Alkyl complexes, osmium

Alkylcadmium alkoxides, 11 399-400 alkylperoxides, 11 399-400 anions, 11 370-371 halides, 11 377 solvated, 11 392-394 Alkylcalcium halides, solvated, 11 390 Alkyl complexes, osmium, 37 239-242 Alkyl copper compounds, 17 140, 142, 143 Alkyl derivatives, phosphoniuilic halides and, 1 363... 

Bromoanions, irivalent uranium, 34 98-99 Bromo complexes, osmium, 37 297-299 Bromocuprates(I), 37 39 Bromocyclophosphazene alkyl and aryl derivatives, 21 43 synthesis, 21 43, 44... 

Detailed mechanistic studies with respect to the application of Speier s catalyst on the hydrosilylation of ethylene showed that the process proceeds according to the Chalk-Harrod mechanism and the rate-determining step is the isomerization of Pt(silyl)(alkyl) complex formed by the ethylene insertion into the Pt—H bond.613 In contrast to the platinum-catalyzed hydrosilylation, the complexes of the iron and cobalt triads (iron, ruthenium, osmium and cobalt, rhodium, iridium, respectively) catalyze dehydrogenative silylation competitively with hydrosilylation. Dehydrogenative silylation occurs via the formation of a complex with cr-alkyl and a-silylalkyl ligands ... 

SiMe3, x = 1-2 R = Me, x = 1-3), have also been prepared from the reaction of HCl(g) with the alkyl complexes (286). Reaction with Au(PPh3)Cl results in the formation of [Ru(N)ClMe3] and Au(PPh3)Me from [Ru(N)Me4], in a manner analogous to that of the HC1 reaction (286). In contrast to the related osmium complexes, Lewis acid adducts of the ruthenium nitrides are thermally unstable. 

Oxo ligands help to stabilize high oxidation state alkyl complexes. Some 0x0 alkyl and aryl complexes of osmium(VI) can be prepared from OSO4. A mesityl complex,... 

A. G. (1980) Cyclopentadienyl-ruthenium and -osmium chemistry X. Reactions of vinylidene complexes with alcohols and water synthesis of alkoxy (alkyl) carbene, aryl and alkyl complexes. Australian Journal of Chemistry, 33, 1471-1483 (c) Bruce, M.I., Swincer, A.G., Thompson,... 

Fifth, the rate of carbonyl insertion as a function of the metal center usually follows the trend 3d > 4d > 5d when the complexes are isostructural. Alkyl complexes of the first-row metals are almost always more reactive than the analogs of the third row, and they are usually more reactive than the analogs of the second row. For example, CpRu(CO)jMe requires higher temperatures to insert CO in the presence of added phosphine than does the analogous iron complex, and the osmium analogue fails to react. Similar trends have been observed for other alkyl complexes of metal-carbonyl fragments. For CpM(CO)jR complexes, the relative rates of insertion are M = Cr and Mo > W, and for RM(CO)j, the relative rates are M = Mn >... 

Organometallic chemistry of pyrrole is characterized by a delicate balance of the ti N)- and -coordination modes. Azacymantrene is an illustration of the considerable nucleophilicity of the heteroatom. However, azaferrocene can be alkylated at C2 and C3 sites. Ruthenium and osmium, rhodium, and iridium chemistry revealed the bridging function of pyrroles, including zwitterionic and pyrrolyne complex formation. The ti (CC) coordination of osmium(2- -) allows versatile derivatizations of the heteroring. 

The osmium(VI) complexes 0s02X2(PR3)2 are not generally obtainable with the smaller alkyl and alkyl(aryl)phosphines, which tend to be good... 

B. Ruthenium and Osmium o-Bonded Alkyl and Aryl Complexes. 266... 

Diazoalkanes are u.seful is precursors to ruthenium and osmium alkylidene porphyrin complexes, and have also been investigated in iron porphyrin chemistry. In an attempt to prepare iron porphyrin carbene complexes containing an oxygen atom on the /(-carbon atom of the carbene, the reaction of the diazoketone PhC(0)C(Ni)CH3 with Fe(TpCIPP) was undertaken. A low spin, diamagnetic carbene complex formulated as Fe(TpCIPP)(=C(CH3)C(0)Ph) was identified by U V-visible and fI NMR spectroscopy and elemental analysis. Addition of CF3CO2H to this rapidly produced the protonated N-alkyl porphyrin, and Bit oxidation in the presence of sodium dithionitc gave the iron(II) N-alkyl porphyrin, both reactions evidence for Fe-to-N migration processes. ... 

The first ruthenium porphyrin alkyls to be reported were prepared from the zerovalent dianion, [Ru(Por)] with iodomethane or iodocthane, giving the ruthe-nium(lV) dialkyl complexes Ru(Por)Me2 or Ru(Por)Et2 (Por = OEP, TTP). Alternatively, the Ru(lV) precursors Ru(Por)X2 react with MeLi or ArLi to produce Ru(Por)Mc2 or Ru(Por)Ar2 (Ar = / -C(,H4X where X = H, Me, OMe, F or Cl) 147-149 The osmium analogues can be prepared by both methods, and Os(Por)R2 where R = Me, Ph and CH2SiMe2 have been reported.Some representative structures are shown in Fig. 5, and the preparation and interconversion of ruthenium porphyrin alkyl and aryl complexes are shown in Scheme 10. 

Non-ionic thiourea derivatives have been used as ligands for metal complexes [63,64] as well as anionic thioureas and, in both cases, coordination in metal clusters has also been described [65,66]. Examples of mononuclear complexes of simple alkyl- or aryl-substituted thiourea monoanions, containing N,S-chelating ligands (Scheme 11), have been reported for rhodium(III) [67,68], iridium and many other transition metals, such as chromium(III), technetium(III), rhenium(V), aluminium, ruthenium, osmium, platinum [69] and palladium [70]. Many complexes with N,S-chelating monothioureas were prepared with two triphenylphosphines as substituents. 

The osmium hydroxycarbene complex 18 is formed in an acid-assisted migratory-insertion reaction of OsClEt(CO)2(PPh3)2. This alkyl compound results from reaction of the ethylene adduct 19 with one equivalent of acid 46). 

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