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Reactions of some unsaturated fluorocarbon derivatives with organo compounds of arsenic, silicon, germanium and tin

University of British Columbia

Hexafluoroacetone readily adds to primary and secondary arsines to form arsino-1,1,1,3,3,3-hexafluoro-propanols and to tetramethyldiarsine to form a moderately stable 1:1 complex at 20° . Trimethylarsine affords a 1:1 complex with hexafluoroacetone at 0° although the complex is completely dissociated at 20°. Trimethylsilahe, trimethylgermane, and trimethyltin hydride react with hexaf luoroacetone to form 1,1,1, 3, 3, 3,-hexaf luoropropoxy derivatives and to dialkyltin dihydrides to form the bis(hexafluoropropoxy) derivatives. Addition of a second mole of hexafluoroacetone to form 1:1 complexes with propoxygermane and propoxysilane occurs at 20°in the presence of excess hexafluoroacetone. The analogous 1:1 tin complex can be isolated and is stable at 25°. Dimethylbis (1,1,1 ,3, 3, 3-hexaf luoropropoxy) tin gives a stable complex containing two moles of hexafluoroacetone. The structures of the arsine- and Group IV- hexafluoroacetone complexes and some of their reactions are discussed. The fluorocycloolefins, perfluorocyclobutene and 1,2-dichlorotetrafluorocyclobutene react with secondary arsines to give arsinocyclobutene derivatives. Perfluorocyclobutene affords the 1:1 adduct when heated with trimethylsilane and trimethylgermane. Trimethyltin hydride adds to perfluorocyclobutene at 20°to form the 1:1 adduct which subsequently slowly decomposes to trimethyltin fluoride. The reaction-of Group IV hydrides with 1, 2-dichlorotetraf luorocyclobutene affords a number of products the nature of which varies with the Group IV metal or metalloid. Thus the reaction of the dichlorocyclobutene with triethyltin hydride gives only triethyltin chloride, with trimethylsilane chlorotrimethylsilane and 1-chlorotetraf luorocyclobutyl-2-trimethylsilane are obtained,and with trimethylgermane reaction gives a variety of cyclobutenyl and cyclobutylgermanes as well as chlorotrimethylgermane. The configuration and conformation of the cyclobutyl derivatives of the Group IV elements are established from an analysis of their ¹H n.m.r. spectra. Hexafluorobut-2-yne adds quantitatively to tin hydrides at 20° to afford the 1,1,1,4,4,4-hexafluorobutenyl derivatives. Hexamethylditin, tetrakis (trifluoromethyl) diarsine, trimethylsilane and triethylgermane add to hexafluorobut-2-yne on ultraviolet irradiation to give 1:1 adducts. The 1:1 trimethylsilane-hexafluorobut-2-yne adduct also forms at 235°. Trimethyltin hydride and 1,1,1,-trifluoropropyne react slowly at 20° to afford the 1:1 adduct. A study of the isomer distribution of the 1:1 acetylene adducts indicates in all cases a predominant formation of the transisomer. Trimethylsilane catalyzes the conversion of trans-1,1,1,4,4,4-hexafluorobutenyltrimethylsilane to the cis-isomer and trimethyltin hydride catalyzes the conversion of cis-1,1,1-trifluoropropenyl-3-trimethyltin to the trans-isomer. The diadducts (CH₃) ₃SiCHCF3-CH(CF₃)Si(CH₃)₃ and ((CH₃)₃Sn)₂CHCH₂CF₃, are also obtained simultaneously with the formation of the respective 1:1 adducts although they are not formed by addition of the hydrides to the 1:1 adducts.

Text

2011-09-26

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http://hdl.handle.net/2429/37630

Chemistry

University of British Columbia

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