Fig. 4. Characterization of the Diels–Alder adduct of complex 1 with isoprene (complex 13) by ESI-MS and MS-MS. The mass spectrum shows the formation of the fulvene-isoprene [4+2] cyclo-addition adduct with coordination of η4-1,2,3,4,8-pentamethylspiro[4,5]deca-1,3,7-triene to RhI, and its fragmentation by MS-MS (blue box).
