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Synthesis of Tin Oxide Precursors and Related Germanium and Lead Compounds

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journal contribution
posted on 09.10.1996, 00:00 by Seigi Suh, David M. Hoffman
The goals of this study were to synthesize volatile tin(II) hexafluoroisopropoxide complexes for use as precursors to tin oxide or fluorine-doped tin oxide and to prepare related germanium(II) and lead(II) compounds. M(N(SiMe3)2)2 reacts with 2 equiv of RfOH (Rf = CH(CF3)2) and 1 equiv of added amine, L, to give M(ORf)2L (M = Ge, L = py or H2NPh; M = Sn, L = HNMe2 or py; M = Pb, L = p-pyNMe2) in high yield. Alternatively, Sn(ORf)2(HNMe2) can be prepared by reacting Sn(NMe2)2 with RfOH. X-ray crystallographic studies of Ge(ORf)2(H2NPh) and Sn(ORf)2(HNMe2) show they are monomers with trigonal pyramidal geometries. An X-ray structure of the Pb compound shows it is the dimer [Pb(μ-ORf)(ORf)(p-pyNMe2)]2. Pb(NMe2)2 reacts with 3 equiv of RfOH to give [Me2NH2][Pb(ORf)3], which an X-ray structure shows is the dimer {[Me2NH2][Pb(μ-ORf)(ORf)2]}2. Both Pb dimers are held together by weak dative Pb−O interactions. Sn(N(SiMe3)2)2 reacts with 2 equiv of RfOH in the absence of added amine to give amine-free Sn(ORf)2. By analogy to known tin(II) alkoxide and related compounds, Sn(ORf)2 is proposed to be a dimer with two bridging alkoxide ligands. The tin compounds are volatile solids, an important criterion for their possible use as conventional tin oxide precursors in chemical vapor deposition processes.