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TitleUnprecedented oxo-titanium citrate complex precipitated from aqueous citrate solutions, exhibiting a novel bilayered Ti8O10 structural core
Publication TypeJournal Article
Year of Publication2004
AuthorsKemmitt, T., Al-Salim N.I., Gainsford G.J., Bubendorfer A., and Waterland M.
JournalInorganic Chemistry
Pagination6300 - 6306
Date Published2004
ISSN00201669 (ISSN)
Keywordsaqueous solution, article, carbon nuclear magnetic resonance, carboxylic acid, Chelation, Citrates, citric acid, crystal structure, Crystallization, Crystallography, X-Ray, microscopy, Models, Molecular, Organometallic Compounds, oxotitanium citrate, powder, precipitation, Solutions, Spectrum Analysis, Raman, structure analysis, Titanium, titanium 2 propoxide, titanium derivative, titanium dioxide, unclassified drug, water, X ray analysis
AbstractAqueous titanium citrate solutions were prepared from the reaction of citric acid with titanium 2-propoxide in a range of molar ratios. Solutions containing two or fewer citrates per titanium resulted in the slow crystallization of an insoluble titanium oxo-citrate complex. Single-crystal X-ray analysis identified the species as Ti8O10(citrate) 4-(H2O)12·14H2O· 3HOPri, crystallized in the tetragonal space group I41/a, with a = 30.775(7) Å, c = 14.528(7) Å, V = 13759(8) Å3, and Z= 8. The trianionic citrate ligands supply both carboxylate and alkoxide coordination and stabilize the structure using simultaneous chelating and bridging modes of attachment. The compound is a neutral species, exhibiting titanium in three contrasting environments. Laser Raman microscopy and 13C CPMAS solid-state NMR data were consistent with those of the X-ray crystal structure. When exposed to air, the crystals rapidly lost water and became a powder. The dehydrated powder was noncrystalline to X-rays and insoluble, but 13C NMR results demonstrated retention of the carboxylate linkages.

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