Polynucleating macrocycles bearing soft and hard metal-binding sites

In contrast, the 1 + 1 macrocyclic product HL1737, able to coordinate two copper ions, is produced in the presence of copper(II) salts of anions with higher coordinating abilities (N03, CFsSOs ) [105]. Note that only phenoxide oxygen atoms and imine nitrogens of both types of macrocycle are involved in coordination to copper(II) ions. 

3 Polynucleating macrocycles bearing soft and hard metal-binding sites 

This behaviour is not very surprising as the cation has been used successfully in the synthesis of a series of crown ethers [111]. The template role of barium(II) is predominantly conformational. By coordination of the polyoxyethylene-containing ligson to barium(II) the terminal aldehyde groups are held in close proximity. Under such circumstances the cyclisation of the 1 4-1 open-chain condensation product occurring inevitably at the next step of the template process, is favoured over intermolecular pathways leading to polymerisation. The assembly of the above binucleating products in the absence of a template yields only small 

By making use of the availability of the metal-free macrocycle H2LI743 the direct reaction with manganese(II) produced the complex [Mn (L1743)]. Oxidation of the latter with dioxygen in acetonitrile afforded the Mn Mn //-oxo dimer [Mn2(L1743)]2(/r-0) [112], 

Template synthesis of analogous compartmental ligands H2LI746-H2LI749 has also been performed (Eq. 8.42) [113]. 

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