Heterodinuclear methylplatinum−molybdenum complexes having a hemilabile P−L ligand,
(P−L)MePt−MoCp(CO)3 (P−L = Ph2PC2H4NEt2 (1), Ph2PC2H4CHCH2 (2)), react with
dialkyl acetylenedicarboxylate to afford the novel heterodinuclear complexes (P−L)MePt{μ-η2:η2-C(O)C2(CO2R)2}MoCp(μ-CO)(CO) (P−L = Ph2PC2H4NEt2, R = Me (5); P−L = Ph2PC2H4CHCH2, R = Me (6); P−L = Ph2PC2H4NEt2, R = Et (7)). An X-ray diffraction study
of 5 has revealed that the complex has a unique structure containing a platinacyclobutenone
framework, where the π-bond coordinates to the molybdenum. Heating of 5 at 50 °C for 2
days results in reductive elimination of methyl and alkenyl ligands followed by decarbonylation to form the new μ-alkenyl type complexes (Ph2PC2H4NEt2-κ2
N,P){μ-MeO2C(Me)CCO2Me}Pt−MoCp(μ-CO)(CO) (8) and (Ph2PC2H4NEt2-κ1
P)(CO){μ-MeO2C(Me)CCO2Me}Pt−MoCp(μ-CO)(CO) (9). Reactions of 5 with tBuNC or PMe3 cause selective ligand displacement
of the amino moiety in the P−N ligand to form (Ph2PC2H4NEt2-κ1
P)(L‘)MePt{μ-η2:η2-C(O)C2(CO2Me)2}MoCp(μ-CO)(CO) (L‘ = tBuNC (10), PMe3 (11)). On the other hand,
nucleophiles such as H2NBu, HNEt2, pyrrolidine, and KOPh add to acyl carbon to give the
trisubstituted μ-alkenyl type complexes (Ph2PC2H4NEt2-κ2
N,P)Me{μ-MeO2C(R2NCO)CCCO2Me}Pt−MoCp(μ-CO)(CO) (NR2 = NHBu (12), NEt2 (13), NC4H8 (14)) and K+[(Ph2PC2H4NEt2-κ1
P)Me{μ-MeO2C(PhO2C)CCCO2Me}Pt−MoCp(μ-CO)(CO)]- (15).