Structure and emission properties of dinuclear copper(i) complexes with pyridyltriazole

Abstract

A new series of five highly emissive binuclear heteroleptic pyridyltriazole-Cu(I)-phosphine complexes 1–5 was synthesized and examined by different experimental (IR, elemental and thermogravimetric analysis, single crystal X-ray diffraction technique, UV-vis and fluorescence spectroscopy) and quantum chemical aproaches. Complexes 1–5 exhibited excellent stimuli-responsive photoluminescent performance in the solid state at room temperature (quantum yield (QY) = 27.5–52.0%; lifetime (s) = 8.3–10.7 ms) and when the temperature was lowered to 77 K (QY = 38.3–88.2; s = 17.8–134.7 ms). The highest QY was examined for complex 3 (52%) that can be explained by the small structural changes between the ground S0 and exited S1 and T1 states leading to the small S1–T1 triplet gap and efficient thermallyactivated delayed fluorescence. Moreover, complex 4 demonstrates reversible mechanochromic and excitation dependent luminescence.