Inorganic Chemistry lated trinuclear metal carbonyl complexes, is given elsewhere.4 i The apical group in each of the diamagnetic complexes Co3(CO)&CHa and Ir4(CO)12is formally a threeelectron donor such that each metal of the ivIa(CO)3 fragment achieves a closed-shell electronic configuration, whereas in the paramagnetic complex SCo3(CO) the sulfur effectively contributes four electrons to the Co3(C0)3 fragment such that the entire molecule contains one electron in excess of the “krypton” configuration for each cobalt atom. A salient structural feature of the SCOs fragment of SCo3(CO)9 is that the average distance of 2.64 A for the Co-Co bonds is longer by 0.1-0.2 A than the Co-Co distances found in Co3(CO)gCCHa (2.46 A) and in other polynuclear cobalt carbonyl complexes.41 The average Co-S length of 2.14 A is a t least 0.1 A shorter than other Co-SR bond lengths in complexes containing triply bridging and/or doubly bridging metal-coordinated mercapto groups12s20 but agrees closely with Co-S bond lengths in other complexes in which the sulfur is symmetrically coordinated to cobalt atoms. 2a A preliminary X-ray investigation of the diamagnetic complex SCo2Fe(CO)9, recently prepared by Khattab, hiark6, Bor, and Mark6,I5 showed that the crystals of this cobalt-iron complex (in which an iron atom is sub-
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stituted for one cobalt atom) are isoniorphous with those of SCoa(CO)9. A complete structural determination of this diamagnetic complex is in progress in order to determine the effect of the one unpaired electron on the metal-metal bonds in SCo3(CO)9. Also, a single-crystal esr study of the paramagnetic SCo3(CO) diluted in the diamagnetic host SCo2Fe(CO) is being carried out in collaboration with Professor John E. Harriman a t the University of Wisconsin for the purpose of unraveling the electron density distribution of the unpaired electron. Details of these investigations will be reported in later papers. Acknowledgments.-This work was made possible through the financial support of the Air Force Office of Air Research and Development Command (518-66). \Ye are especially indebted to Drs. L. Mark6 and G. Bor for furnishing us n-ith a sampleof S C 0 ~ ( C 0 ) ~ afor n d their interest in our work. We also are pleased to acknowledge the partial support of NSF and WARF made by the University Research Committee for the use of the CDC 1604 and 3600 computers a t the University of Wisconsin Computing Center. Part of the calculations were performed on the IBM 704 computer a t the hlidwestern Universities Research Association (JIURA).
DEPARTMENT OF CHEMISTRY, THEOHIO STATE USIVERSITY,COLCMBUS, OHIO 43210, DEPARTMENT OF CHEMISTRY, UNIVERSITYOF WISCOXSIN, MADISON, WISCONSIS 53706
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Preparation and Structure of [CH,SFe2(CO)6]2S : a n Organometallic Complex Containing a Tetrahedral-like Sulfur Atom Coordinated to Four Metal Atoms’ BY JUDITH M. COLEiMAS,2*tbXXDREW WOJCICKI,20PHILIP J. POLLICK,2CASD LAWRENCE F. DAHLZR
Receiued October 3 , 1966 The reaction of Fe3(CO);., with methyl thiocyanate has yielded as a condensation by-product the diamagnetic tetramer [CH8SFe2(CO)6]2S. This complex has been characterized by chemical and physical means including a three-dimensional single-crystal X-ray study which not only unambiguously established the actual composition but also revealed the first known example of an organometallic complex containing a tetrahedral-like sulfur atom bridging four metal atoms. The compound crystallizes with two molecules in a triclinic unit cell of symmetry Pi and of reduced cell parameters a = 8 93 A , b = 9.28 A , c = 16.04 A, a = 81”40’, /3 = 80’ Os’, and y = 66” 35’. A full-matrix, anisotropic-isotropic, least-squares refinement has resulted in discrepancy factors of Rl = 9.1% and R2 = 9.3y0,. The molecular configuration of approximate C2-2symmetry consists of two essentially identical [CH3SFe2(CO)s]fragments bridged by a metal-coordinated tetrahedrallike sulfur atom which donates its six valence electrons t o the four iron atoms. The properties and structural features are O ) ~other ] ~ related complexes. discussed and compared with those of [ C Z H ~ S F ~ ( Cand
Introduction The reactions of sulfur and sulfur-containing cornpounds with metal carbonyls and derivatives have produced a wide variety of unusual organometallic sulfur c ~ r n p l e x e s . ~ - l ~ To date, structural investigations (1) T h e structural characterization of this compound represents t h e T‘IIth paper concerning systematic structural investigations of organometallic sulfur complexes. For paper V I see: C. H. Wei and L. F. Dahl, I n o j g . Chpni., 6 , 1229 (1967). (2) (a) University of Wisconsin; (b) the X-ray work is abstracted in p a r t from t h e Ph.D. thesis of J. M. Coleman, University of Wisconsin, 1966; (c) T h e Ohio S t a t e Uniiwsity. (3) S.E. Livingstone, Q i i a ~ l Rev. . (London), 19, 386 (1065). and references contained therein.
of a number of these compounds have shown sulfur to utilize from one to five Of its six valence electrons (4) I
