Oxo-bridged complexes

In the latter case, a dinuclear oxo bridged complex [Au2(N,N)2(p,-0)2][BF4]2 is also formed in small amounts. The same oxo complexes are obtained in high yields, as the... 

Treatment of the cyclometallated complexes [Au(N,N,C)Cl][PF6] [N,N,CH = 6-methylbenzyl- (a) or 6-(l,l-dimethylbenzyl)-2,2 -bipyridine (b)] [20] with KOH or Ag20 in aqueous media affords the hydroxo complexes [Au(N,N,C)(OH)][PF6] (36) in fairly good yields [45b, 101] these are air-stable white solids, quite soluble in water and in many organic solvents. When refluxed in anhydrous THF they condense to give the oxo-bridged complexes [Au2(N,N,C)2( J--0)] (37) (Equation 2.10 in Scheme 2.5) which, in turn, can be obtained by a different route [102] (see Section 3.2) the reaction can be reversed by refluxing the 0x0 complex in water. 

Dinuclear asymmetric and /u-oxo-bridged complexes in which the two technetium atoms are in intimate electronic communication have been synthesized. The reaction of solutions of [TcOCU]" or [TcClg] with neat pyridines py-R (R = H, 2-Me, 3,5-Mc2) gave asymmetric complexes of the type [Cl2(py-R)3Tc(/r-0)TcCl3(py-R)2] (378), and disymmetric complexes [Cl(py-R)4Tc-... 

The closely related oxo-bridged complex [(H20)5CrOCr(H20)5]4+ is obtained in low yields on the reduction of 1,4-benzoquinone by aqueous solutions of chromium(II).710 The sole product of the hydrolysis of this dimer711 (HC104/LiC104 / = 1.0) is hexaaquachromium(III). 

C. Complexes with Oxygen Ligands and Oxo-Bridged Complexes... 

Various alkane oxidations are catalyzed by iron complexes. Such reactions are important in view of the action of non-heme iron enzymes, such as methane monooxygenase, in hydrocarbon oxidations in biological systems. For example, the oxo-bridged complex [Fe2(TPA)2(ju,-0)(ju.-0Ac)]3+ [TPA = tris(2-pyridylmethyl)-amine] catalyzes the oxidation of cyclohexane with Bu OOH. Related complexes with an Fein2(/i-0)(/i-0Ac)2 core oxidize cyclohexane or adamantane to give a mixture of alcohols and ketones.159 Less well defined systems, e.g., FeCl3-6H20/ aldehyde/AcOH/02 are similarly active.160... 

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