In the title compound, [Co(C
2H
6NS)(C
2H
8N
2)
2](NO
3)
2, the Co
III atom has a slightly distorted octahedral geometry, coordinated by one 2-aminoethanethiolate and two ethylenediamine ligands. The three five-membered chelate rings adopt a
gauche conformation with the unfavoured (
lel)
2(
ob) form, which is ascribed to hydrogen bonds between the amine groups in the complex cation and the nitrate counter-anions [N
O 2.900 (3)–3.378 (3) Å].
Supporting information
CCDC reference: 164631
The title complex was prepared by a method similar to that used for
[Co(aet)(en)2](ClO4)2 (Nosco & Deutsch, 1982). To a deaerated solution
containing cobalt(II) nitrate hexahydrate (5.91 g, 20.3 mmol) in water (15 ml)
was added a deaerated solution containing cystamine dihydrochloride (2.28 g,
10 mmol) and ethylenediamine (3.75 ml, 56 mmol) in water (30 ml). The mixture
was stirred at room temperature for 30 min under a nitrogen atmosphere,
followed by the addition of a saturated aqueous solution of NaNO3 (70 ml).
After the reaction, the mixture was allowed to stand in a refrigerator for 1 d. The resulting black crystals of (I) were collected by filtration and
recrystallized from water by adding several drops of a saturated aqueous
solution of NaNO3 (yield 5.28 g, 82.1%).
H atoms bonded to C were placed at calculated positions and refined with
isotropic displacement parameters and a riding model (C—H distances?). H
atoms bonded to N were refined freely.
Data collection: MSC/AFC Diffractometer Control Software (Molecular Structure Corporation, 1992); cell refinement: MSC/AFC Diffractometer Control Software; data reduction: TEXSAN (Molecular Structure Corporation, 1985); program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: TEXSAN; software used to prepare material for publication: TEXSAN.
Crystal data top
[Co(C2H6NS)(C2H8N2)2](NO3)2 | F(000) = 792.00 |
Mr = 379.28 | Dx = 1.659 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.7107 Å |
a = 9.509 (1) Å | Cell parameters from 25 reflections |
b = 12.824 (1) Å | θ = 14.5–15.0° |
c = 12.635 (1) Å | µ = 1.31 mm−1 |
β = 99.780 (8)° | T = 296 K |
V = 1518.4 (3) Å3 | Polyhedron, black |
Z = 4 | 0.35 × 0.25 × 0.18 mm |
Data collection top
Rigaku AFC-7S diffractometer | 2452 reflections with I > 2σ(I) |
Radiation source: Rigaku sealed tube | Rint = 0.017 |
Graphite monochromator | θmax = 27.5°, θmin = 2.2° |
ω/2θ scans | h = 0→12 |
Absorption correction: ψ-scan (North et al., 1968) | k = 0→16 |
Tmin = 0.688, Tmax = 0.770 | l = −16→16 |
3862 measured reflections | 3 standard reflections every 150 reflections |
3650 independent reflections | intensity decay: −0.6% |
Refinement top
Refinement on F | 0 restraints |
Least-squares matrix: full | 0 constraints |
R[F2 > 2σ(F2)] = 0.031 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.041 | w = 1/[σ2(Fo) + 0.00038|Fo|2] |
S = 1.11 | (Δ/σ)max = 0.001 |
2726 reflections | Δρmax = 0.30 e Å−3 |
266 parameters | Δρmin = −0.29 e Å−3 |
Crystal data top
[Co(C2H6NS)(C2H8N2)2](NO3)2 | V = 1518.4 (3) Å3 |
Mr = 379.28 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 9.509 (1) Å | µ = 1.31 mm−1 |
b = 12.824 (1) Å | T = 296 K |
c = 12.635 (1) Å | 0.35 × 0.25 × 0.18 mm |
β = 99.780 (8)° | |
Data collection top
Rigaku AFC-7S diffractometer | 2452 reflections with I > 2σ(I) |
Absorption correction: ψ-scan (North et al., 1968) | Rint = 0.017 |
Tmin = 0.688, Tmax = 0.770 | 3 standard reflections every 150 reflections |
3862 measured reflections | intensity decay: −0.6% |
3650 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.031 | 0 restraints |
wR(F2) = 0.041 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.11 | Δρmax = 0.30 e Å−3 |
2726 reflections | Δρmin = −0.29 e Å−3 |
266 parameters | |
Special details top
Refinement. Refinement based on F against all reflections. The weighted
R-factor (wR) and goodness of fit (S) are based on
F, conventional R-factors (R) are calculated on F,
with F set to zero for negative F. The threshold expression of
F2 > σ(F2) is used only for calculating
R-factors(gt) etc. thus the refinement was done using all
reflections. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Co1 | 0.18501 (4) | 0.22937 (3) | 0.52177 (3) | 0.02841 (9) | |
S1 | 0.07823 (8) | 0.14295 (6) | 0.37497 (6) | 0.0398 (2) | |
N1 | 0.3590 (3) | 0.1487 (2) | 0.5133 (2) | 0.0374 (7) | |
N2 | 0.0061 (3) | 0.3024 (2) | 0.5289 (2) | 0.0358 (6) | |
N3 | 0.1156 (3) | 0.1248 (2) | 0.6155 (2) | 0.0391 (7) | |
N4 | 0.2442 (3) | 0.3426 (2) | 0.4344 (2) | 0.0357 (6) | |
N5 | 0.2913 (3) | 0.3112 (2) | 0.6471 (2) | 0.0372 (6) | |
C1 | 0.2416 (4) | 0.0980 (3) | 0.3346 (3) | 0.0482 (9) | |
C2 | 0.3433 (4) | 0.0631 (3) | 0.4320 (3) | 0.0467 (9) | |
C3 | −0.0586 (4) | 0.2580 (3) | 0.6172 (3) | 0.0437 (8) | |
C4 | −0.0393 (4) | 0.1424 (3) | 0.6126 (3) | 0.0472 (9) | |
C5 | 0.2988 (4) | 0.4330 (2) | 0.5032 (3) | 0.0425 (8) | |
C6 | 0.3824 (3) | 0.3898 (3) | 0.6063 (3) | 0.0440 (8) | |
O11 | 0.4899 (3) | 0.0069 (2) | 0.8726 (2) | 0.0575 (7) | |
O12 | 0.3550 (3) | −0.0258 (2) | 0.7211 (2) | 0.0599 (7) | |
O13 | 0.4982 (3) | 0.1048 (2) | 0.7370 (2) | 0.0569 (7) | |
N11 | 0.4468 (3) | 0.0280 (2) | 0.7765 (2) | 0.0385 (6) | |
O21 | 0.2379 (2) | 0.1914 (2) | 0.8526 (2) | 0.0641 (8) | |
O22 | 0.0178 (3) | 0.1674 (3) | 0.8602 (3) | 0.091 (1) | |
O23 | 0.1396 (4) | 0.2672 (3) | 0.9731 (3) | 0.107 (1) | |
N12 | 0.1324 (3) | 0.2090 (3) | 0.8955 (2) | 0.0540 (9) | |
H1 | 0.424 (4) | 0.189 (3) | 0.501 (3) | 0.055 (9)* | |
H2 | 0.391 (4) | 0.125 (3) | 0.572 (3) | 0.059 (10)* | |
H3 | 0.018 (3) | 0.364 (2) | 0.540 (2) | 0.025 (7)* | |
H4 | −0.054 (4) | 0.297 (2) | 0.467 (3) | 0.045 (8)* | |
H5 | 0.133 (4) | 0.057 (3) | 0.595 (3) | 0.066 (10)* | |
H6 | 0.167 (4) | 0.139 (3) | 0.684 (3) | 0.061 (9)* | |
H7 | 0.314 (3) | 0.322 (2) | 0.399 (2) | 0.041 (8)* | |
H8 | 0.175 (4) | 0.362 (3) | 0.385 (3) | 0.053 (9)* | |
H9 | 0.230 (3) | 0.344 (3) | 0.681 (2) | 0.045 (9)* | |
H10 | 0.342 (4) | 0.273 (3) | 0.699 (3) | 0.051 (9)* | |
H11 | 0.220 (4) | 0.041 (3) | 0.282 (3) | 0.0577* | |
H12 | 0.286 (4) | 0.149 (3) | 0.303 (3) | 0.0577* | |
H13 | 0.440 (4) | 0.050 (3) | 0.413 (2) | 0.0559* | |
H14 | 0.305 (4) | 0.001 (3) | 0.465 (3) | 0.0559* | |
H15 | −0.005 (4) | 0.290 (3) | 0.683 (3) | 0.0523* | |
H16 | −0.148 (4) | 0.280 (3) | 0.611 (3) | 0.0523* | |
H17 | −0.085 (4) | 0.110 (3) | 0.539 (3) | 0.0567* | |
H18 | −0.068 (4) | 0.107 (3) | 0.672 (3) | 0.0567* | |
H19 | 0.357 (3) | 0.474 (3) | 0.469 (2) | 0.0512* | |
H20 | 0.217 (4) | 0.472 (3) | 0.520 (2) | 0.0512* | |
H21 | 0.407 (4) | 0.444 (3) | 0.653 (3) | 0.0528* | |
H22 | 0.473 (4) | 0.361 (3) | 0.593 (3) | 0.0528* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Co1 | 0.0275 (2) | 0.0274 (2) | 0.0299 (2) | 0.0008 (1) | 0.0034 (1) | 0.0008 (1) |
S1 | 0.0406 (4) | 0.0382 (4) | 0.0377 (4) | 0.0011 (3) | −0.0014 (3) | −0.0064 (3) |
N1 | 0.033 (1) | 0.041 (1) | 0.037 (1) | 0.006 (1) | 0.005 (1) | 0.006 (1) |
N2 | 0.032 (1) | 0.029 (1) | 0.046 (1) | 0.000 (1) | 0.005 (1) | −0.005 (1) |
N3 | 0.043 (1) | 0.031 (1) | 0.045 (1) | 0.000 (1) | 0.011 (1) | 0.003 (1) |
N4 | 0.035 (1) | 0.038 (1) | 0.033 (1) | 0.000 (1) | 0.003 (1) | 0.0046 (10) |
N5 | 0.037 (1) | 0.042 (1) | 0.032 (1) | −0.004 (1) | 0.003 (1) | −0.001 (1) |
C1 | 0.053 (2) | 0.052 (2) | 0.042 (2) | 0.001 (2) | 0.014 (1) | −0.010 (1) |
C2 | 0.046 (2) | 0.044 (2) | 0.051 (2) | 0.012 (1) | 0.012 (1) | −0.005 (1) |
C3 | 0.034 (1) | 0.044 (2) | 0.056 (2) | −0.001 (1) | 0.016 (1) | −0.005 (1) |
C4 | 0.043 (2) | 0.042 (2) | 0.059 (2) | −0.009 (1) | 0.017 (2) | 0.000 (1) |
C5 | 0.044 (2) | 0.036 (2) | 0.048 (2) | −0.009 (1) | 0.009 (1) | 0.001 (1) |
C6 | 0.037 (2) | 0.047 (2) | 0.046 (2) | −0.010 (1) | 0.002 (1) | −0.004 (1) |
O11 | 0.079 (2) | 0.047 (1) | 0.040 (1) | −0.009 (1) | −0.007 (1) | 0.0111 (10) |
O12 | 0.058 (1) | 0.058 (1) | 0.057 (1) | −0.015 (1) | −0.008 (1) | −0.004 (1) |
O13 | 0.070 (2) | 0.050 (1) | 0.049 (1) | −0.011 (1) | 0.005 (1) | 0.014 (1) |
N11 | 0.045 (1) | 0.033 (1) | 0.037 (1) | 0.003 (1) | 0.004 (1) | 0.0022 (10) |
O21 | 0.040 (1) | 0.103 (2) | 0.052 (1) | 0.005 (1) | 0.016 (1) | 0.000 (1) |
O22 | 0.046 (2) | 0.141 (3) | 0.088 (2) | −0.015 (2) | 0.019 (2) | −0.010 (2) |
O23 | 0.067 (2) | 0.168 (4) | 0.084 (2) | 0.021 (2) | 0.007 (2) | −0.050 (2) |
N12 | 0.040 (2) | 0.082 (2) | 0.041 (1) | 0.016 (1) | 0.008 (1) | 0.009 (1) |
Geometric parameters (Å, º) top
Co1—S1 | 2.2494 (8) | O12—N11 | 1.233 (3) |
Co1—N1 | 1.969 (3) | O13—N11 | 1.241 (3) |
Co1—N2 | 1.958 (2) | O21—N12 | 1.240 (3) |
Co1—N3 | 1.976 (2) | O22—N12 | 1.228 (4) |
Co1—N4 | 1.963 (2) | O23—N12 | 1.225 (4) |
Co1—N5 | 2.022 (2) | N1—H1 | 0.84 (3) |
S1—C1 | 1.810 (3) | N1—H2 | 0.81 (3) |
N1—C2 | 1.495 (4) | N2—H3 | 0.81 (2) |
N2—C3 | 1.478 (4) | N2—H4 | 0.89 (3) |
N3—C4 | 1.484 (4) | N3—H5 | 0.92 (4) |
N4—C5 | 1.489 (4) | N3—H6 | 0.94 (3) |
N5—C6 | 1.478 (4) | N4—H7 | 0.91 (3) |
C1—C2 | 1.499 (5) | N4—H8 | 0.87 (3) |
C3—C4 | 1.497 (4) | N5—H9 | 0.89 (3) |
C5—C6 | 1.512 (4) | N5—H10 | 0.90 (3) |
O11—N11 | 1.244 (3) | | |
| | | |
S1—Co1—N1 | 87.85 (8) | C6—N5—H10 | 111 (2) |
S1—Co1—N2 | 89.97 (8) | H9—N5—H10 | 103 (2) |
S1—Co1—N3 | 90.57 (8) | S1—C1—C2 | 109.2 (2) |
S1—Co1—N4 | 91.90 (7) | S1—C1—H11 | 109 (2) |
S1—Co1—N5 | 175.78 (7) | S1—C1—H12 | 112 (2) |
N1—Co1—N2 | 176.9 (1) | C2—C1—H11 | 111 (1) |
N1—Co1—N3 | 92.6 (1) | C2—C1—H12 | 107 (2) |
N1—Co1—N4 | 92.0 (1) | H11—C1—H12 | 107 (2) |
N1—Co1—N5 | 90.1 (1) | N1—C2—C1 | 108.7 (3) |
N2—Co1—N3 | 85.2 (1) | N1—C2—H13 | 107 (1) |
N2—Co1—N4 | 90.3 (1) | N1—C2—H14 | 107 (1) |
N2—Co1—N5 | 92.2 (1) | C1—C2—H13 | 110 (1) |
N3—Co1—N4 | 174.9 (1) | C1—C2—H14 | 110 (1) |
N3—Co1—N5 | 93.2 (1) | H13—C2—H14 | 112 (2) |
N4—Co1—N5 | 84.5 (1) | N2—C3—C4 | 106.4 (2) |
Co1—S1—C1 | 95.8 (1) | N2—C3—H15 | 104 (1) |
Co1—N1—C2 | 115.9 (2) | N2—C3—H16 | 109 (2) |
Co1—N1—H1 | 109 (2) | C4—C3—H15 | 113 (1) |
Co1—N1—H2 | 109 (2) | C4—C3—H16 | 115 (2) |
C2—N1—H1 | 108 (2) | H15—C3—H16 | 107 (2) |
C2—N1—H2 | 108 (2) | N3—C4—C3 | 106.1 (3) |
H1—N1—H2 | 103 (3) | N3—C4—H17 | 103 (1) |
Co1—N2—C3 | 109.1 (2) | N3—C4—H18 | 108 (2) |
Co1—N2—H3 | 112 (2) | C3—C4—H17 | 113 (1) |
Co1—N2—H4 | 110 (2) | C3—C4—H18 | 112 (2) |
C3—N2—H3 | 108 (1) | H17—C4—H18 | 111 (2) |
C3—N2—H4 | 110 (2) | N4—C5—C6 | 107.3 (3) |
H3—N2—H4 | 105 (2) | N4—C5—H19 | 110 (1) |
Co1—N3—C4 | 108.2 (2) | N4—C5—H20 | 108 (1) |
Co1—N3—H5 | 112 (2) | C6—C5—H19 | 110 (1) |
Co1—N3—H6 | 104 (2) | C6—C5—H20 | 108 (1) |
C4—N3—H5 | 111 (2) | H19—C5—H20 | 111 (2) |
C4—N3—H6 | 110 (2) | N5—C6—C5 | 107.3 (2) |
H5—N3—H6 | 110 (3) | N5—C6—H21 | 112 (2) |
Co1—N4—C5 | 110.7 (2) | N5—C6—H22 | 112 (1) |
Co1—N4—H7 | 111 (1) | C5—C6—H21 | 108 (2) |
Co1—N4—H8 | 111 (2) | C5—C6—H22 | 110 (1) |
C5—N4—H7 | 107 (1) | H21—C6—H22 | 104 (2) |
C5—N4—H8 | 110 (2) | O11—N11—O12 | 121.1 (3) |
H7—N4—H8 | 104 (2) | O11—N11—O13 | 118.6 (2) |
Co1—N5—C6 | 109.0 (2) | O12—N11—O13 | 120.4 (3) |
Co1—N5—H9 | 109 (2) | O21—N12—O22 | 119.7 (3) |
Co1—N5—H10 | 115 (2) | O21—N12—O23 | 121.5 (3) |
C6—N5—H9 | 108 (2) | O22—N12—O23 | 118.8 (3) |
| | | |
S1—C1—C2—N1 | −52.7 (3) | N4—C5—C6—N5 | −50.1 (3) |
N2—C3—C4—N3 | 54.1 (3) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H2···O13 | 0.81 (3) | 2.17 (3) | 2.964 (3) | 163 (3) |
N2—H3···O11i | 0.81 (2) | 2.15 (2) | 2.900 (3) | 154 (2) |
N2—H3···O11ii | 0.81 (2) | 2.65 (2) | 3.130 (3) | 119 (2) |
N4—H8···O11ii | 0.87 (3) | 2.42 (3) | 3.088 (3) | 134 (2) |
N4—H8···O13ii | 0.87 (3) | 2.33 (3) | 3.189 (3) | 172 (3) |
N5—H9···O12i | 0.89 (3) | 2.30 (3) | 3.141 (3) | 157 (2) |
N5—H10···O13 | 0.90 (3) | 2.61 (3) | 3.378 (3) | 143 (2) |
N1—H1···O23iii | 0.84 (3) | 2.21 (3) | 3.000 (4) | 156 (3) |
N2—H4···O21ii | 0.89 (3) | 2.25 (3) | 3.089 (3) | 157 (3) |
N3—H6···O21 | 0.94 (3) | 2.22 (3) | 3.142 (3) | 165 (3) |
N4—H7···O22iii | 0.91 (3) | 2.08 (3) | 2.914 (4) | 152 (2) |
C4—H18···O22 | 0.96 (3) | 2.50 (3) | 3.099 (5) | 120 (2) |
C3—H16···O23ii | 0.89 (4) | 2.51 (4) | 3.143 (5) | 129 (3) |
Symmetry codes: (i) −x+1/2, y+1/2, −z+3/2; (ii) x−1/2, −y+1/2, z−1/2; (iii) x+1/2, −y+1/2, z−1/2. |
Experimental details
Crystal data |
Chemical formula | [Co(C2H6NS)(C2H8N2)2](NO3)2 |
Mr | 379.28 |
Crystal system, space group | Monoclinic, P21/n |
Temperature (K) | 296 |
a, b, c (Å) | 9.509 (1), 12.824 (1), 12.635 (1) |
β (°) | 99.780 (8) |
V (Å3) | 1518.4 (3) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 1.31 |
Crystal size (mm) | 0.35 × 0.25 × 0.18 |
|
Data collection |
Diffractometer | Rigaku AFC-7S diffractometer |
Absorption correction | ψ-scan (North et al., 1968) |
Tmin, Tmax | 0.688, 0.770 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3862, 3650, 2452 |
Rint | 0.017 |
(sin θ/λ)max (Å−1) | 0.650 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.031, 0.041, 1.11 |
No. of reflections | 2726 |
No. of parameters | 266 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.30, −0.29 |
Selected geometric parameters (Å, º) topCo1—S1 | 2.2494 (8) | Co1—N3 | 1.976 (2) |
Co1—N1 | 1.969 (3) | Co1—N4 | 1.963 (2) |
Co1—N2 | 1.958 (2) | Co1—N5 | 2.022 (2) |
| | | |
S1—Co1—N1 | 87.85 (8) | N1—Co1—N5 | 90.1 (1) |
S1—Co1—N2 | 89.97 (8) | N2—Co1—N3 | 85.2 (1) |
S1—Co1—N3 | 90.57 (8) | N2—Co1—N4 | 90.3 (1) |
S1—Co1—N4 | 91.90 (7) | N2—Co1—N5 | 92.2 (1) |
S1—Co1—N5 | 175.78 (7) | N3—Co1—N4 | 174.9 (1) |
N1—Co1—N2 | 176.9 (1) | N3—Co1—N5 | 93.2 (1) |
N1—Co1—N3 | 92.6 (1) | N4—Co1—N5 | 84.5 (1) |
N1—Co1—N4 | 92.0 (1) | | |
| | | |
S1—C1—C2—N1 | −52.7 (3) | N4—C5—C6—N5 | −50.1 (3) |
N2—C3—C4—N3 | 54.1 (3) | | |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H2···O13 | 0.81 (3) | 2.17 (3) | 2.964 (3) | 163 (3) |
N2—H3···O11i | 0.81 (2) | 2.15 (2) | 2.900 (3) | 154 (2) |
N2—H3···O11ii | 0.81 (2) | 2.65 (2) | 3.130 (3) | 119 (2) |
N4—H8···O11ii | 0.87 (3) | 2.42 (3) | 3.088 (3) | 134 (2) |
N4—H8···O13ii | 0.87 (3) | 2.33 (3) | 3.189 (3) | 172 (3) |
N5—H9···O12i | 0.89 (3) | 2.30 (3) | 3.141 (3) | 157 (2) |
N5—H10···O13 | 0.90 (3) | 2.61 (3) | 3.378 (3) | 143 (2) |
N1—H1···O23iii | 0.84 (3) | 2.21 (3) | 3.000 (4) | 156 (3) |
N2—H4···O21ii | 0.89 (3) | 2.25 (3) | 3.089 (3) | 157 (3) |
N3—H6···O21 | 0.94 (3) | 2.22 (3) | 3.142 (3) | 165 (3) |
N4—H7···O22iii | 0.91 (3) | 2.08 (3) | 2.914 (4) | 152 (2) |
Symmetry codes: (i) −x+1/2, y+1/2, −z+3/2; (ii) x−1/2, −y+1/2, z−1/2; (iii) x+1/2, −y+1/2, z−1/2. |
It is recognized that mononuclear cobalt(III) complexes with 2-aminoethanethiolate (aet) can function as effective S-donating ligands toward a variety of metal ions to form S-bridged polynuclear complexes (Elder et al., 1980; Konno et al., 1998, 1999). Our recent studies have shown that the structures of these polynuclear complexes can be made to vary by changes in the counteranions (Tokuda et al., 2000; Konno et al., 2000). In order to elucidate this role of the counteranions in the control of S-bridged polynuclear structures, it is desirable to investigate the crystal structures of mononuclear aet complexes by changing the counteranions. Thus, we prepared single crystals of the title complex, [Co(aet)(en)2](NO3)2, (I), and its structure is herein compared with the known structure of [Co(aet)(en)2](SCN)2 (Elder et al., 1973). \sch
The X-ray structural analysis of (I) confirmed the presence of a divalent complex cation, [Co(aet)(en)2]2+, and two nitrate anions. The space group P21/n indicates that the crystal contains a racemic pair (Δ and Λ) of the chiral complex cation. In the cation of (I), the Co atom exhibits a slightly distorted octahedral geometry, coordinated by one S and five N atoms from one aet and two en ligands [trans N—Co—N 174.9 (1) and 176.9 (1)°, and trans N—Co—S 175.78 (7)°; Fig. 1]. The Co—Ntrans(S) bond distance [Co—N5 2.022 (2) Å] is ca 0.05 Å longer than the four Co—Ncis(S) distances [1.958 (2)–1.976 (2) Å, average 1.967 (2) Å], associated with the trans influence of the thiolato S donor atom (Elder et al., 1973; Dickman et al., 1980). A similar difference of 0.04 Å was observed for the trans influence in [Co(aet)(en)2](SCN)2 (Elder et al., 1973). However, the Co—S [2.2494 (8) Å] and Co—Ntrans(S) distances in (I) are longer than those in [Co(aet)(en)2](SCN)2 [Co—S 2.226 (2) Å, Co—Ntrans(S) 2.001 (5) Å, average Co—Ncis(S) 1.960 (9) Å].
The aet and en chelate rings in (I) have a gauche conformation with the lel, lel and ob forms: λ, λ and δ for the Δ isomer, and δ, δ and λ for the Λ isomer. This is distinct from the (lel)3 form found in [Co(aet)(en)2](SCN)2 (Elder et al., 1973). It has been postulated that the (lel)3 form is the most stable for the isolated complex cation, but hydrogen bonds could lead to the formation of other, less favoured, forms (Hawkins, 1971). Thus, the (lel)2(ob) form found in the cation of (I) can be ascribed to the hydrogen-bonding interactions with the nitrate anions (see below), taking into account the fact that only weak hydrogen bonds exist in [Co(aet)(en)2](SCN)2 (Elder et al., 1973).
All the amine H atoms of the aet and en ligands, except H5, are involved in hydrogen bonds with nitrate O atoms in the crystal [N···O 2.900 (3)–3.378 (3) Å]. Additionally, atoms H3 and H8 are hydrogen-bonded to two O acceptors to form three-centre bonds (Table 2). All the nitrate O atoms participate in the hydrogen bonds, which completes a three-dimensional hydrogen-bond network.