Containing Platinum, Tungsten Metal Organic Compounds Involved In The Study Of Reaction Mechanism

Density Function Theory (DFT) calculations at the B3LYP level of theory are carried out to study and analyze the following projects. We researched the mechanisms of small unsaturated molecules react with organometallic compounds which contains platinum or tungsten metal, and analyzed the selectivity of small unsaturated molecules insertion into organometallic compounds.1. Insertion of small unsaturated molecules into late transition metal-oxygen bonds plays an important role in catalytic and stoichiometric reactions. Low valent transition metal-oxygen bonds have been shown to participate in a number of typical organometallic reactions,including reductive elimination,β-H elimination, and insertion reactions with unsaturated molecules such as CO and alkenes. Recently a family of platinaoxetanes has been synthesized, unsatured small molecules such as CO, isocyanide, alkene and alkyne insert exclusively into the Pt-0 bonds rather than the Pt-C bonds. CO insertion into Pt-0 and Pt-C bonds of the platinaoxetane Pt(PMe3)2(C7H10O) are explored with the aid of density functional theory calculations. It is found the CO insertion into Pt-0 and Pt-C bonds undergoes different paths. The former insertion undergoes a one-step process, that is, CO directly inserts into the Pt-0 bond, while the latter insertion undergoes a two-step process (substitution of a phosphine by CO, followed by CO insertion into the Pt-C bond). Why the CO insertion into Pt-0 is thermodynamically and kinetically favorable over the one into Pt-C bond is also discussed.2. The selective activation and subsequent functionalization of hydrocarbon C-H bonds by transition-metal complexes have become important methods in synthetic chemistry. C-H bond activation by metal complexes frequently involves cleavage of the C-H bond to generate a new metal-carbon bond and metal-hydride bond, Peter Legzdins's group presented their investigation of the characteristic chemistry:CO react with Cp*W(NO)(CH2SiMe3)(η3-CH2CHCHMe) by inserting the CO into the tungsten-alkyl linkages; In contrast of the insertion of CO, isonitrile CH3—N≡C inserts preferentially into the tungsten-allyl linkages rather than the tungsten-alkyl linkages of Cp*W(NO)(CH2SiMe3)(η3-CH2CHCHMe); while we replaced the group CH2SiMe3 by C5H11, isonitrile CH3—N≡C inserts preferentially into the tungsten-alkyl linkages. Although some comparative reactivity of alkyl and allyl ligands in the same metal center has been explored in experiments, no detailed theoretical studies are focused on reaction mechanism of these reactions. With the aid of density functional theory (DFT) calculations, we investigate the related reaction mechanism and discussed comparative reactivity of alkyl and allyl ligands in the same metal center.