1.10- Phenanthroline trinuclear complexes

Recently, Lacour, Sauvage and coworkers were able to show that the association of chiral [CuL2] complexes (L=2-R-phen,6-R-bpy and2-iminopyridine) with TRISPHAT 8 leads to an NMR enantiodifferentiation, which allows the determination of the kinetics of racemization of the complexes (bpy=2,2 -bipyri-dine phen=l,10-phenanthroline) [119]. This type of application has recently been reported in conjunction with chiral sandwich-shaped trinuclear silver(l) complexes [122]. Several reports, independent from Lacour s group,have confirmed the efficiency of these chiral shift agents [123-127]. Finally, TRISPHAT can be used to determine the enantiomeric purity of (r] -arene)chromium complexes. These results broaden the field of application of 8 to chiral neutral, and not just cationic, species [114,128,129]. 

The Lehn group synthesised the trinuclear copper(I) complex of the substituted 2,2 -bipyridyl/ether derivative 29 and confirmed its helical structure by X-ray diffraction (Figure 6.15). A dinuclear copper(I) complex of 30 (Figure 6.15) was also synthesised and subsequently the corresponding dimeric ethane-bridged bipyridine and phenanthroline ligands were also demonstrated to yield similar di-helicate copper(I) species. These results thus indicate that helicate formation is tolerant towards minor modification of ligand structure. ... 

Fluorescence properties of two series of trinuclear diimine Re(I) tricarbonyl complexes [Re(CO)3(NN)]3(p -Ll,2) (PF6)3 (NN = ethylenediamine or substituted bipyridine (A) and phenanthroline l,3,5-tris(4-ethenylpyridyl)benzene = LI, 1,3,5-tris(4-ethynylpyridyl)benzene = L2) (B) linked by an isomerizable stilbene-like... 

Copper (I) complexes exhibit catalytic activity for the four-electron (4-e) reduction of O2 to water. Natural occurring enzymes like Cu-containing fungal laccase reduce O2 directly to water very efficiently at very positive potentials, not far from the thermodynamic standard potential of the O2/H2O couple. These enzymes involve a trinuclear Cu active site [149-153]. For this reason some authors have investigated the catalytic activity of Cu(I) complexes for ORR, in particular Cu phenanthrolines confined on graphite or glassy carbon surfaces [154-169], with the aim of achieving the total reduction of O2 via the transfer of four-electrons. 

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