Application of (triphenylphosphinemethylene)boranes to thermally latent catalysts for polyaddition of bisphenol a diglycidyl ether with bisphenol A: Model system of epoxy-novolac resin

Triphenylphosphinemethylene boranes served as novel non-salt-type thermally latent catalysts in the polyaddition of bisphenol A diglycidyl ether with bisphenol A, a model system of thermosetting epoxy-novolac resins. The borane substituents affected the catalytic activity in the order IH>IPh>IF. The structures were reported by the X-ray diffraction technique, where both the phosphorus and boron atoms have nearly tetrahedral orbital hybridizations. The bonds between the boranes and ylide carbons are composed of pπ-pπ orbital overlap, nearly corresponding to freely rotational single bonds.