Near-Infrared Luminescence in Trinuclear Mixed-Metal Chalcogenolate Complexes of the Types [M₂Ti(EPh)₆(PPh₃)₂] (M = Cu, Ag; E = S, Se) and [Na(thf)₃]₂[Ti(SPh)₆]

The optical properties of four new trinuclear chalcogenolato bridged metal complexes [Ag2Ti(SPh)6(PPh3)2], [Na(thf)3]2[Ti(SPh)6], [Cu2Ti(SePh)6(PPh3)2], and [Ag2Ti(SePh)6(PPh3)2] have been investigated by absorption photoluminescence spectroscopy as well time-dependent density functional theory (TDDFT) calculations compared to the results published recently for [Cu2Ti(SPh)6(PPh3)2]. All these compounds are distinguished efficient near-infrared luminescence at ∼880–1200 nm in solid state low temperatures, which remains quite intense copper–titanium ambient temperature with PL quantum yields 9.5 4.8% λPL = 1090 1240 [Cu2Ti(EPh)6(PPh3)2], E S, Se, respectively. According calculations, a peculiar feature lowest-energy electronic transitions is their high localization on chalcogen atoms, negligible contributions “external” ligand groups. Correspondingly, type atoms M2TiE6 (M Cu, Ag, Na) core structure determines such emission wavelengths lifetime.