Design and assembly architectures of interlocked molecules, such as catenanes and rotaxanes, are dictated by various types of noncovalent interactions. In particular, p-p stacking, [C-H���O] hydrogen-bonding, and [C-H���p] interactions in these supramolecular complexes have been identified as important noncovalent interactions. A key question that arises in this research is how well force fields calibrate against quantum mechanical methods? In this context, calibration affords the ability to model and capture important interactions of supramolecular structures, which are computationally expensive with ab initio methods. Our results indicate that the QM (HF, MP2 and DFT) and MM3 structural geometry parameters are in good agreement for a modeled [3] catenane complex. Also, the MM3 calculated complexation energies agree qualitatively with the QM energetic ordering. The qualitative predictions using density functional theory symmetry-adapted intermolecular perturbation theory (DFT-SAPT), which is known to model noncovalent interactions (such as, dispersion and electrostatics) accurately will also be highlighted.

Insight into the nature of noncovalent interactions in supramolecular complexes: Calibrating the MM3 force field with ab initio methods

245th National Meeting (2013)

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