Reactions of organotin compounds. IX. The reactions of tin hydrides with perfluorovinyl germanium and tin compounds

Abstract

The formation of addition products (CH3)3MCFHCFZSn(CH3)3 and (CH3)3MCF[Sn(CH3)3]CF2H where M = Ge or Sn has been observed in reactions involving the ultraviolet irradiation of (CH,),-MCF=CFZ with trimethyltin hydride. The former type of addition product is more stable than the latter, and the stability of both types decreases in the order M = Si, Ge, or Sn. Evidence is presented that decomposition occurs in all cases by a a-fluorine elimination with the formation of fluorovinyl derivatives of M and trimethyltin fluoride. Similar reactions occur between (CH3)3GeCF=CFZ and dimethyltin dihydride and between (CH3),Ge(CF=CF,), and dimethyltin dillydride or trimethyltin hydride. The evidence indicates that a free radical process is involved. Spectroscopic data are presented for new organogermanium compounds.

Spectroscopic and Structural Assignment of the Absolute Stereochemistry in a Series of 1,2-Difluorovinyl Organometalloids. The First Crystallographic Characterization and Structural Series of Group 14 Fluorovinyl Compounds

“…The large magnitude of the mutual 19 F− 19 F coupling would seem consistent with assignment of the trans , or Z , isomer. This is supported by the presence of a high frequency (7.9 ppm) doublet of doublets in the proton NMR spectrum, which exhibits one large (78 Hz), typically geminal 19 F− 1 H coupling and one smaller (10 Hz) cis interaction, concurring with related work by Clark et al On this basis, the higher frequency 19 F resonance is assigned to the fluorine nucleus geminal to the proton.…”

“…However, these systems have been little explored. Only five trifluorovinylgermane compounds have been reported, namely Ge(CFCF 2 ) 4 , , Me 2 Ge(CFCF 2 ) 2 , Me 3 GeCFCF 2 , , Et 3 GeCFCF 2 , and Ph 3 GeCFCF 2 , all in low to moderate yield, while there is a single report of a trifluorovinyllead compound, namely Pb(CFCF 2 ) 4 . There is just one report of the reactivity of such species, namely the reaction of Me 3 GeCFCF 2 with tin hydrides to yield predominantly cis -(1,2-difluorovinyl)trimethylgermane, in addition to smaller amounts of the trans and gem isomers and a range of dimeric species …”

Universal Group 14 Free Radical Photoinitiators for Vinylidene Fluoride, Styrene, Methyl Methacrylate, Vinyl Acetate, and Butadiene

“…Interestingly, due to the weak C−Sn bond (278 kJ/mol in Me 4 Sn), 38 the addition to alkenes (vinylidene chloride, St, acrylonitrile, MMA, and dienes 125 ) is somewhat reversible 3 8 , 1 2 6 but that to alkynes is not. 38,68,69,127−129 As R 3 Sn • is nucleophilic, 38,88 131 or vinyl ketones, while under UV, Me 3 SnH adds to perfluorovinyls (CF 2 CF−Z, Z = Si, Ge, Sn, Re(CO) 5 ) 130,132,133 and norbornadiene. 134 Similarly, other Sn and Pb derivatives add to tetracyanoquinodimethane, quinones, 135−138 and reversibly to allenes, 139 dienes, 140,141 CF 2 CF(CF 3 ), and CF 2 CF 2 .…”

“…As R 3 Sn • is nucleophilic, , electron-poor alkenes are preferred, and Me 3 Sn • and Bu 3 Sn • from the UV irradiation of Me 6 Sn 2 or Bu 3 SnH add to fluoroalkenes, including VDF. Likewise, Bu 3 SnH adds radically to unpolymerizable, beta -substituted acrylates (R–CHCH­(COOR′)) or vinyl ketones, while under UV, Me 3 SnH adds to perfluorovinyls (CF 2 CF–Z, Z = Si, Ge, Sn, Re­(CO) 5 ) ,, and norbornadiene . Similarly, other Sn and Pb derivatives add to tetracyanoquinodimethane, quinones, − and reversibly to allenes, dienes, , CF 2 CF­(CF 3 ), and CF 2 CF 2 .…”

“…It is thus conceivable that group 14 R 3 Q • (Q = C, Si, Ge, Sn, Pb) radicals could initiate an FRP by direct monomer addition, ,− hydride or halide abstraction from a suitable substrate, ,− reaction with O 2 , , etc., while a reversible P n –QR 3 bond would mediate a CRP. However, while some R 6 Q 2 or R 4 Q (Q = Si, Ge, Sn) systems were evaluated as UV co-initiators for acrylates, ,− R 3 Q-TEMPO adducts were suggested as CRP mediators, and Ph 3 C–CPh 3 poorly mediates styrene CRP, − the R 6 Sn 2 polymer photochemistry remains largely ignored, with no reports on initiations by R 3 Q • or R 3 Q • with R′X/R′H, on CRPs mediated by reversible termination with R 3 Q • , or on tin derivatives in FRP or CRP under visible light.…”