9
Organometallics 1986, 5, 9-12
Ring Opening of Dihydro-2( 3H)-thiophenethione on Complexation to Molybdenum-Molybdenum Bonded Complexes Howard Alper,*+’’ Frederick W. B. Einstein,lbFrederick W. Hartstock,la and Anthony C. Willislb Departments of Chemistry, University of Ottawa, Ottawa, Ontario, Canada K I N 984, and Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6 Received April 2, 7985
Dihydro-2(3H)-thiophenethione reacts with the metal-metal triple-bonded complexes (RC5H4)2M02(C0)4 (R = H, CHJ to form the interesting ring-opened complexes [S(CH2)3CS]Mo2(C0)4(C5H4R). The latter were identified on the basis of analytical and spectral data, as well as an X-ray analysis of the R = CH3 compound. Crystal data: space group P21/c, a = 8.057 (1)A, b = 29.857 (a) A, c = 7.992 (3) A, V = 1849.8 A3, 2 = 4; final RF = 0.0185. Novel complexes have been synthesized by the reaction of organic sulfur compounds with cyclopentadienylmolybdenum dicarbonyl dimer (1, R = H) and related complexes containg a metal-metal triple bond. For example, carbon disulfide reacts with 1, R = H, affording C5H5(C0)2Mo-Mo(C0)2(C5H5)(~z-CSz) which contains a nonbridging, terminal q2-CS, ligand.2 Another heteroallene, methyl isothiocyanate, gives traces of a dithiocarbamate complex, C5H5(C0)2MoS2CNHCH3, on treatment with 1, R = H. An interesting desulfurization product results using (pentamethylcyclopentadieny1)molybdenum dicarbonyl dimer as the r e a ~ t a n t . ~ Treatment of thioketones with metal-metal triple bonded complexes at room temperature affords complexes of structural type 2 (M = Mo, W).4 The gross structure of complexes obtained from thiolactones [e.g., dihydro-2(3H)-furanthione, 31 and thio esters is similar to those
A complex similar to 2 is formed at room temperature. R
co
i
co
R 4
It was of interest to react a dithiolactone with 1in order to determine if one could achieve ring opening by cleavage of the carbon-sulfur single bond or whether the dithio analogue of 3 would be formed by complexation of the thione unit to the metal. In the event that carbon-sulfur bond cleavage occurs, the presence of the alkyl chain may influence the bonding situation relative to 4. We now describe the results of this investigation.
Results and Discussion When the in situ generated (methylcyclopentadieny1)molybdenum dicarbonyl dimer 1 (M = Mo, R = CH3) and dihydro-2(3H)-thiophenethione(5) were refluxed overnight in toluene, the ring-opened complex 6 was obtained and characterized on the basis of spectral data and an X-ray crystal structure. The parent triple-bonded complex (M = Mo, R = H) reacts similarly affording 6, R = H. The infrared spectra of 6 [R = H, CH3 (KBr)] shows two in-
(C0)2
I
S 0 1
L
l(M=Mo)
+
?
s
PhCH3
I-
A
/ T / CH2 S
0
\
3
derived from thioketones, but there are interesting differences in detaiL5 Both 2 and 3 have semibridging carbonyl groups, and the thiocarbonyl function is bonded to one of the two metals, with the sulfur donor bound to the other metal atom. It has recently been reported that the use of dithio esters as reactants with 1, M = Mo, in refluxing toluene or xylene affords a new class of organosulfur-metal compounds 4, containing a symmetrically bridging thioacyl function and a bridging thioalkyl group.6 John Simon Guggenhein Fellow, 1985-1986.
\
\
\
CH2
-C Hp
6
(1) (a) University of Ottawa. (b) Simon Fraser University. (2) Brunner, H.; Meier, W.; Wachter, J. J . Organomet. Chem. 1981, 210, C23. ( 3 ) Brunner, H.; Buchner, H.; Wachter, J.; Bernal, I.; Ries, W. H. J . Oganomet. Chem. 1983,244, 247. (4) Alper, H.; Silavwe, N. D.; Birnbaum, G. I.; Ahmed, F. R. J . Am. Chem. SOC.1979, 101, 6582. (5)Alper, H.; Einstein, F. W. B.; Nagai, R.; Petrignani, J. F.; Willis, A. Organometallics 1983, 2, 1291. (6) Alper, H.; Einstein, F. W. B.; Hartstock, F.; Willis, A. C. J. Am. Chem. SOC.1985, 107, 173.
0276-7333/86/2305-0009$01.50/00 1986 American Chemical Society
10 Organometallics, Vol. 5, No. 1, 1986
Alper et al.
Cl22,
01191K-3b
Table 11. Data diffractometer radiation h of radiation, 8, scan mode w scan width, deg w scan speed, deg min-' bkgd cryst size, mm 20 range, deg total no. of reflns obsd reflns" no. of variables final RFb final RWFd final GOF'
Figure 1. A view of the MO~(C~H,CH,)~(CO)~(SCC~H~S) molecule showing the atom-labeling scheme. Thermal ellipsoids enclose 50% probability levels. Hydrogen atoms have been deleted for clarity.
a,
A
b, A
c, A 0,deg
CieHzoMozOzSz
V , A3
monoclinic P2,j c 8.057 (1) 29.857 (2)
Z fw
7.992 (3) 105.80 (2)
Pobs
g
pcalcg cm-3 p , cm-'
1849.8 4 524.36 1.86" 1.883 15.50
By flotation in aqueous ZnBrz solution.
tense carbonyl stretching bands at 1881-1889 and 1849-1852 cm-'. In contrast, complexes of structural type 4 display three carbonyl stretching bands instead of the anticipated two absorptions.6 The carbon-13 nuclear magnetic resonance spectrum of 6, R = H , gave the expected signals for the two different cyclopentadienyl rings and the organic ligand, as well as two carbonyl carbon resonances. The molecular ion was observed in the mass spectrum of 6 (R = H, CHJ, with loss of the carbon monoxide ligands being a significant fragmentation pathway. T h e X-ray crystal structure of 6, R = CH3, was determined and a thermal ellipsoid diagram is shown in Figure 1. Crystal data, data collection information, atomic coordinates, and selected interatomic distances and angles are given in Tables I-IV. The complex consists of two Mo(C5H,CH,)C0 units connected by a Mo-Mo single bond with two sulfur atoms and one a-C atom bonded to both Mo atoms. In contrast to 4,the a-C atom is linked to the nonadjacent S atom by an alkyl chain. Comparison7 of the bond lengths in 46 and 6 indicates that the Mo-Mo and Mo-C(2) distances are shorter in 6 (and the former is also shorter than in related metal carbonyl complexes which range from 2.95 to 3.25 A)6 and the four Mo-S bonds, which are very similar t o each other, tend to be slightly longer. The magnitudes of these differences between 4 and 6 are small. The effect the linking alkyl group has upon the central core of the molecule is significant and is best observed by considering the dihedral angles between planes of the type Mo( l)-Mo(2)-X, where X is a donor atom of the ligand. In particular, the angle between planes Mo(l)-Mo(2)-C(2) and Mo(l)-Mo(2)-S(6) is 96.7 ( 1 ) O for 6 cf. 111.1 (1)' for 4, showing that C(2) and S(6) subtend a smaller angle than when they belong to separate ligands. A consequence of ~~~
~~
(7) For comparative purposes, the atoms in 4 are relabeled according to the scheme used in 6. In general, X ( l n ) are renamed X(2n) and vice versa.
Enraf-Nonius CAD4F Mo K a , graphite monochromator 0.70930 (ai); 0.71359 (ai) coupled W-20 0.55 plus a1-a2dispersion 4-0.57 scan extended by 25% on each side 0.017 X 0.020 X 0.036 0-50 3258 2984 298 0.019' 0.025' 1.81'
"Reflections with I > 2.3(u(Z)). *RF = CIIFoI - IF,JI/F,I. Observed reflections only. dRwF = [Cw(lFoI - lFc1)2/CF,2]1/2. 'GOF = [ ~ u ( l F , , -l IFc1)2/(no. of obs - no. of v a r ~ ) ] ' / ~ .
Table 111. Fractional Atomic Coordinates and Be, (AZ)of the Non-Hydrogen Atomsn
Table I. Crystal Data formula cryst system space group
Collection and Refinement
atom Mo(1) Mo(2)
s(1) C(2) c(3) C(4) C(5)
S(6) C(l1) C(12) C(13) C(14) C(15) C(16) c(19) O(19) c(2l) C(22) C(23) C(24) C(25) C(26) C(29) O(29)
x
0.26019 (3) 0.09020 (3) 0.37089 (8) 0.3389 (3) 0.4461 (4) 0.3753 (4) 0.1810 (4) 0.05625 (8) 0.3717 (4) 0.2829 (4) 0.3725 (4) 0.5154 (4) 0.5172 (4) 0.6538 (6) 0.0669 (3) -0.0367 (3) -0.1869 (9) -0.0884 (4) -0.0444 (4) -0.1151 (4) -0.2044 (3) -0.3099 (5) 0.1637 (4) 0.2038 (4)
Y
2
0.162059 (7) 0.52659 (3) 0.111900 (7) 0.23592 (3) 0.14860 (2) 0.27388 (8) 0.10582 (8) 0.4079 (3) 0.06803 (10) 0.5059 (4) 0.05277 (11) 0.6556 (4) 0.04974 (11) 0.6169 (4) 0.10073 (2) 0.52907 (8) 0.22648 (11) 0.6722 (4) 0.20300 (11) 0.7739 (4) 0.16245 (11) 0.8260 (3) 0.16182 (11) 0.7580 (4) 0.20131 (10) 0.6636 (3) 0.21426 (23) 0.5772 (6) 0.20131 (8) 0.4200 (3) 0.22923 (6) 0.3774 (3) 0.14290 (9) 0.1541 (3) 0.16486 (10) 0.0580 (4) 0.13358 (11) -0.0524 (3) 0.09221 (10) -0.0259 (4) 0.09729 (9) 0.1019 (3) 0.06249 (14) 0.1609 (5) 0.05203 (11) 0.1982 (4) 0.01603 (8) 0.1735 (4)
B,, A' 1.98 2.08 2.70 2.36 3.43 4.04 3.98 2.75 4.24 4.11 3.54 3.43 3.65 6.47 2.69 3.81 2.81 3.05 3.48 3.31 2.85 4.80 4.28 8.05
a Esd's refer to last digit printed. Be, is the arithmetic mean of the principal axes of the thermal ellipsoid.
decreasing the effective bite of C(2)-S(6) is for there to be more space on the opposite side of the Mo-Mo bond for the carbonyl C(19)-0(19) to approach Mo(2) than in 4, giving rise to a shorter Mo(2)-4!(19) distance [3.078 (2) A cf. 3.171 (2) A] and therefore a more bent Mo-C-0 angle [169.4 (2)O cf. 172.5 ( 2 ) O I . Nevertheless, this carbonyl should still be regarded as being intermediate between true semibridging and simple terminal bonding. The S(l)-C(2) distance is shorter than in 46 or the thiocamphor4 or thiolactone5complexes studied previously [respectively 1.769 (61, 1.807 (6), and 1.790 (11)A], suggesting an increased C=S double-bond character and so a greater ( u T ) contribution to bonding of the thione to the Mo atoms. Each Mo atom completes a six-membered chelate ring with C(2), C ( 3 ) ,C(4), C(5), and S(6). The ring with Mo(1) is in a boat conformation, and that with Mo(2) is a chair. Linking C(2) to S(6) also causes angles Mo(n)-C(2)-C(3)and Mo(n)-S(6)
