Enhanced C−C Bond Formation of Heterodinuclear Methylplatinum−Molybdenum Complexes Having a Hemilabile Ligand with Dialkyl Acetylenedicarboxylate

Abstract

Heterodinuclear methylplatinum−molybdenum complexes having a hemilabile P−L ligand, (P−L)MePt−MoCp(CO)3 (P−L = Ph2PC2H4NEt2 (1), Ph2PC2H4CHCH2 (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 = Ph2PC2H4CHCH2, 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)CCCO2Me}Pt−MoCp(μ-CO)(CO) (NR2 = NHBu (12), NEt2 (13), NC4H8 (14)) and K+[(Ph2PC2H4NEt2-κ1 P)Me{μ-MeO2C(PhO2C)CCCO2Me}Pt−MoCp(μ-CO)(CO)]- (15).

Sulfur-Assisted Phenyl Migration from Phosphorus to Platinum in PtW2 and PtMo2 Clusters Containing Thioether-Functionalized Short-Bite Ligands of the Bis(diphenylphosphanyl)amine-Type

“…The Pt–Mo bond distance of 2.9174(5) Å is comparable to those reported for other complexes containing a platinum–molybdenum bond. ,− The values of the Pt1–C35 and Pt1–C36 distances and of the O3–C35–Mo2 and O4–C36–Mo2 angles indicate a weak interaction between the Pt atom and the carbonyl ligands (Figure ). The coordination of the thioether group to Pt results in a pyramidal geometry at sulfur with the sum of the angles ∑θ S = 322.1°.…”

Rearrangement or C−H Activation Processes Promoted by Reaction with the Solvate [cis-Pt(C6F5)2(thf)2]

“…As far as we know, this structural feature has no precedent in the literature, the most similar examples being a (μ-hydroxy)(μ-alkyne) bridging system in a pentanuclear ruthenium cluster and a (μ-hydroxy)(μ-allenylidene) trinuclear osmium cluster . Notwithstanding, a good number of vinyl groups acting as bridging ligands between two transition metals have been reported, − although the examples containing platinum are really scarce, − in particular, those referring to homopolynuclear derivatives. ,, It should be noted that recently a (μ-hydride)(μ-vinyl) dinuclear intermediate species has been proposed in the formation of the (μ-alkylidene) complex [Pt 2 (dppm) 2 (μ-H)(μ-CHCH 2 Ph)](BF 4 ) 5 ORTEP view of [ cis,cis -(PPh 3 ) 2 Pt{μ-1κ C α :η 2 -CHCHC(OH)Ph 2 }(μ-OH)Pt(C 6 F 5 ) 2 ] ( 5f ).…”

Hydrocarbyl Ligand Transformations on Heterobimetallic Complexes

“…The bidentate ligand coordinated to the platinum atom must be capable of generating a vacant coordination site. 189…”