Nitrogen donor macrocycles

Stability of Complexes of the Porphyrin TSPP Compared with the Nitrogen Donor Macrocycles Cyclam and THEC, with Metal Ions of Biological Interest"... 

LogX values for a number of tricarboxymethyl pendant arm derivatives of mixed oxygen nitrogen donor macrocycles have been reported. These include values of 16.09, 12.11, 14.44, and 9.47 for the ring systems (199), (200), (201a), and (201b), respectively. 

Classification of macromonocycles (Figure 2) can be made on the basis of donor atom, i.e. nitrogen, oxygen, sulfur, phosphorus, arsenic and mixed donor systems, as well as topicity, i.e. mono- versus di- or poly-topic. The planar nitrogen donor macrocycles and other tetraaza macro-... 

Dudler, V., Lindoy, L. F., Sallin, D., and Schlaepfer, C. W. (1987) An oxygen-nitrogen donor macrocycle immobilized on silica gel. A reagent showing high selectivity for copper(II) in the presence of cobalt(II), nickel(II), zinc(II) or cadmium(II), Aust. J. Chem. 40(9), 1557-1563. 

Nitrogen-donor macrocycles have also been prepared with other heteroatoms in the ring but not coordinated to the metal. Schrauzer (124) observed that chelate complexes (LVI) could be obtained when certain metal salts were present in the reaction of borinic acid ester... 

Nitrogen-donor macrocycles can bind two metal ions, e.g., the reaction between acetone and 1,4-dihydrazinophthalazine is promoted by Ni(II) ions and can give two products [Ni2(daph)]4 + (LX) and [Ni (taph)]4+ (LXI), depending on the solvent and temperature used for the reaction (119). 

Figure 4.43 The structure of [La(24)(N03)3] [70]. (Reproduced from J.D.J Backers-Dirks et aL, Preparation and properties of complexes of lanthanides with a hexadentate nitrogen-donor macrocycle X-ray crystal structure of the complex [La(N03)31], Journal of the Chemical Society, Chemical Communications, 11 A, 1979, by permission of The Royal Society of Chemistry.)...

We think of coenzyme B12 rather in the schematic way shown on the left in Figure 21—cobalt (III) in a tetradentate nitrogen-donor macrocycle with a Co-alkyl bond and a base in axial sites. Much interest resides in the determination of the characteristics of the macrocycles that lead to the stability of the cobalt-carbon bond. The burgeoning supply of new macrocycles presents the opportunity of studying such relationships, and Table XIV provides the first simple correlation of this kind 42, 43), Two ligands from the list gave stable Co-C bonds. One of these, TIM, contains four imines arranged in a-pairs while the other con-... 

The size of the metal ion has an evident control on the synthesis of the monometallic macrocyclic complexes. For example, all lanthanide(III) ions promote the formation of the six-nitrogen-donor macrocycles with an 18-atom cavity and flexible aliphatic diimine side-chains, even though the yields become progressively lower as the metal atom size decreases. However, when the six-nitrogen, 18-atom macrocycles contain rigid o-phenylene side chains, the smaller lanthanides actually fail to promote... 

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