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.

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