Unexpected discovery of estrone in the rotational spectrum of estradiol: a systematic investigation of a CP-FTMW spectrum

Abstract

We report the reinvestigation of the high-resolution rotational spectrum of estradiol. After removing the known spectral lines corresponding to three conformers of estradiol identified in the gas phase before, a...

Steroid Hormone Androsterone Observed in the Gas Phase by Rotational Spectroscopy

“…Two conformers with a different arrangement of the carbon–carbon backbone were predicted and labeled as androsterone and P-androsterone as a result of the puckering (P) in ring A for the later (Figure S2 of the Supporting Information). As already observed in the other steroids studied, − the rotation of the OH group gives rise to different stable geometries. To make a clear distinction from the conformers that differ in the carbon backbone arrangement, androsterone and P-androsterone, we refer to the different OH geometries as rotamers.…”

“…Aiming at unraveling the preferred molecule conformations, the steroids estrone, estradiol, and estriol were studied in the gas phase by laser spectroscopy methods. , Estrone, estradiol, and testosterone have also been studied in the gas phase by rotational spectroscopy. − Rotational spectroscopy coupled with supersonic expansion is a powerful tool to identify and characterize isolated molecules and weakly bound complexes in isolated environments. From the analysis of the rotational spectrum, it is possible to obtain detailed information on the molecular structures.…”

“…Furthermore, the isolated conditions provided by the supersonic expansion grant for the observation of the inherent structures free of packing effects from the crystal phases or solvent effects . Despite its power, to date, just the few steroid hormones mentioned have been reported by rotational spectroscopy (Figure S1 of the Supporting Information). − The main limitations to the study of such compounds are their size and their low vapor pressures. Steroids are rather big molecules in terms of rotational spectroscopy, complicating the analysis of the spectrum because many rotational levels are populated as a result of the small level spacing, decreasing the intensity of the experimental transitions.…”

“…Estradiol and estrone were investigated using a heatable reservoir, while testosterone was reported using a laser ablation method. The previous rotational spectroscopic studies of steroid hormones showed their versatility in the gas phase.…”

“…As such, this molecular class represents an interesting case to explore the current limits of high-resolution rotational spectroscopy. Estradiol 8 and estrone 10 were investigated using a heatable reservoir, while testosterone 9 was reported using a laser ablation method. The previous rotational spectroscopic studies of steroid hormones showed their versatility in the gas phase.…”