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Chemically modified oximato complexes of titanium(IV) isopropoxide as new precursors for the sol-gel preparation of nano-sized titania: Crystal and molecular structure of [Ti{ONC(10)H(16)}(4)center dot 2CH(2)Cl(2)]

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Title Chemically modified oximato complexes of titanium(IV) isopropoxide as new precursors for the sol-gel preparation of nano-sized titania: Crystal and molecular structure of [Ti{ONC(10)H(16)}(4)center dot 2CH(2)Cl(2)]
 
Creator CHAUDHARY, A
DHAYAL, V
NAGAR, M
BOHRA, R
MOBIN, SM
MATHUR, P
 
Subject INTERNALLY FUNCTIONALIZED OXIMES
OXOVANADIUM(V) COMPLEXES
NANOCRYSTALLINE TIO2
PHASE-TRANSFORMATION
METAL ALKOXIDES
ANATASE
8-COORDINATE
LIGANDS
FILMS
NANOPARTICLES
Oximato complexes
Dihapto eta(2)-(N, O) manner
Hypercoordination
Dimeric
Monomeric
Nano-sized
 
Description Reactions of [Ti(OPr(i))(4)] with various oximes, in anhydrous refluxing benzene yielded complexes of the type [Ti{OPr(i)}(4-n)(L)(n)], where, n = 1-4 and LH = (CH(3))(2)C=NOH (1-4), C(9)H(16)C=NOH (5-8) and C(9)H(18)C-=NOH (9-12). The compounds were characterized by elemental analyses, molecular weight measurements, FAB-mass, FT-IR and NMR ((1)H, (13)C{(1)H}) spectral studies. The FAB-mass spectra of mono- (1), and di- (2), (6), (10) substituted products indicate their dimeric nature and that of tri- (3) and tetra- (4), (8) substituted derivatives suggest their monomeric nature. Crystal and molecular structure of [Ti{ONC(10)H(16)}(4)center dot 2CH(2)Cl(2)] (8A) suggests that the oximato ligands bind the metal in a dihapto eta(2)-(N, O) manner, leading to the formation of an eight coordinated species. Thermogravimetric curves of (3), (6) and (10) exhibit multi-step decomposition with the formation of TiO(2) as the final product in each case, at 900 degrees C. Low temperature (similar to 600 degrees C) sol-gel transformations of ( 2), (3), (4), (6), (7) and (8) yielded nano-sized titania (a), (b), (c), (d), (e) and (f), respectively. Formation of anatase phase in all the titania samples was confirmed by powder XRD patterns, FT-IR and Raman spectroscopy. SEM images of (a), (b), (c), (d), (e) and (f) exhibit formation of nano-grains with agglomer like surface morphologies. Compositions of all the titania samples were investigated by EDX analyses. The absorption spectra of the two representative samples, (a) and (f) indicate an energy band gap of 3.17 eV and 3.75 eV, respectively. (C) 2010 Elsevier Ltd. All rights reserved.
 
Publisher PERGAMON-ELSEVIER SCIENCE LTD
 
Date 2012-06-26T07:48:42Z
2012-06-26T07:48:42Z
2011
 
Type Article
 
Identifier POLYHEDRON,30(5)821-831
0277-5387
http://dx.doi.org/10.1016/j.poly.2010.12.025
http://dspace.library.iitb.ac.in/jspui/handle/100/14176
 
Language English