Azamacrocycles, metal complexes

Synthesis and metal complexes of azamacrocycles with pendant arms having additional ligating groups. T. A. Kaden, Top. Curr. Chem., 1984,121,157-179 (54). 

It is well-established that the molecular and electronic structures of metal complexes of azamacrocycles are greatly affected upon N-alkylation (197). This is mainly due to two factors (a) the decrease of the ligand field strength and (b) the increase in the steric requirements upon going from a secondary to a tertiary amine donor function (251). To examine whether the properties of the dinuclear amine-thiophenolate complexes are affected by the N-alkyl substituents, analogous complexes of the... 

The process of antibody labeling consists of three steps (i) a functionalized azamacrocycle must be developed to coordinate the specific isotope (ii) the macrocycle or its metal complex must be covalently attached to the antibody and (iii), the medical application must be tested. Hereby several points must be fulfilled. As for NMR contrast agents, the macrocyclic metal cornplex must be thermodynamically and kinetically stable so that no dissociation or transmetallation occurs in the body of the patient. The covalent bond between the macrocycle and the antibody must be stable against enzymes which can break it. Finally, the modification of the antibody should not be to drastic as to deactivate it. 

Transition metal complexes of some azamacrocycles and their use in molecular recognition 07COS390. 

In 1937, van Alphen described the synthesis of the aza-cycloalkane (saturated azamacrocycle) 1,4,8,11-tetraazacy-clotetradecane (6), more commonly known as cyclam, obtained by reaction of 1,3-dibromopropane and 1,4,8,11-tetraazaundecane in the presence of an alkali. Twenty-four years later, Stetter and Mayer synthesized the ligand by a different route and showed that the material described by van Alphen contained only a small amount of the claimed ligand, but it took another five years for the first metal complex with cyclam to be reported. After these early works, a huge number of saturated azamacrocycles were synthesized, making the azacycloalkanes one of the most studied class of macrocyclic ligands. " ... 

Catalysis ferrocene [13], Ni-azamacrocyclic complex [14], metal-porphyrin [15]... 

This kind of argument may also be invoked for some Cr(III)-azamacrocyclic complexes. In this regard, it is noted that the macrocycle effect (which is essentially an enhanced chelate effect) stabilizes metal ions entrapped in the cavity formed by macrocyclic organic ligands... 

The appropriate conditions for the synthesis of tris-azamacrocyclic clathrochelates containing dioximate fragments in polyazamacrocyclic rings were not selected. Attempts to use open-chain polyamines, as well as their complexes with transition metals, primarily Ni2+, gave no desired results. 

Kinetic and thermodynamic properties of azamacrocycles and their complexes have been tabulated,10 and the structural features that influence these values have been analyzed,11-14 giving some understanding of metal ion selectivity. Many structures of azamacrocycle compounds have been reported.15-20... 

Lattermann and co-worker have reported a series of mesomorphic metal tricarbonyl complexes, 77, formed by complexation of the metal fragments M(C0)3 (77 M = Cr(0), Mo(0) and W(0)) by the non-mesomorphic tridentate azamacrocyclic ligand, i.e. l,4,7-tri-(3, 4 -didecyloxy)benzyl-l,4,7-triazacyclononane [139]. 

Polyazacycloalkanes of the sales [3k]ane-Nt (7 < k < 12) are known to form polynuclear complexes with metal ions such as Mn +, Co +, Ni +, Zn + and Cd, and can generally include more than one ion, thus forming dinuclear complexes trinuclear complexes have been found with k = 12, 13. When Pd + was used, di- and trinuclear complexes with azamacrocycles [ISJane-Ne and [21]ane-N7 were found and their structures have been ascertained by means of X-ray analyses. In the case of the trinuclear complex, deprotonation of a secondary amino group occurs both iu solution and the solid state (Figure 5). 

The infrared and Raman spectra of dinaphthalenic Ni(ll) and Cu(Il) azamacrocycle complexes methyl and phenyl substituted, Figure 14.19, with different metal surfaces were analyzed. ... 

With respect to the metal-adsorbate interaction it is of interest, for comparison with the experimental results, to develop theoretical calculations based on molecular models that involve the adsorbate molecules and a metal cluster. The INDO/1 semiempirical method has been proved to be very useful in the stmc-ture optimization and in the evaluation of the bond characteristics throughout the Wiberg index - ° The interaction of azamacrocycle complexes with simulated copper surfaces studied by the same method was performed -... 

Robson type azamacrocyclic complexes in Figure 14.42 are of interest as new materials and as models of biomolecules. The availability of a wide variety of planar ligands with different cavities offers the opportunity to study in detail magnetic phenomena, metal ion recognition, encapsulations, transport and... 

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