The preparation and properties of some tertiary phosphine and phosphine chalcogenide adducts of BI3 and BBr3

The adducts of BI3 and BBr3 with various tertiary phosphines and their chalcogenide derivatives are described. The proton and boron-11 NMR spectra of many of these compounds are reported for the first time. Although the methyl proton-phosphorus-31 coupling constants are nearly identical in the (CH3)3PBX3 (X = F, Cl, Br, I) series, the boron-phosphorus coupling constant, JBP, is anomalously low for (CH3)3PBI3 (116 Hz) relative to other members of the series. The phosphine adducts of BBr3 and BI3 are white, air and water insensitive solids, whereas the phosphine chalcogenide adducts are quite moisture sensitive. The BI3 adducts with phosphine chalcogenides lose iodine fairly readily to form intractable material.