Journal of Organometallic Chemistry, 444 (1994) 71-76 71 JOM 23830 Reactions of ( $-diphenylacetylene) chromiumtricarbonyl complexes with polynuclear carbonyls I. Synthesis of Cr( CO) 3( $-diphenylacetylene) complex and its reaction with Co,( CO),. Crystal and molecular structure of Cr( CO) 3( $ : q2-diphenylacetylene)Co,( CO) 6 S.P. Tunik, A.V. Vlasov, A.B. Nikol’skii, G.L. Starova Department of Chemistry, St. Petersburg University, Universitetskii pr., 2, St. Petersburg 198904 (Russia) Shun’ichiro Ooi ’ Department of Chemistry, Faculty of Science, Osaka City University, Sumiyoshi-ku, Osaka 558 (Japan) Hiroshi Nakai and Tomohiro Sato Shionog’ Research Laboratory, Shionogi & Co Ltd., Fukushima-ky Osaka 553 (Japan) (Received March 23, 1993) Abstract The reaction of Cr(CO),(NH,), with diphenylacetylene affords as a main product the complex with CdCO)s moiety bound to a phenyl ring of diphenylacetylene; Cr(CO),($‘-PhC,Ph) (I). Complex 1 readily reacts with Co,(CO)s yielding the mixed metal complex CrfCO),(q6 : n*-PhC,PhjCo,(CO), (II). The reaction proceeds with retention of the Cr(CO)s(#-arene) structural unit, the Co,(CO), fragment being bound to the triple bond of diphenylacetylene in p2,n2-mode. The structure of II yas determine{ by single cryst$ X-ray analysis. The complex crystallizes in space group P2,/c with unit cell parameters a 8.666(3) A, b 18.046(3) A, c 15.155(6) A, @ 97.57(3)“, V 2349f2) A3, Z = 4, D, = 1.70 g/cm’. The structure was solved by direct methods and refined by full-matrix least-squares technique to R and R, values of 0.032 and 0.034, respectively, for 3655 observed reflections. The data obtained show that two structural units in II, Cr(CO),($-Ph-) and Co2(CO)6(~2,q2-<, are distorted due to steric repulsion between these metal carbonyl moieties. The CrfCO)s fragment is shifted from the centre of the phenyl ring and slightly tilted with respect to the phenyl ring plane. The C&C, tetrahedron in the Co2(CO)6(~,,n2-(x) moiety is distorted in such a way that two of the four Coi-Cj bonds are elongated. Key words: Chromium; Carbonyl; Cobalt; Acetylene; Crystal structure 1. Introduction The synthesis of mixed-metal polynuclear complexes has attracted considerable attention over recent years. The presence of a few metal centres in a molecule can lead to unique reactive properties arising from metal- Correspondence to: Dr. S.P. Tunik. ’ Author to whom inquiries concerning X-ray structure data should be addressed. metal or ligand-polymetallic centre(s) interactions. Such interactions and the resulting unusual reactivity are of interest to preparative organometallic chemistry as well as to the understanding of the nature of the catalytic processes proceeding on heterometallic catalytic cen- tres [l-3]. Different reactive metal centres can be joined in a single molecule either by direct metal-metal bonds (as in homo- and heteronuclear clusters) or by bridging polyfnnctional ligands (assembling ligands). The use of bidentate phosphine ligands in the linking of metal carbonyl fragments is an obvious and easy zyxwvut 0022-328X/94/$07.00 SSDI 0022-328X(93)23830-Q 0 1994 - Elsevier Sequoia. All rights reserved