Theoretical study of α-CD based [3] pseudorotaxanes: the role played by threadlike polymer on the stability of Cyclodextrin dimers

Journal of the Brazilian Chemical Society

Universidade Federal de Minas Gerais, Belo Horizonte, Brazil¹  Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil¹  Dos Santos, Hélio F.¹  Nascimento Jr., Clebio S.¹  De Almeida, Wagner B.¹  Anconi, Cleber P. A.¹ 

关键词: DFT;    alpha cyclodextrin;    dimer;    OEG;    inclusion complex;   

DOI  :  10.1590/S0103-50532008000500031

学科分类：化学（综合）

来源: SciELO

【 摘 要 】

Cyclodextrins (CDs) and polymeric chains have attracted considerable attention, being addressed in the literature as novel molecular assembly. The so-called "Molecular Necklace" synthesized by the inclusion of a polymeric chain inside CDs cavity has been employed in the formulation of molecular wires and nanotubes. In this paper we applied our previous reported mixed basis set approach in order to investigate theoretically the α-CD inclusion complexes formed by two CD units and an oligo(ethylene glycol) (OEG). In attempt to analyze the role played by the OEG in the formation of pseudo-rotaxane in gas-phase, DFT calculations were performed for six possible dimer associations of CDs, named head-to-head (HH), tail-to-tail (TT) and head-to-tail (HT) with or without an OEG threadlike molecule included in the cavity formed by the α-CD dimer. The comparison between relative energies of empty (HH, TT and HT) and filled associations (HH-OEG, TT-OEG and HT-OEG) shows that the OEG chain does not interfere significantly in the relative stabilization energies of the supramolecular systems, therefore the relative arrangements of CDs in the necklace structures should be primarily driven by interactions between cyclodextrin units.

【 授权许可】

Unknown