MIXED-MEMBERED-BISFULVALENE DIMETAL-COMPLEXES VIA METALLOCENE-SUBSTITUTED NORBORNENYL ALCOHOLS

A proven synthetic method for mixed-metal [0.0] bimetallocenophanes co ntaining Fe, Ru and Co is presented in detail. Utilising norbonenyl al cohol precursors, doubly lithiated ruthenocene or ferrocene were react ed with bicyclo[2.2.1]-hept-2-en-7-one (norborn-2-en-7-one) to yield a mixture of stereoisomeric alcohols, or respectively spiro-ethers, whi ch can be separated by means of chromatography. The initially formed a lcoholates were further reacted with diethylchlorophosphate to yield t he respective chloro-substituted derivatives. Subsequent reductive cle avage of the chlorine-carbon bonds by lithium-powder in DME afforded t he metallocene-substituted norbornenyl carbanions, which eliminated et hylene at ambient temperature to form dilithium metallocenylenebis(cyc lopentadienylides) In a final step, reaction with cobalt dichloride pr oduced the mixed-metal bimetallocenophanes 1,1'-(1,1'-cobaltocenediyl) -ferrocene and 1,1'-(1,1'-cobaltocenediyl)-ruthenocene respectively. T arget-compounds isolated as monocationic hexafluorophosphate salts as well as isolable intermediate products were characterized mainly by NM R-, LR-and MS-techniques. The X-ray structures of 1,1'-(1,1'-cobaltoce niumdiyl)-ruthenocene PF6- and selected norbornenols are presented. an ti-, anti-Bisnorbornenol Ib exhibits significant sandwich plane distor tions induced by hydrogen bridges. The dimers formed in the solid stat e resemble covalent ansa-type conformations. Furthermore, the syntheti c route of reacting mono-and dilithiometallocenes with norbornenone wa s applied to the lithium and dilithium acetylides of ethynyl and 1,1'- diethynylferrocene. The attempted extension of the described synthetic concept to mono-and dinorbornenol-substituted ferrocenylethynes for t he final conversion to ferrocene-1,1'-bis(ethynylcyclopentadienides) d id not allow the preparation of the desired ethyne-spacered bimetalloc enophane species. (C) 1997 Elsevier Science S.A.