Intercalation behaviors of chiral titanium(IV) (triethanolaminato)-isopropoxide (Ti(C2H4O)3N(OCH(CH3)2) in protonated lamellar metal oxides and characterization of the intercalated resultants

Abstract

The intercalation behaviors of chiral titanium(IV) (triethanolaminato)-isopropoxide (the chemical formula is Ti(C2H4O)3N(OCH(CH3)2), abbreviated as TEAIP) in a series of layered protonated metal oxides (HNb3O8, HTiNbO5, HLaNb2O7, H2Ti4O9 and H2Ti2.8Mn0.2O7) were investigated. TEAIP could be intercalated into the interlayer spaces of layered HNb3O8 as well as HTiNbO5, and as a result, two novel inorganic–organic hybrid nanocomposites, TEAIP-intercalated HNb3O8 and TEAIP-intercalated HTiNbO5, were obtained,respectively. Based on the compositions of the intercalated compounds quantitatively estimated from TG-DTA data, the chemical formulas of the TEAIP-intercalated HNb3O8 and TEAIP-intercalated HTiNbO5 were expressed as (TEAIP)0.17H0.83Nb3O8 and (TEAIP)0.14H0.86TiNbO5, respectively. Neither H2Ti4O9 nor H2Ti2.8Mn0.2O7 formed any intercalated phase through the exchange reaction between the layered protonated metal oxides and TEAIP; HLaNb2O7 could only accommodate a very limited amount of the guest molecules, giving rise to a TEAIP-partially intercalated layered product. The different intercalation behavior of TEAIP in the layered metal oxides was ascribed to the difference of these protonated metal oxides in acidity and the difference of the layered hosts in charge density. The competitively intercalation behavior between TEAIP and n-decylamine in the interlayer space of HNb3O8 as well as HTiNbO5 was also investigated. Both TEAIP and n-decylamine could be simultaneously intercalated into HNb3O8, leading to two different guest-intercalated phases, although n-decylamine-intercalated phase was thermally unstable compared with the TEAIP-intercalated phase. In the case of HTiNbO5, only n-decylamine-intercalated phase was formed. The different basicity and steric hindrance of the two kinds of guest molecules and different acidity of the two layered hosts were mainly responsible for the above results.