Design of N-(benzothiazol-2-yl)benzamide-Pd complexes with amine and diphosphine co-ligands to enhance hydrogen storage: increasing structural diversity while maintaining uniqueness

This study entails the synthesis and characterization of palladium complexes containing N-(benzothiazol-2-yl)benzamide (LH) along with various hybrid ligands, including 2-aminopyridine (2amp), 4-aminopyridine (4amp), phenanthroline (Phen), triphenylphosphine (PPh₃), as well as diphosphines such as dppp and dppb. Characterization of the prepared complexes was performed using molar conductivity analyses, FTIR, ³¹P-NMR, ¹H-NMR, and ¹³C-NMR spectra. The proposed geometry around the metal ion is mostly planar, with the LH bond acting as a bidentate bond via the N atom of the pentameric ring in the benzothiazole and the O atom of the carbonyl group. The hydrogen storage capacities of selected complexes were evaluated under high pressure using the VTI/HPVA method. The results indicate that all complexes studied exhibit hydrogen storage capacity, with the highest storage values observed in [Pd(LH)(4amp)₂]Cl₂, [Pd(LH)(dppb)]Cl₂, and [Pd(LH)(PPh₃)Cl]Cl complexes reach 471, 212, 166 mL g⁻¹, respectively.