DFT and TD-DFT investigation of the ground and excited states for dinuclear and mononuclear copper(I) and silver(I) complexes of 3,5-bis(trifluoromethyl)pyrazole and related bis(pyrazolyl)borate

The ground-state and low-lying excited electronic states in mononuclear, {H2B[3,5-(CF3)2Pz]2M(2,4,6-Cn)} (M1) and dinuclear {[3,5-(CF3)2Pz]M(2,4,6-Cn)}2, (M2) (Pz = pyrazole, Cn = collidine and M = Cu, Ag), are studied using DFT approach. Electronic properties are calculated using B3LYP, while excited singlet and triplet-states are examined using TD-B3LYP. All the calculated low-lying transitions are categorized as 1MLCT transitions. A good agreement was found between experimental spectra and predicted emission wavelengths (λem), the corresponding emissive states being assigned as 3MLCT for Cu1 and Ag2, 3MLLCT for Ag1 and 3LLCT for Cu2.