Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S010827010600206X/sk3001sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S010827010600206X/sk3001Isup2.hkl |
CCDC reference: 603180
All commercially available reagents were of analytical or reagent grade purity and were used as received. Cadmium bis(tri-tert-butoxysilanethiolate) (0.135 g, 0.11 mmol), prepared according to the known procedure (Wojnowski et al., 1992), was dissolved in toluene (15 ml). Sodium N,N-diethyldithiocarbamate trihydrate (0.49 g, 0.22 mmol) and tetraethylammonium iodide (0.056 g, 0.22 mmol) were dissolved in hot water (7 ml each). The aqueous solutions were mixed, and to the resulting mixture the cadmium complex in toluene was added. The mixture was shaken vigorously for ca 3 h and the layers separated. The organic layer was washed with three 15 ml portions of water, dried over anhydrous magnesium sulfate and finally evaporated to dryness. The solid was dissolved in minimal amount of toluene and the solution was left for crystallization at room temperature. After a few days the deposited small yellow crystals were collected and recrystallized from toluene, giving single crystals of quality sufficient for X-ray measurement. The yield was ca 40% and was not optimized.
All H atoms were refined as riding, with their Uiso (H) values constrained to be 1.5Uiso of the pivot atoms for CH3 groups or 1.3 times Uiso for CH2 groups.
Data collection: CrysAlis CCD (Oxford Diffraction, 2005); cell refinement: CrysAlis RED (Oxford Diffraction, 2005); data reduction: CrysAlis RED; 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).
(C8H20N)[Cd(C5H10NS2)2I] | F(000) = 1336 |
Mr = 666.07 | Dx = 1.584 Mg m−3 |
Orthorhombic, Pnma | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2n | Cell parameters from 11478 reflections |
a = 17.859 (2) Å | θ = 2.5–32.5° |
b = 17.994 (2) Å | µ = 2.20 mm−1 |
c = 8.692 (1) Å | T = 293 K |
V = 2793.3 (5) Å3 | Prism, pale-yellow |
Z = 4 | 0.24 × 0.14 × 0.08 mm |
Kuma KM-4 diffractometer with Sapphire-2 CCD detector | 2827 independent reflections |
Radiation source: Enhance (Mo) X-ray Source | 2675 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.038 |
Detector resolution: 8.1883 pixels mm-1 | θmax = 26°, θmin = 2.6° |
ω scans | h = −22→22 |
Absorption correction: analytical (CrysAlis RED, Oxford Diffraction, 2005) Analytical numeric absorption correction using a multifaceted crystal model based on expressions derived by R. C. Clark & J .S. Reid. | k = −22→20 |
Tmin = 0.385, Tmax = 0.778 | l = −10→10 |
19561 measured 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)] = 0.054 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.118 | H-atom parameters constrained |
S = 1.06 | w = 1/[σ2(Fo2) + (0.0372P)2 + 12.9136P] where P = (Fo2 + 2Fc2)/3 |
2827 reflections | (Δ/σ)max < 0.001 |
138 parameters | Δρmax = 1.65 e Å−3 |
0 restraints | Δρmin = −0.5 e Å−3 |
(C8H20N)[Cd(C5H10NS2)2I] | V = 2793.3 (5) Å3 |
Mr = 666.07 | Z = 4 |
Orthorhombic, Pnma | Mo Kα radiation |
a = 17.859 (2) Å | µ = 2.20 mm−1 |
b = 17.994 (2) Å | T = 293 K |
c = 8.692 (1) Å | 0.24 × 0.14 × 0.08 mm |
Kuma KM-4 diffractometer with Sapphire-2 CCD detector | 2827 independent reflections |
Absorption correction: analytical (CrysAlis RED, Oxford Diffraction, 2005) Analytical numeric absorption correction using a multifaceted crystal model based on expressions derived by R. C. Clark & J .S. Reid. | 2675 reflections with I > 2σ(I) |
Tmin = 0.385, Tmax = 0.778 | Rint = 0.038 |
19561 measured reflections |
R[F2 > 2σ(F2)] = 0.054 | 0 restraints |
wR(F2) = 0.118 | H-atom parameters constrained |
S = 1.06 | w = 1/[σ2(Fo2) + (0.0372P)2 + 12.9136P] where P = (Fo2 + 2Fc2)/3 |
2827 reflections | Δρmax = 1.65 e Å−3 |
138 parameters | Δρmin = −0.5 e Å−3 |
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 | Occ. (<1) | |
I1 | 0.22461 (4) | 0.25 | 0.18089 (9) | 0.0857 (3) | |
Cd1 | 0.29080 (3) | 0.25 | 0.47187 (7) | 0.04909 (18) | |
S2 | 0.37870 (7) | 0.13086 (7) | 0.47342 (17) | 0.0485 (3) | |
S1 | 0.23381 (10) | 0.13971 (8) | 0.6355 (2) | 0.0782 (6) | |
N1 | 0.3065 (2) | 0.0135 (2) | 0.5899 (5) | 0.0437 (9) | |
C1 | 0.3063 (3) | 0.0869 (2) | 0.5675 (5) | 0.0398 (10) | |
C4 | 0.3657 (3) | −0.0354 (3) | 0.5285 (7) | 0.0582 (14) | |
H4A | 0.3905 | −0.0107 | 0.4433 | 0.07* | |
H4B | 0.3433 | −0.0807 | 0.4897 | 0.07* | |
C5 | 0.4221 (4) | −0.0543 (4) | 0.6483 (10) | 0.095 (3) | |
H5A | 0.4414 | −0.0094 | 0.6929 | 0.143* | |
H5B | 0.4623 | −0.0818 | 0.6024 | 0.143* | |
H5C | 0.3989 | −0.0838 | 0.727 | 0.143* | |
C2 | 0.2452 (3) | −0.0255 (3) | 0.6701 (6) | 0.0533 (12) | |
H2A | 0.225 | 0.0067 | 0.7494 | 0.064* | |
H2B | 0.2651 | −0.0695 | 0.7198 | 0.064* | |
C3 | 0.1832 (4) | −0.0478 (4) | 0.5628 (8) | 0.0756 (18) | |
H3A | 0.1626 | −0.0043 | 0.5149 | 0.113* | |
H3B | 0.1447 | −0.0729 | 0.6198 | 0.113* | |
H3C | 0.2026 | −0.0805 | 0.4852 | 0.113* | |
N2 | 0.0041 (3) | 0.25 | 0.5966 (6) | 0.0442 (13) | |
C11 | 0.0685 (4) | 0.25 | 0.7108 (10) | 0.061 (2) | |
H11A | 0.0992 | 0.2066 | 0.691 | 0.073* | 0.5 |
H11B | 0.0992 | 0.2934 | 0.691 | 0.073* | 0.5 |
C12 | 0.0476 (6) | 0.25 | 0.8770 (11) | 0.087 (3) | |
H12A | 0.0362 | 0.2998 | 0.909 | 0.131* | 0.5 |
H12B | 0.0887 | 0.2313 | 0.9368 | 0.131* | 0.5 |
H12C | 0.0045 | 0.2189 | 0.8922 | 0.131* | 0.5 |
C13 | −0.0445 (4) | 0.1824 (5) | 0.6173 (9) | 0.093 (3) | |
H13A | −0.0852 | 0.1844 | 0.5435 | 0.111* | |
H13B | −0.0662 | 0.1834 | 0.7195 | 0.111* | |
C14 | −0.0015 (6) | 0.1081 (4) | 0.5960 (13) | 0.143 (5) | |
H14A | 0.02 | 0.1064 | 0.4947 | 0.214* | |
H14B | −0.0354 | 0.0672 | 0.6087 | 0.214* | |
H14C | 0.0377 | 0.1047 | 0.6713 | 0.214* | |
C15 | 0.0387 (6) | 0.25 | 0.4391 (10) | 0.077 (3) | |
H15A | 0.0704 | 0.2065 | 0.4297 | 0.093* | 0.5 |
H15B | 0.0704 | 0.2935 | 0.4297 | 0.093* | 0.5 |
C16 | −0.0172 (8) | 0.25 | 0.3054 (11) | 0.114 (5) | |
H16A | −0.0345 | 0.2998 | 0.2874 | 0.171* | 0.5 |
H16B | −0.059 | 0.2188 | 0.3306 | 0.171* | 0.5 |
H16C | 0.0068 | 0.2315 | 0.2144 | 0.171* | 0.5 |
U11 | U22 | U33 | U12 | U13 | U23 | |
I1 | 0.1137 (5) | 0.0463 (3) | 0.0972 (5) | 0 | −0.0575 (4) | 0 |
Cd1 | 0.0516 (3) | 0.0294 (3) | 0.0662 (4) | 0 | −0.0071 (2) | 0 |
S2 | 0.0396 (6) | 0.0368 (6) | 0.0690 (8) | −0.0015 (5) | −0.0006 (6) | 0.0038 (6) |
S1 | 0.0808 (11) | 0.0431 (8) | 0.1108 (14) | 0.0227 (7) | 0.0460 (10) | 0.0169 (8) |
N1 | 0.049 (2) | 0.0308 (19) | 0.051 (2) | 0.0047 (16) | 0.0011 (18) | 0.0036 (17) |
C1 | 0.046 (2) | 0.031 (2) | 0.043 (2) | 0.0018 (18) | −0.0015 (19) | 0.0000 (19) |
C4 | 0.062 (3) | 0.038 (3) | 0.074 (4) | 0.008 (2) | 0.004 (3) | −0.006 (3) |
C5 | 0.077 (4) | 0.083 (5) | 0.126 (7) | 0.033 (4) | −0.026 (5) | −0.010 (5) |
C2 | 0.064 (3) | 0.040 (3) | 0.057 (3) | −0.001 (2) | 0.004 (3) | 0.011 (2) |
C3 | 0.068 (4) | 0.074 (4) | 0.085 (5) | −0.023 (3) | 0.000 (3) | 0.012 (4) |
N2 | 0.040 (3) | 0.054 (3) | 0.038 (3) | 0 | 0.000 (2) | 0 |
C11 | 0.041 (4) | 0.073 (5) | 0.070 (5) | 0 | −0.005 (4) | 0 |
C12 | 0.081 (7) | 0.125 (9) | 0.055 (5) | 0 | −0.019 (5) | 0 |
C13 | 0.084 (5) | 0.123 (7) | 0.070 (4) | −0.054 (5) | −0.015 (4) | 0.023 (4) |
C14 | 0.208 (12) | 0.048 (4) | 0.171 (10) | −0.038 (6) | −0.059 (9) | 0.022 (5) |
C15 | 0.099 (7) | 0.077 (6) | 0.056 (5) | 0 | 0.028 (5) | 0 |
C16 | 0.177 (13) | 0.120 (10) | 0.045 (5) | 0 | −0.014 (7) | 0 |
I1—Cd1 | 2.7919 (8) | N2—C15 | 1.502 (9) |
Cd1—S1 | 2.6450 (16) | N2—C13 | 1.506 (7) |
Cd1—S1i | 2.6450 (16) | N2—C13i | 1.506 (7) |
Cd1—S2 | 2.6571 (12) | N2—C11 | 1.518 (9) |
Cd1—S2i | 2.6571 (12) | C11—C12 | 1.492 (12) |
S2—C1 | 1.723 (5) | C11—H11A | 0.97 |
S1—C1 | 1.711 (5) | C11—H11B | 0.97 |
N1—C1 | 1.334 (6) | C12—H12A | 0.96 |
N1—C2 | 1.475 (6) | C12—H12B | 0.96 |
N1—C4 | 1.476 (6) | C12—H12C | 0.96 |
C4—C5 | 1.488 (9) | C13—C14 | 1.554 (13) |
C4—H4A | 0.97 | C13—H13A | 0.97 |
C4—H4B | 0.97 | C13—H13B | 0.97 |
C5—H5A | 0.96 | C14—H14A | 0.96 |
C5—H5B | 0.96 | C14—H14B | 0.96 |
C5—H5C | 0.96 | C14—H14C | 0.96 |
C2—C3 | 1.503 (8) | C15—C16 | 1.532 (15) |
C2—H2A | 0.97 | C15—H15A | 0.97 |
C2—H2B | 0.97 | C15—H15B | 0.97 |
C3—H3A | 0.96 | C16—H16A | 0.96 |
C3—H3B | 0.96 | C16—H16B | 0.96 |
C3—H3C | 0.96 | C16—H16C | 0.96 |
S1—Cd1—S1i | 97.23 (7) | C15—N2—C13 | 110.2 (5) |
S1—Cd1—S2 | 67.63 (4) | C15—N2—C13i | 110.2 (5) |
S1i—Cd1—S2 | 146.09 (6) | C13—N2—C13i | 107.8 (8) |
S1—Cd1—S2i | 146.09 (6) | C15—N2—C11 | 106.6 (6) |
S1i—Cd1—S2i | 67.63 (4) | C13—N2—C11 | 111.0 (4) |
S2—Cd1—S2i | 107.56 (5) | C13i—N2—C11 | 111.0 (4) |
S1—Cd1—I1 | 108.91 (5) | C12—C11—N2 | 116.3 (7) |
S1i—Cd1—I1 | 108.91 (5) | C12—C11—H11A | 108.2 |
S2—Cd1—I1 | 104.76 (4) | N2—C11—H11A | 108.2 |
S2i—Cd1—I1 | 104.76 (4) | C12—C11—H11B | 108.2 |
C1—S2—Cd1 | 85.96 (15) | N2—C11—H11B | 108.2 |
C1—S1—Cd1 | 86.58 (16) | H11A—C11—H11B | 107.4 |
C1—N1—C2 | 122.5 (4) | C11—C12—H12A | 109.5 |
C1—N1—C4 | 122.6 (4) | C11—C12—H12B | 109.5 |
C2—N1—C4 | 114.8 (4) | H12A—C12—H12B | 109.5 |
N1—C1—S1 | 120.1 (4) | C11—C12—H12C | 109.5 |
N1—C1—S2 | 121.4 (4) | H12A—C12—H12C | 109.5 |
S1—C1—S2 | 118.4 (3) | H12B—C12—H12C | 109.5 |
N1—C4—C5 | 111.6 (5) | N2—C13—C14 | 113.3 (6) |
N1—C4—H4A | 109.3 | N2—C13—H13A | 108.9 |
C5—C4—H4A | 109.3 | C14—C13—H13A | 108.9 |
N1—C4—H4B | 109.3 | N2—C13—H13B | 108.9 |
C5—C4—H4B | 109.3 | C14—C13—H13B | 108.9 |
H4A—C4—H4B | 108 | H13A—C13—H13B | 107.7 |
C4—C5—H5A | 109.5 | C13—C14—H14A | 109.5 |
C4—C5—H5B | 109.5 | C13—C14—H14B | 109.5 |
H5A—C5—H5B | 109.5 | H14A—C14—H14B | 109.5 |
C4—C5—H5C | 109.5 | C13—C14—H14C | 109.5 |
H5A—C5—H5C | 109.5 | H14A—C14—H14C | 109.5 |
H5B—C5—H5C | 109.5 | H14B—C14—H14C | 109.5 |
N1—C2—C3 | 112.4 (5) | N2—C15—C16 | 115.1 (9) |
N1—C2—H2A | 109.1 | N2—C15—H15A | 108.5 |
C3—C2—H2A | 109.1 | C16—C15—H15A | 108.5 |
N1—C2—H2B | 109.1 | N2—C15—H15B | 108.5 |
C3—C2—H2B | 109.1 | C16—C15—H15B | 108.5 |
H2A—C2—H2B | 107.9 | H15A—C15—H15B | 107.5 |
C2—C3—H3A | 109.5 | C15—C16—H16A | 109.5 |
C2—C3—H3B | 109.5 | C15—C16—H16B | 109.5 |
H3A—C3—H3B | 109.5 | H16A—C16—H16B | 109.5 |
C2—C3—H3C | 109.5 | C15—C16—H16C | 109.5 |
H3A—C3—H3C | 109.5 | H16A—C16—H16C | 109.5 |
H3B—C3—H3C | 109.5 | H16B—C16—H16C | 109.5 |
Symmetry code: (i) x, −y+1/2, z. |
Experimental details
Crystal data | |
Chemical formula | (C8H20N)[Cd(C5H10NS2)2I] |
Mr | 666.07 |
Crystal system, space group | Orthorhombic, Pnma |
Temperature (K) | 293 |
a, b, c (Å) | 17.859 (2), 17.994 (2), 8.692 (1) |
V (Å3) | 2793.3 (5) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 2.20 |
Crystal size (mm) | 0.24 × 0.14 × 0.08 |
Data collection | |
Diffractometer | Kuma KM-4 diffractometer with Sapphire-2 CCD detector |
Absorption correction | Analytical (CrysAlis RED, Oxford Diffraction, 2005) Analytical numeric absorption correction using a multifaceted crystal model based on expressions derived by R. C. Clark & J .S. Reid. |
Tmin, Tmax | 0.385, 0.778 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 19561, 2827, 2675 |
Rint | 0.038 |
(sin θ/λ)max (Å−1) | 0.617 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.054, 0.118, 1.06 |
No. of reflections | 2827 |
No. of parameters | 138 |
H-atom treatment | H-atom parameters constrained |
w = 1/[σ2(Fo2) + (0.0372P)2 + 12.9136P] where P = (Fo2 + 2Fc2)/3 | |
Δρmax, Δρmin (e Å−3) | 1.65, −0.5 |
Computer programs: CrysAlis CCD (Oxford Diffraction, 2005), CrysAlis RED (Oxford Diffraction, 2005), CrysAlis RED, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), WinGX (Farrugia, 1999).
I1—Cd1 | 2.7919 (8) | C4—C5 | 1.488 (9) |
Cd1—S1 | 2.6450 (16) | C2—C3 | 1.503 (8) |
Cd1—S2 | 2.6571 (12) | N2—C15 | 1.502 (9) |
S2—C1 | 1.723 (5) | N2—C13 | 1.506 (7) |
S1—C1 | 1.711 (5) | N2—C11 | 1.518 (9) |
N1—C1 | 1.334 (6) | C11—C12 | 1.492 (12) |
N1—C2 | 1.475 (6) | C13—C14 | 1.554 (13) |
N1—C4 | 1.476 (6) | C15—C16 | 1.532 (15) |
S1—Cd1—S1i | 97.23 (7) | C1—N1—C4 | 122.6 (4) |
S1—Cd1—S2 | 67.63 (4) | C2—N1—C4 | 114.8 (4) |
S1i—Cd1—S2 | 146.09 (6) | N1—C1—S1 | 120.1 (4) |
S2—Cd1—S2i | 107.56 (5) | N1—C1—S2 | 121.4 (4) |
S1—Cd1—I1 | 108.91 (5) | S1—C1—S2 | 118.4 (3) |
S2—Cd1—I1 | 104.76 (4) | C15—N2—C13 | 110.2 (5) |
C1—S2—Cd1 | 85.96 (15) | C13—N2—C13i | 107.8 (8) |
C1—S1—Cd1 | 86.58 (16) | C15—N2—C11 | 106.6 (6) |
C1—N1—C2 | 122.5 (4) | C13—N2—C11 | 111.0 (4) |
Symmetry code: (i) x, −y+1/2, z. |
Only a few mixed cadmium–halide–dithiocarbamate complexes are known. A neutral polymeric [Cd(S2CNEt2)I]n complex was obtained by oxidation of dimeric cadmium bis(N,N-diethyldithiocarbamate) (Domenicano et al., 1968) with a limited amount of elemental iodine (Duhme et al., 1990). The crystal structure of this complex is built up from [Cd(S2CNEt2)2CdI2] repetitive units and can be regarded as an alternating copolymer of cadmium N,N-diethyldithiocarbamate and cadmium iodide. A group of [Cd(S2CNEt2)2X]− (X = Cl, Br, I or NCS) species have been prepared by reacting tetraalkylammonium salts of respective monodentate X− ligands with dimeric cadmium bis(N,N-diethyldithiocarbamate) (Baggio et al., 1992). All complexes but one, viz. [NBu4][Cd(S2CNEt2)2I], were isolated as [NEt4]+ salts. The crystal and molecular structures were determined only for the isothiocyanate adduct. It was found to be mononuclear with strongly distorted trigonal-bipyramidal CdS4N coordination geometry and an N atom occupying one of the equatorial positions. IR and Raman data allowed the authors to suggest monometallic character (but nothing more) also for related Cl-, Br- and I-containing complexes.
This suggestion was later confirmed by synthesis and structure determination by X-ray crystallography of two complexes, viz. [PPh4][Cd(S2CNEt2)2Cl] and [PPh4][Cd(S2CNEt2)2Br] (Baggio et al., 1996). They were found to be not only monometallic but also isomorphous, with the central Cd atom linked to the halide and four S atoms from two chelating dithiocarbamate ligands. The geometry of the resulting CdS4X kernel was described as exactly halfway between trigonal-bipyramidal and square-pyramidal. The iodine-containing complex, [Cd(S2CNEt2)2I]−, was not mentioned.
It is generally accepted that even minor modifications to a material (e.g. the exchange of one alkyl group for another) can have a profound effect on the structure and hence the properties of the compound (Miller, 2005). This fact also means that any predictions of the unknown structure, such as, for example, that of the [Cd(S2CNEt2)2I]− complex anion, should be treated cautiously. The small number of complexes that may be used for comparisons and the different cations that they are bonded to made such predictions even less reliable.
We report here the synthesis, isolation of single crystals and X-ray analysis of the title compound, [NEt4][Cd(S2CNEt2)2I], (I). The compound was formed during the reaction of dimeric cadmium bis(tri-tert-butoxysilanethiolate) (Wojnowski et al., 1992) with sodium N,N-diethyldithiocarbamate in the presence of tetraethylammonium iodide in a toluene/water mixture.
Compound (I) consists of the common tetraethylammonium cation and the complex [Cd(S2CNEt2)2I]− anion where the central CdII ion is coordinated by iodide and two bidentate N,N-diethyldithiocarbamate ligands (Fig. 1). The whole assembly is symmetrical, with atoms Cd1 and I1 (from the anion), as well as atoms N2, C11, C12, C15 and C16 (from the cation), lying on the mirror plane. Fig. 2 shows the packing diagram viewed along the c axis. Selected geometric parameters are collected in Table 1.
The structure of the [NEt4]+ cation is very typical and does not deserve any elaborate discussion. The most notable structural feature of the anion is its square-pyramidal geometry, with atoms S1, S1', S2 and S2' defining the basal plane (Fig. 3). Some deviations are imposed by the bite angle of two symmetry-related chelating dithiocarbamate ligands and the non-equivalence of the necessarily wider S1—Cd1—S1' and S2—Cd1—S2' angles. Further distortion is demonstrated by atom Cd1 being displaced from the basal plane towards the apical I atom of the square pyramid and the apical-to-basal bond angles being greater than 90°. These deviations, however, by no means favor trigonal-bipyramidal configuration of CdS4I kernel. Index parameter τ (Addison et al., 1984), conveniently describing the changes on going from ideal square-pyramidal (τ = 0.0) to ideal trigonal-bipyramidal geometry (τ = 1.0), calculated for the structures of four different [Cd(S2CNEt2)2X]−-type anions equals 0.5 when X is Cl and Br (Baggio et al., 1996), 0.27 when X is NCS (Baggio et al., 1992), and 0.0 when X is I (this paper). It is of little probability that any `special' property of homologous Cl, Br or I ligands (or even the NCS ligand) determines the complex anion geometry. Instead, we conclude that it is the cation and, more precisely, its steric requirements (namely [NEt4]+ versus [PPh4]+) that significantly influence the structure. In the somewhat similar complex anion [Cd(S2P(OEt)2)2I]−, when accompanied by a very large cation such as [µ3-oxo)-tris(µ2-sulfido)-tris((diethyldithiophosphonato)-(pyridine)- molybdenum]+ [Cambridge Structural Database (CSD; Version 5.27 of 2006; Allen, 2002) refcode MAJGIN; Lu et al., 1997], the geometry of the central CdS4I kernel is slightly distorted, but nevertheless it is easily qualified as trigonal-bipyramidal (τ = 0.7).
The dithiocarbamate ligand in the complex anion [Cd(S2CNEt2)2X]− with X = I is bonded to cadmium much more symmetricaly (the Cd—S bond lengths differ of only 0.01 Å) than the same ligand in the cases where X = NCS (0.07 Å; Baggio et al., 1992) and X = Cl or Br (ca 0.16 Å; Baggio et al., 1996). This property seems to be related to the magnitude of advancement of CdS4X kernel geometry towards trigonal bipyramidal where the discrimination in bond lengths formed by the same donor atoms in equatorial and axial positions is usually observed. The mean Cd—S bond length remains, however, the same in all complexes discussed (2.65 Å) and does not differ from that in the neutral dimeric cadmium bis(N,N-diethyldithiocarbamate) complex (Domenicano et al., 1968). Again, the data reported for [Cd(S2P(OEt)2)2I]− (Lu et al., 1997) support this conclusion (Cd—Seq = 2.531 and 2.545 Å, although Cd—Sax = 2.766 and 2.952 Å).
Finally, the Cd—I bond length of 2.7919 (8) Å seems unexceptional as it falls roughly within the upper limit of Cd—I bond lengths reported for different complexes where non-bridging iodine and sulfur are bonded to five-coordinated cadmium (2.70–2.80 Å; CSD).