How water links to cis and trans peptidic groups: the rotational spectrum of N-methylformamide-water.
We investigated the Fourier transform microwave spectra of the hydrated forms of N-methylformamide (NMF) in a supersonic expansion and assigned the rotational spectra of two mono-hydrated species. The conformation of each molecular complex was reliably determined on the basis of the values of the rotational constants, of the relative intensities of mu(a)- and mu(b)-type transitions, and of the features of the (14)N quadrupole hyperfine structure of the rotational transitions. In both complexes water acts as a proton donor and NMF has a trans configuration of the peptidic group. In the most stable of these conformers, water is also weakly bound to the methyl group.
Caminati
Walther
W
Grupo de Espectroscopía Molecular, Departamento de Química Física y Química Inorgánica, Facultad de Ciencias, Universidad de Valladolid, E-47005 Valladolid, Spain. walther.caminati@unibo.it
López
Juan Carlos
JC
Blanco
Susana
S
Mata
Santiago
S
Alonso
Josè Luis
JL
D005559:Formamides / Q000737:chemistry*; D006860:Hydrogen Bonding; D008958:Models, Molecular; D008968:Molecular Conformation; D010455:Peptides / Q000737:chemistry*; D012399:Rotation; D013057:Spectrum Analysis; D013237:Stereoisomerism; D014867:Water / Q000737:chemistry*
D005559:Formamides; D010455:Peptides; D014867:Water; C002950:methylformamide