Sol-Gel Synthesis of Hybrid Organic-Inorganic Tin Oxide Based Materials
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FRANCOIS 0. RIBOT, F. BANSE AND C. SANCHEZ Universit6 Pierre et Marie Curie, Chimie de la Mati~re Condensde (URA CNRS 1466), T54-E5, 4 place Jussieu, 75252 Paris Cedex 05, France.
ABSTRACT RSn(OAmt) 3 with R = n-butyl, n-butenyl or para-styryl, which are monomeric precursors, have been hydrolyzed. The so-obtained products have been characterized mainly by 119 Sn NMR. In every cases, tin expands its coordination from 4 to 5 and 6, and hydrolysis yields tin oxohydroxo species of small size. For n-butyl and n-butenyl, a cage-like tin oxo-hydroxo cluster, {(RSn)12(4t3-O)14(92-OH)6}2,' was evidenced as the major compound formed. Organic polymerization of the unsaturated organic groups linked to tin was initiated on the hydrolysis products and yielded hybrid systems which can be pictured as tin oxo-hydroxo oligomers attached together by polymeric chains.
INTRODUCTION Tin is an element which exhibits a chemical behaviour intermediate between those of silicon and transition metals. Like the latter, tin can be found in several coordinations (generally from 4 to 6), and coordination expansion makes hydrolysis reaction of tin alkoxides very fast. But, as silicon, tin can be linked to carbon with enough covalency to make these bonds stable towards nucleophilic substitutions such as hydrolysis 1. This last characteristic, as well as the chemical conditions of sol-gel process 2, can be taken advantage of to prepare hybrid organic-inorganic systems in which the organic components are chemically bonded to the inorganic part 3-7. A previous study 8 on the hydrolysis-condensation of n-butyl-tin triisopropoxyde has shown the formation of organotin oxo-hydroxo clusters. This work has been extended to three monoorgano-tin tritertioamyloxides, which contain either an inactive (n-butyl) or a functional (nbutenyl, styryl) organic group. Their behaviour upon hydrolysis-condensation and their ability to yield hybrid organic-inorganic materials, based on nano building-blocks 6,7, have been investigated.
EXPERIMENTAL n-butyl-tin tritertioamyloxide (BSA), has been synthesized from n-butyl-tin trichloride as previously described 8. n-butenyl- and para-styryl-tin tritertioamyloxides (BySA and SySA) were 121 Mat. Res. Soc. Symp. Proc. Vol. 346. 01994 Materials Research Society
supplied by Dr. B. Jousseaume 9. Hydrolysis experiments were performed with a water/tertioamyl alcohol (HOAmt), 10 w%, mixture for BSA and BySA, and with a water/tetrahydrofuran (THF), 20 w%, for SySA. Unless hydrolyzed with more than three water molecules per tin atom, compounds were handled under controlled atmosphere (argon-vaccum line, schlenk glassware). Organic polymerization of the hydrolyzed samples was initiated by thermal decomposition, around 70'C, of azobisisobutyronitryl (AIBN). The amount of radical promoter is given in weight percent relative to the precursors. 1 H and 13 C liquid NMR experiments were carried out on a Bruker AC 300 spectrometer operating at 300.13 MHz and 75.47 MHz for 1H and 13 C, respectively. 1 l 9 Sn liquid NMR experiments were perfo
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