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dc.contributor.authorDeng, Yuan-Fu
dc.contributor.authorJiang, Ya-Qi
dc.contributor.author蒋亚琪
dc.contributor.authorHong, Qi-Ming
dc.contributor.authorZhou, Zhao-Hui
dc.contributor.author周朝晖
dc.date.accessioned2011-05-23T03:48:46Z
dc.date.available2011-05-23T03:48:46Z
dc.date.issued2006-09
dc.identifier.citationPOLYHEDRON,2007,26(8):1561-1569zh_CN
dc.identifier.issn0277-5387
dc.identifier.urihttp://dx.doi.org/doi:10.1016/j.poly.2006.08.017
dc.identifier.urihttps://dspace.xmu.edu.cn/handle/2288/9077
dc.description.abstractTitanium(IV) citrate complexes with different anions Na-3[Ti(H(2)cit)(2)(Hcit)] center dot 9H(2)O (1), K-4[Ti(H(2)cit)(Hcit)2] center dot 4H(2)O (2), K-5[Ti(Hcit)(3)] center dot 4H(2)O (3) and Na-7[TiH(cit)(3)] center dot 18H(2)O (4) (H(4)Cit = citric acid) were isolated in pure forms from the solutions of titanate and citrate at various pH values. X-ray structural analyses revealed the presence of a monomeric tricitrato titanium unit in the four complexes. Each Ti(IV) ion is coordinated octahedrally by the three citrate ligands in different protonated forms. The citrate ligand chelates bidentately to the titanium ion through its negatively charged alpha-alkoxy and alpha-carboxy groups. This is consistent with the large downfield C-13 NMR shifts for the carbon atoms bearing the alpha-alkoxy and alpha-carboxy groups. The very strong hydrogen-bonds existing in the protonated and deprotonated beta-carboxy groups may be the key factor for the stabilization of the titanium citrate complexes. When the pH value is lower than 7.0, C-13 NMR spectra of 1:3 Ti:citrate solutions are similar to those of the titanium citrate complexes isolated at the corresponding pH values. The dissociation of free citrate increases with the rise of pH value. However, C-13 NMR spectra of 1:3 Ti:citrate solutions indicate that there may exist different citrate titanium species when the pH value is higher than 7.0. (C) 2006 Published by Elsevier Ltd.zh_CN
dc.language.isoenzh_CN
dc.publisherPERGAMON-ELSEVIER SCIENCE LTDzh_CN
dc.subjecttitaniumzh_CN
dc.subjectcitric acidzh_CN
dc.subjectNMRzh_CN
dc.subjectspecieszh_CN
dc.subjectcrystal structurezh_CN
dc.titleSpeciation of water-soluble titanium citrate: Synthesis, structural, spectroscopic properties and biological relevancezh_CN
dc.typeArticlezh_CN


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