Solvation of lithium iodide cluster cations via bridging diamine coordination

Abstract

Diamines are well-known bidentate ligands that coordinate with metal cations; however, their solvation behavior with ionic clusters remains largely unexplored. In this study, we investigated the structures of lithium iodide ionic clusters solvated by ethylenediamine and N,N,N′,N′-tetramethylethylenediamine using electrospray ionization(ESI)–ion mobility spectrometry–mass spectrometry. Interestingly, diamines were found to stabilize ionic clusters by bridging two metal cations, even though such structures are not the most thermodynamically stable in the gas phase. We propose that these bridging structures were likely formed and kinetically trapped in the solution phase or in the highly concentrated droplets generated during the ESI process. Furthermore, we analyzed the effects of alkali metal and halide identity on solvation behavior.