How to add a five-membered ring to polycyclic aromatic hydrocarbons (PAHs) – molecular mass growth of the 2-naphthyl radical (C10H7) to benzindenes (C13H10) as a case study

• DOI: 10.1039/c9cp02930c
• Publication Date: 2019-07-11T20:04:11Z
• Authors: Long Zhao; Matthew Prendergast; Ralf I. Kaiser; Bo Xu; Utuq Ablikim; Wenchao Lu; Musahid Ahmed; Artem D. Oleinikov; Valeriy N. Azyazov; A. Hasan Howlader; Stanislaw F. Wnuk; Alexander M. Mebel
• Keywords: Polycyclic aromatic hydrocarbon

The three-ring polycyclic aromatic hydrocarbons (PAHs) 3H-benz[e]indene (C13H10) and 1H-benz[f]indene along with their naphthalene-based isomers 2-(prop-2-yn-1-yl)naphthalene (C13H10), 2-(prop-1-yn-1-yl)naphthalene 2-(propa-1,2-dien-1-yl)naphthalene were formed through a "directed synthesis"via high temperature chemical micro reactor under combustion-like conditions (1300 ± 35 K) the reactions of 2-naphthyl isomer (C10H7˙) allene (C3H4) methylacetylene (C3H4). distributions probed utilizing tunable vacuum ultraviolet radiation from Advanced Light Source (ALS) by recording photoionization efficiency curves at mass-to-charge m/z = 166 167 (13CC12H10) products in supersonic molecular beam. Complemented electronic structure calculations, our study reveals critical mass growth processes via annulation five-membered ring reaction between aryl radicals distinct C3H4 elevated temperatures as present combustion circumstellar envelopes carbon stars. underlying mechanisms proceed initial addition radical its center to π-electron density reactants entrance barriers 8 14 kJ mol-1, followed isomerization (hydrogen shifts, closure), termination atomic hydrogen losses accompanied aromatization. reflect formation indene - prototype PAH carrying single five- six-membered synthesized phenyl (C6H5˙) methylacetylene. This leads us predict that upon allene/methylacetylene may undergo de facto form building blocks essential transit planar PAHs out plane.