Bidentate Nitrogen Donor Complexes

Organometallic compounds apart, oxidation states below - -2 are best represented by complexes with tris-bidentate nitrogen-donor ligands such as 2,2 -bipyridyl. Reduction by LiAlH4 in thf yields tris(bipyridyl) complexes in which the formal oxidation state of vanadium is -1-2 to —1. Magnetic moments are compatible with low-spin configurations of the metal but. 

Figure 2.21 Asymmetric unit of complex Eu(L )3 -phen [51b], (Reprinted with permission from S. Biju, D.B.A. Raj, M.L.P. Reddy and B.M. Kariuki, Synthesis, crystal structure, and luminescent properties of novel Eu + heterocyclic -diketonate complexes with bidentate nitrogen donors, Inorganic Chemistry, 45, 10651-10660, 2006. 2006 American Chemical Society.)...

One ligand arrangement particularly common among 5-coordinate complexes of platinum(II) is a trigonal bipyramid with two axial chlorides, an equatorial bidentate nitrogen donor, and an in-plane equatorial olefin. More examples have been reported,along with a useful survey of all the known species. " ... 

Many Ni alkyl or aryl complexes containing bidentate nitrogen donors, among them compound 177, have been used as moderately active catalysts for olefin polymerization. The pyrazolylborate complexes 178 and 179 catalyze the co-polymerization of ethylene and GO, and, in contrast to other Ni catalysts, do not require preactivation with ethylene. The N-N- and N-O-ligated complexes 180 and 181 are even more efficient and the latter can be used in supercritical C02. ... 

Another area of recent interest is the use of a mixture of bidentate nitrogen donors to broaden the structural possibilities of these paddlewheel dimthenium complexes. This is achieved using a combination of dpf- and dmba-detived ligands. 

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