Boron heterocycles. Part VII. Halogeno-, methyl-, phosphino-, and amino-derivatives of 1,3,2-dioxaborolan and 1,3,2-dithiaborolan ring systems

Abstract

Selected derivatives of the rings [graphic omitted]·CH₂·CH₂·O·[graphic omitted]– and [graphic omitted]·CH₂·CH₂·S·[graphic omitted]– are reported. Derivatives of the latter system appear to be more stable thermally and with the exception of [[graphic omitted]·CH₂·CH₂·S·[graphic omitted]·CH₃]₂ and [[graphic omitted]·CH₂·CH₂·S·[graphic omitted]·P·(CH₃)₂]₂ are monomers in solution. Derivatives of [graphic omitted]·CH₂·CH₂·O·[graphic omitted]– are monomers in solution except for [graphic omitted]·CH₂·CH₂·O·[graphic omitted]Cl which is associated, having an apparent molecular weight which is concentration dependent. Its boron-11 n.m.r. spectra in solution correlated with molecular-weight data suggest a chain-like species containing ternary and quaternary boron. Tensiometric titrations reveal that P(CH₃)₃ and P(CH₃)₂H react with [graphic omitted]·CH₂·CH₂·O·[graphic omitted]Cl in 1 : 3 rather than 1:1 molar ratios. The products [[graphic omitted]·CH₂·CH₂·O·[graphic omitted]Cl]₃P(CH₃)₃ and [[graphic omitted]·CH₂·CH₂·O·[graphic omitted]Cl]₃P(CH₃)₂H are crystalline solids.