Nickel aminotroponeiminate

Owen and Thomley (547) have reviewed covalency in transition metal ions and, in particular, in nickel complexes. The NMR contact shift method has been used by Eaton et al. (195) to determine spin densities on organic ligands of paramagnetic molecules. In particular (194), a series of nickel aminotroponeiminates have been studied whereby conjugative and hyperconjugative effects within the molecule may be monitored. Similar studies of contact shifts have been carried out on Co and Ni pyrromethenes and porphyrins (196) and on many transition metal acetylacetonates (193) by Eaton et al. 

Fig. 21. Spin density distribution in some nickel(II) aminotroponeimineates. [Benson et al. (4).]...

Numerous aminotroponeimineate complexes of type e, with nickel (II), have been prepared and are found to undergo square planar-tetrahedral interconversion (27). Extensive nuclear magnetic resonance data have been accumulated on this system along with magnetic moment and electronic spectral measurements (27). 

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