Multinuclear complexes

The most important cation is aluminium. In the absence of fluoride, aluminium is present in solution as the Al(H20)e complex which hydrolyses to form complex multinuclear species such as [Al2(OH)2] and [A1i304(0H)24(H20)i2] + (Avcston, 1965 Waters Henty, 1977). There are also two kinds of phosphate complexes (Akitt, Greenwood Lester, 1971 O Neill et al., 1982) those based on the H3PO4 ligand, A1(H3P04) +... 

Apart from some Weakley-type complexes (Table 22), there has been little systematic investigation of lanthanide-molybdate complexes. Multinuclear NMR studies of solutions of the well-established dodecamolybdates [MIVMo12042]8- (M = Ce, U), with a range of di- and trivalent transition-metal and lanthanide cations, show the formation of complexes incorporating two metal cations. In most cases these complexes are labile on the NMR timescale.368-370... 

With few other ligand classes do zinc and cadmium form such a structurally varied series of complexes. Multinuclear complexes and intriguing geometries abound. 

Prom a practical point of view, the application of biomimetic models to processes of synthetic, or industrial interest depends strongly on the transformation of the current stoichiometric reactions into catalytic reactions (e.g., in the phenol oxygenation reactions), the stability of the catalysts, and the introduction of stereoselectivity characteristics in the reactions, by using structurally more sophisticated and possibly chiral ligands. In addition, the biomimetic chemistry of the more complex multinuclear Cu sites, such as the trinuclear Cu sites of blue oxidases, is still in its infancy, and important contributions are expected in the next few years from the study of new and suitable model compounds. 

Organometallic Compounds. Mononuclear carbon monoxide complexes of palladium are relatively uncommon because of palladium s high labihty, tendency to be reduced, and competing migratory insertion reactions in the presence of a Pd—C bond (201). A variety of multinuclear compounds... 

CN > NO2 > NH3 > H2O, F > Cl . Exceptions do occur. Photochemical Ligand dissociation is useful in the synthesis of multinuclear metal complexes such as diiron nonacarbonyl [15321-51 from iron pentacarbonyl [13463-40-6]... 

Porphyrinic co-complexes as novel multinuclear catalysts for the reduction of dioxygen directly to water 97ACR437. 

Peroxide complexes which are neither peroxyacids nor their derivatives. These may also be divided into mononuclear and multinuclear compds... 

Multinuclear ds-d10 metal ion complexes with sulphur-containing ligands. J. P. Fackler, Prog. Inorg. Chem., 1976, 21, 55-90 (73). 

In general, the carbohydrate-organotin(IV) complexes have been studied by and or, especially by multinuclear NMR ( Sn, H, and... 

Nickel atoms have also been allowed to react with C2H4 under cryogenic conditions (101,123). Depending on the metal-concentration conditions and the deposition temperature, either mononuclear species, Ni(C2H4) , n = 1-3(123), or multinuclear species, Ni2(C2H4) ,m = 1-2, and Ni3(CjH4)i, may be isolated. Unlike the copper complexes, these species are all colorless the mononuclear ethylene complexes each dis-... 

Although this account of gelation is made with reference to organic polyelectrolytes, it is of wider application and may be applied to phosphoric acid cements. Orthophosphoric acid solutions used in these cements contain aluminium, and soluble aluminophosphate complexes are formed. Some appear to be multinuclear and there is evidence for polymers based on the bridging Al-O-P unit. These could be termed polyelectrolytes (Akitt, Greenwood Lester, 1971 Wilson et al., 1972 O Neill et al., 1982). 

The tveak and reversible binding of these complexes to calf-thymus DNA (ct DNA) suggests a dominant electrostatic mode of interaction nevertheless, relevant conformational distortions of the double helix are caused [50]. A multinuclear NMR study of the reactivity of [Au(en)Cl2]Cl and [Au(en)2]Cl3 vith guanosine 5 -monopho-sphate (5 -GMP) reveals that in an aqueous solution only [Au(en)Cl2]Cl binds very weakly to 5 -GMP via N(7) to give a 1 1 adduct [48]. 

Byabartta, P. (2007) Gold(l)-gold(III)-4,4 -bpy-phosphrne complexes synthesis and multinuclear NMR study. Transition Metal Chemistry, 32, 314. 

Bebout DC, Berry SM (2006) Probing Mercury Complex Speciation with Multinuclear NMR 120 81-105... 

Reaction of [Ircp Cl2]2 with AgBF4 and (SPPh2)3CH in CH2C12 or Me2CO to which Et3N is added yields [Ircp ( 73-(SPPh2)3C]BF4, which has been structurally characterized.271 The Irm complexes [Ircp L3](PF6)2 (L3 = MeC(CFl2ER)3, E = Se, R = Me E = Te, R = Me, Ph) have been prepared and characterized by IR and multinuclear NMR spectroscopy.647... 

The tripodal ligand (550) with N2OS donor set reacts with Ni(0Ac)2 4H20 or Ni(C104)2 6H20 to give multinuclear Ni11 complexes (Scheme 7). 

Linear multinuclear metal complexes are attracting attention in the context of molecular electronics due to their projected use as molecular wires. 01igo(pyridyl)amido ligands are efficient scaffolds for lining up several Ni11 ions like a string. The first structurally characterized trinickel complex of this type, [Ni3(dpa)4Cl2] (dpa = bis(2-pyridyl)amide), showed a nearly linear Ni3 unit with Ni—Ni distances of around 244 pm.209 Penta-, hepta-, and nonanuclear systems have... 

There has been considerable interest in the study of multinuclear metal complexes with bridging sulfide ligands.381 The first examples of triangulo palladium(II) are the complexes containing substituted 2,2 -bipyridine and triply bridging sulfide ligands, namely [Pd3(diimine)3(M3-S)2][C104]2382... 

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