Polyoxometalate-based organic-inorganic hybrid compounds containing transition metal mixed-organic-ligand complexes of N-containing and pyridinecarboxylate ligands

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 44; no. 19; pp. 8971 - 8983
• Main Authors: Zhao, De-Chuan, Hu, Yang-Yang, Ding, Hong, Guo, Hai-Yang, Cui, Xiao-Bing, Zhang, Xiao, Huo, Qi-Sheng, Xu, Ji-Qing
• Format: Journal Article
• Language: English
• Published: England 21.05.2015
• Subjects: Carboxylic Acids - chemistry; Chains; Crystallography, X-Ray; Degradation; Diffraction; Isomers; Ligands; Models, Molecular; Molecular Structure; Nicotinic acid; Organometallic Compounds - chemical synthesis; Organometallic Compounds - chemistry; Pyridines - chemistry; Rhodamine; Transition Elements - chemistry; Transition metals; Tungsten Compounds - chemistry; X-ray photoelectron spectroscopy
• DOI: 10.1039/c5dt00201j
• ISSN: 1477-9226

Five new organic–inorganic hybrid compounds based on the Keggin-type polyoxoanion [SiW12O40]4−, namely [Cu3(2,2′-bpy)3(inic)(μ2-OH)(H2O)][SiW12O40]·2H2O (1), [Cu6(phen)6(μ3-Cl)2(μ2-Cl)2Cl2(inic)2][SiW12O40]·6H2O (2), [Cu2(hnic)(2,2′-bpy)2Cl]2[H2SiW12O40] (3), [Cu2(nic)(phen)2Cl2]2[SiW12O40] (4) and [Cu2(pic)(2,2′-bpy)2Cl]2[SiW12O40] (5) (inic = isonicotinic acid, hnic = 2-hydroxy-nicotinic acid, nic = nicotinic acid, pic = picolinic acid, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline) have been synthesized and characterized by IR, UV-Vis, XPS, XRD, cyclic voltammetric measurements, photoluminescence analysis and single crystal X-ray diffraction analysis. Crystal analysis reveals that compound 1 exhibits a 2-D double layered framework structure constructed from [SiW12O40]4− and copper-aqua-2,2′-bipy-hydroxyl-isonicotinate complexes. Compound 2 is a 0-D discrete structure formed by [SiW12O40]4− and copper-chloro-isonicotinate-phenanthroline complexes. Compound 3 shows a 1-D single chain structure based on the linkage of copper-2,2-bpy-chloro-2-hydroxy-nicotinate complexes and [SiW12O40]4−. Compounds 4 and 5 both contain polyoxometalate supported transition metal complexes, one is a polyoxometalate supported copper-chloro-nicotinate-phenanthroline complex in 4, and the other is a polyoxometalate supported copper-2,2-bpy-chloro-nicotinate complex in 5. It should be noted that nicotinic, isonicotinic and picolinic acids are structural isomers and 2-hydroxy-nicotinic acid is an in situ hydroxylated product of nicotinic acid. In addition, photocatalytic degradation of Rhodamine B (RhB) by compounds 1–5 has been investigated in aqueous solutions.