Poly(p-phenylene iminoborane): A Boron-Nitrogen Analogue of Poly(p-phenylene vinylene)

Substitution of selected CC units in π-conjugated organic frameworks by their isoelectronic and isosteric BN units (BN/CC isosterism) has proven to be a successful concept for the development of BN-doped polycyclic aromatic hydrocarbons (PAHs) with intriguing properties and functions. The first examples have just demonstrated the applicability of this approach to polymer chemistry. Herein, we present the synthesis and comprehensive characterization of the first poly(p-phenylene iminoborane). This novel inorganic-organic hybrid polymer can be regarded as a BN analogue of the well-known poly(p-phenylene vinylene) (PPV). Photophysical investigations on the polymer and a series of model oligomers provide clear evidence of some π-conjugation across the B=N bonds and extension of the conjugation path with increasing chain length. TD-DFT calculations provide deeper insight into the electronic structure of the new materials.