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.