supplementary materials


bt5971 scheme

Acta Cryst. (2012). E68, m1166    [ doi:10.1107/S1600536812033673 ]

Di-[mu]-chlorido-[mu]-(dimethyl sulfide)-bis{dichlorido[(dimethyl selenide-[kappa]Se)(dimethyl sulfide-[kappa]S)(0.65/0.35)]niobium(III)}(Nb-Nb)

M. Matsuura, T. Fujihara, A. Nagasawa and S. W. Ng

Abstract top

The dinuclear compound, [Nb2Cl6(C2H6S)1.7(C2H6Se)1.3], features an NbIII=NbIII double bond [2.6878 (5) Å]. The molecule lies on a twofold rotation axis that passes through the middle of this bond as well as through the bridging dimethyl sulfide ligand. The NbIII ion exists in an octahedral coordination environment defined by two terminal and two bridging Cl atoms, and (CH3)2Se/(CH3)2S ligands. The (bridging) ligand lying on the twofold rotation axis is an ordered (CH3)2S ligand, whereas the terminal ones on a general position are a mixture of (CH3)2Se and (CH3)2S ligands in a 0.647 (2):0.353 (2) ratio (the methyl C atoms are also disordered).

Comment top

The chemistry of the lower oxidation states of niobium in discrete complexes remains relatively unexplored. Our research group has already carried out X-ray crystallographic determinations of the complexes of the general formula [Nb2Cl6L3] (L= tetrahydrothiophene C4H8S, dimethyl sulfide (Kakeya et al., 2006a, 2006b). These complexes have a triply bridged face-sharing dioctahedral structure with one thioether as a bridging ligand and two terminal Cl- and thioether. A series of ligand substitution reactions of these complexes with monodentate oxygen donors and substituted phosphanes has been explored. The structures of the face-sharing dioctahedral complexes preserve their original geometry in the case of reaction with monodentate ligands and ligand substitution occurred only at terminal positions (Cotton et al., 1985). We report here the first success in determining the structure of [Nb2Cl6(C2H6Se)1.3(C2H6S)1.7 (Scheme I), which has selenoether as ligands at terminal positions.

The molecule has dinuclear bridging unit [Nb2(µ-Cl)2(µ-Me2X)] (X = mixture of S, Se) with the terminal Me2X ligands in a trans orientation to the bridging Me2S (Fig. 1). The average Nb—(µ-Cl) and Nb—(µ-Me2S) distances fall within the range of those for [Nb2(µ-Cl)2Cl4(µ-Me2S)(Me2S)2], which has the same bridging unit (Kakeya et al., 2006a, 2006b). The terminal Nb—Cl lengths are shorter than the corresponding distances to the bridging atoms. If the terminal metal-chalcogen bond were purely ionic, the distance should coincide with the sum of ionic radii of metal and chalcogen. Since the ionic radii of the trivalent niobium, Se2– and S2– given in the literature are 0.72 Å, 1.98 Å and 1.84 Å, the bond distances of the metal and chalcogen is 2.70 Å for Se2– and 2.56 Å for S2–. We find that the difference between bond lengths and sum of the those radii is smaller in the title compound than in [Nb2Cl6(Me2S)3]. This difference is ascribed to the influence of the covalency of the metal-chalcogen interactions. Other geometrical parameters also lie within the same ranges as in analogous dinuclear niobium complexes (Kakeya et al., 2006a, 2006b).

Related literature top

For background to this study, see: Cotton et al. (1985); Kakeya et al. (2006a,b). For the synthesis of the principal reactant, see: Tsunoda & Hubert-Pfalzgraf (1982). For a related structure, see: Babaian-Kibala et al. (1991).

Experimental top

All the reactions were carried out under a dry argon atmosphere by using standard Schlenk tube techniques. [Nb2Cl6(Me2S)3] was prepared by a literature method (Tsunoda & Hubert-Pfalzgraf, 1982). Me2Se (0.10 ml, 1.3 mmol) was added to [Nb2Cl6(Me2S)3] (200 mg, 0.34 mmol) in CH2Cl2 (20 ml) and stirred for 1 d at room temperature. The resulting solution was concentrated to dryness to give red purple powders. The crude product was washed with hexane and dried under reduced pressure. A mixture of [Nb2Cl6(Me2S)3] and a compound believed to be [Nb2Cl6(Me2Se)2(Me2S)] was obtained as red purple powders (130 mg, yield 58% identified by 1H NMR). The latter compound was recrystallized from CH2Cl2–hexane (1:4) to give red crystals. 1H NMR (CDCl3, 300 K): δ 3.33 (6H, bridging-Me2S), 2.49 (12H, terminal-Me2Se). 13C NMR (300 K, CDCl3): δ 30.0 (2 C, bridging-Me2S), 14.1 (4 C, terminal-Me2S). FAB-MS(nitrobenzyl alcohol matrix): m/z = 644 [M—Cl]+.

As the formulation refined to [Nb2Cl6(C2H6Se)1.3(C2H6S)1.7], the crystal is probably not reprensentative of the bulk formulation.

Refinement top

The H atoms were placed in calculated positions, with C—H = 0.98 Å for CH3, and refined using a riding model, with Uiso(H) = 1.5Ueq of the carrier atoms.

The chalcogen ligand on the general position is disordered; the atom refined to a 0.647 (2)Se : 0.353S mixture. The Se1–C distances were restrained to 1.95±0.01 Å and the S1'–C distances to 1.80±0.01 Å. The temperature factors of Se1 and S1' were made identical.

The refinement led to an Nb1–Se1 distance of 2.72 Å but a much longer Nb1–S1' distance of 2.79 Å (a normal Nb–S bond is approximately 2.40 Å). Refinement then proceeded by setting the Nb1–S1 (ordered sulfur) and the N1b–S1' (disordered sulfur) bond distances to be within 0.01 Å of each other. The two methyl groups were each split into two components, and the temperature factors of the primed atoms were set to those of the unprimed ones. Additionally, the anisotropic temperature factors were tightly restrained to be nearly isotropic. This model gave distances of 2.420 (1) Å for the ordered atom and 2.543 (6) Å for the disordered atom.

The failure of the Hirshfeld test for the Nb1–Se1 and Nb1–S1' bonds is attributed to the tight restraints imposed on the disordered ligand.

Arising from the refinement, the compound is formulated as [Nb2Cl6(C2H6Se)1.3(C2H6S)1.7].

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2010).

Figures top
[Figure 1] Fig. 1. Thermal ellispoid plot (Barbour, 2001) plot of [Nb2Cl6(C2H6Se)1.3(C2H6S)1.7] at the 70% probability level. The disorder is not shown and symmetry-related atoms are not labeled.
Di-µ-chlorido-µ-(dimethyl sulfide)-bis{dichlorido[(dimethyl selenide-κSe)(dimethyl sulfide-κS)(0.65/0.35)]niobium(III)}(NbNb) top
Crystal data top
[Nb2Cl6(C2H6S)1.7(C2H6Se)1.3]F(000) = 1238
Mr = 645.87Dx = 2.219 Mg m3
Orthorhombic, PbcnMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2n 2abCell parameters from 3921 reflections
a = 13.3314 (11) Åθ = 2.9–28.5°
b = 13.5952 (12) ŵ = 4.63 mm1
c = 10.6649 (9) ÅT = 150 K
V = 1932.9 (3) Å3Block, red
Z = 40.10 × 0.09 × 0.08 mm
Data collection top
Bruker APEXII CCD area-detector
diffractometer
2218 independent reflections
Radiation source: Bruker TXS fine-focus rotating anode1975 reflections with I > 2σ(I)
Bruker Helios multilayer confocal mirror monochromatorRint = 0.028
Detector resolution: 8.333 pixels mm-1θmax = 27.5°, θmin = 2.1°
φ and ω scansh = 1517
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
k = 1617
Tmin = 0.655, Tmax = 0.709l = 1213
10299 measured 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)] = 0.023Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.057H-atom parameters constrained
S = 1.03 w = 1/[σ2(Fo2) + (0.0281P)2 + 2.0744P]
where P = (Fo2 + 2Fc2)/3
2218 reflections(Δ/σ)max = 0.001
85 parametersΔρmax = 0.61 e Å3
17 restraintsΔρmin = 0.53 e Å3
Crystal data top
[Nb2Cl6(C2H6S)1.7(C2H6Se)1.3]V = 1932.9 (3) Å3
Mr = 645.87Z = 4
Orthorhombic, PbcnMo Kα radiation
a = 13.3314 (11) ŵ = 4.63 mm1
b = 13.5952 (12) ÅT = 150 K
c = 10.6649 (9) Å0.10 × 0.09 × 0.08 mm
Data collection top
Bruker APEXII CCD area-detector
diffractometer
2218 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
1975 reflections with I > 2σ(I)
Tmin = 0.655, Tmax = 0.709Rint = 0.028
10299 measured reflectionsθmax = 27.5°
Refinement top
R[F2 > 2σ(F2)] = 0.023H-atom parameters constrained
wR(F2) = 0.057Δρmax = 0.61 e Å3
S = 1.03Δρmin = 0.53 e Å3
2218 reflectionsAbsolute structure: ?
85 parametersFlack parameter: ?
17 restraintsRogers parameter: ?
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Nb10.468766 (18)0.233109 (19)0.36981 (2)0.01461 (9)
Se10.43903 (16)0.38286 (10)0.54126 (16)0.0169 (2)0.647 (2)
S1'0.4374 (8)0.3682 (6)0.5299 (8)0.0169 (2)0.353
Cl10.57325 (6)0.16964 (6)0.53247 (6)0.02378 (16)
Cl20.31130 (5)0.16593 (6)0.42645 (7)0.02496 (17)
Cl30.38916 (5)0.33927 (5)0.20578 (6)0.02154 (16)
S10.50000.08504 (7)0.25000.0173 (2)
C10.3683 (5)0.3155 (6)0.6751 (7)0.0327 (8)0.647 (2)
H1A0.34110.25330.64340.049*0.647 (2)
H1B0.31330.35700.70530.049*0.647 (2)
H1C0.41480.30210.74420.049*0.647 (2)
C20.3289 (7)0.4616 (8)0.4702 (10)0.0240 (12)0.647 (2)
H2A0.29460.42340.40510.036*0.647 (2)
H2B0.35620.52190.43330.036*0.647 (2)
H2C0.28120.47850.53670.036*0.647 (2)
C1'0.3660 (7)0.3227 (8)0.6639 (10)0.0327 (8)0.353
H2D0.29420.33300.64900.049*0.3532 (16)
H2E0.38630.35840.73960.049*0.3532 (16)
H2F0.37910.25240.67510.049*0.3532 (16)
C2'0.3338 (14)0.4497 (16)0.489 (2)0.0240 (12)0.353
H3D0.27150.42410.52550.036*0.3532 (16)
H3E0.32730.45340.39810.036*0.3532 (16)
H3F0.34700.51560.52310.036*0.3532 (16)
C30.4005 (2)0.0020 (2)0.2071 (3)0.0246 (6)
H3A0.34150.03980.18110.037*
H3B0.38310.03930.27930.037*
H3C0.42270.03980.13760.037*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Nb10.01621 (14)0.01427 (14)0.01335 (13)0.00034 (9)0.00035 (9)0.00066 (9)
Se10.0202 (2)0.0139 (6)0.0167 (4)0.0004 (4)0.0026 (3)0.0051 (3)
S1'0.0202 (2)0.0139 (6)0.0167 (4)0.0004 (4)0.0026 (3)0.0051 (3)
Cl10.0265 (4)0.0263 (4)0.0185 (3)0.0031 (3)0.0059 (3)0.0021 (3)
Cl20.0209 (4)0.0286 (4)0.0254 (4)0.0064 (3)0.0031 (3)0.0001 (3)
Cl30.0244 (4)0.0224 (4)0.0179 (3)0.0073 (3)0.0008 (3)0.0027 (3)
S10.0198 (5)0.0147 (5)0.0174 (5)0.0000.0024 (4)0.000
C10.045 (2)0.0319 (19)0.0213 (18)0.0017 (16)0.0105 (15)0.0018 (15)
C20.0259 (18)0.022 (3)0.024 (4)0.0093 (15)0.0041 (18)0.003 (2)
C1'0.045 (2)0.0319 (19)0.0213 (18)0.0017 (16)0.0105 (15)0.0018 (15)
C2'0.0259 (18)0.022 (3)0.024 (4)0.0093 (15)0.0041 (18)0.003 (2)
C30.0249 (15)0.0219 (16)0.0270 (16)0.0055 (12)0.0045 (13)0.0007 (12)
Geometric parameters (Å, º) top
Nb1—Cl22.3676 (7)C1—H1A0.9800
Nb1—Cl12.3863 (7)C1—H1B0.9800
Nb1—S12.4204 (8)C1—H1C0.9800
Nb1—Cl32.5039 (7)C2—H2A0.9800
Nb1—Cl3i2.5140 (7)C2—H2B0.9800
Nb1—S1'2.543 (6)C2—H2C0.9800
Nb1—Nb1i2.6878 (5)C1'—H2D0.9800
Nb1—Se12.7650 (10)C1'—H2E0.9800
Se1—C11.941 (6)C1'—H2F0.9800
Se1—C21.968 (6)C2'—H3D0.9800
S1'—C1'1.825 (9)C2'—H3E0.9800
S1'—C2'1.822 (9)C2'—H3F0.9800
Cl3—Nb1i2.5140 (7)C3—H3A0.9800
S1—C31.801 (3)C3—H3B0.9800
S1—C3i1.801 (3)C3—H3C0.9800
S1—Nb1i2.4204 (8)
Cl2—Nb1—Cl1101.10 (3)C3—S1—Nb1i120.94 (10)
Cl2—Nb1—S188.07 (2)C3i—S1—Nb1i121.93 (10)
Cl1—Nb1—S189.00 (2)C3—S1—Nb1121.93 (10)
Cl2—Nb1—Cl391.42 (3)C3i—S1—Nb1120.94 (10)
Cl1—Nb1—Cl3164.53 (3)Nb1i—S1—Nb167.46 (3)
S1—Nb1—Cl3100.57 (2)Se1—C1—H1A109.5
Cl2—Nb1—Cl3i166.23 (3)Se1—C1—H1B109.5
Cl1—Nb1—Cl3i90.05 (3)H1A—C1—H1B109.5
S1—Nb1—Cl3i100.29 (2)Se1—C1—H1C109.5
Cl3—Nb1—Cl3i76.37 (3)H1A—C1—H1C109.5
Cl2—Nb1—S1'87.8 (2)H1B—C1—H1C109.5
Cl1—Nb1—S1'82.5 (3)Se1—C2—H2A109.5
S1—Nb1—S1'169.6 (2)Se1—C2—H2B109.5
Cl3—Nb1—S1'89.0 (3)H2A—C2—H2B109.5
Cl3i—Nb1—S1'85.7 (2)Se1—C2—H2C109.5
Cl2—Nb1—Nb1i121.15 (2)H2A—C2—H2C109.5
Cl1—Nb1—Nb1i120.69 (2)H2B—C2—H2C109.5
S1—Nb1—Nb1i56.272 (14)S1'—C1'—H2D109.5
Cl3—Nb1—Nb1i57.795 (18)S1'—C1'—H2E109.5
Cl3i—Nb1—Nb1i57.431 (17)H2D—C1'—H2E109.5
S1'—Nb1—Nb1i133.6 (2)S1'—C1'—H2F109.5
Cl2—Nb1—Se189.33 (4)H2D—C1'—H2F109.5
Cl1—Nb1—Se182.48 (5)H2E—C1'—H2F109.5
S1—Nb1—Se1170.45 (5)S1'—C2'—H3D109.5
Cl3—Nb1—Se188.67 (5)S1'—C2'—H3E109.5
Cl3i—Nb1—Se184.11 (4)H3D—C2'—H3E109.5
S1'—Nb1—Se11.6 (3)S1'—C2'—H3F109.5
Nb1i—Nb1—Se1132.31 (4)H3D—C2'—H3F109.5
C1—Se1—C2100.2 (3)H3E—C2'—H3F109.5
C1—Se1—Nb1102.0 (3)S1—C3—H3A109.5
C2—Se1—Nb1104.6 (4)S1—C3—H3B109.5
C1'—S1'—C2'89.8 (9)H3A—C3—H3B109.5
C1'—S1'—Nb1111.5 (5)S1—C3—H3C109.5
C2'—S1'—Nb1113.9 (10)H3A—C3—H3C109.5
Nb1—Cl3—Nb1i64.77 (2)H3B—C3—H3C109.5
C3—S1—C3i102.3 (2)
Cl2—Nb1—Se1—C135.3 (2)Cl1—Nb1—Cl3—Nb1i89.16 (10)
Cl1—Nb1—Se1—C166.0 (2)S1—Nb1—Cl3—Nb1i38.270 (17)
Cl3—Nb1—Se1—C1126.7 (2)Cl3i—Nb1—Cl3—Nb1i59.87 (2)
Cl3i—Nb1—Se1—C1156.8 (2)S1'—Nb1—Cl3—Nb1i145.7 (2)
Nb1i—Nb1—Se1—C1168.8 (2)Se1—Nb1—Cl3—Nb1i144.13 (4)
Cl2—Nb1—Se1—C268.8 (4)Cl2—Nb1—S1—C316.75 (12)
Cl1—Nb1—Se1—C2170.1 (4)Cl1—Nb1—S1—C3117.89 (12)
Cl3—Nb1—Se1—C222.7 (4)Cl3—Nb1—S1—C374.34 (12)
Nb1i—Nb1—Se1—C264.8 (4)Cl3i—Nb1—S1—C3152.23 (12)
Cl2—Nb1—S1'—C1'33.1 (6)S1'—Nb1—S1—C383.3 (13)
Cl1—Nb1—S1'—C1'68.4 (6)Nb1i—Nb1—S1—C3113.40 (12)
S1—Nb1—S1'—C1'33.5 (19)Cl2—Nb1—S1—C3i115.09 (12)
Cl3—Nb1—S1'—C1'124.6 (6)Cl1—Nb1—S1—C3i13.95 (12)
Cl3i—Nb1—S1'—C1'159.0 (7)Cl3—Nb1—S1—C3i153.82 (12)
Nb1i—Nb1—S1'—C1'165.8 (4)Cl3i—Nb1—S1—C3i75.93 (12)
Cl2—Nb1—S1'—C2'66.7 (10)S1'—Nb1—S1—C3i48.6 (14)
Cl1—Nb1—S1'—C2'168.2 (10)Nb1i—Nb1—S1—C3i114.76 (12)
S1—Nb1—S1'—C2'133.3 (13)Cl2—Nb1—S1—Nb1i130.15 (2)
Cl3—Nb1—S1'—C2'24.8 (10)Cl1—Nb1—S1—Nb1i128.71 (2)
Cl3i—Nb1—S1'—C2'101.2 (10)Cl3—Nb1—S1—Nb1i39.061 (18)
Nb1i—Nb1—S1'—C2'66.0 (11)Cl3i—Nb1—S1—Nb1i38.832 (17)
Cl2—Nb1—Cl3—Nb1i126.58 (2)S1'—Nb1—S1—Nb1i163.3 (13)
Symmetry code: (i) x+1, y, z+1/2.
Acknowledgements top

This work was partly supported by the programs of the Grants-in-Aid for Scientific Research (to TF, No. 23510115) from the Japan Society for the Promotion of Science.

references
References top

Babaian-Kibala, E., Cotton, F. A. & Shang, M. (1991). Acta Cryst. C47, 1617–1621.

Barbour, L. J. (2001). J. Supramol. Chem. 1, 189–191.

Bruker (2008). APEX2. Bruker AXS Inc., Madison, Wisconsin, USA.

Cotton, F. A., Duraj, S. A. & Roth, W. J. (1985). Acta Cryst. C41, 878–881.

Kakeya, M., Fujihara, T., Kasaya, T. & Nagasawa, A. (2006a). Organometallics, 25, 4131–4137.

Kakeya, M., Fujihara, T. & Nagasawa, A. (2006b). Acta Cryst. E62, m553–m554.

Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Tsunoda, M. & Hubert-Pfalzgraf, L. G. (1982). Inorg. Synth. 21, 16–18.

Westrip, S. P. (2010). J. Appl. Cryst. 43, 920–925.