Regulation mechanism of spin-orbit coupling in charge-transfer-induced luminescence of imidazopyrazinone derivatives

The spin transition in the reactions of the derivatives of imidazo[1,2-a]pyrazin-3(7H)-one with a triplet molecular oxygen is examined by the geometry optimization and the electronic matrix elements for spin-orbit coupling (SOC) is evaluated by using the full Pauli-Breit SOC operator. An optimal state is present for the suppression of SOC in the charge-transfer-induced luminescence (CTIL) for the peroxide, which is related with the ability of a substituent to donate an electron.