Accessing One-Dimensional Chains of Halogenoindates(III) in Organic-Inorganic Hybrids.

Organic-inorganic hybrids of halogenoindates(III) are typically represented by one of the zero-dimensional units: InX 4 - , InX 5 2- , InX 6 3- , or In 2 X 11 5- . Higher dimensional anionic forms, although not forbidden, have remained almost elusive. Here we report for the first time In 3+ -based organic-inorganic hybrids, (C 4 H 5 N 2 S) 2 InCl 5 and (C 4 H 5 N 2 S) 2 InBr 5 , with 1D anionic chains of trans -halide-bridged InX 6 octahedra whose formation is guided by 2-mercaptopyrimidinium cations (C 4 H 5 N 2 S + ). The chains are characterized by the significant ease of deformation, which is reflected in the elongation of the bridging bonds or the displacement of In 3+ ions. The materials show a robust band gap predominantly governed by C 4 H 5 N 2 S + cations. Dielectric relaxation processes in (C 4 H 5 N 2 S) 2 InBr 5 arise from the cations' dynamics and suggest the ability of the brominated system to accommodate even larger cations. Our work represents a successful attempt to expand the structural diversity of halogenoindates(III) and opens a pathway to reach multifunctional 1D In 3+ -based hybrids.