Synthesis, structure and blue-light emission of a zero-dimensional zinc halide with the 4-(4-chlorophenyl)pyridinium cation

Exploring blue emission lead-free halides with high photoluminescence quantum yields (PLQYs) is a significant and challenging issue for luminescent materials. Herein, a zero-dimensional (0D) organic–inorganic hybrid halide, namely, bis[4-(4-chlorophenyl)pyridinium] tetrabromidozincate, (C 11 H 9 ClN) 2 [ZnBr 4 ] or [HCPP] 2 [ZnBr 4 ] [CPP is 4-(4-chlorophenyl)pyridine], was synthesized through acid solution evaporation. The compound crystallizes in the monoclinic space group C 2/ c . The asymmetric unit consists of a [ZnBr 4 ] 2− dianion cluster and two monoprotonated [HCPP] + cations. The [ZnBr 4 ] 2− unit presents an almost undistorted tetrahedral geometry. The [HCPP] + cations adopt nearly coplanar conformations with small dihedral angles of 5.05 (3)°; there are relatively strong π–π interactions between adjacent [HCPP] + cations due to slipped parallel packing, with a distance of 3.81 (1) Å. Significantly, this halide exhibits highly efficient blue-light emission (385–500 nm) with a PLQY of 56.35%.