Intermolecular hydrogen bonding of N-methylformamide in aqueous environment: A theoretical study

Abstract The intermolecular hydrogen bonding of N-methylformamide (NMF) in water is investigated. Ground-state geometry optimizations and binding energies were calculated with density functional theory (DFT). Electronic transition energies, and corresponding oscillator strengths of low-lying electronically excited states of free NMF monomers and hydrogen-bonded NMF–(H 2 O) 2,3 complexes were calculated with time-dependent density functional theory (TDDFT). Electronic absorption spectra red-shift occurs due to the formation of the intermolecular hydrogen bonds O NMF ⋯H O water and N H⋯O water . Larger electronic absorption spectrum red-shift in trans -NMF–(H 2 O) 2,3 than in cis -NMF–(H 2 O) 2,3 can be attributed to stronger excited state hydrogen bond strengthening in trans -NMF–(H 2 O) n complexes.