Steroidal Wheel-and-Axle Host Type Molecules: Insights from Awkward Shape, Conformation,Z′ > 1 and Packing

Abstract

The synthesis and crystal structure of three new molecular rotors derived from levonorgestrel and norethisterone are reported. The conformation, close contacts, and shape characteristics of these molecules exhibiting Z′ = 2 and the inclusion of solvent molecules were analyzed together with the crystal structures of parent molecules retrieved from the Cambridge Structural Database. For the set of estranes studied, we confirmed that whenever an alternative conformer cannot satisfy the crystallographic symmetry, a second molecule is incorporated in the asymmetric unit resulting in conformational isomorphism (Z′ > 1). The shape of these molecules could make them interesting as potential hosts.

Steroidal Molecular Rotors with 1,4-Diethynylphenylene Rotators: Experimental and Theoretical Investigations Toward Seeking Efficient Properties

“…Dimer 3 (1,4-bis[4-estren-17α-ethynyl-18 a -homo-17β-ol-3-one]-benzene) and 3D (1,4-bis[4-estren-17α-ethynyl-18 a -homo-17β-ol-3-one]-benzene- d 4 ) were obtained in the same manner as rotors 1 and 1D (see Scheme 2 ). Compound 3 was proved to be identical to that described by Santillan et al 17 The structure of compound 3D was established by 1 H, 13 C NMR, ATR-IR, and HRMS.…”

“…The theoretical calculations were performed for molecules of rotor 3 , for which the crystallographic structure has been published. 17 The calculated and experimental Raman and IR spectra of rotor 3 are shown in Figure 5 . Moreover, all calculated wavenumbers, activity in Raman and IR spectra, and proposed assignment are presented in Table S1 in the Supporting Information .…”

“…Raman and ATR-IR spectroscopy methods were used, and the experimental results were verified by theoretical calculations using the B3LYP/6-31G­(d) method. The theoretical calculations were performed for molecules of rotor 3 , for which the crystallographic structure has been published . The calculated and experimental Raman and IR spectra of rotor 3 are shown in Figure .…”

“…The dynamics of selected molecular rotors were simulated with the use of Gaussian03 18 and Gaussian16. 19 Density functional theory (DFT) calculations using a B3LYP/6-31G(d) basis set were carried out for an isolated molecule of rotor 3 ( Figure 4 ) on the basis of structural data from the CIF file arising from X-ray analysis reported by Santillan et al 17 In order to select a molecule for the optimization process, structural data analysis was performed using Olex 2 crystallography software.…”

Structural studies on inclusion compounds and solvent sorption behavior of gradually elongated wheel-and-axle-type diol hosts featuring lateral benzo[b]thiophene units

“…Moreover, derived from the existing findings, the length of the central axis is demonstrated to decisively control the void dimensions as well as the mode of aggregation in the crystal including, e.g., wheel-and-axle or shish-kebab type shapes of supramolecular scaffolds [8,9], aside from the kind of subunits that compose the molecular wheels exercising a similar effect. Only recently, steroidal wheel-and-axle-type hosts [11] as well as the exchange of the lateral aryl groups of respective host molecules against heterocycles [12] opened up a further new way of structural modification, showing high potential to control inclusion selectivity of organic guest species. This has been confirmed by the host molecules BTh1 and BTh2 ( Differing from the literature description [15], the dimethyl dicarboxylate 7 was prepared from 4-(methoxycarbonyl)phenylboronic acid (synthesized by literature procedures [16,17]) and methyl 4-iodobenzoate in the presence of Pd(PPh3)2Cl2 and NaHCO3 in water/THF following a Suzuki-Miyaura type reaction [18].…”