Macrocycle mixed donor

Other polydentate and macrocyclic mixed-donor ligands 365... 

Related to the crown ethers are compounds, such as hexamethyl-[14]-4,ll-diene (6), which differ by the replacement of one or more of the oxygen atoms by other kinds of donor atoms, particularly N or S. MacrocycHc amine and thioether compounds have been synthesized. Compounds having more than one kind of heteroatom in the ring are called mixed-donor macrocycles. The naturally occurring metaboUtes nonactin [6833-84-7] and monactin [7182-54-9] have both ether and ester groups incorporated in the macrocyclic stmcture. 

It is appropriate to identify our approach to developing the present review in the context of the Co chapter in CCC(1987). The first-edition chapter on Co featured a focused discussion and tabulation of synthetic methods, and many of these basic methods are still employed in synthesis today. Consequently, to avoid repetition, there will be diminished description here where prior appropriate methods have been provided, and only newer developments featured. The last two decades feature the development of many mixed-donor and sophisticated multidentate and macrocyclic ligands, which found limited coverage in the previous edition, and these will be discussed in more detail herein. Reaction kinetics and mechanism were also described thoroughly in the previous edition. We shall not reiterate this material, since the core mechanisms of many reactions involving Co compounds are now adequately defined. 

Polyimines of low-valent Co are now well represented, particularly with macrocyclic or mixed-donor ligands. The monovalent Co complex (5) of the 14-membered macrocyclic hexamethyl diimine (hmd), may be generated electrochemically from its divalent precursor. Furthermore,... 

Complexes with larger macrocycles containing mixed donor atoms 400... 

Figure 16 Some examples of silver(I) complexes with mixed donor macrocyclic ligands.

Thioether ligand complexes are not very common, however, studies since the mid 1990s have dramatically increased the number of structurally characterized examples. Almost all of these compounds are with chelate or macrocyclic ligands that will stabilize thioether coordination. Mixed donor multidentate ligands containing thioether donors will be discussed in Section 6.8.11. 

A few mixed-donor binucleating macrocycles incorporating some ether oxygen functions have already been mentioned in Chapter 3. This earlier discussion is now expanded to include cyclic systems in which the donor sets consist (totally or predominantly) of ether oxygens. 

Sulfur-containing ligands. Macrocyclic effects have also been documented in mixed donor systems. The Cu(ii) complex of the 14-mem-bered (cis) N2S2-donor analogue of cyclam exhibits a substantial macrocyclic effect with a log K difference of 4.6 relative to the corresponding open-chain species (Figure 6.2) (Micheloni, Paoletti, Siegfried-Hertli Kaden, 1985). The effect in this case is mainly due to a favourable... 

L. F. Lindoy, in Mixed-donor macrocycles solution and structural aspects of their complexation with transition and post-transition ions, Cation Binding by Macrocycles (Y. Inoue and G. W. Gokel, eds.), p. 599, Marcel Dekker, New York (1990). 

Manganese(II) has been commonly employed as a templating metal ion for the synthesis of a wide range of other mixed donor (oxygen/nitrogen) Schiff base macrocycles (and/or their imine-reduced derivatives). 

Mixed donor macrocycles have been employed in a number of applications involving the separation or analysis of manganesetll). These include examples of use of such a ligand as the extractant in solvent extraction processes " and as the ionophore in membrane transport studies. 

Bi sfethylenedithio)tetrathioful valene (BEDT-TTF), synthesis, 29 254-256 Bis(ferrocenecarbonyl)-diazatetrathia mixed-donor macrocyclic ligands, 39 125-126 Bis(ferrtx enyl)-diazatetrathia mixed-donor macrocyclic ligands, 39 125-126 Bis(fluorosulfonyl)amides, 19 197 Bisfluorosulfonylamidourea, synthesis of, 14 364... 

Complexes with mixed-donor macrocycles and with all-phosphorus and all-sulfur macrocycles 257... 

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