Organometallics 1996, 14,3-4
3
Organosamarium Tetrathiometalate Chemistry: Synthesis and Structure of the Mixed-Metal Complexes { [(Cdfed&d2Mo(j2@4} - and [(CsMed2Sdp-s)~wsd William J. Evans,* Mohammad A. Ansari, and Joseph W. Ziller Department of Chemistry, University of California, Irvine, California 92717
Saeed I. Khan Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90024 Received August 1, 1994@ Summary: Mixed-metal Mo-Sm and W-Sm complexes can be readily made by reaction of (C&edzSm(THF)z with (PPh&MoS4 and (PPhJzWS4. In the molybdenum case, a trimetallic M o N ) complex, U(C&ed~Sml~Mo(pS)4}(PPh3, (l),is obtained. With tungsten, a bimetallic (2), is W N I ) complex, [(C&fes)zSm(p-S)zWS~(PPh~ isolated. Both complexes contain tetrahedral MS4 units which coordinate via bridging sulfur atoms to (C&fes)zS m moieties. Tetrathiometalates such as (MOS4l2-, (WS4)2-, and (Re&)- have been found to coordinate t o a wide variety of transition with interesting ramifications in hydrodesulfurization catalysis7 and molybdoenzyme chemistry,* but their utility as ligands for the lanthanide metals has not yet been explored. Although the electropositive lanthanide metals have a stronger preference for oxygen donor ligands than for sulfur, lanthanide complexes involving the lower congeners of main group 16 are known and recent work has shown that an extensive chemistry is available with these donor a t ~ m s . ~ -Given l ~ the tendency of the tetrathiometalates to form chelating bidentate structures, they @Abstractpublished in Advance ACS Abstracts, December 1, 1994. (1) Reported in part at the 207th National Meeting of the American Chemical Society, San Diego, CA March 1994; INOR 73. (2) MWler, A.; Diemann, E.; Jostes, R.; Bogge, H. Angew. Chem., Znt. Ed. Engl. 1981,20, 934-955. (3) Mtiller, A.; Bogge, H.; Schimanski, U.;Penk, M.; Nieradzik, K.; Dartmann, M.; Krickemeyer, E.; Schimanski, J.; Wmer, C.; Romer, M.; Dornfeld, H.; Wienboker, U.;Hellmann, W.; Zimmerman, M. Monatsh. Chem. 1989,120,367-391. (4) Howard, K. E.; Rauchfuss, T. B.; Wilson, J. R. Znorg. Chem. 1988, 27.3561-3567. ( 5 ) Secheresse, F.; Salis, M.; Potvin, C.; Manoli, J. M. Inorg. Chim. Acta 1986,114, L19-L23. (6) Manoli, J. M .; Potvin, C.; Secheresse, F.; Marzak, S. Znorg. Chim. Acta 1988,150,257-268. (7) (a)Picoraro. T. A.: Chianelli. R. R. Catalvsis 1981.67.430-435. (b) Harris, S.; Chianelli, R. R. 'Catalysis f984, 86,'400-412. (c) Chianelli, R. R.; Picoraro, T. A.; Halbert, T. R.; Pan, W.-H.; Steifel, E. I. J. Catal. 1984,86,226-230. (d) Mdler, A. Polyhedron 1986,5,323340. (8) (a)Holm, R. H.; Berg, J. M. Acc. Chem. Res. 1986,19,363-370. (b) Coucouvanis, D. Acc. Chem. Res. 1991,24, 1-8. (9) (a) Tilley, T. D.; Andersen, R. A.; Zalkin, A.; Templeton, D. H. Znorg. Chem. 1982, 21, 2644-2647. (b) Zalkin, A.; Henly, T. J.; Andersen, R. A. Acta Crystallogr. 1987, C43,233-236. (c) Berg, D. J.; Andersen, R. A.; Zalkin, A. Organometallics 1988, 7, 1858-1863. (d) Zalkin, A.; Berg, D. J . Acta Crystallogr. 1988, C44, 1488-1489. (e) Berg, D. J.; Burns, C. J.;Andersen, R. A.; Zalkin, A. Organometallics 1989,8, 1865-1870. (10) Schumann, H.; Albrecht, I.; Hahn, E. Angew. Chem., Znt. Ed. Engl. 1985,24, 985-986. (11) Recknagel, A.; Noltemeyer, M.; Stalke, D.; Pieper, U.;Schmidt, H.-G.; Edelmann, F. T. J. Organomet. Chem. 1991,411, 347-356. (12) Evans, W. J.; Rabe, G. W.; Ziller, J. W.; Doedens, R. J. Znorg. Chem. 1994,33,2719-2726. (13) Strzelecki, A. G.; Timinski, P. A.; Helsel, B. A.; Bianconi, P. A. J.Am. Chem. SOC.1992,114,3159-3160. (14) Cary, D. R.; Arnold, J. J. Am. Chem. SOC.1993, 115, 25202521.
0276-7333/95/2314-0003$09.00/0
seemed to be ideal ligands for formation of mixed-metal species with the (CsMe5)zSm unit,16 which prefers to coordinate to two additional ligands to form eightcoordinate structures.17 We report here on the utility of ( C ~ M ~ ~ ) Z S ~ ( TinHforming F ) ~ ~ *new heterometallic group 6 transition-metal lanthanide complexes using tetrathiometalate anions. Purple (C5Me&Sm(THF)2 reacts immediately with (PPh&MoSq to form a red product (1) and PPh3.19 The IR spectrum of 1 contains an absorption at 431 cm-' in the Mo-S region which is shifted from the 458 cm-l absorption of (M0S4)2-. The lH and 13C NMR spectra of 1 are consistent with the presence of Sm(III),20a single CsMe5 ligand environment, and (PPh)+. An X-ray diffraction study21 revealed that the product contained one (PPhd+per trimetallic Sm2Mo unit; i.e., 1 is the MOW) complex { [(CsMe5)2Sm]zMoS4}(PPh4) (Figure 1). Reduction of the metal center of a tetrathiometalate unit aRer complexation is rare and has been observed only in Fe/Mo cubanes.8b (15) (a) Berardini, M.; Emge, T. J.; Brennan, J. G. J. Am. Chem. SOC.1993, 115, 8501-8502. (b) Berardini, M.; Emge, T. J.; Brennan, J. G. J. Chem. Soc., Chem. Commun. 1993, 1537-1538. (16) Evans, W. J. Polyhedron 1987, 6, 803-835 and references therein. (17) Evans, W. J.; Foster, S. E. J. Organomet. Chem. 1992,433,7994. (18) Evans, W. J.; Grate, J. W.; Choi, H. W.; Bloom, I.; Hunter, W. E.; Atwood, J. L. J.Am. Chem. SOC.1986,107, 941-946. (19) In a glovebox, addition of (C&Te&Sm(THF)z(283 mg, 0.5 mmol) in 10 mL of THF to a suspension of (PPh&MoS4 (226 mg, 0.25 "01) in 5 mL of THF caused an immediate color change from purple to red. The reaction mixture was stirred for 20 min and centrifuged to remove solids, and the solvent was removed by rotary evaporation. The crude product was washed with hexanes to remove any soluble organic byproducts. The 31PNMR spectrum of the hexane wash confirmed the presence of PPha. No signals were observed in the EPR spectrum of 1, probably due to the presence of Sm(II1). Recrystallization from toluene at -35 "C produced {[(CsMes)zSml~MoOl-S)4}(PPh4) (1) as dark red crvstals (316 me. 90%).Anal. Calcd for CuHanPSdMoSm?: C. 54.65: H;5.73; P, 2.20;%,9.13;Mo, 6.82; Sm, 21.46:F&nd C, 55:52; H, 5.81; P, 2.50; S, 8.44; Mo, 6.31; Sm, 21.55. 'H NMR (csD6): 6 7.39, 7.03, 6.85, 6.48 and 6.29 (PPh,+), 1.76 (C5Me5). NMR (THF-d8): 6 137.3, 136.3, and 132.7 (PPL+),119.9 (CsMes), 34.0 (CsMes). W-vis (1.42 x M in THF; 1,nm ( E ) ) : 470 (6320). IR (Nujol): 2980-2850 (9, br), 1460 (s), 1375 (s), 1186 (w), 1106 (m), 1066 (w), 996 (w), 742 (w), 722 (SI, 689 (m), 526 (s), 431 ( 8 , Mo-S), 301 (m, Sm-S) cm-l. Magnetic ~ x ~ ~ cgsu; p,$98 = susceptibility (Evans methodz8): , y ~= 290 1.2 /&. (20) Evans, W. J.; Ulibani, T. A. J . Am. Chem. Soc. 1987, 109, 4292-4297. (21) Crystal data for C&I8oPS&IoSmz: monoclinic s stem with cell dimensions at 183 K of a = 17.212(3)A, b = 13.754(2) c = 26.378(4) A, /3 = 103.63(1)",and V = 6068(2) A3. The space group is P21/c with 2 = 4 and D&d = 1.538 Mg/m3. The structure was solved by direct methods and refined by full-matrix least-squares techniques using 6505 reflections with lFol > 3.O0(JF0I). At convergence, RF = 4.27%,Rwp = 4.27%,and GOF = 1.37 for 649 variables. Recrystallization from THF/ benzene at ambient glovebox temperature produces the same compound with one benzene solvent molecule per formula unit in the same space group with a = 18.139(7)A, b = 14.208(5)A, c = 27.3041(10)A, 8 , = 103.01(1)",and V = 6858.4 (20) A3.
x
0 1995 American Chemical Society
4 Organometallics, Vol. 14, No. 1, 1995
Communications
Figure 1. Thermal ellipsoid plot of { [(CsMe&Sm12Mo(JLS)4}- with ellipsoids drawn at the 50% probability level. The solid-state structure of 1 contains essentially identical (CsMe&Sm@-S)2 units which have metrical Figure 2. Molecular structure of ((CsMes)zSm(JL-S)zWSz}with ellipsoids drawn at the 50% probability level. parameters typical of eight-coordinate Sm(III).17 The 2.791(2) and 2.796(2)A Sm-S distances are longer than M o S ~ vs ~ -WSd2-. Similar differences have been noted those in [(CsMe5)2Sm(THF)12@-S) (2.663(1) and in some monomeric Mom compounds.27 2.665(1) &.I2 The structure of 2 is similar t o that of 1 except that Mo-S distances in tetrathiomolybdate complexes the moiety in 2 is less symmetrical than the typically do not vary be ond a range of 2.2-2.4 A,2 and tetrathiometalate in 1 since only two of the sulfur atoms the 2.225(2)-2.241(2) Mo-S distances in 1 are no are bridging. As ex ected, the bridging W-S distances exception. For comparison, free M o S ~ has ~ - 2.178(5) A (2.209(7)-2.217(7) ) are larger than the terminal W-S distances22and the trimetallic MoS4-bridgedcomplexes 2.154(8)-2.164(9) A. In comparison, undistances of ( P P ~ ) ~ [ ( C ~ ~ F ~ and )~M ( NOMS ~~~I)~~ ~[ ( N C C U ) ~ M O S ~ I ~ ~ W-S distance 2.177 coordinated has an average ) 2.209(3)A, respectively. have distances of 2 . 2 0 4 ~and A.2 W-S distances, like Mo-S distances, do not typiIn mixed-valence [(MoS4)2Fe13-, the bridging Mo-S cally span a wide range, and the M-S distances in the distances are 2.251(5) and 2.260(4)A.23bThe mixedtwo complexes are similar. The (C5Me5 ring centroid)valence complex [ ( M o ~ S ~ ) M O ~ O ( M has O ~ an S ~av)~~Sm-(ring centroid) angles in 1 and 2 are similar (Mo, erage Mo(IV)-S distance of 2.408(16)A and an average 136.8 and 136.2";W, 135.1 and 138.5"),and the Sm-C Mo(VI)-S(bridging) distance of 2.245(14) A.24 and Sm-S distances are equivalent within statistical Interestingly, under similar conditions reactions of limits (Sm-(CsMes ring centroid) distance: Mo, 2.439(PPh&WS4 with (C5Me5)2Sm(THF)2 in THF did not 2.462 A; W, 2.400-2.419 A and Sm-S: Mo, 2.784(2)produce a tungsten analog of 1 but instead yielded [(C52.796(2)A; W, 2.817(8)-2.841(7) A). In both complexes, Me5)2Sm@-S)2WS21(PPh4) Although the spectral the cations are well separated from the anions and do characteristics of 2 were similar to those of 1,they were not show any unusual features. not identical and X-ray crystallography was needed for These results show that tetrathiometalates are viable 2 crystallizes with two indefinitive identification.26 ligands for the lanthanides and provide a facile way to dependent molecules in the unit cell, each containing a make molecular mixed-metal species containing this (PPh4)+ group and a bimetallic monoanion having an combination of metals. In addition, by using (C5Me&eight-coordinate Sm center ligated to a @-S)zWS2unit Sm(THF)2with (MoSd2- an unusual Mo(V) derivative (Figure 2). Apparently, in this case reduction of the can be obtained. tetrathiometalate metal center did not occur. This is consistent with the difference in redox potentials of Acknowledgment. This research was supported by the National Science Foundation. (22) Lapasset, P. J.; Chezeau, N.; Belougne, P. Acta Crystallogr.
w
1976, B32, 3087-3088. (23) (a) Coucouvanis, D.; Baenziger, N. C.; Simhon, E. D.; Stremple, P.; Swenson, D.; Simpoulos, A.; Kosticas, A.; Petrouleas, V.; PapaeRhymiou, V . J . Am. Chem. SOC.1980, 102, 1732-1734. (b) Coucouvanis, D.; Simhon, E. D.; Baenziger, N. C. J . Am. Chem. SOC.1980,102,66446646. (24) Muller, A.; Dartmann, M.; Romer, C.; Clegg, W.; Sheldrick, G. M. Angew. Chem., Int. Ed. Engl. 1981,20, 1060-1061. (25) In a glovebox, (CbMe&Sm(THF)z (56 mg, 0.1 "01) in 5 mL of THF was added to a suspension of (PPh&WS4 (99 mg, 0.1 mmol) in 5 mL of THF. The color of the solution changed immedately from purple to red. The reaction mixture was stirred for 30 min and centrifuged. Solvent was removed by rotary evaporation, and the resulting solid was washed with hexanes and toluene. Slow evaporation of a THF solution at ambient temperature produced [(CsMes)zSmOc-S)zWSzI(PPLYTHF (2) as red crystals (67 mg, 60%).P P h was identified as a hexane-soluble byproduct. Anal. Calcd for C M H ~ ~ O P S ~ S C,~50.37; W: H, 5.11; P, 2.71; S, 11.21. Found C, 52.08; H, 5.19 P, 2.84; S, 9.28. 'H NMR (THF-ds): 6 7.76, 7.72, and 7.31 (PPlq+),1.05 (C&fes). Bulk samples were obsellred to have an additional resonance in the C a e 5 region a t 1.13 ppm. 13C NMR (THFds): 6 137.0, 136.1, and 132.4 (PPb+), 118.5 (CsMes),44.7 (CsMes).UV-vis (7 x M in THF; A, nm ( E ) ) 397 (3735). IR (Nujol): 2980-2850 (8, br), 1460 (s), 1375 (s), 1185 ( ~ 1 , 1 1 6 3(w), 1106 (m), 1062 (w), 996 (w), 743 (w), 723 (81, 690 (m), 526 (s), 414, 426 (8, v(W-S)), 300 (m, Sm-S) cm-I. Magnetic cgsu; p e p 8 = susceptibility (Evans methodz8): x~~~~ = 5138 x 1.1 flB.
A)
Supplementary Material Available: Tables of crystal data and refinement details, positional and thermal parameters, and bond distances and angles and fully labeled ORTEP drawings for compounds 1 and 2 (31 pages). Ordering information is given on any current masthead page. OM940608E (26) 2 crystallizes with two independent molecules in the asymmetric unit, and structure solution requires the determination of two cations, two anions and two noncoordinated THF molecules. Crystal data for C48HmOPS4SmW: triclinic, space grou P1, with cell dimensions a t 176 K a = 22.158(6) A, b = 23.323(6) c = 9.611(2)A, a = 98.28(1Y, = 91.31(1)', y = 101.29(1Y, and V = 4813(2) A3 with 2 = 4 and D d d = 1.561 Mg/m3. The structure was solved by heavy-atom methods of SHEIX 86 and refined by using SHEIX 76. Due to a low data to parameter ratio all the phenyl carbon atoms of P P b + were refined as rigid groups. All the CsMes carbon atoms were treated isotropically. The final refinement using 4885 reflections with 1FI. > 6dlF.I) converged to RF = 6.20% and R,F = 6.0%,for 476 variables. (27)Pan, W.-H.; Halbert, T. R.; Hutching, L. L.; Stiefel, E. I. J. Chem. SOC.,Chem. Commun. 1986, 927-929. (28) Evans, D. F. J . Chem. SOC.1959,2003-2005. Becconsall, J. K. Mol. P h p . 1968, 15, 129-139.
1,
