Sodium alginate-modified copper catalytic membrane for carbene N–H insertion

Abstract

A novel copper-based catalytic membrane (Cu@SA-CM) was fabricated via surface cross-linking using sodium alginate as a green modifier. Characterization via FTIR, FESEM, EDS, and XPS confirms that copper is uniformly dispersed on the membrane and predominantly exists in the +2 oxidation state (Cu²⁺). This membrane efficiently catalyzes N–H insertion of carbenes, generated from diazo compounds, into N-heterocycles under mild conditions with high selectivity. In a continuous-flow system, Cu@SA-CM maintained consistent performance over 20 cycles, attributed to sodium alginate's dual role in coordination and gel network formation. Gram-scale synthesis and recycling tests further demonstrated its robust activity and stability, highlighting its potential for sustainable catalytic applications.