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, H3 B ⋅ PRH2 (R=Ph, n-hexyl), using the simple pre-catalyst [Rh(Ph2 PCH2 CH2 PPh2 )2 ]Cl. Speciation, mechanism and polymer chain growth studies support a step-growth process where reversible chain transfer occurs, i.e. H3 B ⋅ PRH2 /oligomer/polymer can all coordinate with, and be activated by, the catalyst. Block copolymer [H2 BPPhH]110 -b-[H2 BP(n-hexyl)H]11 can be synthesized and self-assembles in solution to form either rod-like micelles or vesicles depending on solvent polarity.