Synthesis, photophysics, and transient absorption spectroscopic studies of luminescent copper(I) chalcogenide complexes. Crystal structure of [Cu 4(μ-dtpm) 4(μ 4-S)](PF 6) 2 {dtpm = bis[bis(4-methylphenyl)phosphino]methane}

Abstract

A luminescent copper(I) sulfido cluster [Cu4(μ-dtpm) 4(μ 4-S)](PF 6) 2 (3) {dtpm = bis[bis(4-methylphenyl)-phosphino]methane} has been synthesized and characterized by X-ray crystallography. Its photophysical and electrochemical properties have also been studied. The long-lived photoluminescence of 3 is assigned to originate from an excited state with a parentage of large ligand-to-metal charge-transfer LMCT [(S 2-) → Cu 4] character, with mixing of metal-centered MC [(ds/dp) Cu(I) 4] state. The phosphorescent state of 3, as well as those of its analogues [Cu 4(μ-dppm) 4(μ 4-S)](PF 6) 2 (1) and [Cu 4(μ-dppm) 4(μ 4-Se)](PF 6) 2 (2), have been found to undergo facile electron-transfer reactions with different pyridinium acceptors, which have been investigated with nanosecond transient absorption spectroscopy. Crystal data for 3: a = 37.38(1) Å, b = 15.905(7) Å, c = 27.761(5) Å, β = 128.69(1)°, V = 12881(6) Å 3, Z = 4.