Arenes => benzene

The equivalent mthenium complex can be prepared from [RuCl2(r/ -arene)]2 precursors where >/ -arene = benzene, mesitylene, hexamethylbenzene. 

The hydrogenation of aromatics (benzene, toluene, a-methylstyrene) can be carried out under very low (1 12,000) catalyst substrate ratio, and mild conditions on Rh and Ni organometallic complexes anchored to USY zeolites.474 A Rh complex anchored to functionalized MCM-41 exhibits excellent performance in the hydrogenation of arenes (benzene, toluene, p-xylene, mesitylene) under mild conditions (45°C and 1 atm) 475 A uniquely selective hydrogenation of acenaphthene and acenaphthylene was performed by using a triruthenium carbonyl cluster 476... 

Dimercury(I) n complexes are formed between aromatic compounds and Hg2(AsF6)2 in liquid S02 as solvent.113,121 Insoluble complexes with the ratio arene Hg2+ = 1 1 (arene = benzene, naphthalene, 2-methylnaphthalene, 2,6-dimethylnaphthalene, acenaphthene, fluor-anthrene, phenanthrene, anthracene, 9,10-dimethylanthracene or 1,3-dinitrobenzene) or 1 2 (arene = 9,10-benzophenanthrene) have been characterized by elemental analysis and, in some cases, by Raman spectrometry.113,120 The 13CNMR data allow the estimation of formation constants for the hexamethylbenzene, p-xylene and 1,4-dichlorobenzene complexes together with the chemical shifts for the bound substrates in these cases.121 Probably the coordination compounds of dimercury(I) salts with carbazole, dibenzofuran and diben-zothiophene are also n complexes.122... 

Hydroxylation of arenes. Benzene and alkyl derivatives are oxidized to monophenols in 35-60% yield by 30% H202 in combination with HF/BF, etherate at — 78-60°. The reactive reagent is probably H302 + BF4 . 

It is not always easy to ascertain if the addition reaction proceeds via the triplet excited state of the arene. Benzene and its simple derivatives such as anisole and benzonitrile have high triplet energies (benzene, 84 kcal/mol 1 anisole, 81 kcal/mol" benzonitrile, 77 kcal/mol-1) which makes sensitization impracticable. Results of quenching experiments are sometimes difficult to interpret, as has become evident from the work of Cantrell. He found [109] that the formation of adducts from benzonitrile and 2,3-dimethylbut-2-ene, vinyl acetate, and 2-methoxypropene in solutions 0.5 M in cri-l,3-pentadiene occurs at a rate only approximately one-fourth that in the absence of added quencher. Five years later, the author reported [110] that m-l,3-pentadicnc itself adds slowly to benzonitrile to give ortho adducts. When a correction was made for the reaction of benzonitrile with the quencher, it became apparent that little, if any, triplet quenching had occurred. 

Treatment of aliphatic N-methoxyamides with BTI resulted in the formation of an intermediate, RCON(I+ Ph)Me, which in the presence of arenes (benzene, anisole) in excess underwent arylation to give N-aryl-N-methoxy-amides. 

Photolysis of complex 125 (arene = benzene) in acetonitrile gives a quantitative yield of cyclopentadienyl tris(acetonitrile) ruthenium complex... 

The synthesis and reactivity of arene cyclooctatetraene osmium(O) complexes of type 216 (arene = benzene, mesitylene) (13,132) and arene dicyclopentadiene osmium(O) complexes 212 (arene = mesitylene) (102) have been discussed previously (Section III,A,2). Arene osmium(O) complexes of type Os( 7j6-C6H6)(PR3) (L) (230) have been prepared by reduction... 

The neutral complex 244 (arene = benzene) has been found to react with nucleophiles such as hydride, hydroxide, and cyanide to give cyclohexadienyl derivatives, but they were too unstable to be isolated (7). The complex [Ru(C6H6)Cl(PMe3)2](PF6) (5) reacts with methyllithium to give... 

A more general route to make bis(cyclophane)ruthenium(II) complexes involves a reduction of 263 (arene = benzene) with Red-Al to afford the [ 174-1,3-cyclohexadiene)(tf-cyclophane)]ruthenium(O) derivatives 271 (Scheme 28, p. 224). Treatment of 271 with hydrochloric acid gives the dimeric chloride complexes 272, which lead the desired bis(r)6-[2 ]cyclo-phane)ruthenium(II) complexes 274 via Bennett s procedure (145). Synthesis of the oligomer 275a is also achieved in quantitative yield by heating 274 with the solvated complex 7 (arene = C6Me6) in neat trifluoroacetic acid. 

Monolayered cyclophane complexes of type 263 are also reduced by sodium bis(methoxyethoxy)aluminum hydride (Red-Al) to give (i74-diene)-(i76-cyclophane)ruthenium(0) complexes (Scheme 33). If the benzene ring of 263 (arene = benzene) is converted to the (1,3-cyclohexadiene)-ruthenium(O) derivative 271, however, when the corresponding rj6-hexa-methylbenzene is reduced with Red-Al, the product is the (if-1, 4-cyclohexadiene)ruthenium(0) complex 288. Synthesis of 271 can... 

E. O. Fischer was the first to prepare arene complexes of technetium. Arene ligands in these compound are typically six-electron donors. The nature of the Tc-arene bond is probably very similar to the one of the Tc-Cp bond. The [Tc(arene)2] complexes (arene = benzene or hexamethylbenzene) are prepared by the reaction of TcCLt with the appropriate arene in the presence of AICI3/AI. In a typical reaction, TcCLt, AICI3, and aluminum were heated with benzene in a sealed tube to 135 °C for two days. The product is precipitated as a salt using the hexafluorophosphate ion. A variety of other 18-electron compounds can be prepared from this material, particularly through chemical reduction. 

Several complexes having arenes, [Cr(CO)3(arene)] (arene = benzene, mesitylene, methyl benzoate, etc.) and [Cr(CO)3(cycloheptatriene)], are excellent catalysts for selective 1,4-hydrogen addition to 1,3-dienes. " 1,4-Hydrogenation of methyl sorbate (34), isoprene (36) and 1,3-pentadiene (38) in cyclohexane affords methyl cw-3-hexenoate (35), 2-methyl-2-butene (37) and cw-2-pentene (39), respectively. [Cr(CO)3(MeCN)3] is also an active catalyst under mild conditions (40 C, H2 1.4 atm), as are [Cr(CO)e] or [Cr(NBD)(CO)4] under UV irradiation. ... 

Arene = benzene, toluene, fluorobenzene, phenol, methyl benzoate, etc. 

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