Crystal structure and semiconductor properties of copper(II) complex incorporating chiral (R)-(+)-α-Ethylbenzylammonium cations:[(R)-C9H14N]3[CuBr4]•Br.

The molecular organic-inorganic hybrid halogenometallate [(R)-C9H14N](3)[CuBr4]center dot Br has been synthesized by a slow evaporation method. The single-crystal X-ray diffraction experiment evidences that [(R)-C9H14N](3)[CuBr4]center dot Br crystallizes in the monoclinic system with the non-centrosymmetric space group P2(1) at T = 150K. The compound displays a zero-dimensional (0D) structure which consists in three chiral [(R)-C9H14N](+) cations, one anionic [CuBr4](2-) and free Br- ion. The structure analysis reveals that the Cu(II) has an intermediate geometry between regular tetrahedron (T-d) and square planar (D-4h). In the crystal structure, the cations and anions are arranged in alternating stacks which are interconnected via hydrogen bonding contacts N-H center dot center dot center dot Br. This hybrid compound presents good thermal stability up to 370 K. The DSC and electric measurements show that no phase transition occurs in the compound over the temperature range 223-423 K. Optical absorption measurements suggest that [(R)-C9H14N](3)[CuBr4]center dot Br has a narrow direct optical band gap (E-g) of similar to 2.15 eV which makes it a promising material in optoelectronic devices.