Coinage metal complexes of 2-diphenylphosphino-3-methylindole

Abstract

Coordination of P,N indolyl-phosphine ligands to Au^I, Ag^I and Cu^I metal ions under weakly basic conditions results in easy deprotonation of the indolyl N–H function and effective formation of a family of homo- and heterobimetallic complexes MM′(PPh₂C₉H₇N)₂ (M = M′ = Au (2), Ag (5); M = Au, M′ = Cu (3), Ag (4)). The latter (4) exists as an inseparable mixture of four different complexes, which are in equilibrium driven by slow dynamics. The reaction of silver(I) and copper(I) ions with PPh₂(C₉H₈N) affords a rare tetranuclear Z-shaped cluster Ag₂Cu₂(PPh₂C₉H₇N)₄ (6), which exhibits red luminescence in solid state (650 nm) and a weak dual emission in solution with the main component in the near-IR region (746 nm).