Swantje V M Caliebe, Pablo Pinacho, Melanie Schnell
Rotational spectroscopy was used to investigate decahydro-2-naphthol and 5,6,7,8-tetrahydro-2-naphthol, smaller molecules that resemble a part of larger steroids like estradiol, estrone, and androsterone. Quantum-chemical computations were used to explore the conformational landscape, molecular structures, and conversion pathways for different isomers and conformers of the model molecules. Eight new species were characterized, and their experimental structures showed excellent agreement with corresponding steroid hormones.
Despite the improvements in instrumentation, recording rotational spectra of large molecules (>20 non-hydrogen atoms) is still challenging. Steroid hormones are among some of the most important biomolecules due to their roles and implications in diseases and conditions. However, because of their large size and high melting points (>170 °C), there are just a handful of rotational spectroscopy studies on steroid hormones that allow for detailed structural characterization. In this work, we explore the feasibility of investigating smaller molecules as building blocks, modeling a part of larger steroids to extrapolate information on their structures and interactions. The molecules chosen, decahydro-2-naphthol and 5,6,7,8-tetrahydro-2-naphthol, resemble a part of the steroids estradiol, estrone, and androsterone. With the support of quantum-chemical computations, we explored the conformational landscape, molecular structures, and conversion pathways for different isomers and conformers for both model molecules. In total, eight new species have been characterized, and their experimental structures are compared with the corresponding steroid hormones, showing excellent agreement.