Construction of two novel indium phosphites with (3,6)- and (3,5)-connected frameworks: Synthesis, structure and characterization

Two novel anionic indium phosphites, formulated as [H3O][In(HPO3)2] (1) and [C4H12N2][In2(HPO3)3(C2O4)] (2), were prepared under hydrothermal conditions by using piperazine (PIP) as a structure-directing agent (SDA). Single-crystal X-ray diffraction analysis reveals that compounds 1 and 2 crystallize in the hexagonal space group P63mc (No. 186) and orthorhombic space group Cmcm (No. 63), respectively. Compound 1, constructed from InO6 octahedra and HPO3 pseudo-pyramids, exhibits a rare (3,6)-connected layer structure with kgd (Kagome dual) topology. Compound 2, on the other hand, features a 3D phosphite-oxalate hybrid structure with intersecting 8- and 12-MRs channels. From a topological perspective 2 can be regarded as a (3, 5)-connected binodal net with the Schläfli symbol (42.6)(42.65.83).