3,3′-Bipyridine and N-Alkyl Glycinates as Building Blocks for Cu-Based Bio-Inspired MOFs

Bio-inspired metal–organic frameworks have attracted considerable attention due to their structural versatility and potential applications in catalysis, sensing, and drug delivery. We report the synthesis, structural elucidation, thermal behaviour, and catalytic properties of the first copper(II)-based coordination polymers constructed from 3,3′-bipyridine and N-alkylated glycine derivatives. SCXRD showed that all compounds {[Cu(μ-MeGly)(NO3)(μ-3,3′-bpy)]·DMF·0.5H2O}n (1a), {[Cu(μ-MeGly)(NO3)(μ-3,3′-bpy)]·solvate}n (1b), {[Cu(μ-EtGly)(NO3)(μ-3,3′-bpy)]·DMF·0.5H2O}n (2a), and {[Cu(μ-EtGly)(NO3)(μ-3,3′-bpy)]·solvate}n (2b), (3,3′-bpy = 3,3′-bipyridine; MeGly = N-methylglycine; EtGly = N-ethylglycine) form three-dimensional coordination networks in which Cu(II) centres are interconnected through donor N-alkylated glycinate and 3,3′-bipyridine linkers. Bulk-phase characterisation confirmed the reproducible formation of 1a and 2b, while instability and solvent loss limited the isolation and characterisation of 2a and 1b. The bulk materials of 1a and 2b were further characterised by PXRD and 1a by FTIR, ESR, SEM/EDS, TGA, simultaneous TGA-FTIR and CHN analysis. Catalytic studies of compound 1a demonstrated moderate-to-high activity in the oxidation of cyclooctene, linalool, limonene, and cyclohexane. The catalytic results suggest that 1a acts as a precatalyst, with the catalytically active species potentially forming under the reaction conditions; thus, the observed activity cannot necessarily be attributed to the intact MOF structure. These findings establish N-alkylated glycine derivatives as promising bio-inspired building blocks for the design of Cu-based MOFs and provide valuable insight into structure–property relationships and the potential role in catalysis.