| Abstract
| - The conversion of methane to methanol by dichloro(η2-{2,2‘-bipyrimidyl})platinum(II) [Pt(Bpym)Cl2] (Catalytica) and Pt(NH3)2Cl2 (cisplatin) [Science1998, 280, 560] has been studied using hybriddensity functional theory in conjunction with the conductor-like polarizable continuum solvent model(CPCM). We have determined the full potential energy profiles for plausible catalytic pathways alongthe three major phases of the catalytic cycle, namely, (a) C−H activation, (b) Pt(II) to Pt(IV) oxidation,and (c) functionalization. For Catalytica, oxidation of Pt(II) to Pt(IV) is the highest barrier step for allactive catalytic forms considered. Oxidation of Pt(II) to Pt(IV) is significantly easier for cisplatin comparedto Catalytica, explaining the faster catalytic transformation by cisplatin. Our calculations suggest that theoxidation barrier is significantly affected by the ligand environment on the Pt center of the catalyst. Wepredict that monoprotonation of the bipyrimidine ring of Catalytica significantly affects the oxidationprocess only if catalysis proceeds through electrophilic C−H activation cis to the protonated pyrimidinering. We also determine a full potential energy profile for catalytic conversion by cisplatin proceedingthrough oxidative C−H addition, subsequent deprotonation, followed by oxidation of Pt(II) to Pt(IV),and then functionalization.
- The full potential energy profiles of methane to methanol conversion by dichloro(η2-{2,2‘-bipyrimidyl})platinum(II), [Pt(Bpym)Cl2], and cisplatin are elucidated using hybrid density functional theory.
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