Benzoate acid-dependent formation of a series of interpenetrating metal-organic frameworks based on the cobalt boolean AND 1,4-bis(imidazolyl)benzene coordination substrate

In this work, three structurally related aromatic polycarboxylic acids, 1,4-benzenedicarboxylic acid (H(2)bdc), 1,3,5-benzenetricarboxylic acid (H(3)btc), and 1,2,4,5-benzenetetracarboxylic acid (H(4)bttc), have been utilized as the ancillary ligands to perform a systematic study on the structure diversity of coordination polymer based on the Cobalt boolean AND 1,4-bis(imidazolyl)benzene matrix. The solvothermal reactions of Co(NO3)(2) with the aromatic acids and bib ligand afford three novel coordination polymers, [Co(bib)(bdc)](infinity) (1), {[Co-3(btc)(2)(bib)(2)(H2O)(2)](H2O)(2)}(infinity) (2), and {[Co-2(bttc)(bib)(2)](H2O)(2)}(infinity) (3). Compounds 1-3 illustrate a series of interpenetrating networks built up of different benzoate-bridging 1D chains. Owing to the different situation of the carboxylic group, the benzoates adopt bidentate linear, tridentate T-shaped and tetradentate double-track bridging modes to link metal centers into a W-type chain, ladder and double-center chain, respectively. These chains are further decorated by bib rods to afford a parallel interpenetrating (4,4) sheet for 1, and two three-fold interpenetrating alpha-Po networks based on different units for 2 and 3. The variety of structures and topologies indicates that aromatic acids play essential roles in the assembly of the final frameworks.