A VUV Photoionization Study of the Formation of the Indene Molecule and Its Isomers

作者:Zhang Fangtong; Kaiser Ralf I*; Kislov Vadim V; Mebel Alexander M; Golan Amir; Ahmed Musahid
来源:Journal of Physical Chemistry Letters, 2011, 2(14): 1731-1735.
DOI:10.1021/jz200715u

摘要

The aromatic indene molecule (C(9)H(8)) "together with its acyclic isomers (phenylallene, 1-phenyl-1-propyne, and 3-phenyl-1-propyne) were formed via a "directed synthesis" in situ utilizing a high-temperature chemical reactor under combustion-like conditions (300 Torr, 1200-1500 K) through the reactions of the phenyl radical (C(6)H(5)) with propyne (CH(3)CCH) and allene (H(2)CCCH(2)). The isomer distributions were probed utilizing tunable vacuum ultraviolet (VUV) radiation from the Advanced Light Source by recording the photoionization efficiency (PIE) curves at mass-to-charge of m/z = 116 (C(9)H(8)(+)) of the products in a supersonic expansion for both the phenyl-allene and phenyl-propyne systems; branching ratios were derived by fitting the recorded PIE curves with a linear combination of the PIE curves of the individual C9H8 isomers. Our data suggest that under our experimental conditions, the formation of the aromatic indene molecule via the reaction of the phenyl radical with allene is facile and enhanced compared to the phenyl-propyne system by a factor of about 7. Reaction mechanisms and branching ratios are explained in terms of new electronic structure calculations. Our newly developed high-temperature chemical reactor presents a versatile approach to study the formation of combustion-relevant polycyclic aromatic hydrocarbons (PAHs) under well-defined and controlled conditions.

  • 出版日期2011-7-21