The structures of dimethyldithiocyanatotin(IV), [Sn(CH3)2(NCS)2], and diethyldithiocyanatotin(IV), [Sn(C2H5)2(NCS)2], have been determined. The dimethyl derivative has 2mm crystallographic symmetry and the diethyl derivative has twofold crystallographic symmetry. The experimental differences in the distances and angles around the Sn atom between the two structures agree reasonably well with the differences expected from the reaction path mapped previously [Britton & Dunitz (1981). J. Am. Chem. Soc. 103, 2971-2979].
Supporting information
CCDC references: 603204; 603205
See Chow (1970) for the synthesis of (I). The synthesis of (II) was similar, with diethyltin chloride replacing dimethyltin chloride as the starting material.
The solution and refinement were straightforward. As a test of the data, the H-atom positions and isotropic displacement parameters were refined and reasonable values were ontained even in the presence of the Sn atom.
For both compounds, data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
(I) dimethyldithiocyanatotin(IV)
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Crystal data top
[Sn(CH3)2(NCS)2] | Dx = 2.106 Mg m−3 |
Mr = 264.92 | Melting point = 457–461 K |
Orthorhombic, Pmmn | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ab 2a | Cell parameters from 3997 reflections |
a = 9.654 (2) Å | θ = 2.6–27.5° |
b = 7.769 (2) Å | µ = 3.48 mm−1 |
c = 5.5692 (14) Å | T = 174 K |
V = 417.70 (17) Å3 | Needle, colorless |
Z = 2 | 0.50 × 0.10 × 0.10 mm |
F(000) = 252 | |
Data collection top
Siemens SMART area-detector diffractometer | 543 independent reflections |
Radiation source: fine-focus sealed tube | 523 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.018 |
ω scans | θmax = 27.5°, θmin = 3.4° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996; Blessing, 1995) | h = −12→12 |
Tmin = 0.50, Tmax = 0.71 | k = −9→10 |
4698 measured reflections | l = −7→7 |
Refinement top
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)] = 0.009 | All H-atom parameters refined |
wR(F2) = 0.022 | w = 1/[σ2(Fo2) + (0.011P)2 + 0.108P] where
P = (Fo2 + 2Fc2)/3 |
S = 1.11 | (Δ/σ)max = 0.001 |
543 reflections | Δρmax = 0.23 e Å−3 |
37 parameters | Δρmin = −0.19 e Å−3 |
0 restraints | Extinction correction: SHELXTL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.018 (3) |
Crystal data top
[Sn(CH3)2(NCS)2] | V = 417.70 (17) Å3 |
Mr = 264.92 | Z = 2 |
Orthorhombic, Pmmn | Mo Kα radiation |
a = 9.654 (2) Å | µ = 3.48 mm−1 |
b = 7.769 (2) Å | T = 174 K |
c = 5.5692 (14) Å | 0.50 × 0.10 × 0.10 mm |
Data collection top
Siemens SMART area-detector diffractometer | 543 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996; Blessing, 1995) | 523 reflections with I > 2σ(I) |
Tmin = 0.50, Tmax = 0.71 | Rint = 0.018 |
4698 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.009 | 0 restraints |
wR(F2) = 0.022 | All H-atom parameters refined |
S = 1.11 | Δρmax = 0.23 e Å−3 |
543 reflections | Δρmin = −0.19 e Å−3 |
37 parameters | |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Sn1 | 0.2500 | 0.2500 | 0.55294 (3) | 0.02054 (7) | |
S1 | 0.53344 (4) | 0.2500 | −0.16813 (7) | 0.02979 (11) | |
N1 | 0.40056 (16) | 0.2500 | 0.2735 (3) | 0.0298 (3) | |
C1 | 0.45554 (16) | 0.2500 | 0.0885 (3) | 0.0215 (3) | |
C2 | 0.2500 | −0.0094 (2) | 0.6582 (3) | 0.0284 (3) | |
H2B | 0.2500 | −0.021 (3) | 0.826 (5) | 0.054 (7)* | |
H2A | 0.332 (2) | −0.057 (3) | 0.604 (3) | 0.058 (5)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Sn1 | 0.02847 (10) | 0.01875 (9) | 0.01438 (9) | 0.000 | 0.000 | 0.000 |
S1 | 0.0272 (2) | 0.0444 (2) | 0.0178 (2) | 0.000 | 0.00493 (15) | 0.000 |
N1 | 0.0347 (7) | 0.0347 (8) | 0.0200 (7) | 0.000 | 0.0043 (6) | 0.000 |
C1 | 0.0232 (7) | 0.0219 (7) | 0.0195 (7) | 0.000 | −0.0031 (6) | 0.000 |
C2 | 0.0322 (9) | 0.0213 (8) | 0.0317 (9) | 0.000 | 0.000 | 0.0051 (7) |
Geometric parameters (Å, º) top
Sn1—C2 | 2.0986 (17) | S1—C1 | 1.6149 (16) |
Sn1—C2i | 2.0986 (17) | N1—C1 | 1.159 (2) |
Sn1—N1i | 2.1296 (15) | C2—H2B | 0.94 (3) |
Sn1—N1 | 2.1296 (15) | C2—H2A | 0.925 (19) |
| | | |
C2—Sn1—C2i | 147.57 (11) | C1—N1—Sn1 | 164.22 (13) |
C2—Sn1—N1i | 101.78 (4) | N1—C1—S1 | 179.51 (15) |
C2i—Sn1—N1i | 101.78 (4) | Sn1—C2—H2B | 111.6 (16) |
C2—Sn1—N1 | 101.78 (4) | Sn1—C2—H2A | 107.3 (12) |
C2i—Sn1—N1 | 101.78 (4) | H2B—C2—H2A | 106.5 (13) |
N1i—Sn1—N1 | 86.08 (8) | | |
Symmetry code: (i) −x+1/2, −y+1/2, z. |
(II) Diethyltindithiocyanatotin(IV)
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Crystal data top
[Sn(C2H5)2(NCS)2] | Dx = 1.916 Mg m−3 |
Mr = 292.97 | Melting point: 467-470 with decomposition K |
Orthorhombic, Pbcn | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2n 2ab | Cell parameters from 2765 reflections |
a = 14.449 (4) Å | θ = 3.2–27.4° |
b = 5.5526 (14) Å | µ = 2.88 mm−1 |
c = 12.660 (3) Å | T = 174 K |
V = 1015.7 (5) Å3 | Plate, colorless |
Z = 4 | 0.35 × 0.25 × 0.05 mm |
F(000) = 568 | |
Data collection top
Siemens area detector diffractometer | 1166 independent reflections |
Radiation source: fine-focus sealed tube | 1137 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.021 |
ω scans | θmax = 27.5°, θmin = 2.8° |
Absorption correction: multi-scan SADABS; Sheldrick, 1996; Blessing, 1995 | h = −18→18 |
Tmin = 0.40, Tmax = 0.87 | k = −7→7 |
10750 measured reflections | l = −16→16 |
Refinement top
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)] = 0.014 | All H-atom parameters refined |
wR(F2) = 0.033 | w = 1/[σ2(Fo2) + (0.013P)2 + 0.49P] where
P = (Fo2 + 2Fc2)/3 |
S = 1.16 | (Δ/σ)max = 0.001 |
1166 reflections | Δρmax = 0.39 e Å−3 |
73 parameters | Δρmin = −0.24 e Å−3 |
0 restraints | Extinction correction: SHELXTL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.0014 (2) |
Crystal data top
[Sn(C2H5)2(NCS)2] | V = 1015.7 (5) Å3 |
Mr = 292.97 | Z = 4 |
Orthorhombic, Pbcn | Mo Kα radiation |
a = 14.449 (4) Å | µ = 2.88 mm−1 |
b = 5.5526 (14) Å | T = 174 K |
c = 12.660 (3) Å | 0.35 × 0.25 × 0.05 mm |
Data collection top
Siemens area detector diffractometer | 1166 independent reflections |
Absorption correction: multi-scan SADABS; Sheldrick, 1996; Blessing, 1995 | 1137 reflections with I > 2σ(I) |
Tmin = 0.40, Tmax = 0.87 | Rint = 0.021 |
10750 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.014 | 0 restraints |
wR(F2) = 0.033 | All H-atom parameters refined |
S = 1.16 | Δρmax = 0.39 e Å−3 |
1166 reflections | Δρmin = −0.24 e Å−3 |
73 parameters | |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Sn1 | 0.0000 | 0.13925 (2) | 0.7500 | 0.01958 (7) | |
S1 | 0.15673 (3) | −0.59587 (7) | 0.63634 (3) | 0.02864 (10) | |
C1 | 0.11223 (10) | −0.3358 (3) | 0.66391 (11) | 0.0211 (3) | |
N1 | 0.08028 (10) | −0.1498 (2) | 0.68338 (12) | 0.0307 (3) | |
C3 | 0.16130 (13) | 0.0669 (4) | 0.90144 (16) | 0.0400 (4) | |
H3A | 0.1938 (15) | 0.115 (4) | 0.9589 (18) | 0.046 (6)* | |
H3B | 0.2031 (15) | 0.075 (4) | 0.8438 (18) | 0.048 (6)* | |
H3C | 0.1440 (16) | −0.106 (4) | 0.9073 (18) | 0.051 (6)* | |
C2 | 0.07781 (11) | 0.2285 (3) | 0.88700 (12) | 0.0286 (3) | |
H2B | 0.0950 (15) | 0.385 (4) | 0.8771 (17) | 0.041 (6)* | |
H2A | 0.0331 (16) | 0.211 (4) | 0.9432 (17) | 0.046 (6)* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Sn1 | 0.02204 (9) | 0.01699 (9) | 0.01971 (9) | 0.000 | −0.00309 (5) | 0.000 |
S1 | 0.02773 (19) | 0.02036 (17) | 0.0378 (2) | 0.00317 (15) | 0.01069 (16) | −0.00055 (15) |
C1 | 0.0205 (7) | 0.0228 (7) | 0.0201 (6) | −0.0036 (5) | 0.0024 (5) | 0.0011 (5) |
N1 | 0.0326 (7) | 0.0229 (7) | 0.0367 (8) | 0.0019 (5) | 0.0056 (6) | −0.0023 (5) |
C3 | 0.0316 (9) | 0.0558 (12) | 0.0327 (9) | 0.0056 (9) | −0.0113 (8) | 0.0022 (9) |
C2 | 0.0279 (8) | 0.0371 (9) | 0.0209 (7) | −0.0013 (7) | −0.0051 (6) | −0.0035 (6) |
Geometric parameters (Å, º) top
Sn1—C2 | 2.1255 (15) | C3—C2 | 1.514 (3) |
Sn1—C2i | 2.1255 (15) | C3—H3A | 0.91 (2) |
Sn1—N1i | 2.1523 (14) | C3—H3B | 0.95 (2) |
Sn1—N1 | 2.1523 (14) | C3—H3C | 0.99 (2) |
S1—C1 | 1.6189 (15) | C2—H2B | 0.91 (2) |
C1—N1 | 1.1577 (19) | C2—H2A | 0.97 (2) |
| | | |
C2—Sn1—C2i | 153.04 (10) | H3A—C3—H3B | 105.9 (18) |
C2—Sn1—N1i | 98.00 (7) | C2—C3—H3C | 112.3 (14) |
C2i—Sn1—N1i | 102.04 (6) | H3A—C3—H3C | 110.6 (19) |
C2—Sn1—N1 | 102.04 (6) | H3B—C3—H3C | 105.1 (19) |
C2i—Sn1—N1 | 97.99 (7) | C3—C2—Sn1 | 112.44 (12) |
N1i—Sn1—N1 | 83.57 (8) | C3—C2—H2B | 111.4 (14) |
N1—C1—S1 | 179.82 (17) | Sn1—C2—H2B | 104.7 (13) |
C1—N1—Sn1 | 164.46 (13) | C3—C2—H2A | 112.7 (13) |
C2—C3—H3A | 109.7 (13) | Sn1—C2—H2A | 103.0 (13) |
C2—C3—H3B | 112.8 (13) | H2B—C2—H2A | 112 (2) |
Symmetry code: (i) −x, y, −z+3/2. |
Experimental details
| (I) | (II) |
Crystal data |
Chemical formula | [Sn(CH3)2(NCS)2] | [Sn(C2H5)2(NCS)2] |
Mr | 264.92 | 292.97 |
Crystal system, space group | Orthorhombic, Pmmn | Orthorhombic, Pbcn |
Temperature (K) | 174 | 174 |
a, b, c (Å) | 9.654 (2), 7.769 (2), 5.5692 (14) | 14.449 (4), 5.5526 (14), 12.660 (3) |
V (Å3) | 417.70 (17) | 1015.7 (5) |
Z | 2 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 3.48 | 2.88 |
Crystal size (mm) | 0.50 × 0.10 × 0.10 | 0.35 × 0.25 × 0.05 |
|
Data collection |
Diffractometer | Siemens SMART area-detector diffractometer | Siemens area detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996; Blessing, 1995) | Multi-scan SADABS; Sheldrick, 1996; Blessing, 1995 |
Tmin, Tmax | 0.50, 0.71 | 0.40, 0.87 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4698, 543, 523 | 10750, 1166, 1137 |
Rint | 0.018 | 0.021 |
(sin θ/λ)max (Å−1) | 0.650 | 0.650 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.009, 0.022, 1.11 | 0.014, 0.033, 1.16 |
No. of reflections | 543 | 1166 |
No. of parameters | 37 | 73 |
H-atom treatment | All H-atom parameters refined | All H-atom parameters refined |
Δρmax, Δρmin (e Å−3) | 0.23, −0.19 | 0.39, −0.24 |
Distances(Å) and bond ordersa topBond | d(I) | d(II) | n(I) | n(II) |
Sn1—N1 | 2.130 (2) | 2.152 (1) | 0.750 (3) | 0.719 (2) |
Sn1—S1B | 3.146 (1) | 3.060 (1) | 0.230 (1) | 0.271 (1) |
a. The bond orders, following B&D, are based on the difference between the observed bond lengths and the Pauling (1960) single bond distances: Sn—N = 1.98 Å and Sn—S = 2.38 Å. |
Table 2. Bond angles (°) observed and calculated.a topAngle | Iobs | IIobsb | Ic(N) | IIc(N) | Ic(S) | IIc(S) |
C2—Sn1—C2A | 147.6 (1) | 153.0 (1) | 146.4 | 150.7 | 143.7 | 149.4 |
C2—Sn1—N1 | 101.8 (1) | 102.0 (1) | - | - | - | - |
C2—Sn1—N1A | - | 98.0 (1) | - | - | - | - |
C2—Sn1—N1avg | 101.8 | 100.0 | 100.4 | 98.8 | 99.6 | 98.4 |
C2—Sn1—S1B | 82.1 (1) | 83.1 (1) | - | - | - | - |
C2—Sn1—S1C | - | 84.0 (1) | - | - | - | - |
C2—Sn1—S1avg | 82.1 | 83.5 | 79.6 | 81.2 | 80.4 | 81.6 |
a. The first set of calculated values, Ic, are based on the Sn—N bond orders, the second on the Sn···S bond orders. b. Because the N1—Sn1—N1A and S1B···Sn1···S1C planes differ from coplanarity by 3.6 (1)° there are two sets of C—Sn—N and C—Sn···S angles; these are averaged for the comparison with the angles calculated from the bond orders. |
The path of the reaction R2SnX2 + 2Y → R2SnY2 + 2X was mapped (Britton & Dunitz, 1981; hereafter B&D) using the structure correlation method (Bürgi, 1975; Dunitz, 1975). A variety of R groups and X and Y atoms were used in this mapping, which showed rough but reasonable agreement for a variety of R2SnX2Y2 intermediates. One of the compounds used in this study was (CH3)2Sn(NCS)2 (Forder & Sheldrick, 1970; Chow, 1970). The availability of the corresponding diethyl compound suggested examining how the mapping changed with very small chemical differences.
In the structure of (CH3)2Sn(NCS)2, Sn···S interactions from adjacent molecules form partial bonds and lead to the weakening of the Sn—N bonds. A redetermination of this structure, (I), is reported here, along with the structure of (C2H5)2Sn(NCS)2, (II). The replacement of CH3 groups by C2H5 groups must lead to a different overall packing arrangement, and the question of interest is the extent to which any changes in the Sn—N and Sn···S distances, and the C—Sn—C, C—Sn—X and C—Sn···S angles, are consistent with each other and with the structure correlation model.
Fig. 1 shows the atom labelling and displacement ellipsoids for (I), along with a second molecule of (I) to make clear the Sn···S interactions. Fig. 2 shows the same for (II). The bond lengths and angles will be described below with one exception. In the B&D study it appeared that the Sn—C distances did not vary significantly from the Sn—C bond length of 2.10 Å given by Pauling (1960). In the present work, the Sn—C distance in (I) [2.099 (2) Å] is significantly smaller that that in (II) [2.126 (2) Å]. This discrepancy suggests that the original approach needs to be fine-tuned, but this difference has been ignored in the rest of the discussion.
The bond distances and bond angles are given in Tables 1 and 2. The Sn—N distance increases by 0.022</span><span style=" font-weight:600;">(2) Å from (I) to (II). The B&D model would predict that the Sn···S distance should decrease, the C– Sn—C angle should increase, the C—Sn—N angle should decrease and the C—Sn···S angle should increase. All of these qualitative changes are correct.
Using Pauling's (1947) bond length–bond order relationship [d(n) − d(1) = clogn], with c = 1.20 as used previously (B&D), the bond orders, n, are those given in Table 1. They do not add to 1.000 owing to the approximate nature of the model. The sums of the n values could be brought closer to 1.000 by adjusting c slightly, but this does not seem justified.
In Table 2, the experimental C—Sn—C, C—Sn—N and C—Sn···S values are compared with the values predicted from the model of B&D. There are two sets of predicted values depending on whether the C—N or C···S bond orders are used; in a perfect model these would be the same. The predicted values are in reasonable agreement with the experimental values, being within about 2°; the changes in going from (I) to (II) are within about 0.5° in all three cases.