A mixed-valence copper coordination polymer generated by a hydrothermal metal/ligand redox reaction process.
The title coordination polymer, poly[(mu(4)-2-oxidoisophthalato-kappa(6)O(1),O(2):O(2),O(3):O(3'):O(3'))(mu(2)-quinoxaline-kappa(2)N:N')copper(I)copper(II)], [Cu(2)(C(8)H(3)O(5))(C(8)H(6)N(2))](n), contains two crystallographically distinct Cu ions, one quinoxaline (QA) unit and one 2-oxidoisophthalate trianion (L) derived from 2-hydroxyisophthalic acid (H(3)L). The Cu(II) ion is strongly coordinated by four O atoms in a distorted square geometry, of which two belong to two phenoxide groups and the other two to carboxylate groups of two L ligands. In addition, the Cu(II) cation interacts weakly with a symmetry-related carboxylate O atom which belongs to the L ligand in an adjacent layer, giving a square-pyramidal coordination geometry. The Cu(I) ion is trigonally coordinated by two N atoms from two QA molecules and one O atom from an L carboxylate group. The Cu(I) centres are bridged by QA ligands to give a chain along the c axis. Two Cu(II) ions and two L ligands form a [Cu(2)L(2)](2-) ;metallo-ligand', which coordinates two Cu(I) ions. Thus, the chains of Cu(I) and QA are linked by the [Cu(2)L(2)](2-) metallo-ligand to yield a two-dimensional (6,3) sheet. These sheets are further linked by symmetry-related carboxylate O atoms of neighbouring layers into a three-dimensional framework. The in situ reaction from benzene-1,2,3-tricarboxylic acid (H(3)L1) to L in the present system has rarely been observed before, although a few novel in situ reactions, such as ligand oxidative coupling, hydrolysis and substitution, have been observed during the hydrothermal process.
College of Chemistry, Jilin Normal University, Siping 136000, People's Republic of China. wangxiuyan2001@yahoo.com.cn
Xiu-Yan
XY
Wang
Jia-Jun
JJ
Wang