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The synthesis and X-ray structure analysis of the title compound, [SnBr2(CH3)2(C4H9NO)2], are described. The crystal contains mol­ecules which are separated by normal van der Waals distances. Organotin(IV) compounds are found in a variety of structural types, in which the Sn atom can, for example, be hexacoordinated. In this case, the preferred solid-state molecular structure of the central atom is octahedral. The degree of distortion and the configuration depend on the ligands.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S010827010001221X/qa0387sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S010827010001221X/qa0387Isup2.hkl
Contains datablock I

CCDC reference: 152662

Comment top

A comparative study of the title compound, [SnBr2(CH3)2(C4H9NO)2], (I), and cis-dibromo-trans-dimethyl-cis-bis(N-methylpyrrolidinone)tin(IV) (König et al., 2000), [SnBr2(CH3)2(C5H9NO)2], may help to point out possible differences in the coordination of dibromodimethylstannane by cyclic and acyclic amides, particularly because the compounds chosen are of a similar constitution. This topic has not been dealt with in the literature and the available data seem to contain little information (Aslanov et al., 1978). The Sn—C bond lengths of the title DMA complex are 2.107 (4) and 2.117 (5) Å. The differences from those in the analogous NMP (N-methylpyrrolidinone) compound [2.111 (5) and 2.115 (4) Å] are obviously small (König et al., 2000), but both are in the range of reported values (Skinner & Sutton, 1944; Fujii et al., 1971; Aslanov et al., 1978). In the DMA adduct, the Sn—O bond lengths are longer (2.348 and 2.398 Å) than in the corresponding NMP compound [2.308 (3) and 2.352 (3) Å]. Although the differences between equivalent bonds in each compound are small, the Sn—O bonds in both cases are shorter than in related complexes (Yoshida et al., 1968; Kimura et al., 1969). However, the Sn—Br bond lengths in the DMA complex have values of 2.6385 (7) and 2.6589 (8) Å. As expected from other observations (Aslanov et al., 1978), they are indeed shorter than those in the NMP complex with values of 2.6717 (14) and 2.6791 (10) Å, but the difference of 0.0204 Å between the two bonds in the DMA derivative is large compared with the NMP complex (0.0074 Å). Consequently, the Sn—Br bonds in both complexes are longer than in similarly configured compounds with coordination via oxygen (Yoshida et al., 1968; Kimura et al., 1969) and the uncomplexed Me2SnBr2 (Skinner & Sutton, 1944), but they are shorter than in compounds coordinated via nitrogen (Rivarola et al., 1987) and in all-trans configured compounds (Aslanov et al., 1978). The values of the C—O bond lengths in the DMA compound [1.236 (8) and 1.256 (8) Å] are comparable with those in the analogous NMP complex [1.246 (5) and 1.253 (4) Å]. The deviation from ideal geometry is demonstrated most clearly by the angles around the central atom. The value of the angle C1—Sn1—C2 in the DMA complex is 164.2 (2)° compared with 169.10 (18)° in the NMP complex. In the equatorial plane, the deviation from the ideal angle of 180° by the trans ligands in the DMA adduct becomes less obvious. The values found for the angles O1—Sn1—Br1 and O2—Sn1—Br2 are 176.46 (9) and 172.61 (8)°, respectively. The two methyl groups are distorted somewhat towards the two DMA ligands. This becomes obvious from the values of the angles between the methyl groups and the axial ligands: (a) O1—Sn1—C1 83.70 (16)°, O1—Sn1—C2 87.75 (16)°, O2—Sn1—C1 82.48 (16)°, O2—Sn1—C2 83.44 (16)°; (b) Br1—Sn1—C1 93.51 (14)°, Br1—Sn1—C2 94.45 (14)°, Br2—Sn1—C1 96.91 (14)°, Br2—Sn1—C2 96.12 (14)°. The orientation of the two DMA ligands is defined by some bond and torsion angles. The values of the angles C11—O1—Sn1 and C21—O2—Sn1 are 135.5 (3) and 137.9 (4)°. The difference in the NMP complex is more obviously demonstrated by the two appropriate angles 138.7 (2) and 133.8 (13)°. The torsion angles Sn1—O1—C11—C12, Sn1—O1—C11—N2, Sn1—O2—C21—C22 and Sn1—O2—C21—N2 which represent the orientation of the DMA ligands have the following values: 72.0 (7), −109.9 (9), −69.1 (7) and 115.1 (8)°. They therefore differ considerably from the corresponding values in the NMP complex: 10.5 (7), −172.0 (3), 29.8 (6) and −151.8 (3)°.

Experimental top

The title compound was prepared by the reaction of N,N-dimethylacetamide (1.31 g, 1.39 ml, 15.0 mmol) with freshly sublimed dibromodimethylstannane (2.27 g, 7.5 mmol) derived from the reaction of dimethyltin oxide with HBr (Pfeiffer, 1902) in 15 ml dry diethyl ether. The reaction mixture was stirred for 30 min and afterwards stored in a refrigerator at 278 K. Colourless crystals were obtained in quantitative yield after filtration and drying in vacuo. A solution of the complex (50 mg) in CDCl3 (820 mg) gives the following values for the structure-relevant NMR parameters: 2J(119Sn—1H) = 79 Hz, 1J(119Sn—13C) = 589 Hz and δ(119Sn) = −68.6 p.p.m. These values represent an equilibrium, which is as expected shifted when a solution of the complex (70 mg) dissolved in DMA (460 mg) is studied: 2J(Sn—C—H) = 105 Hz, 1J(Sn—C) = 855 Hz, δ(119Sn)= −206.9 p.p.m. It is obvious that the relevant NMR parameters of both samples correlate well with the values for cis-dibromo-trans-dimethyl-cis-bis(N-methylpyrrolidinon)tin(IV) (König et al., 2000).

Refinement top

H atoms were placed in calculated positions with Uiso constrained to be 1.2Ueq of the carrier atom. The largest features in the final difference synthesis are close to N1; this, together with relatively high displacement parameters, indicates possible unresolved disorder.

Computing details top

Data collection: KappaCCD Software (Nonius, 1998); cell refinement: DENZO and SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO and SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); software used to prepare material for publication: SHELXL97 and PARST95 (Nardelli, 1995).

(I) top
Crystal data top
[SnBr2(CH3)2(C4H9NO)2]F(000) = 936
Mr = 482.83Dx = 1.901 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 13.798 (3) ÅCell parameters from 4990 reflections
b = 9.3350 (19) Åθ = 2.9–25.0°
c = 13.729 (3) ŵ = 6.25 mm1
β = 107.42 (3)°T = 173 K
V = 1687.3 (6) Å3Parallelepiped, colourless
Z = 40.14 × 0.13 × 0.13 mm
Data collection top
Nonius KappaCCD
diffractometer
2307 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.022
Graphite monochromatorθmax = 25.0°, θmin = 2.9°
Detector resolution: 10 vertical, 18 horizontal pixels mm-1h = 1515
294 frames via ω rotation (Δω = 1°) at different κ values and two times 80 s per frame scansk = 119
4990 measured reflectionsl = 1616
2849 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.033Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.078H-atom parameters constrained
S = 1.09Calculated w = 1/[σ2(Fo2) + (0.0276P)2 + 1.0314P]
where P = (Fo2 + 2Fc2)/3
2849 reflections(Δ/σ)max < 0.001
162 parametersΔρmax = 1.33 e Å3
0 restraintsΔρmin = 1.07 e Å3
Crystal data top
[SnBr2(CH3)2(C4H9NO)2]V = 1687.3 (6) Å3
Mr = 482.83Z = 4
Monoclinic, P21/cMo Kα radiation
a = 13.798 (3) ŵ = 6.25 mm1
b = 9.3350 (19) ÅT = 173 K
c = 13.729 (3) Å0.14 × 0.13 × 0.13 mm
β = 107.42 (3)°
Data collection top
Nonius KappaCCD
diffractometer
2307 reflections with I > 2σ(I)
4990 measured reflectionsRint = 0.022
2849 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0330 restraints
wR(F2) = 0.078H-atom parameters constrained
S = 1.09Δρmax = 1.33 e Å3
2849 reflectionsΔρmin = 1.07 e Å3
162 parameters
Special details top

Experimental. The data collection covered almost the whole spere of reciprocal space. The crystal to detector distance was 35 mm. Crystal decay was monitored by repeating the initial frames at the end of data collection. Analysing the duplicate reflections there was no indication for any decay.

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Sn10.25081 (2)0.11729 (3)0.06699 (2)0.02993 (13)
Br10.11096 (4)0.24649 (6)0.13359 (4)0.04875 (18)
O10.3783 (2)0.0032 (4)0.0182 (3)0.0422 (8)
C10.3659 (3)0.1436 (5)0.2067 (4)0.0401 (13)
H1A0.33760.13210.26210.060*
H1B0.39480.23770.20950.060*
H1C0.41790.07310.21210.060*
N10.4003 (4)0.2093 (8)0.0510 (7)0.114 (3)
Br20.29303 (4)0.34828 (5)0.02339 (4)0.04081 (16)
O20.2289 (2)0.1078 (3)0.1419 (2)0.0390 (8)
C20.1445 (3)0.0304 (6)0.0644 (4)0.0449 (13)
H2A0.16640.06320.07770.067*
H2B0.13950.09160.12190.067*
H2C0.07920.02350.05320.067*
N20.1149 (4)0.2757 (7)0.1400 (5)0.095 (2)
C110.3802 (4)0.0921 (8)0.0479 (7)0.081 (3)
C120.3473 (4)0.0276 (7)0.1691 (5)0.0632 (17)
H12A0.40370.03740.19600.095*
H12B0.32920.07170.16890.095*
H12C0.29040.08070.21090.095*
C130.4375 (4)0.2673 (7)0.0659 (4)0.0592 (17)
H13A0.51030.27380.08870.089*
H13B0.40880.36020.06910.089*
H13C0.41540.20210.10900.089*
C140.4113 (4)0.3119 (6)0.1266 (4)0.0483 (14)
H14A0.38650.27040.19340.072*
H14B0.37310.39670.12330.072*
H14C0.48170.33630.11290.072*
C210.1598 (5)0.1739 (8)0.1653 (7)0.094 (3)
C220.1237 (4)0.1084 (6)0.2614 (4)0.0483 (14)
H22A0.05130.09660.24010.072*
H22B0.15580.01730.28150.072*
H22C0.14330.17340.31810.072*
C230.0355 (4)0.3579 (5)0.1615 (4)0.0443 (13)
H23A0.01750.31470.21720.066*
H23B0.05900.45390.17970.066*
H23C0.02290.36000.10210.066*
C240.1525 (5)0.3455 (6)0.0460 (4)0.0560 (16)
H24A0.09760.34170.01650.084*
H24B0.17260.44330.06180.084*
H24C0.20910.29180.03830.084*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Sn10.0284 (2)0.0303 (2)0.0308 (2)0.00073 (13)0.00845 (14)0.00065 (14)
Br10.0469 (3)0.0491 (4)0.0592 (4)0.0127 (3)0.0294 (3)0.0090 (3)
O10.0372 (19)0.039 (2)0.051 (2)0.0032 (16)0.0138 (16)0.0110 (17)
C10.035 (3)0.046 (3)0.035 (3)0.008 (2)0.005 (2)0.004 (2)
N10.055 (4)0.097 (5)0.209 (9)0.037 (4)0.068 (4)0.105 (6)
Br20.0465 (3)0.0350 (3)0.0461 (3)0.0018 (2)0.0218 (3)0.0078 (2)
O20.038 (2)0.034 (2)0.045 (2)0.0086 (16)0.0137 (16)0.0033 (16)
C20.036 (3)0.047 (3)0.046 (3)0.008 (2)0.004 (2)0.006 (3)
N20.044 (3)0.094 (5)0.130 (6)0.009 (3)0.002 (3)0.078 (4)
C110.042 (4)0.053 (5)0.161 (8)0.025 (3)0.049 (4)0.047 (5)
C120.061 (4)0.065 (4)0.061 (4)0.002 (3)0.014 (3)0.029 (3)
C130.059 (4)0.088 (5)0.028 (3)0.010 (3)0.009 (3)0.012 (3)
C140.046 (3)0.041 (3)0.060 (4)0.005 (3)0.019 (3)0.017 (3)
C210.048 (4)0.061 (5)0.134 (7)0.011 (4)0.033 (4)0.065 (5)
C220.057 (3)0.056 (4)0.036 (3)0.010 (3)0.021 (3)0.015 (3)
C230.041 (3)0.039 (3)0.055 (4)0.009 (2)0.019 (3)0.001 (3)
C240.068 (4)0.061 (4)0.043 (3)0.017 (3)0.021 (3)0.019 (3)
Geometric parameters (Å, º) top
Sn1—C12.107 (4)C11—C121.698 (10)
Sn1—C22.117 (5)C12—H12A0.9600
Sn1—O12.348 (3)C12—H12B0.9600
Sn1—O22.398 (3)C12—H12C0.9600
Sn1—Br22.6385 (7)C13—H13A0.9600
Sn1—Br12.6589 (8)C13—H13B0.9600
O1—C111.236 (8)C13—H13C0.9600
C1—H1A0.9600C14—H14A0.9600
C1—H1B0.9600C14—H14B0.9600
C1—H1C0.9600C14—H14C0.9600
N1—C111.133 (8)C21—C221.659 (11)
N1—C141.453 (7)C22—H22A0.9600
N1—C131.624 (10)C22—H22B0.9600
O2—C211.256 (8)C22—H22C0.9600
C2—H2A0.9600C23—H23A0.9600
C2—H2B0.9600C23—H23B0.9600
C2—H2C0.9600C23—H23C0.9600
N2—C211.130 (8)C24—H24A0.9600
N2—C231.439 (7)C24—H24B0.9600
N2—C241.662 (9)C24—H24C0.9600
C1—Sn1—C2164.2 (2)C11—C12—H12B109.5
C1—Sn1—O183.70 (16)H12A—C12—H12B109.5
C2—Sn1—O187.75 (16)C11—C12—H12C109.5
C1—Sn1—O282.48 (16)H12A—C12—H12C109.5
C2—Sn1—O283.44 (16)H12B—C12—H12C109.5
O1—Sn1—O284.46 (11)N1—C13—H13A109.5
C1—Sn1—Br296.91 (14)N1—C13—H13B109.5
C2—Sn1—Br296.12 (14)H13A—C13—H13B109.5
O1—Sn1—Br288.15 (9)N1—C13—H13C109.5
O2—Sn1—Br2172.61 (8)H13A—C13—H13C109.5
C1—Sn1—Br193.51 (14)H13B—C13—H13C109.5
C2—Sn1—Br194.45 (14)N1—C14—H14A109.5
O1—Sn1—Br1176.46 (9)N1—C14—H14B109.5
O2—Sn1—Br193.02 (8)H14A—C14—H14B109.5
Br2—Sn1—Br194.37 (2)N1—C14—H14C109.5
C11—O1—Sn1135.5 (3)H14A—C14—H14C109.5
Sn1—C1—H1A109.5H14B—C14—H14C109.5
Sn1—C1—H1B109.5N2—C21—O2136.3 (11)
H1A—C1—H1B109.5N2—C21—C22106.7 (8)
Sn1—C1—H1C109.5O2—C21—C22117.0 (7)
H1A—C1—H1C109.5C21—C22—H22A109.5
H1B—C1—H1C109.5C21—C22—H22B109.5
C11—N1—C14137.9 (10)H22A—C22—H22B109.5
C11—N1—C13107.1 (7)C21—C22—H22C109.5
C14—N1—C13114.6 (6)H22A—C22—H22C109.5
C21—O2—Sn1137.9 (4)H22B—C22—H22C109.5
Sn1—C2—H2A109.5N2—C23—H23A109.5
Sn1—C2—H2B109.5N2—C23—H23B109.5
H2A—C2—H2B109.5H23A—C23—H23B109.5
Sn1—C2—H2C109.5N2—C23—H23C109.5
H2A—C2—H2C109.5H23A—C23—H23C109.5
H2B—C2—H2C109.5H23B—C23—H23C109.5
C21—N2—C23140.0 (9)N2—C24—H24A109.5
C21—N2—C24107.4 (7)N2—C24—H24B109.5
C23—N2—C24112.6 (6)H24A—C24—H24B109.5
N1—C11—O1137.3 (10)N2—C24—H24C109.5
N1—C11—C12107.6 (8)H24A—C24—H24C109.5
O1—C11—C12115.0 (6)H24B—C24—H24C109.5
C11—C12—H12A109.5
C1—Sn1—O1—C11158.8 (7)C13—N1—C11—O11.2 (10)
C2—Sn1—O1—C117.8 (7)C14—N1—C11—C125.0 (10)
O2—Sn1—O1—C1175.8 (7)C13—N1—C11—C12176.9 (4)
Br2—Sn1—O1—C11104.0 (7)Sn1—O1—C11—N1109.9 (9)
Br1—Sn1—O1—C11120.6 (13)Sn1—O1—C11—C1272.0 (7)
C1—Sn1—O2—C21121.4 (7)C23—N2—C21—O2179.6 (6)
C2—Sn1—O2—C2165.9 (7)C24—N2—C21—O22.2 (10)
O1—Sn1—O2—C21154.3 (7)C23—N2—C21—C224.3 (10)
Br2—Sn1—O2—C21152.9 (7)C24—N2—C21—C22178.3 (4)
Br1—Sn1—O2—C2128.2 (7)Sn1—O2—C21—N2115.1 (8)
C14—N1—C11—O1173.2 (6)Sn1—O2—C21—C2269.1 (7)

Experimental details

Crystal data
Chemical formula[SnBr2(CH3)2(C4H9NO)2]
Mr482.83
Crystal system, space groupMonoclinic, P21/c
Temperature (K)173
a, b, c (Å)13.798 (3), 9.3350 (19), 13.729 (3)
β (°) 107.42 (3)
V3)1687.3 (6)
Z4
Radiation typeMo Kα
µ (mm1)6.25
Crystal size (mm)0.14 × 0.13 × 0.13
Data collection
DiffractometerNonius KappaCCD
diffractometer
Absorption correction
No. of measured, independent and
observed [I > 2σ(I)] reflections
4990, 2849, 2307
Rint0.022
(sin θ/λ)max1)0.595
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.033, 0.078, 1.09
No. of reflections2849
No. of parameters162
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)1.33, 1.07

Computer programs: KappaCCD Software (Nonius, 1998), DENZO and SCALEPACK (Otwinowski & Minor, 1997), DENZO and SCALEPACK, SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), SHELXL97 and PARST95 (Nardelli, 1995).

Selected geometric parameters (Å, º) top
Sn1—C12.107 (4)Sn1—O22.398 (3)
Sn1—C22.117 (5)Sn1—Br22.6385 (7)
Sn1—O12.348 (3)Sn1—Br12.6589 (8)
C1—Sn1—C2164.2 (2)O1—Sn1—Br288.15 (9)
C1—Sn1—O183.70 (16)O2—Sn1—Br2172.61 (8)
C2—Sn1—O187.75 (16)C1—Sn1—Br193.51 (14)
C1—Sn1—O282.48 (16)C2—Sn1—Br194.45 (14)
C2—Sn1—O283.44 (16)O1—Sn1—Br1176.46 (9)
O1—Sn1—O284.46 (11)O2—Sn1—Br193.02 (8)
C1—Sn1—Br296.91 (14)Br2—Sn1—Br194.37 (2)
C2—Sn1—Br296.12 (14)
 

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