Monosolvation of R-1-phenyl-2,2,2-trifluoroethanol with amines: configurational effects on the excitation, ionization, and fragmentation of diastereomeric complexes.
Wavelength and mass selected resonant two-photon ionization spectra of molecular clusters between R-1-phenyl-2,2,2-trifluoroethanol (FER) and methylamine (M) or the enantiomers of 2-aminobutane (AR and AS) were recorded after supersonic molecular beam expansion and analyzed with the aid of ab initio molecular orbital calculations. The experimental results agree with theoretical calculations pointing to the predominance of the two most stable conformers of monosolvated FER whose CF3 group establishes intense NH...F interactions with the selected amines so as to orient them away from the aromatic ring. This reduces the enantioselectivity of FER toward the 2-aminobutane enantiomers as compared to that exhibited by the R-1-phenylethanol (ER) analogue, where obviously NH...F interactions are absent.
Giardini
Anna
A
Dipartimento di Chimica, Università di Roma La Sapienza, P. zle Aldo Moro 5, I-00185 Rome, Italy. anna.giardini@uniroma1.it
Cattenacci
Gianfranco
G
Paladini
Alessandra
A
Piccirillo
Susanna
S
Satta
Mauro
M
Rondino
Flaminia
F
Speranza
Maurizio
M
D000588:Amines / Q000737:chemistry*; D007477:Ions; D008968:Molecular Conformation; D012995:Solubility; D013237:Stereoisomerism; D014270:Trifluoroethanol / Q000031:analogs & derivatives* / Q000737:chemistry
C528617:1-phenyl-2,2,2-trifluoroethanol; D000588:Amines; D007477:Ions; D014270:Trifluoroethanol