Other O-Donors

Another example of the lanthanide contraction at work, verified by crystallographers, lies in the complexes of the lanthanide nitrates with dimethyl sulfoxide (dmso). The early lanthanides form 10-coordinate Ln(dmso)4(N03)3 (Ln = La-Sm), whilst the heavier metals form Ln(dmso)3(N03)3(Ln = Eu-Lu, Y). 

These are an important class of compounds with a general formula Ln(R. CO.CH.CO.R )3. The acetylacetonates, Ln(acac)3 (R = R = CH3) can readily be made from a lanthanide salt and acetylactone by adding sodium hydroxide  

Using bulkier R groups (R = R = CMes, for example) affords more congested diketo-nate complexes that are more tractable Ln(Me3.CO.CH.CO.CMe3)3 [often abbreviated to Ln(dpm)3 or Ln(tmhd)3] are monomers in solution and sublime in vacuo at 100-200 °C in the solid state they are dimers for Ln = La-Dy (CN 7) and monomers for Dy-Lu (CN 6) and have trigonal prismatic coordination. They tend to hydrate readily, forming adducts [e.g. capped trigonal prismatic Ln(dpm)3(H20)]. 

Complexes of fluorinateddiketones (R = CF3, R = CH3, L = tfac R = R = CF3, L = hfac R = cyclo-C4H3S, R = CF3, L = tta R = CF3CF2CF2, R = CMe3, L = fod) are also important. Again, the initial complexes obtained in synthesis are hydrates that can be dehydrated in vacuo. 2-Thenoyltrifluoroacetone complexes Ln(tta)3.2H2O are important in 

The structures are known for a number of these compounds thus, of the eight-coordinate compounds, Eu(acac)3(phen) is square antiprismatic, Eu(dpm)3(py)2 and Nd(tta)3(Ph3PO)2 are dodecahedral seven-coordinate Lu(dpm)3(3-picoline) is a face-capped trigonal prism and Eu(dpm)3(quinuclidine) a capped octahedron. Nine-coordination is found in Eu(dpm)3(terpy) and also in Pr(facam)3(DME)3(facam = 3-trifluoroacetyl-D-camphorate). 

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One consequence of a bent MOP linkage is that the space required to accommodate the ligand around a metal centre is targe, and the coordination numbers displayed by metals are often less than shown with other O-donors. 

Among other O-donor solvents, diethyl ether, THF, and acetone are applied to synthesize molecular complexes [10,211,221]. However, in the majority of cases... 

The donor atom(s) of each ligand is listed oxo is indicated to differentiate between other O-donor ligands. 

Surprisingly, redox chemistry involving Al(lll) species supported by quinones and other O-donor non-innocent ligands remains in its infancy since early studies on the reaction of alkylaluminum dichlorides with 1,4-quinones for the production of aryl ethers via a radical-radical coupling process [270-272]. 

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