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Dialkyldithiocarbamate complexes of tungsten(VI). Synthesis, properties and structure of thiodichlorobis(dimethyldithiocarbamato)tungsten(VI)
Polyhedron Vol. II, No. 2, pp. 279-284, Printed in Great Britain
1992
0277-5X37/92 SS.OO+.oO 0 1992 Pergamon Press plc
DIALKYLDITHIOCARBAMATE COMPLEXES OF TUNGSTEN(W). SYNTHiESIS, PROPERTIES AND STRUCTURE THIODICHLOROBIS(DIMETHYLD~HIOCARBAMATO)TUNGSTEN(VI) V. P. FEDIN,*
OF
Yu. V. MIRONOV, A. V. VIROVETS, N. V. PODBEREZSKAYA, V. Ye. FEDOROV and P. P. SEMYANNIKOV
Institute of Inorganic Chemistry, Siberian Branch of the Academy of Sciences of the U.S.S.R., Novosibirsk 630090, U.S.S.R. (Received 30 May 1991; accepted 12 August 1991) Abstract-(Et4N)pWS4 and (Et,N),W,S, react with (Et2NCS2),Se in CH3CN to form WS3(S2CNEt2)2. The reactions of WS3(S2CNEt2)2 and WS3(S2CNMe& with HX (X = Cl, Br) in CH&N led to WSX2(S2CNR2)2. The thiohalogenide complexes react with (Bu~N)~& and (NH4)2Sx to form WS,(S2CNR2)2. It is shown that the interaction of WSC12 (S2CNMe2)2 with (Bu~N)~~~S, gives rise to W32S(34S-34S)(S2CNMe2)2 and W34S (32S---34S)(S2CNMe2)2. The structure of WSC12(S2CNMe2)2 has been determined by X-ray structural analysis. The coordination polyhedron about the tungsten atom is a slightly distorted pentagonal bipyramid whose equator is defined by the sulphurs of the dimethyldithiocarbamate ligands and one of the terminal chlorines w---Cl 2.403(5) A] and the apices are occupied by chlorine [W-Cl 2.458(5) A] and sulphur [w=S 2.101(5) A] atoms.
Comparison of thio- and thiohalogenide complexes of transition metals indicates that they often contain the same M-S-containing fragments,lm6 but mutual transitions between thio- and thiohalogenide complexes have not been studied extensively. The only known examples of such transitions involve the Group VI metals. Thus the triangular complex Mo,S:, reacts with HX to form the triangular thiohalogenide complexes Mo$~X~-.~ On the other hand, M&X4X4,2 (M = MO, w) lWiCt with ammonium polysulphide to form Mo,S:; and 8*9 The interaction of (Et4N)*WS4 W~SI~(NHJ):-. with HX (X = Cl, Br) in CH2C12 afforded the binuclear thiohalogenide complexes W,S,Xj-, W2S3Bri- and WzS4Xi-.‘o The interaction of WSC14 with (Et4N)2WS4 gave rise to (Et,N), w,s9. ’ ’ In the present work mutual transformations of the tungsten (VI) dialkylthiocarbamate complexes WS3(S2CNR2), and WSX2(S2 CNR2), have been studied for the first time and the structure of WSC12(S2CNMe2), has been determined by X-ray crystallography.
EXPERIMENTAL
All reactions were carried out in the air. CH,CN was distilled over P40,0. The compounds (Et, WS3(S2CNMe2)2,*3 N)ZWS4,” (Et4W2W39,‘l (Et2CNS2)2Se,‘4(Bu4N)2S6,(Bu4N)234S6,~4)2Sx’5
* Author to whom correspondence should be addressed.
were prepared by the respective literature procedures. The 34S-containing compounds were synthesized from the elemental 34Ss containing 99.5% of the isotope. All other reagents were analytically pure. Determinations of C, H, N, S, Cl, Br were performed at the Laboratory of Microanalysis of the Institute of Organic Chemistry (Novosibirsk). W, S, Se were determined gravimetrically as WO,, BaSO, and Se, respectively. The IR spectra were recorded in the KBr pellets on an IR-75 spectrometer. The Raman spectra were measured on a Triplemate Spex spectrometer using a multichannel detector and the 632.8 nm line of an He-Ne laser for excitation. The NMR ‘H spectra were obtained at room temperature on a SXP-4100 (Bruker) instrument. The structure of WSC12(S2CNMe2)2 was established by X-ray structural analysis. A red-brown single crystal of a prismatic needle-like habit with
279
V. P. FEDIN
280 Table 1. Crystallographic
data for WSC12(S2CNEt2)2
Formula Formula weight Crystal system Space group
C,H,,Cl,N&W 527.25 Orthorhombic Pnd , 11.972(2) 8.255(l) 15.393(4) 1521.3(5) 4 2.302 0.60 x 0.90 x 0.35 Syntex P2, Cu-K, Graphite e/20, V,,,i, = 2.9” min- ’ 3-115 236 Room 1224 857 Z > 3(Z) 0.0288
a (4 b (A) c (A) V(A3) z Calc. density (g cnDimensions (mm) Diffractometer Radiation Monochromator Scan mode 20 range (“)
‘)
p (cm- ‘) Temperature Total reflections Independent reflections RF
Table 2. Bond distances
well-shaped heads was obtained by diffusing ether into a solution of the complex in CH2C12. The unit cell parameters and reflection intensities were obtained by the standard procedure. The structure was solved by direct methods using the program SHELX-8616 and refined by full-matrix least squares method (the set of programs YANX’ 7, in the anisotropic approximation for the non-hydrogen atoms with a unit weighing scheme. Absorption was taken into account using the DIFABS program. I8 The hydrogen atoms were located either from a difference Fourier synthesis or geometrically and were included into the refinement with fixed coordinates and Vi,, = 0.07 A’. The crystallographic data for complex 1 are given in Table 1. The bond lengths and the main angles are shown in Table 2. Preparation of WS3(S2CNEt2)2
(a) From (Et4N)2WS4. (Et4N)2WS4 (0.57 g, 1.0 mmol) and (Et2NCS2)2Se (1.51 g, 4.0 mmol) were stirred in 30 cm3 of acetonitrile for 30 min at room
(A) and angles (“) in WSC12(Me2NCS& Bond distances
w-Cl( 1) w-S( 1) W-S(3) W-S(5) S(2)--c(l) S(4)-~(2) N(lk--C(ll) C(2)-N(2) N(2)-C(22)
et al.
(A) w-Cl(2) W-S(2) W-S(4)
2.458(5) 2.50(l) 2.50(2) 2.101(5) 1.66(6) 1.77(3) 1.40(8)
S(l)--c(l) S(3)--c(2) C(l)-N(1) N(l)-C(12) N(2)-C(21)
1.26(5)
2.403(5) 2.57(l) 2.48(2) 1.85(5) 1.66(4) 1.28(7) 1.26(5) 1.53(6)
1.68(5) Bond angles (“)
Cl( 1)-W--x1(2) Cl(l)-W-S(2) Cl( 1)-W-S(4) C1(2)---w-S( 1) C1(2)-W-S(3) C1(2)-W-S(5) S( 1)---W-S(3) S(l)-W-S(S) S(2 )-W-S(4) S(3)--W-S(4) S(4)---W-S(5)
87.8(2) 86.1(4) 82.7(5) 74.5(6) 75.4(6) 95.7(2) 148.5(5) 96.4(7) 72.5(5) 69.7(5) 94.0(5)
W-S(2)-C(l) W-S(4)--C(2)
95(2) 88(l) 122(4) 128(5) 119(4) 126(3) 120(4) ill(3)
S(l)_C(l)_N(l) C(l)---N(l)--C(l1) C(1 l)-N(l)-C(12) S(3k--C(2)-N(2) C(2)---N(2t-C(2 1) C(21)--N(2)--C(22)
Cl(l)-W-S(l) Cl( 1)---W-S(3) Cl(l)-W-S(S) C1(2)-W-S(2) C](2)-W-S(4) S( 1)--W-S(2) S( 1)-W-S(4) S(2)--W-S(3) S(2)-W-S(5) S(3)-W-S(S)
85.2(5) 84.5(6) 176.5(3) 141.0(6) 144.4(6) 66.6(4) 138.0(5) 141.9(5) 91.6(5) 95.7(7)
W-S(l)--c(l) W-S(3)--cx2) S(l)--c(l)_S(2) S(2)--c(lk-N(1) C(l)--N(lHXl2) S(3)_C(2)-S(4) S(4)-C(2)-N(2) C(2)--N(2)---C(22)
93(2) 90(l) 105(3) 133(4) ill(4) 112(2) 122(3) 126(3)
281
Dialkyldithiocarbamate complexes of tungsten(V1) temperature. The mixture was heated until it boiled, filtered to remove selenium and cooled down. Obtained 0.15 g of the complex WS3(S2CNEtJ2. Yield 26%. Found: C, 20.8; H, 3.5; N, 4.2; S, 31.5. Calc. for CloHZoN&W: C, 20.8; H, 3.5; N, 4.9; S, 31.9%. IR : 539(s), 493(vs), 440(w) cm-‘. Raman (700-20 cm-‘) : 543(m), 496(vs), 331(s), 31 l(s) cm-‘. (b) From (Et4N)2W3S9. 0.10 g of WS&CNEt& was obtained from (Et4N)ZW3S9 (0.43 g, 0.4 mmol) and (Et,NCS&Se (0.55 g, 1.47 mmol) by a procedure analogous to the above one. Yield 15%. Preparation of WSC12(S2CNMe2)2 Dry HCl was passed through a suspension of WS&CNMe& (0.20 g) in 20 cm3 of CH3CN until the solid was completely dissolved. The resulting yellow-brown solution was cooled to -20°C the red crystals were filtered off, washed with alcohol, ether and dried in vacua. Obtained 0.10 g of WSCl&CNMe&. Yield 50%. Found: C, 13.8; H, 2.0; N, 4.8; S, 30.6; Cl, 13.7. Calc. for C10HZ,,N2C12S5W: C, 13.6; H, 2.3; N, 5.3; S, 30.4; Cl, 13.7%. IR: 508(vs), 493(w) cm-‘. Raman : 51I, 476(m), 238(w), 220(m), 179(m), 153(m), 125(w) cm- ‘. Preparation of WSBr2(S2CNEt2)2 0.09 g of WSBr&CNEtJ was obtained from 0.16 g of WS3(S2CN&)2 by a procedure analogous to that described above for the synthesis of WSCl&CNMe&. Yield 48%. Found: C, 17.9; H, 2.9; N, 4.2; S, 23.0; Br, 23.7. Calc. for C,,,H10N2Br2SSW: C, 17.9; H, 3.0; N, 4.2; S, 23.9; Br, 23.8%. IR: 513(s), 487(w) cm-‘. Raman : 51I, 205(m), 156(m) cm- ‘.
solid was separated, washed with alcohol and recrystallized from a CH,Cl,/ether mixture. Obtained 0.07 g of WS3(SzCNMe&. Yield 23%. RESULTS
AND DISCUSSION
Dialkyldithiocarbamate complexes of WV1were first obtained by E. I. Stiefel and co-workers when interacting WS:- with tetraalkylthiuram disulphides13 (eq. 1) : WS:- +(R2CNS2)2-
WS(SZ)(S&NRJZ.
(1)
The structure of the complex with R = i-Bu was determined by X-ray structural analysis.13 In the present work we have found that an analogous mononuclear thiocomplex WS&S2CNEt2)2 is produced when reacting (Et2CNS2)$e with mononuclear WS:- or trinuclear W&- (eqs 2 and 3) : WS:- + (Et2NCS&Se W$-
+ (Et2NCS&Se -
WS&CNEt& WS3(S2CNEtJ2+
+ Se (2) Se. (3)
We have attempted these reactions in the hope of obtaining diethyldithiocarbamate complexes of tungsten which would also contain simultaneous sulphur and selenium but the hope did not realize. Reactions (2) and (3) proceed in a complicated manner to give a mixture of products from which we were only able to isolate elemental selenium and WS3(S2CNEt&. The yield of WS&CNEt& in reactions (2) and (3) is not high. In reaction (2) at the ratio WS:-/(Et$NS&Se = 1:4 it is, for example, only 26%. With decreasing WS:-/ (Et2CNS2),Se ratio the yield of WS3(S2CNEt& decreases. Thus, from the point of view of the synthesis of WS3(S2CNR,), the Stiefel method13 is of obvious advantages. Synthesis of the WSX2(S2CNRJ2 complexes
Interaction of WSCl&CNMeJ,
with (Bu4N)&
0.17 g of WSC12(S2CNMe2)2 and 0.30 g of (Bu~N)$~ in 30 cm3 of CH$ZN were stirred for 1 h. The resulting green precipitate was filtered off, washed with acetonitrile, ether and dried in uacuo. Obtained 0.14 g of analytically pure WS3(S2CN Me& (characterization by elemental analysis, IR, Raman). Yield 83%. IR: 539(s), 493(vs), 440(m) cm-‘. Raman : 533(vs), 495(s), 434(m), 179(m), 129(s) cm-‘. Interaction of WSC12(S2CNMe2), with (NH,)& 0.30 g of WSC1,(S2CNMe2)2 and 15 cm3 of (NH&S, were stirred for 30 min. The dark green
The presence in the easily available complexes WS(S2)(S2CNR& of two structural fragments W=S
and W
/
makes these compounds
con-
‘S venient objects on which to study the differences in reactivity of the thioligands depending on the type of coordination. In the present work the interaction of WS3(S2CNR& with hydrohalogen acids HX (X = Cl, Br) in acetonitrile has been studied. The reaction afforded the thiohalogenide complexes WSX2(S2CNR2)2 in yields of about 50% (eq. 4) : WS3(SzCNR&+HX-
WSCl@&NR&.
(4)
282
V. P. FEDIN
The WSC12(S2CNR2)2 complexes are dark-red crystalline substances which are stable in the solid state in the air and in solutions. They are well soluble in DMF and in acetonitrile upon heating and moderately soluble in CH2C12. The PMR spectrum of WSC12(S2CNMe2)2 (1) in CD&l2 shows two singlets of equal intensity with close values of the chemical shifts (6 = 3.31 and 3.33 ppm) indicating non-equivalence of the methyl groups of the chelate dimethyldithiocarbamate ligands. In the IR and Raman spectra of the complexes WSX2(S2CNR2)2 there are intense bands of vwzs in the region 5OG 520 cm- I. The structure of WSCl,(&CNMe&
(1)
The structure of 1 is a molecular one. The general appearance is shown in Fig. 1; the molecular packing in the crystal lattice is shown in Fig. 2. The coordination polyhedron about the tungsten atom is a slightly distorted pentagonal bipyramid. The pyramid equator is formed by the sulphurs of the dimethyldithiocarbamate ligands (deviations of these atoms from the plane do not exceed 0.17 A) and a chlorine, the apices are occupied by the Cl( 1)
Fig. 1. The structure
of WSCl,(S2CNMe2)2
(1).
et al.
atom and the sulphide ligand [S(5)], the value of the angle Cl(l)---W-S(5) = 176.5(3)O being equal to 180”. The small value of the W-S bond length for the S atom of the sulphide ligand indicates that it has a multiple character. The bond lengths and bond angles in the W(&CNMe& fragment have normal values. No substantially short molecular contacts are observed within the structure. The literature describes the structure of a whole number of complexes having a pentagonal-bipyramidal environment about the W or MO atom and containing dithiocarbamate, sulphide or 0x0, halogenide or disulphide ligands : WO(S2)(S2CNEt2)2 (2), WW2)MWi-W21~ (3), MoOXdWNEtd2, X = Cl (4), X = Br (5). 19-*’In complexes 2 and 3
(& sw,wb 1 XIX
M = W; Y = S; X = CL (1) M = Mo;Y = 0; X = CL (4) M = Mo;Y=O;X = Br(5)
M = W; Y = 0 (2) M = W;Y = S (3)
both sulphur atoms of the S2 ligand occupy equatorial positions along with the sulphurs of one of the (S$NRJ ligands ; the sulphurs of the second (S2CNR2) ligand occupy an equatorial and a semiaxial position. The pentagonal pyramid is strongly distorted due to the apex being drawn towards the equatorial plane as a result of which the “transangle” S(S,CNR,)---W-S(O) decreases to 162.4” in 2 and 162.2” in 3. It can be assumed, with a high probability, that the structure of the complex WS(SJ(!!&CNMe& (6) from which 1 has been obtained is analogous to that of 2 and 3 since the S2 ligand with a S-S bond of about 2 A most
Fig. 2. The unit cell of 1.
Dialkyldithiocarbamate
** “I:;’
likely will not be able to occupy an equatorialaxial position (drawing of the apex towards the equatorial plane would have been in this case still greater than in 2 and 3). A structural relation between the molecules of 6 and 1 is then apparent : replacement of the Sz ligand in 6 by two chlorine atoms in 1 results in a change in the coordination environment about the W atom consisting in the chelate cycle plane of one of the (S&NMEr) ligands being turned in such a way that it begins to occupy the equatorial position with both of its sulphurs. One of the chlorine atoms occupies an equatorial position and the other an axial position. The sulphide ligand remains axial (eq. 5).
+=
283
complexes of tungsten(V1)
a
HX(X CL,Br)
(5)
-t-G%
X
In 1 there is a lengthening of the W-Cl bond by 0.055 A (at o(W-Cl) = 0.005 A) for the chlorine atom in the trans-position with respect to the sulphide ligand. An analogous situation is observed in 4 for the chlorine atom trans with respect to the terminal oxoligand but the size of this lengthening is substantially greater-by 0.087 8, (at a(W-Cl) = 0.001 A). In all other respects, the geometrical parameters of the molecules for 4 and 5 are close to those for 1. Interaction of WSX2(S2CNR&
with (Bu,,N)&
The thiohalogenide complexes of tungsten interact with (Bu,N)& in WSXz(S&NR& acetonitrile to give high yields of WS$$CNR& (eq. 6) :
+
(Bu,N)ISI
-
The reaction with a solution of ammonium polysulphide in water proceeds analogously but the yield is substantially lower. The formal result of reaction (6) is nucleophilic substitution of the halogenide ligands by S:- and a change in the coordination environment of the tungsten atoms. An unexpected result has been obtained in the reaction of WSC12(S&NMe2)2 with (Bu$)~~~&. Figure 3 shows IR spectra of the products of this reaction in the region 400-600 cm-’ and, for comparison, IR spectra of WS3(S2CNMe&. It is known that in the IR spectra of WS3(S2CNR2)r there are bands of v(S-S) at 550 cm- ’ and of v(W=S) at 500 cm --I. I3 It is well seen that in the reaction products
600
500
IOcm-1
Fig. 3. IR spectrum of WS3(S2CNMeJ2 (a) and IR spectrum of the products of the reaction of WSCl,(S,CNMe& with (Bu.,N)~~~& (b) in the region 400-600 cm-’ (* bands of the ligand Me2NCS2-).
WSCl&CNMer)r and (Bu,N),‘~& there are two bands of v(S-S) (shifts by 8 and 17 cm- ‘) and two bands of v(W=S) (shifts by 1 and 14 cm-‘). The vibrational bands of the S2CNMe2 ligands are not changed. It has been shown earlier that in thioand thiohalogenide complexes of molybdenum and tungsten the v(M--C) band undergoes an isotopic shift of 12-13 cm-’ upon replacement of 32Sby 34S and the v(S-S) band undergoes a shift by 1417 cm-’ on going to complexes with (34S-34S) ligands and of 7-9 cm-’ on going to complexes with (32S-34S) ligands.“*” Thus, the data of the vibrational spectroscopy unambiguously indicate the presence in the products of the reaction of W32SC12(S2CNMe2)2with (Bu~N)~~~S~of products with the structural fragments W=32S, W=34S, 34S-34S and 32S-34S. A possible scheme explaining formation of these products is shown below (eq. 7) :
A key point in this scheme is the addition of 34Szat the W=S bond to form a product containing a four-membered cycle W32S34S34$. Further transformation of this product allows one to easily understand the formation of the reaction products. Note also, that no isotopic exchange takes place upon heating W32S3(S2CNMe2)2 with (Bu~N)~‘~&, in acetonitrile.
284
V. P. FEDIN REFERENCES
1. D. A. Rice, Coord. Chem. Rev. 1978,25, 199. 2. J. Fenner, A. Rabenau and G. Tragezer, Adv. Inorg. Chem. Radiochem. 1979,22,171. 3. V. Ye. Fedorov, A. V. Mischenko and V. P. Fedin, Uspekhi Khimii, 1985,54,694 (in Russian). 4. A. Miiller, Polyhedron 1986,5,323. 5. A. Mtiller, W. Jaegermann and J. H. Enemark, Coord. Chem. Rev. 1982,&i, 245. 6. V. P. Fedin, M. N. Sokolov and V. Ye. Fedorov, Koord. Khim. 1990,16,291. 7. V. P. Fedin, M. N. Sokolov, Yu. V. Mironov, B. A. Kolesov, S. V. Tkachev and V. Ye. Fedorov, Znorg. Chim. Acta 1990, 167, 39. 8. V. P. Fedin, B. A. Kolesov, Yu. V. Mironov and V. Ye. Fedorov, Polyhedron 1989, 8,2419. 9. V. P. Fedin, M. N. Sokolov, 0. A. Geras’ko, B. A. Kolesov, V. Ye. Fedorov, A. V. Mironov, D. S. Yufit, Yu. L. Slovohotov and Yu. T. Struchkov, Znorg. Chim. Acta 1990, 175,217. 10. V. P. Fedin, Yu. V. Mironov, M. N. Sokolov, Yu. I. Mironov and V. Ye. Fedorov, Znorg. Chim. Acta 1989, 163, 65.
et al.
11. V. P. Fedin, Yu. V. Mironov and V. Ye. Fedorov, Zh. Neorg. Khim. 1988,33, 2531. 12. J. W. McDonald, G. D. Friesen, L. D. Rosenheim and W. E. Newton, Znorg. Chim. Acta 1983, 72, 205. 13. W.-H. Pan, T. R. Halbert, L. L. Hutchings and E. I. Stiefel, J. Chem. Sot., Chem. Commun. 1985, 927. 14. 0. Foss, Acta Chem. Stand. 1949,3, 1385. 15. V. P. Fedin, B. A. Kolesov, Yu. V. Mironov, 0. A. Geras’ko and V. Ye. Fedorov, Polyhedron, has been accepted for publication. 16. G. M. Sheldrick, in Crystallographic Computing 3 (Edited by G. M. Sheldrick, C. Kruger and R. Goddard). Oxford University Press, London (1985). 17. R. G. Gerr, A. I. Yanovskii and Yu. T. Struchkov, Kristallograjia 1983, 28, 1029. 18. N. Walker and D. Stuart, Acta Cryst. 1983, A39, 158. 19. J. A. Broomhead, J. H. Enemark, B. Hammer, R. B. Ortega and W. Pienkowski, Aust. J. Chem. 1987,40, 381. 20. J. Dirand, L. Ricard and R. Weiss, J. Chem. Sot., Dalton Trans. 1976,278.
1992
0277-5X37/92 SS.OO+.oO 0 1992 Pergamon Press plc
DIALKYLDITHIOCARBAMATE COMPLEXES OF TUNGSTEN(W). SYNTHiESIS, PROPERTIES AND STRUCTURE THIODICHLOROBIS(DIMETHYLD~HIOCARBAMATO)TUNGSTEN(VI) V. P. FEDIN,*
OF
Yu. V. MIRONOV, A. V. VIROVETS, N. V. PODBEREZSKAYA, V. Ye. FEDOROV and P. P. SEMYANNIKOV
Institute of Inorganic Chemistry, Siberian Branch of the Academy of Sciences of the U.S.S.R., Novosibirsk 630090, U.S.S.R. (Received 30 May 1991; accepted 12 August 1991) Abstract-(Et4N)pWS4 and (Et,N),W,S, react with (Et2NCS2),Se in CH3CN to form WS3(S2CNEt2)2. The reactions of WS3(S2CNEt2)2 and WS3(S2CNMe& with HX (X = Cl, Br) in CH&N led to WSX2(S2CNR2)2. The thiohalogenide complexes react with (Bu~N)~& and (NH4)2Sx to form WS,(S2CNR2)2. It is shown that the interaction of WSC12 (S2CNMe2)2 with (Bu~N)~~~S, gives rise to W32S(34S-34S)(S2CNMe2)2 and W34S (32S---34S)(S2CNMe2)2. The structure of WSC12(S2CNMe2)2 has been determined by X-ray structural analysis. The coordination polyhedron about the tungsten atom is a slightly distorted pentagonal bipyramid whose equator is defined by the sulphurs of the dimethyldithiocarbamate ligands and one of the terminal chlorines w---Cl 2.403(5) A] and the apices are occupied by chlorine [W-Cl 2.458(5) A] and sulphur [w=S 2.101(5) A] atoms.
Comparison of thio- and thiohalogenide complexes of transition metals indicates that they often contain the same M-S-containing fragments,lm6 but mutual transitions between thio- and thiohalogenide complexes have not been studied extensively. The only known examples of such transitions involve the Group VI metals. Thus the triangular complex Mo,S:, reacts with HX to form the triangular thiohalogenide complexes Mo$~X~-.~ On the other hand, M&X4X4,2 (M = MO, w) lWiCt with ammonium polysulphide to form Mo,S:; and 8*9 The interaction of (Et4N)*WS4 W~SI~(NHJ):-. with HX (X = Cl, Br) in CH2C12 afforded the binuclear thiohalogenide complexes W,S,Xj-, W2S3Bri- and WzS4Xi-.‘o The interaction of WSC14 with (Et4N)2WS4 gave rise to (Et,N), w,s9. ’ ’ In the present work mutual transformations of the tungsten (VI) dialkylthiocarbamate complexes WS3(S2CNR2), and WSX2(S2 CNR2), have been studied for the first time and the structure of WSC12(S2CNMe2), has been determined by X-ray crystallography.
EXPERIMENTAL
All reactions were carried out in the air. CH,CN was distilled over P40,0. The compounds (Et, WS3(S2CNMe2)2,*3 N)ZWS4,” (Et4W2W39,‘l (Et2CNS2)2Se,‘4(Bu4N)2S6,(Bu4N)234S6,~4)2Sx’5
* Author to whom correspondence should be addressed.
were prepared by the respective literature procedures. The 34S-containing compounds were synthesized from the elemental 34Ss containing 99.5% of the isotope. All other reagents were analytically pure. Determinations of C, H, N, S, Cl, Br were performed at the Laboratory of Microanalysis of the Institute of Organic Chemistry (Novosibirsk). W, S, Se were determined gravimetrically as WO,, BaSO, and Se, respectively. The IR spectra were recorded in the KBr pellets on an IR-75 spectrometer. The Raman spectra were measured on a Triplemate Spex spectrometer using a multichannel detector and the 632.8 nm line of an He-Ne laser for excitation. The NMR ‘H spectra were obtained at room temperature on a SXP-4100 (Bruker) instrument. The structure of WSC12(S2CNMe2)2 was established by X-ray structural analysis. A red-brown single crystal of a prismatic needle-like habit with
279
V. P. FEDIN
280 Table 1. Crystallographic
data for WSC12(S2CNEt2)2
Formula Formula weight Crystal system Space group
C,H,,Cl,N&W 527.25 Orthorhombic Pnd , 11.972(2) 8.255(l) 15.393(4) 1521.3(5) 4 2.302 0.60 x 0.90 x 0.35 Syntex P2, Cu-K, Graphite e/20, V,,,i, = 2.9” min- ’ 3-115 236 Room 1224 857 Z > 3(Z) 0.0288
a (4 b (A) c (A) V(A3) z Calc. density (g cnDimensions (mm) Diffractometer Radiation Monochromator Scan mode 20 range (“)
‘)
p (cm- ‘) Temperature Total reflections Independent reflections RF
Table 2. Bond distances
well-shaped heads was obtained by diffusing ether into a solution of the complex in CH2C12. The unit cell parameters and reflection intensities were obtained by the standard procedure. The structure was solved by direct methods using the program SHELX-8616 and refined by full-matrix least squares method (the set of programs YANX’ 7, in the anisotropic approximation for the non-hydrogen atoms with a unit weighing scheme. Absorption was taken into account using the DIFABS program. I8 The hydrogen atoms were located either from a difference Fourier synthesis or geometrically and were included into the refinement with fixed coordinates and Vi,, = 0.07 A’. The crystallographic data for complex 1 are given in Table 1. The bond lengths and the main angles are shown in Table 2. Preparation of WS3(S2CNEt2)2
(a) From (Et4N)2WS4. (Et4N)2WS4 (0.57 g, 1.0 mmol) and (Et2NCS2)2Se (1.51 g, 4.0 mmol) were stirred in 30 cm3 of acetonitrile for 30 min at room
(A) and angles (“) in WSC12(Me2NCS& Bond distances
w-Cl( 1) w-S( 1) W-S(3) W-S(5) S(2)--c(l) S(4)-~(2) N(lk--C(ll) C(2)-N(2) N(2)-C(22)
et al.
(A) w-Cl(2) W-S(2) W-S(4)
2.458(5) 2.50(l) 2.50(2) 2.101(5) 1.66(6) 1.77(3) 1.40(8)
S(l)--c(l) S(3)--c(2) C(l)-N(1) N(l)-C(12) N(2)-C(21)
1.26(5)
2.403(5) 2.57(l) 2.48(2) 1.85(5) 1.66(4) 1.28(7) 1.26(5) 1.53(6)
1.68(5) Bond angles (“)
Cl( 1)-W--x1(2) Cl(l)-W-S(2) Cl( 1)-W-S(4) C1(2)---w-S( 1) C1(2)-W-S(3) C1(2)-W-S(5) S( 1)---W-S(3) S(l)-W-S(S) S(2 )-W-S(4) S(3)--W-S(4) S(4)---W-S(5)
87.8(2) 86.1(4) 82.7(5) 74.5(6) 75.4(6) 95.7(2) 148.5(5) 96.4(7) 72.5(5) 69.7(5) 94.0(5)
W-S(2)-C(l) W-S(4)--C(2)
95(2) 88(l) 122(4) 128(5) 119(4) 126(3) 120(4) ill(3)
S(l)_C(l)_N(l) C(l)---N(l)--C(l1) C(1 l)-N(l)-C(12) S(3k--C(2)-N(2) C(2)---N(2t-C(2 1) C(21)--N(2)--C(22)
Cl(l)-W-S(l) Cl( 1)---W-S(3) Cl(l)-W-S(S) C1(2)-W-S(2) C](2)-W-S(4) S( 1)--W-S(2) S( 1)-W-S(4) S(2)--W-S(3) S(2)-W-S(5) S(3)-W-S(S)
85.2(5) 84.5(6) 176.5(3) 141.0(6) 144.4(6) 66.6(4) 138.0(5) 141.9(5) 91.6(5) 95.7(7)
W-S(l)--c(l) W-S(3)--cx2) S(l)--c(l)_S(2) S(2)--c(lk-N(1) C(l)--N(lHXl2) S(3)_C(2)-S(4) S(4)-C(2)-N(2) C(2)--N(2)---C(22)
93(2) 90(l) 105(3) 133(4) ill(4) 112(2) 122(3) 126(3)
281
Dialkyldithiocarbamate complexes of tungsten(V1) temperature. The mixture was heated until it boiled, filtered to remove selenium and cooled down. Obtained 0.15 g of the complex WS3(S2CNEtJ2. Yield 26%. Found: C, 20.8; H, 3.5; N, 4.2; S, 31.5. Calc. for CloHZoN&W: C, 20.8; H, 3.5; N, 4.9; S, 31.9%. IR : 539(s), 493(vs), 440(w) cm-‘. Raman (700-20 cm-‘) : 543(m), 496(vs), 331(s), 31 l(s) cm-‘. (b) From (Et4N)2W3S9. 0.10 g of WS&CNEt& was obtained from (Et4N)ZW3S9 (0.43 g, 0.4 mmol) and (Et,NCS&Se (0.55 g, 1.47 mmol) by a procedure analogous to the above one. Yield 15%. Preparation of WSC12(S2CNMe2)2 Dry HCl was passed through a suspension of WS&CNMe& (0.20 g) in 20 cm3 of CH3CN until the solid was completely dissolved. The resulting yellow-brown solution was cooled to -20°C the red crystals were filtered off, washed with alcohol, ether and dried in vacua. Obtained 0.10 g of WSCl&CNMe&. Yield 50%. Found: C, 13.8; H, 2.0; N, 4.8; S, 30.6; Cl, 13.7. Calc. for C10HZ,,N2C12S5W: C, 13.6; H, 2.3; N, 5.3; S, 30.4; Cl, 13.7%. IR: 508(vs), 493(w) cm-‘. Raman : 51I, 476(m), 238(w), 220(m), 179(m), 153(m), 125(w) cm- ‘. Preparation of WSBr2(S2CNEt2)2 0.09 g of WSBr&CNEtJ was obtained from 0.16 g of WS3(S2CN&)2 by a procedure analogous to that described above for the synthesis of WSCl&CNMe&. Yield 48%. Found: C, 17.9; H, 2.9; N, 4.2; S, 23.0; Br, 23.7. Calc. for C,,,H10N2Br2SSW: C, 17.9; H, 3.0; N, 4.2; S, 23.9; Br, 23.8%. IR: 513(s), 487(w) cm-‘. Raman : 51I, 205(m), 156(m) cm- ‘.
solid was separated, washed with alcohol and recrystallized from a CH,Cl,/ether mixture. Obtained 0.07 g of WS3(SzCNMe&. Yield 23%. RESULTS
AND DISCUSSION
Dialkyldithiocarbamate complexes of WV1were first obtained by E. I. Stiefel and co-workers when interacting WS:- with tetraalkylthiuram disulphides13 (eq. 1) : WS:- +(R2CNS2)2-
WS(SZ)(S&NRJZ.
(1)
The structure of the complex with R = i-Bu was determined by X-ray structural analysis.13 In the present work we have found that an analogous mononuclear thiocomplex WS&S2CNEt2)2 is produced when reacting (Et2CNS2)$e with mononuclear WS:- or trinuclear W&- (eqs 2 and 3) : WS:- + (Et2NCS&Se W$-
+ (Et2NCS&Se -
WS&CNEt& WS3(S2CNEtJ2+
+ Se (2) Se. (3)
We have attempted these reactions in the hope of obtaining diethyldithiocarbamate complexes of tungsten which would also contain simultaneous sulphur and selenium but the hope did not realize. Reactions (2) and (3) proceed in a complicated manner to give a mixture of products from which we were only able to isolate elemental selenium and WS3(S2CNEt&. The yield of WS&CNEt& in reactions (2) and (3) is not high. In reaction (2) at the ratio WS:-/(Et$NS&Se = 1:4 it is, for example, only 26%. With decreasing WS:-/ (Et2CNS2),Se ratio the yield of WS3(S2CNEt& decreases. Thus, from the point of view of the synthesis of WS3(S2CNR,), the Stiefel method13 is of obvious advantages. Synthesis of the WSX2(S2CNRJ2 complexes
Interaction of WSCl&CNMeJ,
with (Bu4N)&
0.17 g of WSC12(S2CNMe2)2 and 0.30 g of (Bu~N)$~ in 30 cm3 of CH$ZN were stirred for 1 h. The resulting green precipitate was filtered off, washed with acetonitrile, ether and dried in uacuo. Obtained 0.14 g of analytically pure WS3(S2CN Me& (characterization by elemental analysis, IR, Raman). Yield 83%. IR: 539(s), 493(vs), 440(m) cm-‘. Raman : 533(vs), 495(s), 434(m), 179(m), 129(s) cm-‘. Interaction of WSC12(S2CNMe2), with (NH,)& 0.30 g of WSC1,(S2CNMe2)2 and 15 cm3 of (NH&S, were stirred for 30 min. The dark green
The presence in the easily available complexes WS(S2)(S2CNR& of two structural fragments W=S
and W
/
makes these compounds
con-
‘S venient objects on which to study the differences in reactivity of the thioligands depending on the type of coordination. In the present work the interaction of WS3(S2CNR& with hydrohalogen acids HX (X = Cl, Br) in acetonitrile has been studied. The reaction afforded the thiohalogenide complexes WSX2(S2CNR2)2 in yields of about 50% (eq. 4) : WS3(SzCNR&+HX-
WSCl@&NR&.
(4)
282
V. P. FEDIN
The WSC12(S2CNR2)2 complexes are dark-red crystalline substances which are stable in the solid state in the air and in solutions. They are well soluble in DMF and in acetonitrile upon heating and moderately soluble in CH2C12. The PMR spectrum of WSC12(S2CNMe2)2 (1) in CD&l2 shows two singlets of equal intensity with close values of the chemical shifts (6 = 3.31 and 3.33 ppm) indicating non-equivalence of the methyl groups of the chelate dimethyldithiocarbamate ligands. In the IR and Raman spectra of the complexes WSX2(S2CNR2)2 there are intense bands of vwzs in the region 5OG 520 cm- I. The structure of WSCl,(&CNMe&
(1)
The structure of 1 is a molecular one. The general appearance is shown in Fig. 1; the molecular packing in the crystal lattice is shown in Fig. 2. The coordination polyhedron about the tungsten atom is a slightly distorted pentagonal bipyramid. The pyramid equator is formed by the sulphurs of the dimethyldithiocarbamate ligands (deviations of these atoms from the plane do not exceed 0.17 A) and a chlorine, the apices are occupied by the Cl( 1)
Fig. 1. The structure
of WSCl,(S2CNMe2)2
(1).
et al.
atom and the sulphide ligand [S(5)], the value of the angle Cl(l)---W-S(5) = 176.5(3)O being equal to 180”. The small value of the W-S bond length for the S atom of the sulphide ligand indicates that it has a multiple character. The bond lengths and bond angles in the W(&CNMe& fragment have normal values. No substantially short molecular contacts are observed within the structure. The literature describes the structure of a whole number of complexes having a pentagonal-bipyramidal environment about the W or MO atom and containing dithiocarbamate, sulphide or 0x0, halogenide or disulphide ligands : WO(S2)(S2CNEt2)2 (2), WW2)MWi-W21~ (3), MoOXdWNEtd2, X = Cl (4), X = Br (5). 19-*’In complexes 2 and 3
(& sw,wb 1 XIX
M = W; Y = S; X = CL (1) M = Mo;Y = 0; X = CL (4) M = Mo;Y=O;X = Br(5)
M = W; Y = 0 (2) M = W;Y = S (3)
both sulphur atoms of the S2 ligand occupy equatorial positions along with the sulphurs of one of the (S$NRJ ligands ; the sulphurs of the second (S2CNR2) ligand occupy an equatorial and a semiaxial position. The pentagonal pyramid is strongly distorted due to the apex being drawn towards the equatorial plane as a result of which the “transangle” S(S,CNR,)---W-S(O) decreases to 162.4” in 2 and 162.2” in 3. It can be assumed, with a high probability, that the structure of the complex WS(SJ(!!&CNMe& (6) from which 1 has been obtained is analogous to that of 2 and 3 since the S2 ligand with a S-S bond of about 2 A most
Fig. 2. The unit cell of 1.
Dialkyldithiocarbamate
** “I:;’
likely will not be able to occupy an equatorialaxial position (drawing of the apex towards the equatorial plane would have been in this case still greater than in 2 and 3). A structural relation between the molecules of 6 and 1 is then apparent : replacement of the Sz ligand in 6 by two chlorine atoms in 1 results in a change in the coordination environment about the W atom consisting in the chelate cycle plane of one of the (S&NMEr) ligands being turned in such a way that it begins to occupy the equatorial position with both of its sulphurs. One of the chlorine atoms occupies an equatorial position and the other an axial position. The sulphide ligand remains axial (eq. 5).
+=
283
complexes of tungsten(V1)
a
HX(X CL,Br)
(5)
-t-G%
X
In 1 there is a lengthening of the W-Cl bond by 0.055 A (at o(W-Cl) = 0.005 A) for the chlorine atom in the trans-position with respect to the sulphide ligand. An analogous situation is observed in 4 for the chlorine atom trans with respect to the terminal oxoligand but the size of this lengthening is substantially greater-by 0.087 8, (at a(W-Cl) = 0.001 A). In all other respects, the geometrical parameters of the molecules for 4 and 5 are close to those for 1. Interaction of WSX2(S2CNR&
with (Bu,,N)&
The thiohalogenide complexes of tungsten interact with (Bu,N)& in WSXz(S&NR& acetonitrile to give high yields of WS$$CNR& (eq. 6) :
+
(Bu,N)ISI
-
The reaction with a solution of ammonium polysulphide in water proceeds analogously but the yield is substantially lower. The formal result of reaction (6) is nucleophilic substitution of the halogenide ligands by S:- and a change in the coordination environment of the tungsten atoms. An unexpected result has been obtained in the reaction of WSC12(S&NMe2)2 with (Bu$)~~~&. Figure 3 shows IR spectra of the products of this reaction in the region 400-600 cm-’ and, for comparison, IR spectra of WS3(S2CNMe&. It is known that in the IR spectra of WS3(S2CNR2)r there are bands of v(S-S) at 550 cm- ’ and of v(W=S) at 500 cm --I. I3 It is well seen that in the reaction products
600
500
IOcm-1
Fig. 3. IR spectrum of WS3(S2CNMeJ2 (a) and IR spectrum of the products of the reaction of WSCl,(S,CNMe& with (Bu.,N)~~~& (b) in the region 400-600 cm-’ (* bands of the ligand Me2NCS2-).
WSCl&CNMer)r and (Bu,N),‘~& there are two bands of v(S-S) (shifts by 8 and 17 cm- ‘) and two bands of v(W=S) (shifts by 1 and 14 cm-‘). The vibrational bands of the S2CNMe2 ligands are not changed. It has been shown earlier that in thioand thiohalogenide complexes of molybdenum and tungsten the v(M--C) band undergoes an isotopic shift of 12-13 cm-’ upon replacement of 32Sby 34S and the v(S-S) band undergoes a shift by 1417 cm-’ on going to complexes with (34S-34S) ligands and of 7-9 cm-’ on going to complexes with (32S-34S) ligands.“*” Thus, the data of the vibrational spectroscopy unambiguously indicate the presence in the products of the reaction of W32SC12(S2CNMe2)2with (Bu~N)~~~S~of products with the structural fragments W=32S, W=34S, 34S-34S and 32S-34S. A possible scheme explaining formation of these products is shown below (eq. 7) :
A key point in this scheme is the addition of 34Szat the W=S bond to form a product containing a four-membered cycle W32S34S34$. Further transformation of this product allows one to easily understand the formation of the reaction products. Note also, that no isotopic exchange takes place upon heating W32S3(S2CNMe2)2 with (Bu~N)~‘~&, in acetonitrile.
284
V. P. FEDIN REFERENCES
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