Macrocyclic ring size

Figure 6.4. The variation of log K with macrocyclic ring size for the Ni(n) complexes of 02N2-donor macrocycles of type (279) (Anderegg, Ekstrom, Lindoy Smith, 1980).

Multidentate polyaza and mixed polyaza-polyoxa macrocycles in their polyammonium form complex a variety of anions. Complexation ability is, as anticipated, related to macrocyclic ring size, macrocyclic topology and the relation of these factors to the substrate to be complexed. Polyammonium macromonocydes of various ring sizes and binding subunits complex polycarboxylate... 

Bridger, G. J., Skerlj, R. T., Thornton, D., Padmanabhan, S., Martelluci, S. A, Henson, G. W., Abrams, M. J., Yamamoto, N., De Vreese, K., Pauwels, R., De Clercq, E. Synthesis and structure-activity relationships of phenylenebis(methylene)-linked bis-tetraazamacrocycles that inhibit HIV replication. Effects of macrocyclic ring size and substituents on die aromatic linker, J. Med. Chem. 38 (1995), 366 — 378. 

A, the d-d transition v and its extinction coefficient 8 with the macrocycle ring size. 

The change in macrocyclic ring size of L has only a slight effect on the E° values. However, a shift to more positive redox potential has been observed upon substitution of a tertiary nitrogen by a pyridyl group as in CRMe3, attributed to the preferential stabilization of the electron-rich low-valent state of osmium by the 7r-acceptor ability of the pyridyl group. 

A remarkable dependence of pK values on macrocyclic ring size has been shown for a series of complexes of general formula [Zn(L)(H20)], where L represents a saturated tri- or tetraaza macrocycle (Fig. 4). Kimura et al. (24) reported that complexes of the 12-membered macrocycles [12]aneN3 and iso[12]aneN3 show a marked reduction in pK, to values almost identical to that observed for carbonic anhydrase... 

Cyclodene Complexes Relationships between Macrocyclic Ring Size, Lacunar Cavity Shape, and Dioxygen Affinity of the Cobalt-Cyclidene Dioxygen Carriers. 

Curtis has discussed the preparation of complexes of this general class in a comprehensive review. Condensation of several nickel and copper diamine complexes with a range of aliphatic aldehydes and ketones has led to the synthesis of a wide variety of macrocycles containing varying substituents and/or varying macrocyclic ring sizes. " The mechanism of the general reaction is not understood. 

These polynucleating macrocyclic ligands sometimes have a mind of their own and do not form the desired tetranuclear species. Thus, under certain conditions, ligands of type L H4 or L H4, which contain short-chain alcohol backbones, do not deprotonate at the secondary alcohol moiety. They form polymeric species with Cu(II) halides or azides, probably because of the small macrocyclic ring size (304). Somewhat similar effects were alluded to earlier in regard to the tetraphenolic Schiff-base macrocycles (263), and we have had related experiences with open-chain analogues (305). 

Tiddy, G.J.T. (1980) Srrrfactant-water Liqtrid Crystal Phases. Physics Reports, SI, 1-46. Tuffin, R.P., Toyne, K.J., and Goodby, J.W. (1995) Effect of Macrocyclic Ring Size on the Liquid-crystalline Properties of Calarrritic Materials. Journal of Materials Chemistry, 5,2093-2104. 

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