Poly(p-phenylene phosphaborene): A Modified Poly(p-phenylene vinylene) with π-Conjugated B═P Linkages

Area of Science:

• Materials Science
• Organic Chemistry
• Polymer Science

Background:

• Isoelectronic substitution in π-conjugated organic compounds is a key strategy for developing novel hybrid materials.
• While boron-nitrogen (B═N) substitution is established, the use of valence isoelectronic boron-phosphorus (B═P) units remains underexplored.

Purpose of the Study:

• To explore the potential of B═P units in π-conjugated systems.
• To synthesize and characterize novel polymers and oligomers incorporating B═P linking groups.
• To investigate the optoelectronic and photophysical properties of these new materials.

Main Methods:

• Synthesis of soluble polymers and monodisperse oligomers of the B═P-substituted poly(p-phenylene vinylene) (BP-PPV) type.
• Structural and photophysical investigations.
• Density Functional Theory (DFT) calculations.

Main Results:

• Successful synthesis of soluble BP-PPV polymers and monodisperse oligomers.
• Evidence of effective π-conjugation along the polymer backbone, comparable to B═N analogs.
• Observation of distinct fluorescence emission in solution.
• Demonstration of aggregation-induced emission enhancement (AIEE) from a P-pyramidalized excited state.

Conclusions:

• The first successful substitutional doping of poly(p-phenylene vinylene) with B═P linking groups has been achieved.
• The novel BP-PPV materials exhibit promising optoelectronic properties, including effective π-conjugation and AIEE.
• This work opens new avenues for designing advanced organic materials using B═P units.