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, (C11H9ClN)2[ZnBr4] or [HCPP]2[ZnBr4] [CPP is 4-(4-chloro­phen­yl)pyridine], was synthesized through acid solution evaporation. The com­pound crystallizes in the monoclinic space group C2/c. The asymmetric unit consists of a [ZnBr4]2− dianion cluster and two monoprotonated [HCPP]+ cations. The [ZnBr4]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%.