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Molecular precursors for the preparation of homogenous zirconia-silica materials by hydrolytic sol-gel process in organic media. Crystal structures of [Zr{OSi((OBu)-Bu-t)(3)}(4)(H2O)(2)]center dot 2H(2)O and [Ti((OBu)-Bu-t){OSi((OBu)-Bu-t)(3)}(3)]

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Title Molecular precursors for the preparation of homogenous zirconia-silica materials by hydrolytic sol-gel process in organic media. Crystal structures of [Zr{OSi((OBu)-Bu-t)(3)}(4)(H2O)(2)]center dot 2H(2)O and [Ti((OBu)-Bu-t){OSi((OBu)-Bu-t)(3)}(3)]
 
Creator DHAYAL, V
CHAUDHARY, A
CHOUDHARY, BL
NAGAR, M
BOHRA, R
MOBIN, SM
MATHUR, P
 
Subject LOW-TEMPERATURE TRANSFORMATION
COMPLEXES
ALKOXIDES
POLYMERIZATION
NANOPARTICLES
TITANIUM(IV)
CHEMISTRY
TITANIA
OXIDES
 
Description Zr(OPri)(4)center dot(PrOH)-O-i] reacts with [HOSi((OBu)-Bu-t)(3)] in anhydrous benzene in 1 : 1 and 1 : 2 molar ratios to afford alkoxy zirconosiloxane precursors of the types [Zr(OPri)(3){OSi((OBu)-Bu-t)(3)}] (A) and [Zr(OPri)(2){OSi-((OBu)-Bu-t)(3)}(2)] (B), respectively. Further reactions of A or B with glycols in 1 : 1 molar ratio afforded six chemically modified precursors of the types [Zr(OPri)(OGO){OSi((OBu)-Bu-t)(3)}] (1A-3A) and [Zr(OGO)-{OSi((OBu)-Bu-t)(3)}(2)] (1B-3B), respectively [where G = (-CH2-)(2) (1A, 1B); (-CH2-)(3) (2A, 2B) and (-CH2CH2CH(CH3-)} (3A, 3B)]. The precursors A and B are viscous liquids, which solidify on ageing whereas the other products are all solids, soluble in common organic solvents. These were characterized by elemental analyses, molecular weight measurements, FAB mass, FTIR, H-1, C-13 and Si-29-NMR studies. Cryoscopic molecular weight measurements of all the products, as well as the FAB mass studies of 3A and 3B, indicate their monomeric nature. However, FAB mass spectrum of the solidified B suggests that it exists in dimeric form. Single crystal structure analysis of [Zr{OSi((OBu)-Bu-t)(3)}(4)(H2O)(2)]center dot 2H(2)O (3b) (R-fac = 11.9%) as well as that of corresponding better quality crystals of [Ti((OBu)-Bu-t){OSi((OBu)-Bu-t)(3)}(3)] (4) (R-fac = 5.97%) indicate the presence of a M-O-Si bond. TG analyses of 3A, B, and 3B indicate the formation of zirconia-silica materials of the type ZrO2 center dot SiO2 from 3A and ZrO2 center dot 2SiO(2) from B or 3B at low decomposition temperatures (
 
Publisher ROYAL SOC CHEMISTRY
 
Date 2014-10-16T14:27:38Z
2014-10-16T14:27:38Z
2012
 
Type Article
 
Identifier DALTON TRANSACTIONS, 41(31)9439-9450
http://dx.doi.org/10.1039/c2dt12127a
http://dspace.library.iitb.ac.in/jspui/handle/100/15783
 
Language en