Chelating amide ligands

Fig. 6. Structures of the chelating amide ligands and the irans, cis-a, and cis- Q geometric isomers of their complexes.

An osmium(VI) nitrido complex with tetraanionic chelating amide ligand was prepared by the reaction of [Os(T 4-HBA-B)(PPh3)2] with phenyl azide in benzene at room temperature. The X-ray structure of [Osvi(N)(t)4-HBA-B)]- revealed a square-pyramidal structure with a measured Os=N distance of 1.64(1) A (282). 

Figure 2.13 Selected examples of gold(lll) complexes containing chelating bis(amidate) ligands.

Kilpin, K.J., Henderson, W. and Nicholson, B.K. (2007) Organogold(III) complexes containing chelating bis (amidate) ligands Synthesis, characterisation and biological activity. Polyhedron, 26, 434. 

Zirconium bis(amides) such as (35) and (36) display moderate ethylene polymerization activities.133,134 Complex (37) containing a chelating diamide ligand has been shown to initiate the living polymerization of a-olefins such as 1-hexene (Mw/Mn= 1.05-1.08) with activities up to 750gmmol-1 h-1.135-137 The living polymerization of propylene using this system activated with... 

The low affinity of the alkali metals for neutral P-donor ligands has hampered efforts to synthesize complexes in which there is a genuine R3P-M interaction (see Section I). However, this poor affinity may be overcome by incorporating a remote phosphine functionality into a potentially chelating anionic ligand, such as a phosphine-substituted alkoxide, amide, or aryl, and several alkali metal complexes of such ligands have been isolated. 

Aluminium complexes of chelating amido ligands are perhaps the most common type of monomeric four-coordinate aluminium amide. A full listing of such complexes will not be provided and selected examples will suffice to illustrate synthetic approaches and... 

OPPh3 complexes with porphyrinato ligands and chelating amides are discussed in Sections II,C,4,d and II,C,4,x, respectively, and cis- and frreversibly oxidized to their Os(III) analogs (415). 

Fig. 7. ORTEP drawing (50% probability level) of Sr(N(SiMe,)2),(DME) showing the trans arrangement of the amide ligands and the octahedral geometry around the strontium atom. X-M-X angles range from 61.5(2)° for the chelating cis DME oxygen atoms up to 160.9(3)° for the trans DME oxygen atoms. (Redrawn from Ref. 56.)...

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