Synthesis and molecular structure of cisoid and transoid isomers of [Re-2(CO)(6)(1,1 '-bis(indenylidene)] derived from the reaction of [Re-2(CO)(8)(MeCN)(2)] and diazoindene

The compound [Re-2(CO)(8)(MeCN)(2)] reacts with diazoindene (C9H6N2) while refluxing in THF to afford three dirhenium products in which C9H6N2 is clea ved with loss of N-2 and with incorporation of the residual indenylidene gr oup into the products. Two indenylidene groups are coupled in two diastereo mers of [Re-2(CO)(6)(mu,eta(5):eta(5)-1,1'-C18H12)] where C18H12 = bis(inde nylidene). X-ray structures show that these isomers are related as RR/SS an d RS isomers. These have the two Re(CO), groups coordinated transoid and ci soid, respectively to a trans bis(indenylidene) bridge. The third product i s the mu-indenylidene complex [Re-2(CO)(8)(mu,eta(1):eta(5)-C9H6)], Which w as also structurally characterised by X-ray diffraction. (C) 1999 Elsevier Science S.A. All rights reserved.