Polyphosphinoborane Block Copolymer Synthesis using Catalytic Reversible Chain Transfer Dehydropolymerization

An amphiphilic block copolymer of polyphosphinoborane has been prepared by a mechanism-led strategy of the sequential catalytic dehydropolymerization of precursor monomers, H3B·PRH2 (R = Ph, n-hexyl), using the simple pre-catalyst [Rh(Ph2PCH2CH2PPh2)2]Cl. Speciation, mechanism and polymer chain growth studies support a step-growth process where reversible chain transfer occurs, i.e. H3B·PRH2/oligomer/polymer can all coordinate with, and be activated by, the catalyst. Block copolymer [H2BPPhH]110–b–[H2BP(n-hexyl)H]11 can be synthesized and self-assembles in solution to form either rod-like micelles or vesicles depending on solvent polarity