Structural Evolution and Optical Property Tunability by Halogen Substitution in [N(CH)]MX (M = Ga, In, X = Cl, Br): A Family of Organically Templated Metal Halides.

Structural transformation in hybrid halides is an attractive way to modulate and improve their optical properties. Following newly reported monovalent-metal-based organic-inorganic chlorides [N(CH)]MCl (M = Ga, In), their bromide analogues [N(CH)]MBr (M = Ga, In) were subsequently synthesized. Impressively, their structure transforms from noncentrosymmetric 4̅2 space group for chlorides to centrosymmetric 4/ space group for bromides. As the halogen changes, the (MBr) units are partially rotated along the -axis, which can be attributed to the difference in the anion radius and H-bond interactions between host networks and guest molecules. In addition, the tunable electronic structure and optical anisotropy in this family are also presented. This work provides a typical example for exploring new asymmetric and symmetric organic-inorganic hybrid halides as appliable photoelectric functional materials.