Three novel bismetallacyclopropa[60]fullerene complexes formed via intermediate monometallacyclopropa[60]fullerene diphosphine ligands

The homodinuclear bismetallacyclopropa[60]fullerene complexes (η2-C60)M(μ-η1,η1-trans-Ph2PCHdouble bond; length as m-dashCH PPh2)2M(η2-C60) (1, M = Pt; 2, M = Pd) were prepared by reaction of C60 with M(dba)2 (dba = dibenzylideneacetone) and trans-1,1′-bis(diphenylphosphino)ethylene in 82% and 92% yield, whereas reaction of C60 with Pd(dba)2 and trans-dppet followed by treatment with C60 and Pt2(dba)3 gave rise to the heterodinuclear complex (η2-C60) Pd(μ-η1,η1-trans-Ph2PCHdouble bond; length as m-dashCH PPh2)2Pt(η2-C60) (3) in 65% yield. Mechanistic study showed that these reactions involve the intermediates of monometallacyclopropa[60]fullerene diphosphine ligands (η2-C60)M(η1-trans-Ph2PCHdouble bond; length as m-dashCHPPh2)2 (4, M = Pt; 5, M = Pd). All the mono- and bismetallacyclopropa[60]fullerene complexes 1–5 have been fully characterized by elemental analysis and spectroscopy, as well as for 2 by X-ray crystallography.