The Length of Substituents on Ligands Regulates the Structural Diversity of Coordination Polymers

Three coordination polymers, namely, {[Co(L 1 )(HBTC)]·0.5L 1 } n ( I ), {[Co(L 2 )(HBTC)]·H 2 O} n ( II ), {[Co(L 3 )(HBTC)]·H 2 O} n ( III ), have been synthesized based on three semi-rigid nitrogen-containing ligands (L 1 = 4,4'-(2,5-dimethoxy-1,4-phenylene)dipyridine; L 2 = 4,4'-(2,5-diethoxy-1,4-phenylene)dipyridine; L 3 = 4,4'-(2,5-dibutoxy-1,4-phenylene)dipyridine) and 1,3,5-benzenetricarboxylic acid (H 3 BTC). Both I and II are a 4-connected uninodal sql net with point symbol {4 4 ∙6 2 }, III is a 6-connected uninodal rob net with point symbol {4 8 ∙6 6 ∙8}. The complexes were characterized by X-ray single-crystal diffraction (CIF files CCDC nos. 2034103 ( II ), 2034104 ( III )), PXRD, IR spectra and TGA. Interestingly, the structural diversity of these complexes derived from the length of substituents on L n ( n = 1, 2, 3) ligands.