Light-Controlled Selective Synthesis of fac and mer Isomers of Heteroleptic [Ru(CN)(N?N?)(DMSO)(Cl)]+ Complexes

Abstract

Selective synthesis of geometrical isomers remains a paramount challenge in coordination chemistry with profound implications for development in optoelectronics and catalysis. Herein, we report an operationally simple strategy for the selective synthesis of fac and mer isomers of heteroleptic ruthenium(II) complexes with a general formula [Ru(CN)(N?N?)(DMSO)(Cl)]PF6 from a single common precursor [Ru(CN)(DMSO)2(Cl)2] by exploiting photoinduced linkage isomerization of the DMSO ligand. Ambient-temperature reactions in the dark selectively afford the fac isomer, whereas identical reactions under blue light irradiation exclusively yield the thermodynamically more stable mer isomer. The resulting isomeric pairs exhibit distinct electronic structures and provide a foundation for the rational design of heteroleptic complex libraries with tailored properties for applications in photocatalysis, luminescent materials, and redox-active catalysis. � 2026 American Chemical Society