Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536802003070/tk6054sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536802003070/tk6054Isup2.hkl |
CCDC reference: 182590
Key indicators
- Single-crystal X-ray study
- T = 168 K
- Mean (C-C) = 0.004 Å
- R factor = 0.027
- wR factor = 0.061
- Data-to-parameter ratio = 18.0
checkCIF results
No syntax errors found ADDSYM reports no extra symmetry
Alert Level C:
ABSTM_02 Alert C The ratio of expected to reported Tmax/Tmin(RR) is > 1.10 Tmin and Tmax reported: 0.843 1.000 Tmin and Tmax expected: 0.361 0.541 RR = 1.266 Please check that your absorption correction is appropriate. PLAT_420 Alert C D-H Without Acceptor N(4) - H(4B) ? PLAT_420 Alert C D-H Without Acceptor N(6) - H(6B) ? General Notes
ABSTM_02 When printed, the submitted absorption T values will be replaced by the scaled T values. Since the ratio of scaled T's is identical to the ratio of reported T values, the scaling does not imply a change to the absorption corrections used in the study. Ratio of Tmax expected/reported 0.541 Tmax scaled 0.541 Tmin scaled 0.456
0 Alert Level A = Potentially serious problem
0 Alert Level B = Potential problem
3 Alert Level C = Please check
A solution of mer-(exo)- and mer-(endo)-[Co(dien)(dapo)N3]ZnCl4 (1.1 g) in water (5 ml) containing NaN3 (0.55 g) was allowed to stand for 1 h at pH 7.85, then for a further 1 h at pH 9.3. Precipitated Zn(OH)2 was removed by filtration, the filtrate was acidified (HOAc, pH 4.5) and complexes separated by ion-exchange chromatography (Dowex 50Wx2, 1 M NaCl, pH 4.2). The slower moving of the two major bands was collected and evaporated to near dryness at room temperature. MeOH was added and solid NaCl removed by filtration. This treatment was repeated until all the NaCl was removed. The final filtrate was evaporated to dryness, and the residue in water (4 ml) was treated with aqueous Li2ZnCl4 (2 M, 1 ml). The first two fractions to crystallize (ice cooling) deposited rapidly and consisted mainly of mer-(exo)-[Co(dien)(dapo)N3]ZnCl4. The third fraction which was obtained on storage overnight at 277 K (0.3 g, unsym-fac(exo-OH plus endo-OH)-[Co(dien)(dapo)N3]ZnCl4) was dissolved in the minimum volume of hot water to give large rhombohedral crystals of the unsym-fac(exo-OH)- isomer on slow cooling at room temperature.
H atoms were included in calculated positions and refined in the riding approximation with individual (or group, if appropriate) isotropic displacement parameters.
Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: WinGX (Farrugia, 1999); software used to prepare material for publication: WinGX.
Fig. 1. The structure of the cation of (I) with displacement ellipsoids drawn at the 50% probability level (Farrugia, 1999). |
[Co(N3)(C4H13N3)(C3H10N2O)][ZnCl4] | F(000) = 1016 |
Mr = 501.43 | Dx = 1.891 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 8.119 (3) Å | Cell parameters from 3138 reflections |
b = 21.373 (6) Å | θ = 2.2–26.5° |
c = 10.249 (3) Å | µ = 2.92 mm−1 |
β = 98.071 (4)° | T = 168 K |
V = 1760.8 (9) Å3 | Irregular-b, red |
Z = 4 | 0.79 × 0.30 × 0.21 mm |
CCD area detector diffractometer | 3138 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.032 |
ϕ and ω scans | θmax = 26.5°, θmin = 2.2° |
Absorption correction: multi-scan (SADABS; Bruker, 1997) | h = −10→10 |
Tmin = 0.843, Tmax = 1 | k = −20→26 |
22443 measured reflections | l = −12→12 |
3600 independent 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)] = 0.027 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.061 | H-atom parameters constrained |
S = 1.10 | w = 1/[σ2(Fo2) + (0.0243P)2 + 1.8355P] where P = (Fo2 + 2Fc2)/3 |
3600 reflections | (Δ/σ)max = 0.001 |
200 parameters | Δρmax = 0.58 e Å−3 |
0 restraints | Δρmin = −0.41 e Å−3 |
[Co(N3)(C4H13N3)(C3H10N2O)][ZnCl4] | V = 1760.8 (9) Å3 |
Mr = 501.43 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 8.119 (3) Å | µ = 2.92 mm−1 |
b = 21.373 (6) Å | T = 168 K |
c = 10.249 (3) Å | 0.79 × 0.30 × 0.21 mm |
β = 98.071 (4)° |
CCD area detector diffractometer | 3600 independent reflections |
Absorption correction: multi-scan (SADABS; Bruker, 1997) | 3138 reflections with I > 2σ(I) |
Tmin = 0.843, Tmax = 1 | Rint = 0.032 |
22443 measured reflections |
R[F2 > 2σ(F2)] = 0.027 | 0 restraints |
wR(F2) = 0.061 | H-atom parameters constrained |
S = 1.10 | Δρmax = 0.58 e Å−3 |
3600 reflections | Δρmin = −0.41 e Å−3 |
200 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 | ||
Co1 | 0.84605 (4) | 0.128749 (15) | 0.28525 (3) | 0.01706 (8) | |
N1 | 0.6209 (3) | 0.15998 (10) | 0.2824 (2) | 0.0284 (5) | |
N2 | 0.5804 (3) | 0.21329 (11) | 0.2793 (2) | 0.0260 (5) | |
N3 | 0.5276 (4) | 0.26386 (13) | 0.2759 (4) | 0.0527 (8) | |
N4 | 0.7781 (3) | 0.10520 (10) | 0.0997 (2) | 0.0304 (5) | |
H4A | 0.8184 | 0.066 | 0.0853 | 0.037* | |
H4B | 0.6638 | 0.1036 | 0.0827 | 0.037* | |
N5 | 0.9339 (3) | 0.20546 (10) | 0.2147 (2) | 0.0231 (4) | |
H5 | 0.8991 | 0.239 | 0.2617 | 0.028* | |
N6 | 1.0726 (3) | 0.09394 (10) | 0.2853 (2) | 0.0272 (5) | |
H6A | 1.1186 | 0.085 | 0.3705 | 0.033* | |
H6B | 1.0655 | 0.0571 | 0.2383 | 0.033* | |
N7 | 0.9044 (3) | 0.15863 (10) | 0.4695 (2) | 0.0227 (4) | |
H7A | 1.0057 | 0.1415 | 0.5026 | 0.027* | |
H7B | 0.9188 | 0.2013 | 0.4668 | 0.027* | |
N8 | 0.7678 (3) | 0.04839 (9) | 0.3456 (2) | 0.0232 (5) | |
H8A | 0.7081 | 0.0291 | 0.2739 | 0.028* | |
H8B | 0.8601 | 0.024 | 0.3713 | 0.028* | |
C1 | 0.8405 (4) | 0.15027 (13) | 0.0085 (3) | 0.0324 (6) | |
H1A | 0.7622 | 0.1528 | −0.0746 | 0.039* | |
H1B | 0.9501 | 0.1365 | −0.0127 | 0.039* | |
C2 | 0.8560 (4) | 0.21262 (13) | 0.0743 (3) | 0.0326 (6) | |
H2A | 0.7445 | 0.2318 | 0.0709 | 0.039* | |
H2B | 0.9253 | 0.2405 | 0.0273 | 0.039* | |
C3 | 1.1208 (4) | 0.20315 (14) | 0.2420 (3) | 0.0375 (7) | |
H3A | 1.1683 | 0.2313 | 0.1803 | 0.045* | |
H3B | 1.1584 | 0.218 | 0.3328 | 0.045* | |
C4 | 1.1820 (3) | 0.13816 (14) | 0.2267 (3) | 0.0330 (6) | |
H4C | 1.181 | 0.1285 | 0.1321 | 0.04* | |
H4D | 1.2978 | 0.1341 | 0.2716 | 0.04* | |
C5 | 0.7860 (3) | 0.14528 (12) | 0.5656 (3) | 0.0285 (6) | |
H5A | 0.6793 | 0.1669 | 0.5367 | 0.034* | |
H5B | 0.8324 | 0.162 | 0.6531 | 0.034* | |
C6 | 0.7547 (3) | 0.07632 (13) | 0.5771 (3) | 0.0288 (6) | |
H6 | 0.6868 | 0.0696 | 0.6501 | 0.035* | |
C7 | 0.6648 (3) | 0.04716 (13) | 0.4534 (3) | 0.0281 (6) | |
H7C | 0.6361 | 0.0033 | 0.4717 | 0.034* | |
H7D | 0.5599 | 0.0702 | 0.4257 | 0.034* | |
O1 | 0.9084 (3) | 0.04301 (9) | 0.6082 (2) | 0.0344 (5) | |
H1 | 0.957 | 0.0549 | 0.6818 | 0.052* | |
Zn1 | 0.84880 (4) | 0.402393 (14) | 0.32047 (3) | 0.02397 (9) | |
Cl1 | 1.05089 (8) | 0.47604 (3) | 0.34137 (6) | 0.02903 (15) | |
Cl2 | 0.80150 (8) | 0.37407 (3) | 0.10145 (6) | 0.02809 (14) | |
Cl3 | 0.61875 (8) | 0.45042 (3) | 0.38439 (7) | 0.02862 (15) | |
Cl4 | 0.91206 (10) | 0.31615 (3) | 0.44702 (7) | 0.03424 (16) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Co1 | 0.01748 (16) | 0.01275 (16) | 0.02010 (16) | −0.00075 (12) | −0.00029 (12) | 0.00054 (12) |
N1 | 0.0187 (11) | 0.0231 (12) | 0.0417 (13) | 0.0024 (9) | −0.0015 (9) | 0.0058 (10) |
N2 | 0.0186 (10) | 0.0318 (13) | 0.0271 (12) | 0.0002 (10) | 0.0012 (9) | −0.0004 (10) |
N3 | 0.0382 (16) | 0.0308 (15) | 0.089 (2) | 0.0124 (12) | 0.0085 (15) | −0.0056 (15) |
N4 | 0.0456 (14) | 0.0195 (11) | 0.0238 (11) | 0.0002 (10) | −0.0035 (10) | −0.0021 (9) |
N5 | 0.0271 (11) | 0.0152 (10) | 0.0265 (11) | −0.0007 (9) | 0.0026 (9) | 0.0013 (9) |
N6 | 0.0263 (11) | 0.0209 (11) | 0.0351 (13) | 0.0035 (9) | 0.0067 (9) | 0.0011 (10) |
N7 | 0.0267 (11) | 0.0168 (10) | 0.0235 (11) | −0.0016 (9) | −0.0005 (9) | 0.0010 (8) |
N8 | 0.0261 (11) | 0.0164 (10) | 0.0268 (11) | −0.0030 (9) | 0.0026 (9) | 0.0001 (9) |
C1 | 0.0428 (17) | 0.0320 (15) | 0.0233 (14) | 0.0014 (13) | 0.0078 (12) | 0.0001 (12) |
C2 | 0.0456 (17) | 0.0248 (14) | 0.0279 (14) | 0.0013 (13) | 0.0070 (12) | 0.0051 (12) |
C3 | 0.0288 (15) | 0.0310 (16) | 0.0541 (19) | −0.0087 (12) | 0.0102 (14) | 0.0028 (14) |
C4 | 0.0224 (13) | 0.0358 (16) | 0.0424 (17) | 0.0015 (12) | 0.0100 (12) | 0.0089 (13) |
C5 | 0.0352 (15) | 0.0257 (14) | 0.0253 (13) | 0.0036 (12) | 0.0071 (11) | −0.0019 (11) |
C6 | 0.0321 (14) | 0.0269 (14) | 0.0300 (14) | 0.0041 (11) | 0.0133 (11) | 0.0052 (11) |
C7 | 0.0239 (13) | 0.0222 (13) | 0.0395 (16) | −0.0026 (11) | 0.0088 (11) | 0.0064 (12) |
O1 | 0.0392 (12) | 0.0288 (11) | 0.0334 (11) | 0.0086 (9) | −0.0011 (9) | 0.0024 (9) |
Zn1 | 0.02795 (16) | 0.02072 (16) | 0.02279 (16) | −0.00238 (12) | 0.00204 (12) | −0.00018 (12) |
Cl1 | 0.0301 (3) | 0.0306 (3) | 0.0259 (3) | 0.0028 (3) | 0.0023 (3) | 0.0044 (3) |
Cl2 | 0.0285 (3) | 0.0303 (3) | 0.0245 (3) | 0.0029 (3) | 0.0005 (2) | 0.0041 (3) |
Cl3 | 0.0293 (3) | 0.0261 (3) | 0.0315 (3) | 0.0003 (3) | 0.0082 (3) | 0.0017 (3) |
Cl4 | 0.0511 (4) | 0.0205 (3) | 0.0286 (3) | −0.0021 (3) | −0.0032 (3) | −0.0023 (3) |
Co1—N1 | 1.943 (2) | C1—C2 | 1.491 (4) |
Co1—N4 | 1.970 (2) | C1—H1A | 0.9900 |
Co1—N5 | 1.966 (2) | C1—H1B | 0.9900 |
Co1—N6 | 1.984 (2) | C2—H2A | 0.9900 |
Co1—N7 | 1.986 (2) | C2—H2B | 0.9900 |
Co1—N8 | 1.961 (2) | C3—C4 | 1.491 (4) |
N1—N2 | 1.185 (3) | C3—H3A | 0.9900 |
N2—N3 | 1.162 (3) | C3—H3B | 0.9900 |
N4—C1 | 1.481 (4) | C4—H4C | 0.9900 |
N4—H4A | 0.9200 | C4—H4D | 0.9900 |
N4—H4B | 0.9200 | C5—C6 | 1.503 (4) |
N5—C2 | 1.497 (3) | C5—H5A | 0.9900 |
N5—C3 | 1.505 (3) | C5—H5B | 0.9900 |
N5—H5 | 0.9300 | C6—O1 | 1.433 (3) |
N6—C4 | 1.481 (3) | C6—C7 | 1.506 (4) |
N6—H6A | 0.9200 | C6—H6 | 1.0000 |
N6—H6B | 0.9200 | C7—H7C | 0.9900 |
N7—C5 | 1.497 (3) | C7—H7D | 0.9900 |
N7—H7A | 0.9200 | O1—H1 | 0.8400 |
N7—H7B | 0.9200 | Zn1—Cl1 | 2.2621 (9) |
N8—C7 | 1.477 (3) | Zn1—Cl2 | 2.3045 (9) |
N8—H8A | 0.9200 | Zn1—Cl3 | 2.3054 (9) |
N8—H8B | 0.9200 | Zn1—Cl4 | 2.2709 (9) |
N1—Co1—N4 | 86.44 (10) | N4—C1—H1A | 110.1 |
N1—Co1—N5 | 95.59 (9) | C2—C1—H1A | 110.1 |
N1—Co1—N6 | 177.91 (9) | N4—C1—H1B | 110.1 |
N1—Co1—N7 | 90.12 (9) | C2—C1—H1B | 110.1 |
N1—Co1—N8 | 87.71 (9) | H1A—C1—H1B | 108.4 |
N4—Co1—N6 | 92.21 (10) | C1—C2—N5 | 109.9 (2) |
N4—Co1—N7 | 175.51 (9) | C1—C2—H2A | 109.7 |
N5—Co1—N4 | 85.71 (9) | N5—C2—H2A | 109.7 |
N5—Co1—N6 | 85.90 (9) | C1—C2—H2B | 109.7 |
N5—Co1—N7 | 91.76 (9) | N5—C2—H2B | 109.7 |
N6—Co1—N7 | 91.31 (9) | H2A—C2—H2B | 108.2 |
N8—Co1—N4 | 91.23 (9) | C4—C3—N5 | 110.7 (2) |
N8—Co1—N5 | 175.34 (9) | C4—C3—H3A | 109.5 |
N8—Co1—N6 | 90.73 (9) | N5—C3—H3A | 109.5 |
N8—Co1—N7 | 91.52 (9) | C4—C3—H3B | 109.5 |
N2—N1—Co1 | 125.99 (18) | N5—C3—H3B | 109.5 |
N3—N2—N1 | 174.5 (3) | H3A—C3—H3B | 108.1 |
C1—N4—Co1 | 111.66 (17) | N6—C4—C3 | 108.9 (2) |
C1—N4—H4A | 109.3 | N6—C4—H4C | 109.9 |
Co1—N4—H4A | 109.3 | C3—C4—H4C | 109.9 |
C1—N4—H4B | 109.3 | N6—C4—H4D | 109.9 |
Co1—N4—H4B | 109.3 | C3—C4—H4D | 109.9 |
H4A—N4—H4B | 107.9 | H4C—C4—H4D | 108.3 |
C2—N5—C3 | 117.5 (2) | N7—C5—C6 | 111.7 (2) |
C2—N5—Co1 | 108.21 (16) | N7—C5—H5A | 109.3 |
C3—N5—Co1 | 108.23 (16) | C6—C5—H5A | 109.3 |
C2—N5—H5 | 107.5 | N7—C5—H5B | 109.3 |
C3—N5—H5 | 107.5 | C6—C5—H5B | 109.3 |
Co1—N5—H5 | 107.5 | H5A—C5—H5B | 107.9 |
C4—N6—Co1 | 111.68 (16) | O1—C6—C5 | 110.7 (2) |
C4—N6—H6A | 109.3 | O1—C6—C7 | 106.6 (2) |
Co1—N6—H6A | 109.3 | C5—C6—C7 | 114.0 (2) |
C4—N6—H6B | 109.3 | O1—C6—H6 | 108.5 |
Co1—N6—H6B | 109.3 | C5—C6—H6 | 108.5 |
H6A—N6—H6B | 107.9 | C7—C6—H6 | 108.5 |
C5—N7—Co1 | 118.34 (16) | N8—C7—C6 | 111.3 (2) |
C5—N7—H7A | 107.7 | N8—C7—H7C | 109.4 |
Co1—N7—H7A | 107.7 | C6—C7—H7C | 109.4 |
C5—N7—H7B | 107.7 | N8—C7—H7D | 109.4 |
Co1—N7—H7B | 107.7 | C6—C7—H7D | 109.4 |
H7A—N7—H7B | 107.1 | H7C—C7—H7D | 108.0 |
C7—N8—Co1 | 119.61 (16) | C6—O1—H1 | 109.5 |
C7—N8—H8A | 107.4 | Cl1—Zn1—Cl4 | 114.07 (3) |
Co1—N8—H8A | 107.4 | Cl1—Zn1—Cl2 | 107.13 (3) |
C7—N8—H8B | 107.4 | Cl4—Zn1—Cl2 | 109.66 (3) |
Co1—N8—H8B | 107.4 | Cl1—Zn1—Cl3 | 105.61 (3) |
H8A—N8—H8B | 106.9 | Cl4—Zn1—Cl3 | 109.05 (3) |
N4—C1—C2 | 108.1 (2) | Cl2—Zn1—Cl3 | 111.28 (3) |
Experimental details
Crystal data | |
Chemical formula | [Co(N3)(C4H13N3)(C3H10N2O)][ZnCl4] |
Mr | 501.43 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 168 |
a, b, c (Å) | 8.119 (3), 21.373 (6), 10.249 (3) |
β (°) | 98.071 (4) |
V (Å3) | 1760.8 (9) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 2.92 |
Crystal size (mm) | 0.79 × 0.30 × 0.21 |
Data collection | |
Diffractometer | CCD area detector diffractometer |
Absorption correction | Multi-scan (SADABS; Bruker, 1997) |
Tmin, Tmax | 0.843, 1 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 22443, 3600, 3138 |
Rint | 0.032 |
(sin θ/λ)max (Å−1) | 0.628 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.027, 0.061, 1.10 |
No. of reflections | 3600 |
No. of parameters | 200 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.58, −0.41 |
Computer programs: SMART (Bruker, 1997), SAINT (Bruker, 1997), SAINT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), WinGX (Farrugia, 1999), WinGX.
Co1—N1 | 1.943 (2) | N5—C3 | 1.505 (3) |
Co1—N4 | 1.970 (2) | N6—C4 | 1.481 (3) |
Co1—N5 | 1.966 (2) | N7—C5 | 1.497 (3) |
Co1—N6 | 1.984 (2) | N8—C7 | 1.477 (3) |
Co1—N7 | 1.986 (2) | C1—C2 | 1.491 (4) |
Co1—N8 | 1.961 (2) | C3—C4 | 1.491 (4) |
N1—N2 | 1.185 (3) | C5—C6 | 1.503 (4) |
N2—N3 | 1.162 (3) | C6—O1 | 1.433 (3) |
N4—C1 | 1.481 (4) | C6—C7 | 1.506 (4) |
N5—C2 | 1.497 (3) | ||
N1—Co1—N4 | 86.44 (10) | N5—Co1—N7 | 91.76 (9) |
N1—Co1—N5 | 95.59 (9) | N6—Co1—N7 | 91.31 (9) |
N1—Co1—N6 | 177.91 (9) | N8—Co1—N4 | 91.23 (9) |
N1—Co1—N7 | 90.12 (9) | N8—Co1—N5 | 175.34 (9) |
N1—Co1—N8 | 87.71 (9) | N8—Co1—N6 | 90.73 (9) |
N4—Co1—N6 | 92.21 (10) | N8—Co1—N7 | 91.52 (9) |
N4—Co1—N7 | 175.51 (9) | N2—N1—Co1 | 125.99 (18) |
N5—Co1—N4 | 85.71 (9) | N3—N2—N1 | 174.5 (3) |
N5—Co1—N6 | 85.90 (9) |
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[Co(dien)(dapo)(N3)]2+ complexes are rapidly hydrolyzed in weakly alkaline solution at room temperature. The mer(exo)- and mer(endo)- forms of the [Co(dien)(dapo)OH]2+ product quickly equilibrate [t1/2 = 0.20 s, 298 K, I = 1.0 M (NaClO4)], and at longer times (1–2 h, pH 9), significant production of unsym(fac) isomers occurs. The title complex, (I), was obtained by anation with azide ion and was isolated using a combination of ion-exchange chromatography and fractional crystallization (Browne et al., 2002). The structure of the cation consists of a central Co atom coordinated to a tridentate dien ligand bound in a facial configuration, a bidentate dapo ligand, and a monodentate azide ligand. As can be seen in Fig. 1, the dapo –OH group adopts an exo configuration with respect to the azide ligand. The geometry about the Co atom is approximately octahedral, with the greatest deviations from 90° being found in the five-membered chelate rings of the dien ligand. The Co—N distances lie in the range 1.943 (2)–1.986 (2) Å, with the bond to the azide ligand being significantly shorter than the others. This contrasts with the three previous structurally characterized [Co(dien)(dapo)N3]2+ complexes, namely Λ(-)436-mer(exo)-[Co(dien)(dapo)N3](di-O-benzoyl-L-tartH)2·4H2O, Λ(-)436-Λ(-)436-mer(endo)-[Co(dien)(dapo)N3](di-O-benzoyl-L– tartH)2·2.75H2O and Δ(+)436-mer(endo)-[Co(dien)(dapo)N3](di-O-benzoyl-L-tartH)2·5.75H2O (Comba et al., 1992) in which the bond between the Co atom and the secondary N atom of the dien ligand is the shortest of the Co—N distances.