Luminescent heteroleptic copper(I) complexes with polydentate benzotriazolyl-based ligands

Bis(benzotriazol-1-yl)phenylmethane CHPh(btz)(2) and tris(benzotriazol-1-yl)methane CH(btz)(3) were used as N-donor ligands to prepare luminescent heteroleptic copper(I) complexes. [Cu{CHPh(btz)(2)}(PPh3)(2)][BF4] and [Cu{CHPh(btz)(2)}(DPEphos)][BF4] (DPEphos = bis[(2-diphenylphosphino)phenyl] ether) were obtained from the corresponding borohydride complexes [Cu(BH4)(PPh3)(2)] and [Cu(BH4)(DPEphos)] and tetrafluoroboric acid. [Cu{CH(btz)(3)}(PPh3)][BF4] and [Cu{CH(btz)(3)}((PPr3)-Pr-i)][BF4] were prepared from the acetonitrile complex [Cu(NCCH3)(4)][BF4]. The complexes exhibited bright yellow or orange emissions upon excitation with near-UV and violet light. The photoluminescent properties were attributed to metal-to-ligand charge transfer transitions on the basis of experimental data and DFT calculations.