Akademik Veri Yönetim Sistemi
JOURNAL OF PHYSICAL CHEMISTRY A, cilt.123, sa.17, ss.3831-3839, 2019 (SCI-Expanded)
Conformers and near-IR-induced conformational transformations were studied for monomers of glycolamide isolated in low-temperature matrixes. Two conformational isomers of the compound, Tt and Cc, were trapped from the gas phase into solid Ar matrixes. Selective near-IR excitation of glycolamide molecules adopting the Tt form led to the Tt -> Cc conformational conversion. Analogously, selective near-IR excitation of Cc conformers resulted in the Cc -> Tt transformation. Monochromatic near-IR light, generated by frequency-tunable laser sources, was used for irradiation of matrix-isolated monomers. Near-IR-induced Tt -> Cc and Cc -> Tt conformational transformations occurred upon excitation of 2 nu OH, 2 nu aNH(2), and 2 nu sNH2 overtones, as well as upon excitation of nu aNH2 + nu sNH2 combination modes. In spite of the structural similarity of glycolamide and N-hydroxyurea, no conformational conversions were observed for monomers of the latter compound isolated in Ar matrixes and excited with near-IR light. The comparison of the effects of near-IR excitations of glycolamide and N-hydroxyurea demonstrates that transformations involving rotation of molecular fragments around a single C-C bond occur much easier than transformations involving rotation of the fragments around a C-N bond. The efficiency of the latter conversions is extremely low.