Microwave spectrum of 2,6-lutidine: barrier to internal rotation from the inertial defect of the AA state

✍ Scribed by Walther Caminati; Salvatore Di Bernardo

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 242 KB
• Volume: 171
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(90)80046-g

✦ Synopsis

The microwave spectrum of the AA sublevel of the ground state of 2,6-lutidine has been assigned. The discrepancy between the experimental inertial defect and that expected from the out-of-plane hydrogens of the two methyl groups has been used to estimate the effect of the internal rotation on the rotational constants, and therefore the V, barrier.

Changes of rotational constants due to the methyl group internal rotation are well known in the case of a single top [ I], and they have been used occasionally to evaluate the VJ barrier to internal rotation [ 21. Although several molecules with two equivalent internal rotors have been studied by microwave spectroscopy [ 31, the method to determine the V, barrier from the inertial defect has never, to our knowledge, been used or outlined for this problem.

2,Nutidine (abbreviated as LUT, see fig. 1) is an important molecule from a biological point of view. It plays, for example, an important role in the quality of taste and flavour of bread [ 4 ] and whiskey [ 51.