PUB - Publikationen an der Universität Bielefeld

Trisilacyclohexanes and bissilylmethanes with acetylene units attached to silicon sites have been converted into tri- and di-nuclear gold(I)phosphane complexes and characterized by NMR spectroscopy and X-ray diffraction. The bissilylmethane-based gold complexes were used as a test system to work out the synthetic routes before transferring them to the trisilacyclohexane scaffolds, because the latter are more difficult to access. The occurrence of aurophilic interactions (short Au & sdot; & sdot; & sdot; Au contacts) depends on the steric bulk of the phosphorus-bonded alkyl and aryl groups. DFT studies show that dispersion effects play an important role in the ability to form intramolecular Au & sdot; & sdot; & sdot; Au interactions. QTAIM analyses show that a subtle change of the steric bulk of the phosphane groups alters the relative strength of the dispersion and aurophilic interactions. The combination of DFT studies and X-ray diffraction experiments shows that the conformation of the trisilacyclohexane backbone is also phase dependent. Di- and tridentate alkyne backbones were synthesized and functionalized with gold-phosphane groups to study their ability to form intramolecular aurophilic interactions. Especially the trisilacyclohexane is an interesting backbone due to its geometric flexibility. Crystal structures as well as DFT calculations show differences between the experimental observations in the solid state and predictions for free molecules, respectively. image