A computational, X-ray crystallographic and thermal stability analysis of TETROL and its pyridine and methylpyridine inclusion complexes

Clathrates of TETROL: selective inclusion of methylcyclohexanones in their energetically unfavorable axial methyl conformations

“…We recently described a computational study on 1 which revealed that in its lowest energy structure, the butane chain adopts an anti conformation, with the four hydroxy groups in a syn arrangement with respect to the butane backbone, and stabilized through a pair of 1,3-hydrogen bonding interactions. 1 A single crystal X-ray diffraction analysis of 1 confirmed this geometry. Six independent molecules were located in the asymmetric unit of the crystal, forming three distinct dimeric motifs via intermolecular O-HÁ Á ÁO hydrogen bonds.…”

Clathrates of TETROL: Further Aspects of the Selective Inclusion of Methylcyclohexanones in Their Energetically Unfavorable Axial Methyl Conformations

“…The crystals were collected, washed thoroughly with petroleum ether, and dried under suction filtration. 1 H NMR experiments were conducted on the resultant solids to determine whether inclusion had occurred and, if so, the host/guest (H/G) ratios. All four cyclohexanones formed inclusion complexes in this way, each with a 1:1 H/G ratio.…”

“…This compound was synthesized according to a published procedure. 1 This afforded a gum that was crystallized and recrystallized from CH 2 Cl 2 /hexane/MeOH to afford (+)-(2R,3R)-1,1,4,4-tetraphenylbutane-1,2,3,4-tetrol 1 as a white solid (45%), mp 147−149°C (lit., 10 Preliminary structures were determined using the MMFF (Merck Pharmaceuticals) force field, followed by further geometry refinement at the DFT level using the B3LYP functional and progressively employing the 6-31G*, 6-311++G**, and 6-311++G(2df,2p) basis sets. Thermochemical calculations were carried out at the G3(MP2) and MP2/6-311++G(2df,2p) levels, with the former approach providing standard enthalpies of formation, and the latter, total Gibbs free energies at 298.15 K and 1 atm of pressure.…”

“…1 As TETROL is chiral, it has the potential for stereoselective inclusion of guest compounds, similar to that with the structurally related TADDOLs. 2 We subsequently reported as a short communication 3 that TETROL enclathrates cyclohexanone 2a as well as the isomeric 2-, 3-, and 4-methylcyclohexanones (2b, 2c, and 2d), with 2c and 2d in their energetically unfavorable axial conformations.…”

A simple polarimetry technique for predicting the absolute configuration of the preferred enantiomer in chiral host-guest inclusion complexes

“…Our research group has shown that the chiral host compound (+)-(2R,3R)-1,1,4,4-tetraphenylbutane-1,2,3,4-tetraol (TETROL, 1) and its derivatives (2-4) (Scheme 1) are able to form inclusion complexes with a large number of guests. 10 Some of the successful guests are chiral, and we were required to determine whether these hosts are able to discriminate between enantiomers of the racemic chiral guests during recrystallization experiments. More specifically, guests in this category of interest to us were 2and 3-methylcyclohexanone, methyl phenyl sulfoxide and 2-butanol, all of which are included with 1:1 host:guest ratios by these hosts, as shown by 1 H-NMR spectroscopy.…”