Mesocyclic transition metal clusters with d10-d10 contacts

The increasing diversity and availability of metal clusters associated with the exact knowledge of their molecular structure and stereochemistry have stimulated considerable academic and industrial research interest. The importance of d10-d10 loose clusters derives from their interesting photophysical properties and their relevance discussed for biological systems (arthritis therapy) due to bonding energies similar to that of hydrogen bonds. The ten-membered mesocyclic compound [Hg{Fe[Si(OMe)3](CO)3(micro-dppm)2}Cu](PF6), which exhibits an unprecedented very short contact between the d10-metals Cu and Hg, shall be the basis for a systematic extensive study of d10-d10 interations involving group 10, 11 and 12 metals. Up to now a comparable investigation has not yet been performed, probably due to the lack of a suitable system. Furthermore the interesting dynamic behaviour of the ten-membered mesocycle shall be studied in more detail: The sensitivity of the "molecular torsion pendulum motion" shall be tested upon variation of metal or ligand atoms, ring size or bond angles, and introduction of new substituents. New derivatives of [Hg{Fe[Si(OMe)3](CO)3(micro-dppm)2}Cu](PF6) will be synthethised, where (i) the copper atom is replaced by another group 10, 11 or 12 d10 metal, (ii) the mercury atom is replaced by the homologs Cd or Zn, (iii) the dppm ligands are replaced by related bidendate ligands, (iv) the ring size is extended from ten to twelve by replacement of the dppm ligands by the monosulfide/-selenide of dppm. The new compounds will be characterised (i) in the solid state by single crystal x-ray diffraction and (ii) in solution by multinuclear NMR spectroscopy. (iii) The molecular dynamics shall be determined by variable temperature NMR spectroscopy and the kinetic parameters calculated by line shape analysis. Major outcomes will include the generation of (yet unknown) considerably short d10-d10 contacts in the range of the sum of the metal covalence radii, a second goal of this project is the modification of the dynamic behaviour of the mesocyclic compounds in solution.