Synthesis, Crystal Structure and Photoluminescence of a TADF Cuprous Complex

A cuprous mononuclear copper complex [Cu(adpypz)CH3CNPPh3]BF4 center dot CH2Cl2 (1, adpypz = 9,9-dimethyl-10-(6-(3-phenyl-1H-pyrazol-1-yl)pyridin-2-yl)-9,10-dihydroacridine) was synthesized and characterized by Elemental Analysis, NMR, UV-Vis and X-ray single-crystal structure analysis. It crystallizes in triclinic, space group P (1) over bar with a = 11.3388(4), b = 13.4569(4), c = 16.2561(6) angstrom, alpha = 97.154(3), beta = 92.187(3), gamma = 114.119(4)degrees, V = 2235.38(13) angstrom(3), Z = 2, M-r = 967.12, D-c = 1.437 g/cm(3), F(000) = 996, mu = 2.62 mm(-1), GOOF = 1.031, the final R = 0.0417, and wR = 0.1024 for 8043 observed reflections with I > 2 sigma(I). The Cu(I) atoms in the complex are four-coordinated and adopt a tetrahedral coordination geometry. In the solid state, the complex exhibits bluish-green photoluminescence with emission peaks lambda(max) = 492 nm (1), lifetimes 235 mu s and quantum yields (Phi= 0.279) at room temperature. The studies of varied temperature emission spectra and decay behaviours of the complex indicate that the complex displays thermally activated delayed fluorescence (TADF) at room temperature. The results of the experimental and DFT calculations suggest that the emission in the solid state originates from the ILCT excited states.