Perfluorocycloalkene
Class of chemical compounds
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A perfluorocycloalkene (PFCA) fluorocarbon structure with a cycloalkene core. PFCAs have shown reactivity with a wide variety of nucleophiles including phenoxides, alkoxides, organometallic, amines, thiols, and azoles.[1] They or their derivatives are reported to have nonlinear optical activity,[2] and be useful as lubricants,[3] etching agents,[4] components of fuel cells,[5] low-dielectric materials, and superhydrophobic and oleophobic coatings.[6]
- Examples of perfluorocycloalkenes
Tetrafluorocyclopropene
Octafluorocyclopentene
Decafluorocyclohexene
Reactivity
Derivatization of these PFCA rings via displacement of fluorine atoms with nucleophiles occurs through an addition-elimination reaction in the presence of a base. Attack of the nucleophile on the PFCA ring generates a carbanion which can eliminate a fluoride ion, resulting in vinyl substituted and allyl substituted products (Scheme 1). The ratio of vinylic to allylic products depends on the ring size, reaction conditions, and nucleophile.[1][7]
Under favorable conditions, a good nucleophile can replace all the fluorine atoms on PFCA ring (Scheme 2).[8]
PFCAs have a huge potential to be used as a monomer to produce a variety of polymers. The polycondensation of bisphenols with PFCAs can be done. A unique class of aromatic ether polymers containing perfluorocyclopentenyl (PFCP) enchainment was prepared from the simple step-growth polycondensation of commercial available bisphenols and octafluorocyclopentene (OFCP) in the presence of triethylamine (Scheme 3 and 4).[6][9]
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Fluoropolymers, namely, perfluorocyclohexenyl (PFCH) aryl ether polymers, may be formed via step-growth polycondensation of commercial bisphenols and decafluorocycloalkene (DFCH) in the presence of triethylamine (Scheme 5).[7][10]
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