Computational study of solution equilibria formed by diiodine (I2) and the pincer complex [2,6-bis{(Me2NCH2)2}C6H3]PtIII, including intramolecular mobility of I2 involving 'Pt-I2', 'Pt-I···I2' and 'Cpara···I2' species

<p>DFT computation indicates the presence of 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-<em>N,C,N</em>]^-) in dichloromethane. Species present include square-planar Pt(NCN)(h¹-I₃) and square-pyramidal Pt(NCN)I(h¹-I₂) interconverted via a triangular transition state with I₂ bridging a Pt-I bond, and interaction of diiodine at the <em>para</em>-position of the arene ring interconverted with Pt(NCN)I(h¹-I₂) via a transition state with diiodine bridging the C<em>_ortho</em> and C<em>_meta</em> 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)(h¹-I₃)(h¹-I₂) and mobility of diiodine over the (pincer)PtI plane.</p>