MASS-SPECTROMETRY OF TRANSITION-METAL PI-COMPLEXES .40. A-4-NORBORNADIENE)-(ETA-5-CYCLOPENTADIENYL)RHODIUM DERIVATIVES

Electron impact mass spectra of substituted norbornadienecyclopentadie nylrhodium complexes have been studied. The decompositions of molecula r ions are (i) metal-ligand bond rupture, (ii) norbornadiene skeleton destruction, (iii) substituent or hydrogen atom elimination from the n orbornadiene moiety and (iv) radical or neutral molecule elimination f rom the substituent(s) on the diene ligand. Norbornadiene ligand loss occurs more easily than loss of the cyclopentadienyl ring. Elimination of C2H2R and C2H, from the diene ligand leads to the formation of rho docenium or its corresponding substituted derivatives. It is proposed that bridging C-C bond rupture followed by migration of the endo-H ato m around the six-membered ring precedes the loss of the substituent. S ome decomposition pathways of the norbornadiene ligand are explained i n terms of specific interaction between the metal atom and substituent .