The Conformation of Pentanoates in the Solid and in the Gas Phase
-
Carina Merkens
,
Halima Mouhib
Suitable derivatives of the four isomeric pentanoates have been structurally characterized in the solid and the gas phase. For the latter, the volatile ethyl esters of valeric, isovaleric, methylbutyric, and pivalic acid were investigated by a combination of molecular beam Fourier transform microwave (MB-FTMW) spectroscopy and theoretical calculations. Crystalline salts rather than esters were formed by reaction between the carboxylic acids and trans-1,2-diaminocyclohexane. For both gaseous and crystalline methylbutyrates, an essentially perpendicular arrangement of carboxylate and methyl group was observed; earlier structure determinations documented in the data base agree with this result. Two competing conformers of favourable energy were relevant for the corresponding isovalerates: They were associated with torsion angles around 20° and 50° between the carboxylate and the alkyl chain. Good agreements in conformation have also been achieved for our experimentally observed unbranched valerate derivatives and fully branched pivalates in solid and gas phase. Despite the apparent simplicity of the pentanoates, the identification of their lowest energy conformers represents a challenge for different methods and levels of theory.
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Artikel in diesem Heft
- Dedicated Editorial Communication: Jörg Fleischhauer 75
- Towards Correlated Sampling for the Fixed-Node Diffusion Quantum Monte Carlo Method
- Maxwell’s Demon Observing Creation of a Molecular Vibration
- Electronic and Magnetic Properties of the Graphene/Eu/Ni(111) Hybrid System
- The Conformation of Pentanoates in the Solid and in the Gas Phase
- The Role of Heme Chirality in the Circular Dichroism of Heme Proteins
- Convenient Small-Scale Preparation of p-Carborane by Pyrolysis of o-Carborane
- Computational Study of the Structure, the Flexibility, and the Electronic Circular Dichroism of Staurosporine – a Powerful Protein Kinase Inhibitor
- Quantum-Chemical Investigations on the Structural Variability of Anion–π Interactions
- Quantum-Chemical Ab Initio Calculations on Ala-(C5H5Al) and Galabenzene (C5H5Ga)
- A Short Review on the Magnetic Effects Occurring at Organic Ferromagnetic Interfaces Formed between Benzene-Like Molecules and Graphene with Ferromagnetic Surfaces
- Theoretical Analysis of the Unusual Vicinal Effects on Electronic Circular Dichroism Spectra of Cobalt(III) Complexes with ED3A-Type and Related Ligands
- Bonding Situation in Dimeric Group 15 Complexes [(NHC)2(E2)] (E = N–Bi)
