New Examples of Metal Coordination Architectures of 3,3 ',4,4 '-Biphenyltetracarboxylic Acid - Syntheses, Crystal Structures, and Physical Properties

摘要

Four new metal-organic frameworks [Cu-2(2,2'- bipy)(2)(ox)(H2O)(2)]center dot(H(2)bptc) (1), [Cu(bptc)(0.5)(phen)(H2O) center dot H2O (2), Co-2(bptc)(bmb)(1.5) (3) and [Cd-2(bptc) (bmb)}center dot 3H(2)O (4) (H(4)bptc = 3,3',4,4'-biphenyltetracarboxylic acid, ox = oxalate. phen = 1,10-phenanthroline, 2,2'-bipy = 2,2'-bipyridine and bmb = 4.4'-bis((1H-imidazol-I-yl)methyl)biphenyl), were obtained by reactions of the corresponding metal salts with H4bptc and N-containing auxiliary ligands and their structures were determined by single-crystal X-ray diffraction. The results reveal that 1 has a 0-D structure Consisting Of discrete ionic entities, while 2 features a 1-D ladder structure. Additionally, there exist pi-pi stacking and intermolecular hydrogen-bonding interactions in 1 and 2. respectively. forming 3-D supramolecular structures. In 3-4, undulating 2-D metal-bptc layer structures are formed with two different coordination modes of bptc carboxylate groups, respectively, which are further extended by bmb into 3-D Structures. Magnetic properties of I and 3 have been Studied. The photoluminescence property of 4 has also been investigated. Moreover, nonlinear optical measurements showed that 4 displayed a second-harmonic-generation (SHG) response of 0.7 times of that for Urea.