Modeling of a Rotaxane-Based Molecular Device

A computational procedure is presented for investigating photoinduced switchable rotaxanes and demonstrated for a known system. This procedure starts with the generation of > 10 4 chemically reasonable rotaxane coconformations based on an empirical intramolecular potential-energy function. Each of the structures is then assigned by its gross structural features (coiled or extended) and by the position of the ring along the shaft. Single-point energy calculations at the semiempirical (AM 1) level are then carried out for each structure in the singlet (ground), triplet, and anionic doublet states. The structural features are then correlated with energy for each state. What emerges is a profile of the structure-energy relationship that captures the salient features of the system that endow it with devicelike character. The full geometry optimization of a subset of the coconformations demonstrates that the procedure based on single-point calculations is sufficient to obtain a profile of the relationship of the structural features to energy that is consistent with experiments at a greatly reduced computational cost.

[1]  I. V. van Stokkum,et al.  Enhanced hydrogen bonding induced by optical excitation: unexpected subnanosecond photoinduced dynamics in a peptide-based [2]rotaxane. , 2001, Journal of the American Chemical Society.

[2]  F. Paolucci,et al.  Photoinduction of Fast, Reversible Translational Motion in a Hydrogen-Bonded Molecular Shuttle , 2001, Science.

[3]  Bobby G. Sumpter,et al.  Semi-empirical study of a prototype rotaxane-based molecular shuttle , 1999 .

[4]  K. Sohlberg,et al.  Computational prediction of trends in the selectivity of macrocyclic receptors for anions , 1995 .

[5]  Q. Guo,et al.  PM3 studies on the complexation of α-cyclodextrin with benzaldehyde and acetophenone , 2000 .

[6]  A. Troisi,et al.  A quantum-mechanical description of macrocyclic ring rotation in benzylic amide. , 2001, Chemistry.

[7]  Mark S. Gordon,et al.  General atomic and molecular electronic structure system , 1993, J. Comput. Chem..

[8]  R. Schmieder,et al.  From rotaxanes to knots. Templating, hydrogen bond patterns, and cyclochirality , 2000 .

[9]  A. Troisi,et al.  Reducing Molecular Shuttling to a Single Dimension. , 2000, Angewandte Chemie.

[10]  J. F. Stoddart,et al.  Making molecular-necklaces from rotaxanes , 2002 .

[11]  W. Fabian.  AM1 calculations of rotation around essential single bonds and preferred conformations in conjugated molecules , 1988 .

[12]  A. Raudino,et al.  Hydrogen bonding and rotation barriers: A comparison between MNDO and AM1 results , 1988 .

[13]  Liliana Y. A. Dávila,et al.  Applicability of MNDO techniques AM1 and PM3 to ring‐structured polymers , 2002, J. Comput. Chem..

[14]  W. L. Jorgensen,et al.  Development and Testing of the OPLS All-Atom Force Field on Conformational Energetics and Properties of Organic Liquids , 1996 .