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	Hydrogen bonding-controlled assemblies of polymeric and octanuclear tungsten citrates
	Zhang, Rong-Hua ; Zhou, Xin-Wen ; Xiao, Shu-Zhang ; Zhou, Zhao-Hui ; Zhou CH(周朝晖)
	2012-08-30
关键词	Tungsten Citric acid NMR Hydrogen bond Crystal structure
英文摘要	Water-soluble polymeric tungsten citrate (Him)(10n)(NH4)(2n)[(WO2)(2)O(Hcit)(2)](3n)center dot 10nH(2)O (1) and octanuclear tungsten citrate (Him)(8)(NH4)(13){[(WO2)(2)O(Hcit)(cit) H(cit)(Hcit)O(WO2)(2)][(WO2)(2)O(cit)(2)](2)}center dot 14H(2)O (2) (H(4)cit = citric acid, im = imidazole), were obtained from aqueous solution. They were characterized by elemental analyses, NMR and IR spectra, thermogravimetric (TG) analyses and X-ray structural analyses. The basic units of the two complexes contain a dimeric tungsten citrate in different protonated forms, where tungsten atom is six-coordinated in an approximately octahedral geometry. Each citrate ligand uses its alpha-alkoxy, alpha-carboxy and one beta-carboxy group to act as a tridentate ligand, while the other beta-carboxy or carboxylic acid group is uncoordinated. The presences of the protonated/deprotonated terminal carboxylates and their participation in hydrogen-bonding interactions play an important role in the overall structures. In complex 1, a hexanuclear tungsten citrate species [(WO2)(2)O(Hcit)(2)](3)(12) is linked by strong H-bonding between beta-carboxylic acid group and terminal oxygen [2.587(6) angstrom], which extends into one-dimensional polymeric chain. In complex 2, there exist two types of strong hydrogen bonds between b-carboxy and carboxylic acid groups [2.467(8), 2.516(6) angstrom], forming an octanuclear species {[(WO2)(2)O(Hcit)(cit)H(cit)(Hcit)O(WO2)(2)][(WO2)(2)O(cit)(2)](2)}(21). This is supported by the absence of IR band around 1700 cm(-1) for protonated carboxylic acid. C-13 NMR spectra show the coordination of alpha-alkoxy and alpha-carboxy groups of citrate ligand in both complexes. (C) 2012 Elsevier B.V. All rights reserved.; National Science Foundation of China [21073150]; Ministry of Science Technology [2010CB732303, 2010CB126504]; Scientific Research Funds for the Talents of China Three Gorges University [KJ2009B049]
语种	英语
出版者	ELSEVIER SCIENCE SA
内容类型	期刊论文
源URL	[http://dx.doi.org/10.1016/j.ica.2012.04.025]
专题	化学化工－已发表论文
推荐引用方式 GB/T 7714	Zhang, Rong-Hua,Zhou, Xin-Wen,Xiao, Shu-Zhang,et al. Hydrogen bonding-controlled assemblies of polymeric and octanuclear tungsten citrates[J],2012.
APA	Zhang, Rong-Hua,Zhou, Xin-Wen,Xiao, Shu-Zhang,Zhou, Zhao-Hui,&周朝晖.(2012).Hydrogen bonding-controlled assemblies of polymeric and octanuclear tungsten citrates..
MLA	Zhang, Rong-Hua,et al."Hydrogen bonding-controlled assemblies of polymeric and octanuclear tungsten citrates".(2012).

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