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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.
The Journal of Physical Chemistry. A
|September 10, 2025
Summary
The microwave spectrum of 1-fluoronaphthalene and water (H₂O) complex reveals a rare rigid rotor structure. This study identifies specific O-H···F and C-H···O hydrogen bonds in the weakly bound complex.
Area of Science:
- Molecular spectroscopy
- Physical chemistry
- Supramolecular chemistry
Background:
- Weakly bound complexes offer insights into non-covalent interactions.
- Understanding hydrogen bonding in fluorinated aromatic systems is crucial.
Purpose of the Study:
- To investigate the structure and hydrogen bonding of the 1-fluoronaphthalene-water complex.
- To analyze the rotational spectra of various isotopologues.
Main Methods:
- Chirped pulse Fourier transform microwave spectroscopy (CP-FTMW)
- Analysis of rotational constants for four isotopologues (H₂O, D₂O, DOH, H₂¹⁸O)
- Atoms in Molecules (AIM) and Natural Bond Orbital (NBO) theoretical analyses
Main Results:
- The 1-fluoronaphthalene-water complex exhibits a rare rigid rotor structure.
- Water acts as both a hydrogen bond donor (O-H···F) and acceptor (C-H···O).
- The complex forms in an in-plane orientation with specific hydrogen bond types.
Conclusions:
- The structure of the 1-fluoronaphthalene-water complex is determined via rotational spectroscopy.
- AIM and NBO analyses confirm the presence and nature of the identified hydrogen bonds.
- The rigid rotor behavior is an unusual characteristic for such weakly bound complexes.
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