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Microwave Spectroscopy and Structure of the 1-Fluoronaphthalene···H2O Complex: Two Hydrogen Bonds Make the Complex a
Surabhi Gupta1, Charlotte N Cummings2, Nicholas R Walker2
1Department of Inorganic and Physical Chemistry, Indian Institute of Science Bangalore, Bengaluru560012, India.
Abstract:
The microwave spectrum of the complex formed between 1-fluoronaphthalene and H2O has been recorded using a chirped pulse Fourier transform microwave spectrometer within the frequency range of 2.0 to 8.0 GHz, with neon as the carrier gas. The rotational spectra of the isotopologues 1-fluoronaphthalene···H2O, 1-fluoronaphthalene···D2O, 1-fluoronaphthalene···DOH, and 1-fluoronaphthalene···H218O have been assigned and analyzed. By considering the rotational constants of all four isotopologues, the structure of the complex has been determined. Specifically, H2O interacts with 1-fluoronaphthalene in an in-plane orientation, acting as a hydrogen bond donor and a weak hydrogen bond acceptor, resulting in the formation of O-H···F and C-H···O hydrogen bonds, respectively. The observed rotational spectra could be fit as a rigid rotor without any centrifugal distortion constants, a rare observation for a weakly bound complex formed in a supersonic beam. Atoms in molecules (AIM) and natural bond orbital (NBO) theoretical analyses of the complex confirm the presence of O-H···F and C-H···O hydrogen bonds.
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