title: Syntheses and characterizations of copper(II) polymeric complexes constructed from 1,2,4,5-benzenetetracarboxylic acid.
abstract: Four polymeric complexes with rectangular grids or channels, [Cu2(btec)(H2O)4*2H2O]n (2), [Cu2(btec)4/4[Cu(Hbtec)2/2(4,4'-Hbpy)(H2O)2]2*4H2O]n (3), [Cu2(btec)(hmt)(H2O)4*8H2O]n (4), and [Cu3(btec)(OH)2]n (5), were designed and constructed from Cu(II) ion and 1,2,4,5-benzenetetracarboxylic acid along with auxiliary ligands (where H4btec = 1,2,4,5-benzenetetracarboxylic acid, 4,4'-Hbpy = monoprotonated 4,4'-bipyridine, and hmt = hexamethylenetetramine). Complexes 2, 3, and 4 have rectangular pores with the size of 6.5 A x 4.5 A, 6 A x 7 A, and 10.1 A x 11.8 A, respectively, while 5 has a channel of 7.4 A x 9.6 A. The complexes show interesting magnetic properties due to the different coordination modes of the carboxylate groups and the presence of auxiliary ligands. On lowering the temperature, the magnetic interactions in 2 are changed from antiferromagnetic to ferromagnetic. For 3, the antiferromagnetic interactions weaken sharply at low temperature. Complex 4 shows ferromagnetic interactions while 5 is antiferromagnetic.
authors.affiliation: State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, The Chinese Academy of Sciences, Fuzhou, 350002, P.R. China. rcao@ ms.fjirsm.ac.cn
authors.forename: Rong
authors.initials: R
authors.lastname: Cao
authors.forename: Qian
authors.initials: Q
authors.lastname: Shi
authors.forename: Daofeng
authors.initials: D
authors.lastname: Sun
authors.forename: Maochun
authors.initials: M
authors.lastname: Hong
authors.forename: Wenghua
authors.initials: W
authors.lastname: Bi
authors.forename: Yingjun
authors.initials: Y
authors.lastname: Zhao