Urea derivatives have significant applications in the synthesis of resin precursors, dyes, agrochemicals, and pharmaceutical drugs. Furthermore, polyureas are useful plastics with applications in coating, adhesive, and biomedical industries. However, the conventional methods for the synthesis of urea derivatives and polyureas involve toxic reagents such as (di)isocyanates, phosgene, CO, and azides. We present here the synthesis of (poly)ureas using much less toxic reagents(di)amines and methanolvia a catalytic dehydrogenative coupling process. The reaction is catalyzed by a pincer complex of an earthabundant metal, manganese, and liberates H 2 gas, valuable by itself, as the only byproduct, making the overall process highly atomeconomic. A broad variety of symmetrical and unsymmetrical urea derivatives and polyureas have been synthesized in moderate to quantitative yields using this catalytic protocol. Mechanistic insights have also been provided using experiments and DFT computation, suggesting that the reaction proceeds via an isocyanate intermediate.
We report here the synthesis of polyureas from the dehydrogenative coupling of diamines and diformamides. The reaction is catalysed by a manganese pincer complex and releases H2 gas as the only by-product making the process atom-economic and sustainable. This work advances the current state-of-the-art by replacing a toxic feedstock – diisocyanates (used to make polyureas) with a safer feedstock – diformamides and using a catalyst based on an earth-abundant metal. We also report here the physical and mechanical properties of the isolated polyureas. We suggest that the reaction proceeds via isocyanate intermediates that are formed by the manganese catalysed dehydrogenation of formamides.
We report here the first example of the use of an organic “polyurea” polymer as a SEI-forming additive for the lithium metal anode for lithium oxygen batteries. The presence of a suitable polyurea can significantly increase the coulombic efficiency and cycling of the anode in the presence of oxygen in the liquid electrolyte. The findings demonstrate proof of concept for the application of polyureas and other organic polymers for next-generation type batteries with metal anode.
We report here the synthesis of polyureas from the dehydrogenative coupling of diamines and diformamides. The reaction is catalysed by a manganese pincer complex and releases H2 gas as the...
Urea derivatives are prevalent intermediates in the synthesis of resin precursors, dyes, agrochemicals, and pharmaceutical drugs. Furthermore, polyureas are useful plastics with applications in coating, adhesive, and biomedical industries and have a current annual market of USD 885 million. However, the conventional methods for the synthesis of urea derivatives and polyureas involve toxic reagents such as (di)isocyanates, phosgene, CO, and azides. We present here the synthesis of (poly)ureas using much less toxic reagents - (di)amines, and methanol via a catalytic dehydrogenative coupling process. The reaction is catalyzed by a pincer complex of an earth-abundant metal, manganese, and liberates H2 gas, valuable by itself, as the only by-product making the overall process atom-economic, and sustainable. A broad variety of symmetrical, and unsymmetrical urea derivatives and polyureas have been synthesized in moderate to quantitative yields using this catalytic protocol. Mechanistic insights have also been provided using experiments and DFT computation suggesting that the reaction proceeds via an isocyanate intermediate.
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