Mass spectrometry of transition metal π‐complexes. 40—(η4‐Norbornadiene)‐(η5‐cyclopentadienyl)rhodium derivatives

Abstract

AbstractElectron impact mass spectra of substituted norbornadienecyclopentadienylrhodium complexes have been studied. The decompositions of molecular ions are (i) metal–ligand bond rupture, (ii) norbornadiene skeleton destruction, (iii) substituent or hydrogen atom elimination from the norbornadiene moiety and (iv) radical or neutral molecule elimination from the substituent(s) on the diene ligand. Norbornadiene ligand loss occurs more easily than loss of the cyclopentadienyl ring. Elimination of C2H2R and C2H3 from the diene ligand leads to the formation of rhodocenium or its corresponding substituted derivatives. It is proposed that bridging CC bond rupture followed by migration of the endo‐H atom around the six‐membered ring precedes the loss of the substituent. Some decomposition pathways of the norbornadiene ligand are explained in terms of specific interaction between the metal atom and substituent.