Metal-Free Addition/Head-to-Tail Polymerization of Transient Phosphinoboranes, RPH-BH2: A Route to Poly(alkylphosphinoboranes).

Abstract

Mild thermolysis of Lewis base stabilized phosphinoborane monomers R1R2P–BH2⋅NMe3 (R1,R2=H, Ph, or tBu/H) at room temperature to 100 °C provides a convenient new route to oligo- and polyphosphinoboranes [R1R2P-BH2]n. The polymerization appears to proceed via the addition/head-to-tail polymerization of short-lived free phosphinoborane monomers, R1R2P-BH2. This method offers access to high molar mass materials, as exemplified by poly(tert-butylphosphinoborane), that are currently inaccessible using other routes (e.g. catalytic dehydrocoupling).