Synthesis, crystal structure, and topology of a polycatenated bismuth coordination polymer

Solvothermal reaction of Bi(NO3)(3)center dot 5H(2)O with the flexible ligand 1,3,5-tris[4-(carboxyphenyl)oxamethyl]-2,4,6-trimethylbenzene (H3TBTC) in methanol at 120 degrees C for 1 h led to the formation of a novel coordination polymer (CP) with the composition of Bi(TBTC). The structure of the microcrystalline material was determined through threedimensional electron diffraction (3DED) measurements and phase purity was confirmed by a Pawley refinement, elemental analysis, and thermal analysis. The compound crystallizes in the triclinic space group P (1) over bar with one Bi3+ cation and one TBTC3- trianion in the asymmetric unit. Edge-sharing of BiO7 polyhedra leads to the formation of dinuclear Bi2O12 units, which through coordination to six TBTC3- ions form a layered two-periodic structure. Upon heating the material in air, the unit cell volume contracts by 9%, which is attributed to a shift in the inter-layer arrangement and to the flexibility of the building units of the structure. The compound starts to decompose at similar to 300 degrees C. Topological analysis revealed layers consisting of 3-c and 6-c nodes, consistent with the two-periodic kgd net - the dual of the Kagome net (kgm). However, due to the non-planar nature of the Bi(TBTC) layers, adjacent layers are interlaced by polycatenation.