Three bismuth(III) complexes constructed by N-containing heterocyclic carboxylic acids: Synthesis, crystal structure and photocatalytic activity

Three novel bismuth(III) complexes of the formulae [Bi(3-apac)(2)(H2O)Cl-3](3-apac) 2 (1), [Bi(mu-pda)(H2O)Cl](n) (2) and [Bi(6,6'-bpdc)(H2O)(mu-Cl)] (3) (where 3-apac = 3-aminopyrazine-2-carboxylic acid, H(2)pda = pyridine-2,6-dicarboxylic acid, 6,6'-H(2)bpdc = 2,2'-bipyridine-6,6'-dicarboxylic acid) were synthesized. The X-ray crystallo-graphic investigation reveals that 1 is a mononuclear compound and offers the first example of Bi(III) complex which proton transfer occurs in ligand molecules. 2 is a dinuclear coordination polymer, which consists of two [Bi(mu-pda)(H2O)Cl] units via two bridging O atoms of two pda(2-) ions. And the dinuclear complex 3 is built up from two Bi3+ ion cores which are bridged through two Cl- ions. Furthermore, the photocatalytic activity of 1-3 toward the degradation of Rhodamine B (RhB) was explored, and the mechanism of the photocatalytic degradation was discussed. The results indicate that 2 and 3 are good candidates for the photocatalytic degradation of RhB.