Controlled Synthesis of Well-Defined Polyaminoboranes on Scale Using a Robust and Efficient Catalyst

Area of Science:

• Organometallic Chemistry
• Polymer Chemistry
• Catalysis

Background:

• The synthesis of polyaminoboranes is crucial for advanced materials.
• Dehydropolymerization offers a pathway to these polymers, but requires efficient catalysts.

Purpose of the Study:

• To develop an air-tolerant precatalyst for selective N-methylpolyaminoborane synthesis.
• To elucidate the catalytic mechanism and control polymer properties.

Main Methods:

• Kinetic studies
• Speciation analysis
• Density Functional Theory (DFT) calculations
• Isotopic labeling
• Eyring analysis
• Thermal analysis (TGA, DSC)

Main Results:

• An air-tolerant rhodium precatalyst, [Rh(L)(NBD)]Cl, selectively produces N-methylpolyaminoborane.
• The active catalyst Rh(L)H3 is formed during an induction period.
• A cooperative ligand facilitates dehydrogenation, leading to chain propagation.
• High molecular weight polymers with controllable molecular weights were obtained.
• Polyaminoboranes exhibit a processing window for various fabrication techniques.

Conclusions:

• The study presents a robust catalytic system for polyaminoborane synthesis.
• The mechanism involves catalyst activation, templated dehydrogenation, and controlled propagation.
• The resulting polymers are processable into diverse forms, highlighting their material potential.