Diiodides, metallic complexes

Roesky used 7 to prepare heteroleptic calcium (35), strontium (36), and barium (37) complexes from the corresponding metal diiodides.32 Complex 35 was found to be monomeric, exhibit a calcium-methanide contact, and to be isostructural to the analogous ytterbium(II) complex 93 (vide infra). In contrast, complexes 36 and 37 were found to be dimeric, the former is isostructural to the samarium and europium analogues 91 and 92 (vide infra), and constructed around four-membered M2l2 rings but the larger size of barium compared to strontium is reflected by the inclusion of one coordinated THF molecule per strontium in 36 but two coordinated molecules of THF per barium in 37. Both 36 and 37 exhibit metal-methanide contacts which for 37 contrasts with the situation in 34. Complex 38 was prepared from two equivalents of 7 and strontium diiodide and, in contrast to 34, was found to exhibit metal-methanide contacts.33... 

The effect of metal promoter species on the rate of carbonylation of [Ir(CO)2l3Me] was tested. Neutral ruthenium iodocarbonyl complexes such as [Ru(CO)3l2]2> [Ru(CO)4l2] or [Ru(CO)2l2]n were found to give substantial rate enhancements (by factors of 15-20 for a Ru Ir ratio of 1 13 at 93 °C, PhCl). Indium and gallium triiodides and zinc diiodide had comparable promotional effects. By contrast, addition of anionic ruthenium(II) species [Ru(CO)3I3] or [Ru(CO)2I4]2 did not lead to any appreciable promotion or inhibition. This behaviour indicates that the ability to accept an iodide ligand is a key property of the promoter. Indeed, it has been demonstrated that an iodide ligand can be transferred from [ Ir(C0)2l3Me] to neutral ruthenium or indium species [73,74],... 

Analogous lithium ate complexes 53 are detected by NMR when solutions of PhLi are treated with HMPA,65 and the formation of an intensely yellow solution in the halogen-metal exchange of the diiodide 54 with BuLi suggests the intermediacy of the ate complex 55.66... 

Utilisation of transition metal benzothiazol-2-yMene and especially thiazol-2-ylidene complexes in homogenous catalysis reactions are very rare [42-44], Calo et al. reported the use of bis-(3-methyl-benzothiazol-2-ylidene) palladium diiodide in the Heck reaction of aryl bromides and iodides with a catalyst loading of down to KU mol% and near quantitative yields [42,44],... 

More recently, methods based on the use of mild reductants, able to transfer a single electron to the polyhaloalkyl halide, have been described. Various metals or their derivatives have been employed ruthenium, platinum and their complexes in low oxidation state, iron" and its carbonyl complexes, or tetrakis(triphenylphosphane)palladium. Sodium arcncsul-finate, sodium dithionite" and various oxidants have also been used. Other examples of polyhaloalkyl halide additions to simple alkenes are summarized in Table 1. Typical examples are the formation of diiodide 6, chloro iodide 7, and iodo steroid 8. ... 

Pyrazolin-5-ones react with salts of various metals to form compounds in which the pyrazolinone has reacted in its enolic form with replacement of the enolic hydrogen to give a salt and having semipolar bonds formed by donation of electrons to the metal by the nitrogen atoms393 394 Usually these compounds contain the number of pyrazolinone residues corresponding to the valence of the metal atom. Such salts as cuprous iodide, ferric iodide, cobaltous iodide, silver iodide and silver diiodide participate in such reactions.393,394 In addition, complexes may be formed in which there has been no elimination of a small molecule between the reactants and no formation of ionic bonds.432... 

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