The application of manganese complexes of ligands derived from 1,4,7-triazacyclononane in oxidative catalysis.

Since the disclosure that manganese complexes of certain azamacrocyclic ligands were potent low-temperature bleaching catalysts, considerable effort has focussed on their development towards the efficient catalytic oxidation of other substrates, principally with the environmentally benign oxidant H(2)O(2). These efforts have resulted in a broad substrate scope for the system, including alkenes (to give both epoxides and cis-diols as potential products), alcohols, sulfides and C-H oxidation. Additional developments include the heterogenisation of catalytic systems as well as the first generation of enantiomerically pure ligand systems for application in asymmetric epoxidation catalysis.

Rare and unexpected coordination to copper(II) by a tertiary amide in a macrocyclic ligand.

Incorporation of a tertiary amide donor within the framework of a C(2)-symmetric analogue of 1,4,7-triazacyclononane derived from L-valine results in the isolation of a very rare example of a classical Werner copper(II) complex in which tertiary amide coordination occurs; despite the monomeric nature of the complex in the solid state, frozen solution EPR studies reveal the presence of a triplet ground state consistent with a dimeric species.

The synthesis of unsymmetrically N-substituted chiral 1,4,7-triazacyclononanes.

A number of chiral unsymmetrically N-substituted 1,4,7-triazacyclononane ligands have been prepared by modular methods. The key step in the synthesis centres on the macrocyclisation of three tertiary amide precursors under standard Richman-Atkins conditions which allows for subsequent N-functionalisation.

Structure, modelling and dynamic behaviour of aza- and azaoxamacrocyclic ligands derived from (R,R)-1,2-diaminocyclohexane.

Investigations into the conformational behaviour of macrocyclic ligands 5 and 6 derived from (R,R)-1,2-diaminocyclohexane have been undertaken using molecular modelling, single crystal X-ray diffraction and variable temperature 1H NMR spectroscopy. These have revealed that the lowest energy conformers in both cases do not possess the expected C2-element of symmetry, which can only be accessed at higher temperatures. Instead both molecules exist as C1-conformers at room temperature and in the solid state.