Rhenium main group complex

W. A. Herrmann, J. D. G. Correia, G. R. J. Artus, R. W. Fischer, C. C. Romao, Multiple bonds between main group elements and transition metals, 155. (Hexamethylphosphoramide) methyl (oxo) bis(Ti -peroxo)rhenium(Vll), the first example of an anhydrous rhenium peroxo complex Crystal structure and catalytic properties, J. Organomet. Chem. 520 (1996) 139. 

Dinitrogen-bridged complexes of /rani-ReCl(N2)(PMe2ph)4 with NbClj and TaCl, (1 1 adducts) and ZrCl, (2 1 adduct like TiC ) have been isolated. The N NMR spectra of these and other complexes of this type as well as dinitrogen complexes of rhenium(I) with the main group acceptor A1Mc3 have been studied. Fenske-Hall MO calculations have been carried out on the molecule [ MoQ4(OH) (/i-N2) ReCl(PH3)4 ]. ... 

Two distinct classes of promoters have been identified for the reaction simple iodide complexes of zinc, cadmium, mercury, indium and gallium, and carbonyl complexes of tungsten, rhenium, ruthenium and osmium. The promoters exhibit a unique synergy with iodide salts, such as hthium iodide, under low water conditions. Both main group and transition metal salts can influence the equilibria of the iodide species involved. A rate maximum exists under low water conditions and optimization of the process parameters gives acetic acid with a selectivity in excess of 99% based upon methanol. IR spectroscopic studies have shown that the salts abstract iodide from the ionic methyl iridium species and that in the resulting neutral species the migration is 800 times faster [127]. 

The polymerization is effected by a complex catalyst system. One such system has three main components. The first of these is typically a halide or acetyl-acetonate of tungsten, molybdenum, tantalum or rhenium the second a trialkyl aluminium or dialkyl aluminium chloride and the third component an activator such as epichlorhydrin or 2-chloroethanol. The polymerization may be carried out in bulk in the temperature range -50 to 0°C. The molecular weight may be regulated by the addition of small amounts of butene. The final polymer molecules are not necessarily macrocyclic in nature due to bond scission. This explanation has been shown to be consistent with the existence of vinyl end-groups even where no chain terminating non-cyclic mono-olefins have been specificaUy added. 

---