Coordination and Transformations of Benzothienyl Ligands by

Organometallics 1996, 14,2238-2245

2238

Coordination and Transformations of Benzothienyl Ligands by Triosmium Cluster Complexes Richard D. Adams" and Xiaosu Qu Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208 Received January 9, 1995@ The reactions benzothiophene and 1-bromobenzothiophene with Os3(CO)lo(NCMe)2have been investigated. The reaction of benzothiophene with Os3(CO)lo(NCMe)zat 25 "C yielded n n two products OS~(CO)~O~~-SCCHC~H~)~~-H), 1 (lo%), and OS~(C~)~~~~-SCCC~H~)CU-H)Z, 2 (8%). Both products were characterized by single crystal X-ray diffraction analyses. Both products contain benzothiophene ligands transformed by the activation of one and two of the C-H bonds, respectively, of the benzothiophene molecule. Compound 1 consists of a closed triosmium cluster with a p-q2-benzothienyl ligand coordinated to a n edge of the cluster through the C-C double bond in the five-membered ring of the ligand. Compound 2 contains a p3-q2-benzothiophyne ligand coordinated to the face of a closed triosmium cluster. Compound 1was transformed to 2 in 80%yield by heating to 125 "C in octane solvent. The reaction of 1-bromobenzothiophene with Os3(CO)lo(NCMe)2a t 25 "C yielded two products: n n OS~(CO)~O~~-SCCHC~H~)(~-B~), 3 (32%), and Os3(C0)g013-SCCHCsH5,(l1-Br),4 (10%). Both products were characterized by single crystal X-ray diffraction analyses. Both products contain benzothienyl ligands formed by the oxidative addition of the C-Br bond of the bromobenzothiophene to the cluster. In 3 the benzothienyl ligand is coordinated across the open edge of a n open triosmium cluster through the sulfur and adjacent carbon atom. In 4 the benzothienyl ligand is a triply bridging ligand using the sulfur atom and the C-C double bond of the five-membered ring. Compound 3 was transformed to 4 in 74% yield by heating to 97 "Cin heptane solvent for 30 min. Crystal data for 1: space group = P21/n, a = 7.668(2) A, b = 31.464(5) A, c = 9.452(2) A, p = 105.48(2)",2 = 4, 2563 reflections, R = 0.035. Crystal data for 2: space group = Pi, a = 9.791(1) A, b = 14.576(2)A, c = 8.094(1) A, a = 95.44(1)",p = 107.47(1)",y = 95.23(1)",2 = 2, 2218 reflections, R = 0.024. Crystal data for 3: space group = P21/c, a = 9.116(2) A, b = 15.577(3)A, c = 16.270(3)A, /?= 100.16(1)",2 = 4, 2193 reflections, R = 0.038. Crystal data for 4: space group = P21/n, a = 7.796(1) A, b = 15.543(3) A, c = 17.640(2)A, /3 = 90.48(1)", 2 = 4, 2288 reflections, R = 0.028. at the carbon atom adjacent to the sulfur atom to yield

Introduction

n

Interest in the coordination and transformations of thiophene and its derivatives by metal complexes1,2is derived from the desire to understand the nature of the important reactions involved in the metal-catalyzed hydrodesulfurization of these molecules in petroleum purification proce~ses.~ The reactions of thiophene and derivatives with cluster complexes of the iron subgroup have not received a great deal of study even though it has been shown that the reactions of thiophenes with Fe3(C0)12 and Ru3(C0)12 lead t o ring opening and ultimately to desulfurization of the thiophene^.^ Following our studies of the ring opening of tetrahy, ~ undertook drothiophene by a triosmium c l u ~ t e r we investigations of the reactions of benzothiophene and 1-bromobenzothiophenewith Os3(CO)lo(NCMe)2. Both compounds undergo oxidative addition of the C-X bond ~

~~

~

Abstract published in Advance ACS Abstracts, April 15, 1995. (1)(a)Angelici, R. J. Coord. Chem. Reu. 1990,105,61. (b) Rauchfuss, T. B. Prog. Inorg. Chem. 1991,39,259.(c) Angelici, R. J. Ace. Chem. @

Res. 1988,21,387. (2)(a) Rim, U.; Curnow, 0. J.;Curtis, M. D. J . Am. Chem. SOC.1994, 116,4357.(b) Jones, W. D.; Chin, R. M. J . Am. Chem. SOC.1994,116, 198.(c) Bianchini, C. Meli, A.; Peruzzini, M.; Vizza, F.; Moneti, S.; Herrera, V.; Sbchez-Delgado, R. A. J.Am. Chem. SOC.1994,116,4370. (d) Chen, J.;Angelici, R. J. Appl. Organomet. Chem. 1992,6,479.(e) Luo, S.;Ogilvy, A. E.; Rauchfuss, T. B. Organometallic 199O,lO,1002.

0 2 7 6 - 7 3 3 3 ~ ~ 14-2238$09.00/0 23

products Os3(CO)loCu-SCCHCsHs)Cu-X),1, X = H, and 3, X = Br, which contain benzothienyl ligands. Interestingly, the benzothienyl ligands are coordinated to the clusters in two different ways. Both products undergo decarbonylation when heated. Compound 1 was transn formed into the complex O S ~ ( C ~ ) ~ C ~ ~ - S C C C ~ H ~ ) ~ (3)(a) Schuman, S.C.; Shalit, H. Catal. Rev. 1970,4,245. (b)Gates, B. C.; Katzer, J. R.; Schuit, G. C. A. Chemistry of Catalytic Processes, McGraw-Hill: New York, 1978;Chapter 5. (c) Topsee, H.; Clausen, B.; Topsee, N.-Y.; Pedersen, E.; Niemann, W.; Muller, A.; Bogge, H.; Lengeler, B. J. Chem. Soc., Faraday Trans. 1987,83,2157. (d) Friend, C. M.; Roberts, J. T. ACC.Chem. Res. 1988,21,394. (e) Markel, E.J.; Schrader, G. L.; Sauer, N. N.; Angelici, R. J. J. Catal. 1989,116,11. (DPrins, R.; De Beer, V. H. H.; Somorjai, G. A. Catal. Reu. Sci. Eng. 1989,31,1. (g) Sauer, N. N.; Markel, E. J.; Schrader, G. L.; Angelici, R. J. J . Catal. 1989,117,295.(h) Kwart, H.; Schuit, G. C. A.; Gates, B. C. J. Catal. 1980,61, 128.(i) Curtis, M. D.; Penner-Hahn, J. E.; Schwank, J.; Beralt. 0.; McCabe, D. J.; Thompson, L.; Waldo, G. Polyhedron 1988,7, 2411.(i) Curtis, M. D. Appl. Organomet. Chem. 1992,6,429.(k) Roberts, J. T.; Friend, C. M. J . Am. Chem. SOC.1987, 109,7899. (4)(a)Kaesz, H. D.; King, R. B.; Manuel, T. A.; Nichols, L. D.; Stone, F. G. A. J.Am. Chem. SOC.1960,82,4749. (b)King, R. B.; Treichel, P. M.; Stone, F. G. A. J.Am. Chem. SOC.1961,83,3600. ( c ) Ogilvy, A. E.; Draganjac, M.; Rauchfuss, T. B.; Wilson, S. R. Organometallics 1988, 7, 1171.(d) Arce, A. J.; Arrojo, P.; Deeming, A. J.; DeSanctis, Y. J. Chem. SOC.,Dalton Trans. 1992,2423.(e) Arce, A. J.; DeSanctis, Y.; Karam, A.; Deeming, A. J.Angew. Chem.,Int. Ed. Engl. 1994,33,1381. ( 5 )Adams, R. D.; Pompeo, M. P.; Wu W.; Yamamoto, J. H. J. Am. Chem SOC.1993,115,8207.

0 1995 American Chemical Society

Organometallics, Vol. 14, No. 5, 1995 2239

Triosmium Cluster Complexes

Table 1. Crystal Data for Compounds 1-4 compound 2

1 formula

fw cryst system lattice params a (A) b (A) c (A) a (de@ P (deg) ; $ ; )

space group Z value ecalc(g/cm3) p(Mo Ka)(cm-') temp ("C) 28" (deg) no. obs (I > 3 d GOF" residuals:" R; Rw abs corr largest peak in final diff map

"R = Ch~(IlFo1-

IFclIEhkM'oI;

4

3

OS3SOioCisHs 984.90 monoclinic

~ S ~ S ~ ~ C I ~ H Os3BrS0&8H5 S 956.89 1063.80 triclinic monoclinic

Os3BrOgC17H5 1035.79 monoclinic

7.668(2) 31.464(5) 9.452(2) 90 105.48(2) 90 2197.8(8) P21/n (No. 14)

9.791(1) 14.576(2) 8.094(1) 95.44 107.47(1) 95.23(1) 10_88.2(3) P1 (No. 2) 2 2.92 176.0 20 43.0 2218 1.73 0.024; 0.027 empirical 1.06

9.116(2) 15.577(3) 16.270(3) 90 100.16(1) 90 2274.1(7) P21k (NO.14) 4 3.11 186.2 20 43.0 2193 2.45 0.038; 0.043 empirical 1.83

7.796(1) 15.543(2) 17.640(3) 90 90.48(1) 90 2137.3(5) P2lln (No. 14) 4 3.22 198.0 20 45.0 2288 1.50 0.028; 0.030 empirical 1.03

4

2.98 174.4 20 47.0 2563 1.91 0.035; 0.038

DIFAB 1.08

Rw = [ChklW(lFol -

IFc12)&kflo211/2,

W

= l/02(Fo); GOF = [ C h ~ ( l F o l-

IFcl/dFo)Y(ndata

- &aril.

(sh, w), 2025 (s), 2014 (s), 2005 (s), 1996 (w), 1991 (m). IH NMR (6 in CDCl3) for 2: 7.74-7.63 (m, 2H), 7.33-7.30 (m, 2H), -18.95 (s,2H). Anal. Calc (found) for 2: C, 21.34 (21.12); n transformed t o the complex O S ~ ( C O ) ~ O ~ ~ - S C C H C ~ H ) - (0.55). H,~0.63 b-Br), 4, simply by engaging the uncoordinated C-C Transformationof 1 to 2. A 15.0-mg amount of 1 (0.015 mmol) was dissolved in 10 mL of octane. The solution was double bond of the benzothienyl to form a triply bridging heated to reflux for 30 min. The solvent was then removed in benzothienyl ligand. Details of these studies are revacuo, and the residue was separated by TLC using hexane ported herein. solvent. This yielded 11.5 mg of yellow compound 2 (80%).

2, containing a triply bridging benzothiophyne ligand

by a second C-H activation step. Compound 3 was

Experimental Section General Procedures. All reactions were performed under a dry nitrogen atmosphere. Reagent grade solvents were purified by distillation under nitrogen from the appropriate drying agents (CaHz for CHzCl2 and heptane) and stored over molecular sieves and deoxygenated by purging with nitrogen prior t o use. Os3(CO)lo(NCMe)zwas prepared from Os3(CO)12 by the standard procedure.6 1-Bromobenzothiophene was prepared according to the published procedure.' IR spectra were recorded on a Nicolet 5DXB FT-IR spectrophotometer. lH NMR spectra were recorded on Bruker AM-300 FT-NMR spectrometer. Elemental microanalyses were performed by Desert Analytics Organic Microanalysis, Tucson, AZ. TLC separations were performed in air by using silica gel (60 F254) on glass plates (Analtech, 0.25 mm).

Reaction of Oss(CO)lo(NCMe)zwith 1-Bromobenzothiophene. A 100.0-mg amount of OsdCO)lo(NCMe)z (0.107

mmol) and a 35.0-mg amount of 1-bromobenzothiophene (0.164 mmol) were dissolved in 25 mL of CH2C12. The solution was stirred at room temperature for 3 days. The solvent was then removed in vacuo, and the residue was separated by TLC on silica gel using hexane as solvent to yield in the order of elution n 36.5 mg of an orange band of OS~(CO)~O~~-SCCHC~H~)O~-B~ 3 (32%), and 11.1 mg of a yellow band of 093(cO)9(~3n SCCHC&)(u-Br), 4 (10%). Spectroscopic data for the products are as follows. IR (YCO in hexane, cm-l) for 3: 2107 (m), 2075 (vs), 2058 (m), 2025 (s), 2017 (m), 2014 (sh, m), 2003 (m), 1998 (m), 1989 (w), 1983 (w). 'H NMR (6 in CDZC12) for 3: 7.75 (d, lH, 3Jm= 7.9 Hz), 7.70 (d, 1H, 3 J= ~ 7.9 Hz), ~ 7.51 (s, l H , br), 7.46 (dt, l H , 3Jm= 7.7 Hz, 4 J= 1.1 ~ Hz), ~ 7.32 (t, Reaction of Oss(CO)lo(NCMe)zwith Benzothiophene. 1H, 3 J= 7.9 ~ Hz). ~ Anal. Calc (found) for 3: c, 20.32 (20.13); A 100.0-mg amount of Os3(CO)lo(NCMe)z(0.107 mmol) and a H, 0.47 (0.64). IR (YCO in hexane, cm-l) for 4: 2093 (w), 2072 28.7-mg amount of benzothiophene (0.214 mmol) were dis(vs), 2034 (vs), 2017 (s), 2006 (m), 1991 (m), 1969 (w). lH NMR solved in 25 mL of CHZC12, and the resulting solution was (6 in CDC13) for 4: 7.77(d, l H , 3 J= 7.60 ~ Hz), 7.67 (dd, l H , stirred at room temperature for 4 days. The solvent was then 3 J= 7.80 ~ ~ Hz, 5Jm= 1.0 Hz), 7.40 (td, 1H, 3 J =~7.60 ~ Hz, removed in vacuo, and the residue was separated by TLC using 5 J= 1.0 ~ Hz), 7.28 (dd, l H , 3 J= 7.60 ~ Hz, 5Jm = 1.0 Hz), hexane as solvent to yield in the order of elution 10.4 mg of a 5.20 ( 8 , 1H). Anal. Calc (found) for 4: C, 19.70 (19.72); H, n 0.48 (0.50). yellow band of OS~(CO)~O~~-SCCHC~H~)C~-H), 1 (lo%),and 8.2 Pyrolysis of 3. A 60.0-mg amount of 3 (0.056 mmol) was mg of a yellow band of O S ~ ( C ~ ) ~ ~ ~ ~ - ~ C C ~ G 2H (8%). ~)OL-H )~, dissolved in 15 mL of heptane. The solution was heated to Spectroscopic data for the products are as follows. IR (YCO in reflux for 30 min. The solvent was then removed in vacuo, hexane, cm-l) for 1: 2106 (m), 2069 (vs), 2055 (s), 2023 (vs), and the residue was separated by TLC using hexane solvent 2013 (s), 2001 (m), 1995 (s), 1984 (m). lH NMR (6 in CDCM to yield 42.9 mg of yellow 4 (74%). for 1: 7.96 (d, l H , 3 J= 7.7 ~ Hz), ~ 7.67 (d, l H , 3 J= 7.7 ~ Hz), 7.42 (dt, l H , 3Jm= 7.5 Hz, 4 J= 1.4 ~ Hz), ~ 7.34 (dt, 1H, 3 J ~ ~Crystallographic Analyses. Crystals of 3 suitable for X-ray diffraction analysis were grown from a solution of a = 7.5 Hz, 4Jm = 1.4 Hz), 7.33 (9, l H ) , -15.39 (s,lH). Anal. solvent mixture of dichloromethane and hexane by slow Calc (found) for 1: C, 21.95 (21.23); H, 0.61 (0.53). IR (YCO in evaporation of the solvent a t -14 "C. Crystals of 4 suitable hexane, cm-l) for 2: 2112 (m), 2085 (s), 2062 (s), 2039 (s), 2034 for X-ray diffraction analysis were grown from a solution of benzene by slow evaporation of the solvent a t 25 "C. Crystals (6) Nicholls, J. N.; Vargas, M. D. Inorg. Synth. 1989,28, 232. of 1 suitable for X-ray diffraction analysis were grown from a (7) Shirley, D. A.; Cameron, M. D. J.Am. Chem. SOC. 1952, 74,664.

A,

Adams and Qu

2240 Organometallics, Vol. 14, No. 5, 1995

Table 2. Positional Parameters and B(eq) Values (k) for 1 atom Os(1) Os(2) Os(3) S O(11)

X

0.09550(8) 0.22124(8) 0.34386(9) 0.1914(6) -0.194(2) 0.219(2) -0.179(2) 0.023(2) 0.588(2) 0.091(2) 0.392(2) 0.006(2) 0.566(2) 0.688(2) 0.279(2) 0.354(2) 0.344(2) 0.413(2) 0.388(2) 0.299(3) 0.2382) 0.259(2) -0.081(2) 0.175(2) -0.071(3) 0.099(2) 0.448(2) 0.143(2) 0.374(2) 0.128(2) 0.480(3) 0.556(2)

Y

z

B(ed

0.10727(2) 0.15647(2) 0.17639(2) 0.0553(1) 0.1519(4) 0.0606(4) 0.0408(5) 0.1408(4) 0.1775(4) 0.2486(4) 0.1582(5) 0.2302(5) 0.2571(5) 0.1302(5) 0.0903(5) 0.0657(5) 0.0197(5) -0.0122(5) -0.0532(5) -0.0624(6) -0.0315(6) 0.0103(5) 0.13546) 0.0781(6) 0.0656(6) 0.1453(6) 0.1699(5) 0.2149(7) 0.1668(6) 0.2093(5) 0.2271(6) 0.1456(5)

0.11754(7) 0.37710(7) 0.12529(7) 0.4668(5) -0.110(2) -0.120(1) 0.149(2) 0.610(1) 0.578(1) 0.364(2) -0.176(2) 0.021(1) 0.200(2) 0.302(2) 0.360(1) 0.268(2) 0.285(2) 0.215(2) 0.249(5) 0.358(3) 0.429(2) 0.394(2) -0.024(2) -0.029(2) 0.138(2) 0.527(2) 0.504(2) 0.369(2) -0.061(2) 0.059(2) 0.174(2) 0.231(2)

2.58(2) 2.59(3) 3.02(3)

O(12) O(13) O(21) O(22) O(23) O(31) O(32) O(33) O(34) C(1) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(11) C(12) C(13) C(21) 0 3 3 u 0 3 2 u C(22) C(23) n C(31) Figure 1. ORTEP diagram of OS~(CO)~~OA-SCCHC~HS)~~C(32) H), 1, showing 50% probability thermal ellipsoids. C(33) C(34) solution of a solvent mixture of dichloromethane and hexane by slow evaporation of the solvent at -14 "C. Crystals of 2 Compound 2 crystallized in the triclinic crystal system. The suitable for X-ray diffraction analysis were grown from a space group Pi was assumed and confirmed by the successful solution in hexane by slow evaporation of the solvent at -5 solution and refinement of the structure. All non-hydrogen "C. All crystals were mounted in thin-walled glass capillaries. atoms of the complex were refined with anisotropic thermal Diffraction measurements were made on a Rigaku AFCGS parameters. The hydrogen atoms on the benzothiophyne automatic diffractometer by using graphite-monochromated ligand were calculated by assuming idealized geometries. The Mo Ka radiation. Unit cells were determined from 15 ranprobable position of the two hydride ligands were obtained domly selected reflections obtained by using the AFC6 autofrom a difference Fourier map, but they could not be refined matic search, center, index, and least-squares routines. Crysto a convergence. Thus, the hydride ligands and the hydrogen tal data, data collection parameters, and results of the analyses atoms on the benzothiophyne ligand were added to the are listed in Table 1. All data processing was performed on a structure factor calculations without refinement. Digital Equipment Corp. V a s t a t i o n 3520 computer by using Compound 3 crystallized in the monoclinic crystal system. the TEXSAN structure solving program library obtained from The space group P21Ic was established on the basis of the the Molecular Structure Corp., The Woodlands, TX. Lorentzpatterns of systematic absences observed in the data. All nonpolarization (Lp)and absorption corrections were applied t o hydrogen atoms were refined with anisotropic thermal pathe data in each analysis. Neutral atom scattering factors rameters. The hydrogen atoms on the benzothienyl ligand were calculated by the standard procedures.8a Anomalous were calculated by assuming idealized geometries and were dispersion corrections were applied to all non-hydrogen atoms.8b added to the structure factor calculations without refinement. All structures were solved by a combination of direct methods (MITHRIL) and difference Fourier syntheses. Full matrix Results least-squares refinements minimized the following function: &kiW(IFol - IF#', where w = 1 / d F j 2 , ofFj = dFZ)/2Fo, and The reaction of Os3(CO)lo(NCMe)z with benzothiophene d F Z j = [dIr,d2 (0.02Zn,J211/2/Lp. in CHzCl2 at 25 "C for 4 days yielded two new comn Compounds 1 and 4 crystallized in the monoclinic crystal p o u n d s OS~(CO)~~C~-SCCHC~H~)C~-H), 1,a n d o s 3 ( c o ) g system. The space group P21In was established for both compounds on the basis of the patterns of systematic absences observed in the data. All nonhydrogen atoms of the complex were refined with anisotropic thermal parameters. The hydrogen atoms on the benzothienyl ligand were calculated by assuming idealized geometries with C-H = 0.95 A. The probable position of the hydride ligand in 1was obtained from a difference Fourier map, but it could not be refined to a convergence. Thus, the hydride ligand and the hydrogen atoms on the benzothienyl ligand in both analyses were added 1 5 to the structure factor calculations without refinement. m @ ~ - S C C C ~ H ~ ) ( U -2, Hin ) ~rather , low yields 10%and 8%, (8) (a) International Tables for X-ray Crystallography; Kynoch respectively. B o t h compounds w e r e characterized by a Press: Birmingham, England, 1975; Vol. N,Table 2.2B, pp 99-101. (b)Ibid., Table 2.3.1, pp 149-150. combination of IR, l H NMR, and single-crystal X-ray

+

Organometallics, Vol. 14,No. 5,1995 2241

Triosmium Cluster Complexes Table 3. Intramolecular Distances for 1" Os(l)-Os(2) Os(l)-Os(3) Os( 1)-C( 1) Os(l)-C(2) 0~(2)-0~(3) Os(2)-C(l) S-C(l) S-C(8) C(l)-C(2) C(2)-C(3)

2.843(1) 2.8788(9) 2.41(1) 2.48(1) 2.853(1) 2.14(1) 1.75(1) 1.71(2) 1.40(2) 1.46(2)

C(3)-C(4) C(3)-C(8) C(4)-C(5) C(5)-C(6) C(6)-C(7) C(7)-C(8) Os-C(av) C-O(av) Os(l)-H Os(2)-H

1.38(2) 1.39(2) 1.36(2) 1.41(3) 1.34(3) 1.38(2) 1.90(2) 1.14(2) 2.01 1.76

021

a Distances are in angstroms. Estimated standard deviations in the least significant figure are given in parentheses.

Table 4. Intramolecular Bond Angles for 1" 0 ~ ( 2 ) - 0 ~ ( 1 ) - 0 ~ ( 3 ) 59.80(2) 0 ~ ( 1 ) - 0 ~ ( 2 ) - 0 ~ ( 3 ) 60.72(2) 0 ~ ( 1 ) - 0 ~ ( 3 ) - 0 ~ ( 2 ) 59.48(2) C(l)-S-C(8) 95.0(8) S-C(l)-C(P) 107(1) 116(1) C(l)-C(2)-C(3) C(2)-C(3)-C(8) llO(1) C(4)-C(3)-C(8) 121(1)

C(3)-C(4)-C(5) C(4)-C(5)-C(6) C(5)-C(6)-C(7) C(6)-C(7)-C(8) S-C(8)-C(3) C(3)-C(8)-C(7) Os-C(av)-0

119(2) 120(2) 122(2) 119(2) 112(1) 120(2) 177(2)

Angles are in degrees. Estimated standard deviations in the least significant figure are given in parentheses.

diffraction analyses. An ORTEP diagram of the molecular structure of compound 1 is shown in Figure 1. Final atomic positional parameters are listed in Table 2, and selected interatomic distances and angles are listed in Tables 3 and 4. The molecule consists of a closed triangular cluster of three osmium atoms with 10 linear terminal carbonyl ligands. The most interesting ligand is a p-v2-benzothienyl ligand coordinated to an edge of the cluster through the C-C double bond in the five-membered ring in a a n coordination mode. The reaction of Oss(CO)lo(NCMe)2 with furan and thiophene has been reported to yield similar complexes

-

+

Os3(CO)&-OCCHCHCH)~-H), m

and Os3(C0)10(~-

SCCHCHCH)b-H),6,1°containing p-v2-furyl and thienyl ligands, respectively, and the furyl complex 5 has been characterized cry~tallographically,~ but this appears to be the first example of this coordination for a benzothienyl ligand. The metal-carbon a-bonding distance, Os(2)-C(l) = 2.14(1) A, is similar to that found in 5, Os-C = 2.11(1) A. The metal-carbon n-bonding distances, Os(l)-C(l) = 2.41(1) A and Os(l)-C(2) = 2.48(1) A, are not greatly different from those found in 5, 2.34(1) and 2.63(1) A, respectively, although the distances are considerably more asymmetric in 5. The p-v2-benzothienylligand has adopted a conformation similar to that of the furyl ligand in 5 in which the sulfur atom points away (anti) from the Os(CO)r grouping in the cluster. This is different from most a-n coordinated alkenyl ligands where the substitutent on the bridging carbon atom is oriented syn to the Os(C0)r grouping.ll Compound 1 contains one hydride ligand, 6 = -15.39 ppm. It was located crystallographically in a bridging position across the same metal-metal bond as the benzothienyl ligand, but it could not be refined. Interestingly, the metal(9) Himmelreich, D.; Miiller, G. J. Organomet. Chem. 1986,297,341. (10)Arce, A. J.; Deeming, A. J.; De Sanctis, Y.;Machado, R.; Manzur, J.; Rivas, C. J . Chem. Soc., Chem. Commun. 1990, 1568. ( l l ) ( a ) Deeming, A. J. Adu. Organomet. Chem. 1986, 26, 1. (b) Orpen, A. G.; Pippard, D.; Sheldrick, G. M. Acta Crystallogr. 1978, B34, 2466. (c) Guy, J. J.; Reichert, B. E.; Sheldrick, G. M. Acta Crystallogr. 1976, B32, 3319. (d) Sappa, E.; Tiripicchio, A.; Manotti, A. M. J . Organomet. Chem. 1983,249, 391.

012

0

Figure 2. ORTEP diagram of Os3(CO)g(p&!CC6H5)(pH)z, 2, showing 50%probability thermal ellipsoids.

metal bond distance, Os(l)-Os(2) = 2.843(1) A, is no lon er than that of a normal Os-Os single bond, 2.877(3) .12 It is possible the usual bond lengthening effect produced by hydride ligands may be counteracted by the bridging benzothienyl ligand. The hydride ligand in 5 occupied a similar p o ~ i t i o n . ~ Compound 1 is a precursor to 2, and 2 was obtained in 80%yield when octane solutions of 1 were heated t o

1

2

7

reflux (125 "C) for 30 min. A n ORTEP diagram of the molecular structure of compound 2 is shown in Figure 2. Final atomic positional parameters are listed in Table 5 , and selected interatomic distances and angles are listed in Tables 6 and 7. This molecule also contains a closed triangular cluster of three osmium atoms but has only nine linear terminal carbonyl ligands, three on each metal atom. Compound 2 contains a benzothiophyne ligand formed by the cleavage of the carbonhydrogen bond of the carbon of the coordinated C-C double bond and a transfer of the hydrogen atom to the cluster. The C(l)-C(2) bond in 2 is formally triple, but the C-C distance of 1.43(1) A is longer than that of an uncoordinated triple bond as a result of the coordination. The ligand is coordinated to the face of the cluster through the C-C triple bond in the usual p-lIor di-a + (12)Churchill, M. R.; DeBoer, B. G. I n o g . Chem. 1977, 16, 878.

2242 Organometallics, Vol. 14,No.5, 1995

Adams and Q u

Table 5. Positional Parameters and B(eq) Values for 2

Table 8. Positional Parameters and B(eq) Values (&> for 3

atom

X

0.80331(4) 0.60719(4) 0.91279(4) 0.8622(3) 1.087(1) 0.829(1) 0.626(1) 0.530(1) 0.342(1) 0.477(1) 1.190(1) 0.933(1) 1.059(1) 0.797(1) 0.727(1) 0.723(1) 0.664(1) 0.676(1) 0.747(1) 0.805(1) 0.794(1) 0.979( 1) 0.818(1) 0.591(1) 0.558(1) 0.438(1) 0.525(1) 1.086(1) 0.928(1) 1.006(1)

Y

z

B(eq)

atom

0.12036(3) 0.23345(3) 0.27759(3) 0.3105(2) 0.0947(6) --0.0269(7) 0.0034(7) 0.3971(6) 0.2135(7) 0.1029(8) 0.3173(7) 0.4 733(6) 0.1748(7) 0.2521(7) 0.3118(7) 0.4031(6) 0.4801(7) 0.5614(8) 0.5705(8) 0.4967(9) 0.4120(7) 0.1041(8) 0.0237(9) 0.0468(8) 0.3373(8) 0.2201(7) 0.1491(9) 0.3039(8) 0.3990(9) 0.213(1)

0.21405(6) 0.35926(6) 0.45336(5) -0.0057(4) 0.149(1) 0.464( 1) -0.127(1) 0.560(1) 0.041(2) 0.563(2) 0.361(1) 0.638(1) 0.757(1) 0.140(1) 0.231(1) 0.169(1) 0.221( 1) 0.152(2) 0.033(2) -0.026(2) 0.043(1) 0.172(2) 0.369(2) 0.003(2) 0.483(2) 0.162(2) 0.488(2) 0.396(2) 0.572( 1) 0.642(2)

3.13(2) 3.03(2) 3.03(2) 4.2(1) 6.8(5) 7.3(5) 7.3(4) 6.8(5) 7.9(5) 9.1(6) 7.3(5) 5.6(4) 7.9(5) 3.5(4) 2.9(4) 2.7(4) 3.9(5) 4.7(5) 5.1(5) 4.9(5) 3.3(4) 4.8(5) 4.7(5) 5.0(5) 4.3(5) 4.6(5) 5.0(5) 4.3(5) 3.7(5) 5.1(5)

Os(1) Os(2) Os(3) Br S O(11) O(12) O(13) O(21) O(22) O(23) O(31) O(32) O(33) O(34)

Table 6. Intramolecular Distances for 2" Os(l)-Os(2) 0~(1)-0~(3) Os(1)-C( 1) 0~(2)-0~(3) Os(2)-C(2) 0~(3)-C(1) 0~(3)-C(2) S-C(l) S-C(8)

1.43(1) 1.46(1) 1.92(1) 1.14(1) 1.96 1.77 1.60 1.82

3.0581(7) 2.7600(7) 2.07( 1) 2.8522(7) 2.12(1) 2.42(1) 2.27(1) 1.75(1) 1.74(1)

Distances are in angstroms. Estimated standard deviations in the least significant figure are given in parentheses.

Table 7. Intramolecular Bond Angles for 2" 0 ~ ( 2 ) - 0 ~ ( 1 ) - 0 ~ ( 3 ) 58.44(2) 0 ~ ( 1 ) - 0 ~ ( 2 ) - 0 ~ ( 3 ) 55.54(2) Os(l)-O~(3)-0~(2) 66.01(2) C(l)-S-C(8) 92.7(5) S-C(l)-C(Z) 111.1(7)

C(l)-C(2)-C(3) C(2)-C(3)-C(8) S-C(8)-C(3) Os-C(av)-O

111.5(9) 112.6(8) 112.0(7) 177(1)


n mode. The thiophyne ligand in the complex Os3(CO)g@3-SCCCHCH)@-H)z,7,13J4that was formed by the decarbonylations of 61° and the p-acyl complex oS3I

(CO)&-O=CCSCHCHCH)@-H), 8, is similarly coordinated. Compound 7 has been characterized crystallographically also. The Os-C a-bond distances, Os(1)C(1) = 2.07(1)A and Os(2)-C(2) = 2.12(1)A, are similar to those found in 7,2.14(2) A [2.16(2) AI and 2.13(2) A [2.17(2)A],respectively. The Os-C n-bonding is quite unsymmetrical, Os(3)-C(l) = 2.42(1) A and Os(3)-C(2) = 2.27(1)A,but similar asymmetry was found in 7,2.43(2) A [2.46(2) AI and 2.31(2) A [2.23(2) AI with the (13)Arce, A. J.;De Sanctis, Y.; Deeming, A. J. J.Organomet. Chem. 1986,311,371. (14)Deeming, A. J.; Arce, A. J.; De Sanctis, Y.; Day, M. W.; Hardcastle, K.I. Orgunometullics 1989,8, 1408.

c(2) C(4) c(3) C(5) C(6) C(7) C(8) C(11) C(12) C(13) C(21) C(22) C(23) C(31) C(32) C(33) C(34)

X

0.19110(8) 0.43679(8) 0.25137(8) 0.2340(2) 0.5522(5) 0.131(2) 0.191(2) -0.137(2) 0.624(2) 0.652(2) 0.273(2) 0.359(2) 0.013(2) -0.002(2) 0.468(2) 0.422(2) 0.488(2) 0.636(2) 0.730(2) 0.870(2) 0.917(2) 0.828(2) 0.686(2) 0.154(2) 0.189(2) -0.014(3) 0.555(2) 0.572(2) 0.337(2) 0.321(2) 0.103(2) 0.098(2) 0.393(2)

Y

0.14994(5) -0.04318(5) 0.03996(5) 0.0097(1) 0.0965(3) 0.257(1) 0.307(1) 0.108( 1) -0.110(1) -0.088(1) -0.212(1) -0.078(1) -0.083(1) 0.121(1) 0.185(1) 0.168(1) 0.208(1) 0.182(1) 0.211(1) 0.173(1) 0.108(1) 0.078(1) 0.116(1) 0.215( 1) 0.246(1) 0.123(1) -0.086(1) -0.074( 1) -0.150(2) -0.038(2) -0.040( 1) 0.094(1) 0.130(1)

B(eq)

2

0.27477(5) 0.28044(5) 0.13874(5) 0.3627(1) 0.2961(3) 0.423(1) 0.169(1) 0.201(1) 0.444(1) 0.166(1) 0.244(1) 0.013(1) 0.188(1) 0.017(1) 0.1128(9) 0.330(1) 0.396(1) 0.432(1) 0.503(1) 0.526(1) 0.480(1) 0.408( 1) 0.386(1) 0.368(1) 0.209(1) 0.231(1) 0.381(1) 0.206(1) 0.255( 1) 0.062(1) 0.171(1) 0.063(1) 0.125(1)

longest Os-C bond being to the sulfur-substituted carbon atom, as found in 2. Compound 2 contains two hydride ligands. They were located in reasonable positions as bridges across the Os(l)-Os(2) and Os(2)Os(3) bonds, but they could not be refined to convergence and were fixed in the final analysis. Although they are inequivalent, only one hydride resonance of intensity two was observed in the lH NMR spectrum, 6 = -18.95 (2H). I t is believed that the hydride ligands are dynamically averaged in the NMR spectrum at room temperature. A similar dynamical averaging of the inequivalent hydride ligands was also observed in 7.14 The reaction 1-bromobenzothiophenewith Os3(CO)10(NCMe12 at 25 "C yielded two products: Os~(C0)10@n

n

SCCHC&)@-Br), 3 (32%), and OS~(CO)~@~-SCCHC,$&,)@-Br), 4 (10%). Both products were characterized by IR, 'H NMR, and single crystal X-ray diffraction analyses. An ORTEP diagram of the molecular structure of compound 3 is shown in Figure 3. Final atomic positional parameters are listed in Table 8, and selected interatomic distances and angles are listed in Tables 9 and 10. This molecule contains an open triangular cluster of three osmium atoms with ten linear terminal carbonyl ligands. There are only two metal-metal bonds, Os(l)-Os(3) = 2.926(1) A and Os(2)-Os(3) = 2.911(1) A. There is a S-coordinated p-q2-benzothienyl ligand and bromo ligand that bridge the open edge of the cluster, Os(l).*-Os(2)= 3.742(1) A. Both of these ligands serve as three electron donors; thus, the cluster has a total of 50 valence electrons and in order for each of the metal atoms to have 18 electron configurations there can be no more than two metal-metal bonds between the three metal atoms. The osmium-sulfur bond distance of 2.411(5) A is typical of the the os-

Organometallics, Vol.14, No. 5, 1995 2243


n

Figure 3. ORTEP diagram of O~~(CO)~OC~-SCCHC~H~)C~-B~), 3,showing 50%probability thermal ellipsoids. Table 9. IntramolecularDistances for 3" Os(l)-Os(3) Os(1)-Br Os( 1)-C( 1) 0~(2)-0~(3) Os(2)-Br Os(2)-S

s-cm

S-C(8) C(l)-C(2) C(2)-C(3)

2.926(1) 2.602(2) 2.16(2) 2.911(1) 2.600(2) 2.411(5) 1.78(2) 1.76(2) 1.30(2) 1.43(2)

C(3)-C(4) C(3)-C(8) C(4)-C(5) C(5)-C(6) C(6)-C(7) C(7)-C(8) Os-C(av) C-O(av) Os(l)-Os(2)

1.40(3) 1.40(2) 1.39(3) 1.38(3) 1.38(3) 1.40(2) 1.91(2) 1.14(2) 3.742(1)


Table 10. Intramolecular Bond Angles for 3" 83.94(5) 95.3(5) 80.7(5) 84.28(5) 82.2(1) 89.8(1) 79.73(3) 91.98(6) 109(1)

118(2) 112(2) 118(2) 119(2) 122(2) 121(2) 117(2) 109(1) 176(2)

a Angles are in degrees. Estimated standard deviations in the least significant figure are given in parentheses.

mium-sulfur

bond distances found in other S-C-

n bridged triosmium clusters (e.g. OS~(CO)~O(LL-SCHCH~Figure 4. ORTEP diagram of O S ~ ( C O ) ~ ~ ~ ~ - S C C H C ~ H ~ ) C ~ 1 CH2CHd@-H),OS-S = 2.37(1)A,5 and OS~(CO)S(PP~)C~-Br), 4, showing 50% probability thermal ellipsoids.

SCHCH~CH~CH~)(D-H), Os-S = 2.407(1) A.15 The S-C(l) distance, 1.78(2)A,is typical of a carbon-sulfur single bond. The C(l)-C(2) bond is double, and the distance 1.30(2) A is in accord with this assignment. There appear to be no previous reports of ,u-S-C-v2thienyl or benzothienyl ligands. The bromide ligand symmetrically brid es the Os(1) and 0 4 2 ) atoms, Os(1)-Br = 2.602(2) and Os(2)-Br = 2.600(2) A. When heated to reflux in a heptane solution (97 "C), compound 3 was decarbonylated and transformed t o 4 in 74% yield in 30 min. An ORTEP diagram of the

!

~

(15) Glavee, G. N.; Daniels, L. M.; Angelici, R. J. Organometallics 1989,8,1856.

molecular structure of compound 4 is shown in Figure 4. Final atomic positional parameters are listed in Table 11and selected interatomic distances and angles are listed in Tables 12 and 13. This molecule also contains of a open triangular cluster of three osmium atoms but has only nine linear terminal carbonyl ligands, three on each metal atom. The metal-metal bonds, Os(l)-Os(3) = 2.8125(8) A and Os(2)-Os(3) = 2.8873(8) A,are shorter than those in 3 presumably because the benzothienyl ligand now bridges these bonds. However, the nonbonding Os(l>* Qs(2) distance of 3.8798(8) A is slightly longer than that in 3. The benzothienyl ligand in 4 bridges all three metal atoms

2244 Organometallics, Vol. 14, No. 5, 1995

Adams and Q u

Table 11. Positional Parameters and B(eq) Values (As)for 4 Os(1)

Os(2) Os(3) Br S O(11) O(12) O(13) O(21) O(22) O(23) O(31) O(32) O(33) C(1) C(2) C(3) C(4) C(5) C(6) C(7) C(8) C(11) C(12) C(13) C(21) C(22) C(23) C(31) C(32) C(33)

0.24807(7) 0.26757(6) 0.01307(6) 0.4735(2) 0.2102(4) 0.494(2) -0.017(1) 0.372(2) 0.335(1) 0.567(1) -0.013(1) -0.225(1) 0.205(1) -0.242(1) 0.109(2) -0.069(2) -0.120(2) -0.284(2) -0.300(2) -0.167(2) O.OOO(2) 0.014(2) 0.402(2) 0.081(2) 0.330(2) 0.307(2) 0.456(2) 0.098(2) -0.140(2) 0.135(2) -0.145(2)

0.17113(3) 0.32214(3) 0.20397(3) 0.22711(9) 0.3808(2) 0.222(1) 0.1051(7) -0.0127(7) 0.2203(6) 0.4443(6) 0.4280(7) 0.0655(7) 0.0742(7) 0.2614(7) 0.2816(8) 0.2965(8) 0.3862(8) 0.4223(9) 0.506(1) 0.559(1) 0.5245(8) 0.4382(8) 0.199(1) 0.1312(9) 0.054( 1) 0.2564(9) 0.401(1) 0.3897(9) 0.119(1) 0.124(1) 0.244(1)

0.03962(3) 0.21461(3) 0.15622(3) 0.13700(8) 0.0894(2) -0.0849(7) -0.0698(6) -0.0721(6) 0.3585(6) 0.2586(6) 0.2848(6) 0.0902(6) 0.2535(7) 0.2765(6) 0.0590(7) 0.0553(7) 0.0723(7) 0.0673(8) 0.0843(8) 0.1052(8) 0.1085(8) 0.0922(7) -0.039( 1) -0.0282(7) 0.0590(7) 0.3036(8) 0.2385(8) 0.2601(7) 0.1128(8) 0.2170(8) 0.2298(9)

2.71(3) 2.29(2) 2.24(2) 3.34(7) 2.7(2) 7.3(8) 5.6(6) 5.2(6) 4.7(6) 4.6(6) 4.2(5) 5.2(6) 6.0(7) 4.3(5) 2.7(6) 2.4(6) 2.4(6) 3.1(7) 3.7(8) 4.3(8) 3.7(8) 2.8(6) 4.3(8) 3.3(7) 3.2(7) 3.0(7) 3.3(7) 2.9(7) 3.3(7) 3.5(7) 3.5(7)

Table 12. Intramolecular Distances for 4" Os(l)-Os(3) Os(1)-Br Os(l)-C(l) 0~(2)-0~(3) Os(2)-Br Os(2)-s 0~(3)-C(1) 0~(3)-C(2) S-C(8) C(l)--C(2)

1.48(2) 1.39(2) 1.36(2) 1.34(2) 1.37(2) 1.41(2) 1.38(2) 1.91(2) 1.14(2) 3.8798(8)

2.8125(8) 2.598( 1) 2.06(1) 2.8873(8) 2.583(2) 2.427(3) 2.23(1) 2.37(1) 1.77(1) 1.41(2)


Table 13. Intramolecular Bond Angles for 4" 84.08(4) 82.85(3) 78.07(8) 85.79(2) 97.00(5) 107(1) 114(1) 114(1)

C(4)-C(3)-C(8) C(3)-C(4)-C(5) C(4)-C(5)-C(6) C(5)-C(6)-C(7) C(6)-C(7)-C(8) C(3)-C(8)-C(7) Os-C(av)-0

118(1) 118(1) 125(1) 119(1) 116(1) 125(1) 176(1)


by using sulfur atom and the C-C double bond C(1)C(2) in the five-membered ring. The sulfur atom is bonded to 0 4 2 ) as in 3, 042)-S = 2.427(3) A, and the C(l)-C(2) double bond has a p-q2 D n coordination across the Os(l)-Os(2) bond with C(1) a-bonded to Os(l),Os(l)-C(l) = 2.06(1)A,and C(1) and C(2) n-bonded to Os(3),Os(3)-C(l) = 2.23(1) A and Os(3)-C(2) = 2.37(1) A. The C(l)-C(2) distance of 1.41(2) A in 4 is significantly longer than that in 3 as a result of the effect of coordination. There appear to be no previous reports of p-S-C-q2-thienylor benzothienyl ligands. The Os-Br distances Os(1)-Br = 2.598(1) A and Os(2)are similar to those in 3. The Br = 2.583(2)

+

A,

Scheme 1 Me C

+

m x S

25\=Br

. = T 5 0

H

.

'1

.

3

125°C

4

2

benzothienyl ligand in 4 serves formally as a 5 electron donor, but the cluster with one less CO ligand still has a total of 50 valence electrons just as in 3. A summary of the results of this study is shown in Scheme 1. Both benzothiophene and l-bromobenzothiophene react with Oss(CO)lo(NCMe)zat 25 "C by displacement of the two NCMe ligands and oxidative addition of the benzothiophene at the C-X bond to form the benzothienyl triosmium complexes 1 and 3,X = H and Br, respectively. The higher yield of 3 relative to 1 can probably be attributed to a higher reactivity of the C-Br bond in the 1-bromobenzothiophene compared to the C-H bond in benzothiophene, itself. In both reactions the X atom is transferred to the cluster and becomes a bridging ligand. Likewise, the benzothienyl ligand becomes a bridging ligand in each cluster. Interestingly, however the benzothienyl ligands bridge the clusters in two different ways in 1 and 3. This is probably related to the distance between the two metal atoms that are bridged. In 1 the metal atoms are separated at a normal bonding distance, whereas in 3 the metal-metal bond was cleaved and the bridged metal atoms are 0.90 A farther apart than those in 1. As a result, the benzothienyl ligand cannot adequately bridge these two metal atoms in 3 using the C-C double bond in the usual 0 n coordination mode since one of the carbon atoms C(1) must be bonded to both metal atoms, and the metal atoms are simply too far apart to form a stable strucutre. Instead the benzothienyl in 3 adopted a configuration that uses two atoms to span the metal atoms, the sulfur atom, and neighboring carbon atom. Both 1 and 3 undergo loss of on CO ligand when heated. The transformation of 3 leads to the formation

+


of a triply bridging benzothienyl ligand serving as a five electron donor by engaging the uncoordinated C-C double bond. In contrast the decarbonylation of 1 does not result in coordination of the sulfur atom but instead results in the oxidative addition of the remaining C-H bond on the carbon of the coordinated C-C double bond. Unlike the reaction of benzothiophene with Fe3(CO)124b>c and R U ~ ( C O we ) ~ have ~ , ~ found no evidence for ring opening in the formation of compounds 1 and 2 or in their transformations into compounds 3 and 4 under the conditions that we have used. Likewise, it was reported that there was no evidence for ring

Organometallics, Vol. 14,No. 5, 1995 2245

opening of the thiophene ring in studies of the reactions of thiophene with OS~(CO)IO(NCM~)~.'~

Acknowledgment. This research was supported by the Office of Basic Energy Sciences of the U S . Department of Energy. SupplementaryMaterial Available: Tables of hydrogen atom positional and thermal parameters and anisotropic thermal parameters for all three structural analyses (10 pages). Ordering information is given on any current masthead page. OM950011E

Coordination and Transformations of Benzothienyl Ligands by

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