INCLUSION-COMPOUNDS - THE PRODUCTS OF THE INTERACTION OF SILICON, GERMANIUM AND BORON FLUORIDES WITH CROWN-ETHERS

This review deals with the problem of the interaction of Si(IV), Ge(IV ) and B(III) fluorides with crown ethers and their aza analogues. The crystallographic structures have been determined of the stable product s obtained by the interaction of H2SiF6 solution with the following cr own ethers: 18-crown-6 (18C6), monoaza-18C6 (MA18C6), 1,10-diaza-18C6 (DA18C6) and 1,7-diaza-15C5 (DA15C5). The complexes obtained are stabi lized by a system of H-bonds of the O-H ... O, N-H ... O, N-H ... F an d O-H ... F types. For H2GeF6 the adducts obtained are similar to thos e obtained using H2SiF6. The crystal structures of three new boron flu oride-containing complexes with 18-membered crown ethers are also desc ribed. During macrocycle complexation the guest entities undergo chemi cal transformations which are stabilized by creation of the H-bond sys tem. The results of vibrational and NMR spectra are also discussed.