WEAK C-H$\cdots$N HYDROGEN BOND AND INTERNAL ROTATION IN THE PYRIDINE-TRIFLUOROMETANE COMPLEX
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Date
2007
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Publisher
Ohio State University
Abstract
\begin{wrapfigure}[11]{r}{6cm} \vspace{-.5cm} \hspace*{-0cm} %\epsfig{file=Fig-Pyr-CHF3.eps} \vspace{3mm} enterline{\epsfig{figure=Fig-Pyr-CHF3.eps,width=6cm}} \end{wrapfigure} The investigation of the rotational spectrum of benzene-trifluoromethane has shown that this complex is a symmetric top, with the two moieties held together through a C-H$\cdots\pi$ interaction.} When replacing the benzene with pyridine, two high electronic density sites become available in the ring. The molecular beam Fourier transform rotational spectra in a supersonic expansion of several isotopologues of pyridine-trifluoromethane show that trifluoromethane acts as a proton donor to the N lone pair. The carbon atom of trifluoromethane is in the plane of pyridine and one of its fluorine atoms makes a contact with the ring hydrogen in position 2. In addition, all rotational transitions are split due to the internal rotation of the HCF$_{3}$ group, corresponding to a barrier $V_{3}$ = 0.45(3) kJ/mol.
Description
Author Institution: Dipartimento di Chimica "G. Ciamician" dell'Universita,; Via Selmi 2, I-40126 Bologna, Italy; Istituto per lo Studio dei Materiali Nanostrutturati (ISMN, Sezione di Bologna),; CNR, Via Gobetti 101, I-40129 Bologna, Italy; Dipartimento di Chimica Fisica e Inorganica dell'Universita,; Viale Risorgimento 4, I-40136 Bologna, Italy