Experimental Evidence of Intramolecular CAr-H···O=C Hydrogen Bonds in the Structure of (Diaryl)tetrahydrofuranones Using Spectroscopic Tools

• Published in: Helvetica chimica acta Vol. 99; no. 9; pp. 716 - 723
• Main Authors: Semenok, Dmitrii V., Medvedev, Jury J., Avdontceva, Margarita S., Selivanov, Stanislav I., Sieler, Joachim, Mereshchenko, Andrey S., Nikolaev, Valerij A.
• Format: Journal Article
• Language: English
• Published: Zürich Blackwell Publishing Ltd 01.09.2016; Wiley Subscription Services, Inc
• Subjects: Diazoketones; Furanones; IR Spectroscopy; Variable-temperature NMR; Weak hydrogen bond; X-ray diffraction analyses
• ISSN: 0018-019X; 1522-2675
• DOI: 10.1002/hlca.201600149

The occurrence of bifurcate H‐bonds CAr–H···O=C in the structure of (diaryl)‐tetrahydrofuranones was experimentally demonstrated using different methods and techniques. The consistent increasing spin–spin coupling constants 1J(C,H) of the ortho‐H‐atoms and low‐field shift of vC=O in IR spectra of 2,2‐(diaryl)tetrahydrofuran‐3(2H)‐ones relative to their 5,5‐diaryl counterparts, as well as pronounced dependence of the ortho‐C–H H‐atoms chemical shifts on the temperature and solvent polarity along with X‐ray diffraction analysis data unambiguously point to the existence of weak CAr–H···O=C H‐bonds in these molecules.