C15 | 1.149 (4) | C11—C12 | 1.420 (4) |
N7—C15 | 1.283 (4) | ||
N3—Cu1—N6 | 90.97 (13) | C16—N8—Cu1iii | 168.2 (3) |
N3—Cu1—N1 | 172.10 (11) | N1—C1—C2 | 121.4 (3) |
N6—Cu1—N1 | 93.18 (11) | C3—C2—C1 | 120.6 (3) |
N3—Cu1—N2 | 92.58 (11) | C2—C3—C4 | 119.7 (3) |
N6—Cu1—N2 | 164.49 (10) | C3—C4—C12 | 116.6 (3) |
N1—Cu1—N2 | 81.68 (9) | C3—C4—C5 | 125.5 (3) |
N3—Cu1—N8i | 94.72 (12) | C12—C4—C5 | 117.9 (3) |
N6—Cu1—N8i | 98.01 (11) | C6—C5—C4 | 122.0 (3) |
N1—Cu1—N8i | 91.35 (10) | C5—C6—C7 | 121.4 (3) |
N2—Cu1—N8i | 96.74 (10) | C11—C7—C8 | 118.0 (3) |
N1—Cu1—N5ii | 81.81 (9) | C11—C7—C6 | 117.4 (3) |
N2—Cu1—N5ii | 81.79 (10) | C8—C7—C6 | 124.6 (3) |
N3—Cu1—N5ii | 92.04 (11) | C9—C8—C7 | 119.1 (3) |
N6—Cu1—N5ii | 83.00 (11) | C8—C9—C10 | 119.6 (3) |
N8i—Cu1—N5ii | 173.14 (10) | N2—C10—C9 | 122.6 (3) |
C1—N1—C12 | 118.5 (3) | N2—C11—C7 | 122.5 (3) |
C1—N1—Cu1 | 128.7 (2) | N2—C11—C12 | 116.2 (3) |
C12—N1—Cu1 | 112.79 (19) | C7—C11—C12 | 121.3 (3) |
C10—N2—C11 | 118.1 (3) | N1—C12—C4 | 123.1 (3) |
C10—N2—Cu1 | 129.5 (2) | N1—C12—C11 | 116.8 (2) |
C11—N2—Cu1 | 112.42 (19) | C4—C12—C11 | 120.0 (3) |
C13—N3—Cu1 | 165.0 (3) | N3—C13—N4 | 168.5 (4) |
C13—N4—C14 | 120.5 (4) | N5—C14—N4 | 167.1 (4) |
C14—N5—Cu1ii | 120.2 (3) | N6—C15—N7 | 174.2 (3) |
C15—N6—Cu1 | 138.1 (3) | N8—C16—N7 | 173.1 (3) |
C15—N7—C16 | 122.3 (3) |
Symmetry codes: (i) x, −y+3/2, z+1/2; (ii) −x+1, −y+2, −z; (iii) x, −y+3/2, z−1/2. |
Experimental details
Crystal data | |
Chemical formula | [Cu(C2N3)2(C12H8N2)] |
Mr | 375.84 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 293 |
a, b, c (Å) | 9.8389 (3), 11.2975 (5), 14.2340 (5) |
β (°) | 100.988 (2) |
V (Å3) | 1553.17 (10) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 1.42 |
Crystal size (mm) | 0.25 × 0.22 × 0.13 |
Data collection | |
Diffractometer | NONIUS KappaCCD diffractometer |
Absorption correction | Empirical (using intensity measurements) (Blessing, 1995, 1997) |
Tmin, Tmax | 0.766, 0.831 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 27425, 3682, 2489 |
Rint | 0.066 |
(sin θ/λ)max (Å−1) | 0.657 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.044, 0.120, 1.02 |
No. of reflections | 3682 |
No. of parameters | 227 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.70, −0.45 |
Computer programs: KappaCCD Software (Nonius, 1998), HKL SCALEPACK (Otwinowski & Minor, 1997), HKL DENZO (Otwinowski & Minor, 1997) and maXus (Mackay et al., 1998), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Sheldrick, 1998), SHELXL97.
Cu1—N3 | 1.959 (3) | Cu1—N2 | 2.024 (2) |
Cu1—N6 | 2.003 (3) | Cu1—N8i | 2.286 (3) |
Cu1—N1 | 2.010 (2) | Cu1—N5ii | 2.821 (3) |
N3—Cu1—N6 | 90.97 (13) | N1—Cu1—N8i | 91.35 (10) |
N3—Cu1—N1 | 172.10 (11) | N2—Cu1—N8i | 96.74 (10) |
N6—Cu1—N1 | 93.18 (11) | N1—Cu1—N5ii | 81.81 (9) |
N3—Cu1—N2 | 92.58 (11) | N2—Cu1—N5ii | 81.79 (10) |
N6—Cu1—N2 | 164.49 (10) | N3—Cu1—N5ii | 92.04 (11) |
N1—Cu1—N2 | 81.68 (9) | N6—Cu1—N5ii | 83.00 (11) |
N3—Cu1—N8i | 94.72 (12) | N8i—Cu1—N5ii | 173.14 (10) |
N6—Cu1—N8i | 98.01 (11) |
Symmetry codes: (i) x, −y+3/2, z+1/2; (ii) −x+1, −y+2, −z. |
Polymeric complexes comprised of transition metals with dicyanamide have attracted considerable attention because of their interesting coordination and physical properties (Kurmoo & Kepert, 1998; Manson, Kmety et al., 1998, Manson, Arif & Miller, 1999; Batten et al., 1999; Jensen et al., 1999; van Albada et al., 2000). Those complexes containing only dca are of a quite limited structural type (Kurmoo et al., 1998; Manson, Kmety et al., 1998; Jensen et al., 1999), while by introducing co-ligands such as pyridine, bipyridine, etc., various types of structure have been obtained, and this presents an opportunity to adjust the physical properties (Manson, Incarvito et al., 1998; Manson, Arif & Miller 1999; Manson, Arif, Incarvito et al., 1999; Batten et al., 1999). So far, only a few such Cu complexes have been structurally characterized (Potočňák et al., 1995, 1996; Dunaj-Jurčo et al., 1996; Kurmoo et al., 1998; van Albada et al., 2000). Among them, only one of these co-ligand complexes is a polymeric compound (van Albada et al., 2000). Recently we have synthesized the title compound, (I), which has an extended structure, and its crystal structure is reported here. \sch
Basically, the structure is sheet-like, consisting of inter-linked [Cu(phen)(dca)2]n chains. In the chain, each Cu2+ is fivefold coordinated by the N atoms of three dca ligands and one phen ligand (Fig. 1). The CuN5 moiety can be described as a distorted square pyramid, because the trigonality criterion, which is 1 for an ideal trigonal bipyramid and 0 for an ideal square pyramid (Addison et al., 1984), is 0.13 for the moiety. The two terminal N atoms from two dca ligands and the two N atoms of the phen ligand form the base of the pyramid. The Cu2+ is 0.183 (1) Å above the base. The apical position is occupied by the terminal N atom of a neighbouring dca ligand. Thus, adjacent CuN5 pyramids are linked by a bridging dca ligand from the apex of one pyramid to the base of the next one to form a zigzag chain running along the c direction (Fig. 2). Since the adjacent Cu centers are related to each other by the c glide plane, all phen ligands attached to the same chain are on the same side of the chain. The plane of the phen ligand and that of the base of the pyramid are approximately coplanar. Of the three dca ligands coordinated to each Cu atom, two dca are bridging ligands connecting Cu centres and the third one is terminal. In fact, these terminal dca ligands cross-link adjacent [Cu(phen)(dca)2]n chains through secondary long Cu—N bonds involving the terminal N atoms to give a sheet-like structure which extends along the bc plane (Fig. 2). In the sheet, the Cu2+ ions are not all in the same plane. As the neighbouring [Cu(phen)(dca)2]n chains in the sheet are centrally symmetric, the phen ligands are arranged on both sides of the sheet, and the planes of the phen ligands are inclinded with respect to the bc plane at an angle of ca 70°. Finally, these sheets stack along the a direction through the aromatic interaction between interlocking phen ligands from adjacent sheets, to build the three-dimensional crystal structure.
In the CuN5 pyramid, the four basal Cu—N distances, being in the range of 1.959 (3)–2.024 (2) Å, are nearly equal to each other, and are similar to those of the pyramidal CuN5 moiety in [Cu(add)(bipy)(dca)] (add = 3-amino-3- methoxy-2-nitrosoacrylonitrilate, bipy=2, 2'-bipyridine) (Dunaj-Jurčo et al., 1996), or the equatorial Cu—N distances of the tetragonal bipyramidal CuN6 moiety in [Cu(phen)2(dca)2] (Potočňák et al., 1995), Cu(dca)2 (Kurmoo et al., 1998) and [Cu(dca)2(ampym)2] (ampym=2-aminopyrimidine) (van Albada et al., 2000). The axial Cu—N distance, 2.286 (3) Å, is slightly longer than in the pyramidal CuN5 moiety reported by Dunaj-Jurčo et al. (1996) [2.188 (4) Å]. The secondary or weak Cu—N bond aforementioned, which has a Cu—N distance of 2.821 (3) Å and is opposite to the axial Cu—N bond, is unusually longer than long Cu—N bonds reported previously for Cu-dca complexes [2.449 (4) and 2.473 (4) Å in Cu(dca)2 (Kurmoo et al., 1998) and 2.365 (3) Å in Cu(phen)2(dca)2 (Potočňák et al., 1995)]. If this secondary Cu—N bond is included, the Cu2+ has a 5 + 1 coordination environment.
The intra-chain Cu—Cu distance, 7.7079 (4) Å, is longer than the shortest inter-chain Cu—Cu distance of 6.4521 (4) Å between two Cu2+ ions related by the screw axis 21 (010) and with no spacer between them. Another short inter-chain Cu—Cu distance of 7.3002 (7) Å is between the two Cu2+ ions connected by two dca ligands via the secondary Cu—N bonds.
The bond distances and angles in the phen ligand, which range from 1.318 (4)–1.431 (5) Å and 116.2 (3)–125.5 (3)°, respectively, are all normal (Potočňák et al., 1995). The phen ligand is nearly planar, with the largest deviation from the mean plane being 0.064 (3) Å for C2. The dca ligands are also planar and the largest deviation from the mean plane is 0.019 (3) Å for C14. Two distinct sets of N—C distances in the dca ligands, which lie in range of 1.098 (4)–1.149 (4) Å, and 1.283 (4)–1.331 (5) Å, respectively, together with the C—N—C angles (120.5 (4) and 122.3 (3)°) and the N—C—N angles [167.1 (4)- 174.2 (3)°], are all comparable with values found in other dca complexes (Kurmoo et al., 1998; Batten et al., 1999; Manson, Arif, Incarvito et al., 1999; Potočňák et al., 1995, 1996; Dunaj-Jurčo et al., 1996; van Albada et al., 2000).
We have also obtained the Co analogue (Sun et al., 19XX) of this structure. The main difference between the two structures is that in the Co complex the Co atom is sixfold coordinated in an octahedral coordination environment in which no weak, secondary Co—N bonds exist and the Co—N distances fall in the range of 2.081 (3)–2.207 (2) Å. A similar behaviour has been observed for the two related structures, Cu(dca)2 and Co(dca)2. This pattern is related to the strong Jahn-Teller effect which influences the Cu2+ ion (Kurmoo et al., 1998).