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  • Open Access

Mechanistic DFT studies – helicate-type complexes with different alcylic spacers

Journal of Cheminformatics20124 (Suppl 1) :P9

  • Published:


  • Long Range
  • Meso
  • Exchange Interaction
  • Transition Energy
  • Supramolecular Chemistry
Metal-controlled self-assembly of complexes is of high interest in the field of Supramolecular Chemistry [1, 2]. In the current study, we synthesized binuclear complexes with different spacers and study the influence of chain length on their relative energy. The considered complexes prefer the zigzag conformation. Thus a bridge with an odd number of methylene units forms a meso-Helicate (ΔΛ or ΛΔ) and one with an even number leads to a Helicate (ΔΔ or ΛΛ) (figure 1) [3, 4].
Figure 1
Figure 1

Geometrically optimized complexes with Ti(IV); left: energies of the complexes with different alcylic spacers; right: ΔΔ and ΛΔ form of the complex with a propylene spacer.

Comparison of the calculated transition energies for the non-dissociative interconversions of the diastereomeres with experimental results provides inside into the isomerization process. Moreover, insertion of different cations (templates) into the cavities of the binuclear complexes and corresponding calculations allow prediction of their influence on the isomerization.

Enlargement of the studied system results in binuclear complexes with imino-bridged ligands. The obtained computational results provide a possible explanation for the experimentally observed high diastereoselectivity.

As the DFT functionals like B3LYP do not describe long-range interactions properly, we chose the coulomb-attenuating method CAM-B3LYP [5] which corrects the exchange interaction at long range. The complexes with Ti(IV) in their helical or meso form have been geometrically optimized at the CAM-B3LYP level of theory with the TZVP basis set and MDF10 as ECP for Ti(IV) as implemented in the program package Gaussian09 [6].

Authors’ Affiliations

Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany


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© Gossen et al; licensee BioMed Central Ltd. 2012

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.