Stereochemical features of the physisorption of linear molecules in β-cyclodextrin

Molecular Dynamics Study of the Factors Influencing the β-Cyclodextrin Inclusion Complex Formation of the Isomers of Linear Molecules

“…The asymmetrical molecules tend to insert that part with larger-sized atoms inside the cavity, forming an angle of about 30 ∘ with the cavity axis when the guest centre of mass is near the narrow rim or about 10 ∘ near the wider rim. The preferential configuration of the isomer (E) was in accordance with that of the minimum interaction energy and was also found in regions of the host with maximum discriminatory power, that is, those with greatest energy differences (near the cavity walls) [19]. In contrast, the preferential configurations of isomers (A) and (B) were very different from those of minimum energy and were located near the cavity centre, where the potential energy is similar for all isomers and thus less selective.…”

“…Figure 2(c) shows the mean value of against 1 (each 1 with the corresponding 1 , Table 1 In previous work, the interaction energy was calculated between -CD and linear guest molecules whose composition was represented by two pairs of potential parameters ( 1 , 1 ; 2 , 2 ) [17][18][19]. It was found that the magnitude of the interaction energy depends mainly on the molecular composition, and the possibility of confinement or temporary residence inside the cavity depends on the potential barrier which is a consequence of the atomic distribution.…”

“…In previous work, we analysed the dependence of the interaction energy between -CD and linear guest molecules on the length, composition, and atomic distribution of the latter [19]. A minimum value of the molecular length was obtained for the differences in the interaction energy between isomers to be appreciable and thus their capacity to be separated.…”

“…With the ensemble ( 1 , 1 ; 2 , 2 ), we try to generalize atoms of different size or type without the obscuring complications of too many material parameters, and represents the ratio of each pair ( 1 , 1 ), ( 2 , 2 ). The positions of different atoms on the linear molecule are represented by the parameters [19]. The same atomic distributions (7 cases) are used as previously to assess the influence of molecular stereochemistry on the interaction energy ( 1 being < 2 ):…”

“…These parameters allow different atomic distributions to be represented in the linear molecule which result in positional isomers. The potential surfaces, energy and configuration of inclusion complexes, Journal of Chemistry and their dependence on molecular length, composition, and atomic distribution have already been analysed [17][18][19]. The curve joining the minimum potential energy for every plane = constant defines the penetration potential, which describes the variation in interaction energy when its path through the cavity is nonaxial.…”