Reversible Transition between Discrete and 1D Infinite Architectures: a Temperature-Responsive Cu(I) Complex with a Flexible Disilane-bridged Bis(pyridine) Ligand.

Abstract

Thermoresponsive molecular structure based on a disilane-bridged bis(pyridine) ligand and CuI is reported. Single-crystal X-ray analysis revealed that there are two polymorphs in the Cu(I) complex: octanuclear copper(I) complex at 20 °C and 1D staircase copper(I) polymer complex at -196 °C. The formation of these polymorphs is due to the flexibility of ligand. Cu-I bond formation is observed upon cooling the sample from -10 °C to -170 °C. The temperature-induced phase transition progression was clarified by DSC, VT-PXRD, and VT-photoluminescence measurements and indicated a reversible temperature-controlled crystal-to-crystal phase transition. Observation on a VT-stage using a high-speed camera showed crystal cracking during single-crystal to single-crystal transitions between these polymorphic forms.