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Aqueous 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 Ti(8)O(10)(citrate)(4)(H(2)O)(12).14H(2)O.3HOPr(i)(), crystallized in the tetragonal space group I4(1)/a, with a = 30.775(7) A, c = 14.528(7) A, V = 13 759(8) A(3), 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 (13)C 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 (13)C NMR results demonstrated retention of the carboxylate linkages.

A family of triethanolamine complexes of titanium with varying metal/ligand ratios have been prepared from reactions of titanium tetraisopropoxide with triethanolamine. Three nonhydrolytic products, having essentially all isopropoxide ligands substituted by triethanolamine, were prepared as hygroscopic, glassy solids. Crystals of two hexameric titanatrane partial hydrolysis analogues [Ti3(mu 2-O)((HOCH2CH2)2NCH2CH2O)(OCH2CH2)2(mu 2-OCH2CH2)N)2(OCH2CH2)(mu 2- OCH2CH2)2N)]2 (1), and [Ti3(mu 2-O)(OCH(CH3)2)((OCH2CH2)2(mu 2-OCH2CH2)N)2(OCH2CH2)(mu 2- OCH2CH2)2N)]2 (2) were isolated and structurally characterized. The structures consist of a central core of two oxo-bridged dititanatranes (TEA)TiOTi(TEA) (TEAH3 = triethanolamine) with the nonhydrolytic residue (TEA)Ti(TEAH2) included as an adduct in (1), analogously to (TEA)Ti(OPri) in (2).