Binuclear organo-rare-earth-metal complexes containing silicon-linked cyclopentadienyl ligands in either a chelating or metal-bridging fashion: a mass spectrometric study

Abstract

Four chloride-bridged, binuclear bis(cyclopentadienyl) rare-earth-metal complexes have been subjected to detailed mass spectrometric studies adopting exhaustively the B/E-linked scan technique: (Me{sub 2}Si(C{sub 5}H{sub 4}){sub 2}Yb({mu}-Cl)){sub 2} (1), ((Me{sub 3}SiC{sub 5}H{sub 4}){sub 2}Yb({mu}-Cl)){sub 2} (2), (Me{sub 2}Si(C{sub 5}H{sub 4}){sub 2}Y({mu}-Cl)){sub 2} (3), and Me{sub 2}Si(C{sub 5}H{sub 4}){sub 2}Yb({mu}-Cl){sub 2}Y(C{sub 5}H{sub 4}){sub 2}SiMe{sub 2} (5). The strict dominance of binuclear fragments in the spectrum of pure 1 indicates, in excellent accordance with a previous crystallographic X-ray study, the presence of metal-bridging Me{sub 2}Si(C{sub 5}H{sub 4}){sub 2} ligands in the vapor state. The existence of the new complex 5, which could not be separated chemically from admixtures of 1 and 3 (i.e., from sample 4), has been confirmed unambiguously by deducing its individual fragmentation pattern from a systematic B/E-linked scan analysis.