2021

Bulatov, Evgeny; Eskelinen, Toni; Ivanov, Alexander Yu.; Tolstoy, Peter M.; Kalenius, Elina; Hirva, Pipsa; Haukka, Matti

Coordination compounds of platinum(II) participate in various noncovalent axial interactions involving metal center. Weakly bound axial ligands can be electrophilic or nucleophilic; however, interactions with nucleophiles are compromised by electron density clashing. Consequently, simultaneous axial interaction of platinum(II) with two nucleophilic ligands is almost unprecedented. Herein, we report structural and computational study of a platinum(II) complex possessing such intramolecular noncovalent I∙∙∙Pt∙∙∙I interactions. Structural analysis indicates that the two iodine atoms approach the platinum(II) center in a “side-on” fashion and act as nucleophilic ligands. According to computational studies, the interactions are dispersive, weak and anti-cooperative in the ground electronic state, but strengthen substantially and become partially covalent and cooperative in the lowest excited state. Strengthening of I∙∙∙Pt∙∙∙I contacts in the excited state is also predicted for the sole previously reported complex with analogous axial interactions.