Platinum aryloxides, arylamides, and arylmercaptides and their reactivity

David Wayne Dockter, Purdue University

Abstract

The reactions of (Pt(triphos)(Cl)) (Cl) (1) (triphos = bis(2-diphenylphosphinoethyl)phenylphosphine) with NaO-C$\rm\sb6H\sb4$-p-R, in the presence of NaPF$\sb6$, yields the aryloxy complexes, (Pt(triphos)(OC$\rm\sb6H\sb4$-p-R)) (PF$\sb6$) (R = OMe (2a), Me (2b), H (2c), F (2d), Cl (2e)). Upon reaction of 2a-e with carbon monoxide at pressures from 10 psi to 134 psi in acetonitrile the aryloxycarbonyl complexes, (Pt(triphos)(C(O)OC$\rm\sb6H\sb4$-p-R)) (PF$\sb6$) 3a-e, were obtained. The kinetics of the carbonylation of 2a-e to form 3a-e were studied by $\rm\sp{31}P(\sp1$H) NMR. Rates of carbonylation exhibit a first order dependence on (CO), but are independent of the concentration of free aryloxide in solution. Rates of aryloxide ligand exchange were also found to be significantly faster than rates of carbonylation. The rates of carbonylation depend on the para-substituent of the aryloxy ligand and follow the order: F (2d) $>$ Me (2b) $>$ OMe (2a). These observations are interpreted in terms of a carbonylation mechanism that proceeds via a migratory insertion pathway, rather than by nucleophilic attack of coordinated carbon monoxide by free or dissociated aryloxide. 2b The reactions of (Pt(triphos)(Cl)) (Cl) (1) with lithium amide in benzonitrile solvent results in the formation of (Pt(triphos)N-(N$\prime$-phenyl-benzamidine)) (PF$\sb6$) (7). The product is the result of the net insertion of benzonitrile into the platinum nitrogen bond. An insertion pathway is supported by the substitution pattern of the produced amidine ligand. The molecular structure of (Pt(triphos)N-(N$\prime$-phenyl-benzamidine)) (PF$\sb6$) was determined by X-ray diffraction.

Degree

Ph.D.

Advisors

Kubiak, Purdue University.

Subject Area

Chemistry|Organic chemistry

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