title: Noncovalent interactions in the gas phase: the anisole-phenol complex.
abstract: The present paper reports on an integrated spectroscopic study of the anisole-phenol complex in a molecular beam environment. Combining REMPI and HR-LIF spectroscopy experimental data with density functional computations (TD-M05-2X/M05-2X//N07D) and first principle spectra simulations, it was possible to locate the band origin of the S(1) ← S(0) electronic transition and determine the equilibrium structure of the complex, both in the S(0) and S(1) electronic states. Experimental and computational evidence indicates that the observed band origin is due to an electronic transition localized on the phenol frame, while it was not possible to localize experimentally another band origin due to the electronic transition localized on the anisole molecule. The observed structure of the complex is stabilized by a hydrogen bond between the phenol, acting as a proton donor, and the anisole molecule, acting as an acceptor through the lone pairs of the oxygen atom. A secondary interaction involving the hydrogen atoms of the anisole methyl group and the π electron system of the phenol molecule stabilizes the complex in a nonplanar configuration. Additional insights about the landscapes of the potential energy surfaces governing the ground and first excited electronic states of the anisole-phenol complex, with the issuing implications on the system photodynamic, can be extracted from the combined experimental and computational studies.
authors.affiliation: LENS, Polo Scientifico e Tecnologico dell'Università di Firenze, Via Nello Carrara 1, 50019 Sesto Fiorentino (FI), Italy. gianni.pietraperzia@unifi.it
authors.forename: Giangaetano
authors.initials: G
authors.lastname: Pietraperzia
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Pasquini
authors.forename: Federico
authors.initials: F
authors.lastname: Mazzoni
authors.forename: Giovanni
authors.initials: G
authors.lastname: Piani
authors.forename: Maurizio
authors.initials: M
authors.lastname: Becucci
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Biczysko
authors.forename: Daniel
authors.initials: D
authors.lastname: Michalski
authors.forename: Julien
authors.initials: J
authors.lastname: Bloino
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Barone
mesh_terms: D000840:Anisoles / Q000737:chemistry*; D002627:Chemistry, Physical; D004583:Electrons; D005740:Gases / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D006860:Hydrogen Bonding; D008958:Models, Molecular; D010100:Oxygen / Q000737:chemistry; D019800:Phenol / Q000737:chemistry*; D011522:Protons; D013057:Spectrum Analysis / Q000379:methods*; D013816:Thermodynamics
chemical_list: D000840:Anisoles; D005740:Gases; D011522:Protons; D019800:Phenol; D006859:Hydrogen; C060998:anisole; D010100:Oxygen