Computational Study of Equilibria Formed by Diiodine (I2) and the Pincer Complex [2,6-bis{(Me2NCH2)2}C6H3]PtIII: Intramolecular Mobility of I2 Using ′Pt-I2′, ′Pt-I ⋅ ⋅ ⋅ I2′ and ′Cpara ⋅ ⋅ ⋅ I2′ Species

Abstract

DFT computation indicates the presence of solution equilibria with very low barriers when diiodine interacts with the square-planar platinum(II) pincer complex Pt(NCN)I (NCN=[2,6-bis{(dimethylamino)methyl}phenyl-N,C,N]−) in dichloromethane. Species present include square-planar Pt(NCN)(η1-I3) and square-pyramidal Pt(NCN)I(η1-I2) interconverted via a triangular transition state with I2 bridging a Pt−I bond, and interaction of diiodine at the para-position of the arene ring interconverted with Pt(NCN)I(η1-I2) via a transition state with diiodine bridging the Cortho- and Cmeta-positions. Similar facile intramolecular rearrangements occur for a model system with a molar ratio of 1 : 2 for Pt : I2, exhibiting species such as Pt(NCN)(η1-I3)(η1-I2) and mobility of diiodine over the (pincer)PtI plane.