title: Dominant conformer of tetrahydropyran-2-methanol and its clusters in the gas phase explored by the use of VUV photoionization and vibrational spectroscopy.
abstract: Tetrahydropyran-2-methanol (THPM) is a typical alcohol containing a six-member cyclic ether, which can be considered as the model molecule of cyclic sugar. Herein, vacuum ultraviolet (VUV) photodissociation spectroscopy is employed to study fragmentation pathways and infrared (IR) plus VUV photoionization spectroscopy to investigate the structures of neutral THPM and its clusters with the size up to the trimer. Qualitative structural assignments are confirmed for the neutral species and ions based on MP2/aug-cc-pVTZ and ωB97X-D/cc-pVTZ calculations. The fragment cations at m/z = 84, 85, and 98 arise by the losing of CH2OH, CH3OH, and H2O from the monomer, respectively, as a result of C-C bond and C-O bond dissociation under the VUV (118 nm) radiation. It is found that the loss of CH3OH and H2O involves hydrogen transfer from the CH2group to the dissociating CH2and OH groups. Comparing the observed and calculated spectra of the monomer THPM, it suggests that the conformer containing a chair tetrahydropyran ring and an intramolecular hydrogen bond would be dominantly survived in a supersonic beam. Moreover, the IR spectra of larger clusters n > 1 (n = 2, 3) show only the broad hydrogen bonded OH stretch mode, and thus these larger clusters would form a closed-cyclic structure, where all OH groups are participating in hydrogen bonding. Partially the CH stretch positions of THPM clusters do not change significantly with the increasing of cluster size, thus the CH and CH2groups are not involved in H-bonding interactions.
authors.affiliation: MOE Key laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, People's Republic of China.
authors.forename: Huaqi
authors.initials: H
authors.lastname: Zhan
authors.affiliation: MOE Key laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, People's Republic of China.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Hu
authors.affiliation: MOE Key laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, People's Republic of China.
authors.forename: Pengchao
authors.initials: P
authors.lastname: Wang
authors.affiliation: MOE Key laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631, People's Republic of China.
authors.forename: Jiaxin
authors.initials: J
authors.lastname: Chen