Fluorovinyl organometallic compounds Ð an historical revie and some recent advances A.K. Brisdon * , K.K. Banger Department of Chemistry, UMIST PO Box 88, Manchester M60 1QD, UK Received 27 May 1999; received in revised form 25 June 1999; accepted 22 July 1999 Abstract This review describes the historically important routes to ¯uorovinyl organometallic species of the type M-(CXCX 2 ), where M is a main-group or transition-metal element and one, or more, of the substituent atoms, X, is ¯uorine, the others being eith hydrogen. A number of newer synthetic methods are described which have resulted in the preparation of a wider rang compounds. The structure, spectrocopy, properties, reactivity and future prospects for this class of compounds are described. # 1999 Elsevier Science S.A. All rights reserved. Keywords: Fluorovinyl; Organometallic; Synthesis; Structure; Spectroscopy; Reactivity 1. Introduction The replacement of hydrogen for ¯uorine in organic fragments results in moieties that are sterically larger than their perprotio analogues, and which possess very different electronic characteristics [1]. These factors are re¯ected in signi®cantly different physical and chemical properties for related C±H and C±F containing compounds and in no area is this more obvious than in the ®eld of organometallic chemistry [2]. While there exists a large arsenal of reagents available for the introduction of alkyl and related perprotio groups onto metal centres, this situation is not matched either in range, or stability, of reagents for the synthesis of metal-¯uorocarbon species. For example whilst the ®rst metal-methyl com- pound Ð methyl mercury Ð was prepared in 1852 it was not until 1949 that the ®rst ¯uoroorganometallic, IHgCF 3 , was reported [3]. Although there have been a number of recent reviews of the synthesis and chemistry of CF 3 -containing organome- tallics most of the reviews of ¯uorovinyl systems are now somewhat outdated [4,5]. During the last few years a number of signi®cant advances have been made in this area resulting in renewed interest in these systems. This papereviews the historically important developments and recent adv in the studyof ¯uorovinylcompoundsof the type M±CX=CX 2 where at leastone of the substituent atoms, X, is ¯uorine, the others being either ¯uorine, other halo or hydrogen, and M is a main-group or transition-metal element. 2. Synthetic methods 2.1.Grignard reagents The ®rst¯uorovinyl-containing compound, CF 2 =CFI, was prepared by Sef¯ in 1956 and this was subsequent used in thepreparation of the per¯uorovinyl Grignard reagent,CF 2 =CFMgI, at low temperature[6]. The ef®ciencyof thisreactionwasestimatedas ca. 20% based on an analysis of the amount of CF 2 CHF formed on hydrolysis of the Grignard reagent. Subsequent work by Knunyants [7,8] on the same system, but utilising lo reaction temperatures, resulted in a signi®cant increase in the yield ofthe Grignard to 70%. Both he and Stone [9] found that bromotri¯uoroethane, which was commer- cially available, unlike C 2 F 3 I, could also be used as the starting material for generation of per¯uorovinyl-Grigna reagents in a similarfashion.This methodwas used to synthesise some of the earliest examples of per¯uor nyl-containing compounds, including a few organometa complexes [10,11] (Table 1). Journal of Fluorine Chemistry 100 (1999) 35±43 * Correspondingauthor.Tel.: 0044-161-2363311; fax: 0044-161- 2287040. E-mail address: alan.brisdon@umist.ac.uk (A.K. Brisdon) 0022-1139/99/$ ± see front matter # 1999 Elsevier Science S.A. All rights reserved. PII: S 0 0 2 2 - 1 1 3 9 ( 9 9 ) 0 0 2 0 0 - 6