Hybrid Cage Compounds with Organic and Inorganic Building Blocks

Two new hybrid ligands that exhibit organic as well as siloxane chains between four phosphorus atoms in bridge-head positions were synthesized. These species show a very different ability with regard to the formation of coordination compounds. Whereas compound 1 with the short (C2H4)2O ether units shows no ability to act as a ligand, the compound with the longer (C2H4O)2C2H4 chains between the siloxane fragments could be obtained as the free ligand and with incorporated Li2I2 and Ag2I2 units. The observed coordination modi of the lithium and silver ions in these complexes corresponds to the HSAB- or Pearson concept. The silver ions prefer the soft phosphorus atoms as a bonding partner, while, for lithium, coordination by the hard oxygen atoms is favoured.