Crystal structures and Hirshfeld surface analyses of the hemi-hydrate and hemi-methanolate of 3α-hydroxy-16α-bromoandrostan-17-one, 3: Differences in supramolecular arrangements

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Abstract

The crystal structures and Hirshfeld surface analyses of two hemi-solvates of 3α-hydroxy-16α-bromoandrostan-17-one, 3, namely [(3)2.(H2O)] and [(3)2.(MeOH)], are reported. Both solvates crystallize in the monoclinic space group, P21, with Z = 4.. The asymmetric unit of the hemi-hydrate [(3)2.(H2O)] contains two independent but similar steroid molecules and a water molecule, while that of the hemi-methanoate [(3)2.(MeOH)] has four similar but independent steroid molecules and two methanol molecules. Very similar conformations are found for the steroid molecules in both solvates. In both solvates, the strongest intermolecular interactions are O–H···O hydrogen bonds, involving hydroxyl groups of the steroid and the solvate molecule, which result in head-to-head directly linked steroid molecules and solvate separated steroid molecules. In both cases, the oxygen atoms of the carbonyl groups of the steroids are involved in weaker C–H···O hydrogen bonds which directly link steroid molecules in tail-to-tail fashions. Combinations of the hydrogen bonds, both O–H···O and C–H···O, result in two-molecule wide sheets in the hemi-hydrate, which are further weakly linked in the hemi--methanoate into a 3-dimensional array. Very different hydrogen bonded chains are found in the two solvates.

There is a higher proportion of C–H···O to O–H···O hydrogen bonds in the hemi-methanoate, [8–6], compared to that in the hemi-hydrate [1–4]: this is an indication of the weaker solvating influence of methanol compared to water.

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