The microwave spectrum of n-hexyl acetate and structural aspects of n-alkyl acetates

- The microwave spectrum of n-hexyl acetate has been measured.
- One conformer has been assigned and the ab initio geometry was validated.
- The lowest energy conformer has no mirror plane.
- The moment of inertia of the internal rotor were fixed to 3.197 uÅ2.
- The torsional barrier of the acetyl methyl group was determined.

The microwave spectrum of n-hexyl acetate was recorded in the range of 10-13.5 GHz using the Aachen MB-FTMW spectrometer. The rotational constants of the most abundant conformer were determined to be A = 3.3591100(32) GHz, B = 0.39596553(53) GHz, and C = 0.36999804(31) GHz. Quantum chemical calculations for specific conformers were carried out at the MP2/6-311++G(d,p) level. The programs XIAM and BELGI were used to analyze the internal rotation of the acetyl methyl group. The observed conformer of n-hexyl acetate was compared to the lowest energy conformers of n-butyl acetate and n-pentyl acetate.