Mixed nitrogen-oxygen ligands

Ligands with nitrogen donor sites not otherwise readily classifiable are discussed in this section. Mixed nitrogen-oxygen-containing donors (other than the Schiff bases discussed earlier) are discussed in Section II,F. 

Macrocyclic polyamines that can be fully or nearly fully protonated in the neutral pH range appear to be the best ligands for the biologically important carboxylate and adenosine phosphate anions because the formation of these anions occurs in these pH regions. Lehn and Dietrich and their coworkers have synthesized macrocyclic polyamines [24]N(,(53) and [32]N8(54), based on propylene units (Dietrich et al., 1981), and macrocycles with mixed nitrogen-oxygen donor atoms connected by ethylene units, [27]Nft03(55) (Dietrich et al., 1981) and [24]N(,02(56) (Hosseini and Lehn, 1987 Hosseini et al., 1983). These macrocycles are similar to those found in natural systems. 

Group VI Donors. Oxygen and mixed oxygen-nitrogen donor ligands. A more convenient synthesis has been reported for the chiral complex [Pd(tfacCam)2] (52), involving the reaction of Ba(tfacCam)2 with PdCl2- ... 

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