Phenolate bridged complexes

Various dinickel(II) complexes related to (724d) but with a phenolate bridging moiety, type (724e), have been investigated. To illustrate the great variety, (729) and (730) are depicted as examples.1883 1884... 

The zinc complex of 2-[[[2-(2-pyridinyl)ethyl]amino]methyl]phenol forms a dimeric species, [ZnL(N03)]2, with the two phenolates bridging and each ligand offering an N20 donor set.866... 

Wang, Z. Reibenspies, J. Martell, A. E. Design, synthesis and X-ray structural characterization of new dinucleating macrocyclic ligands and a novel phenolate-bridged dilanthanum(III) complex. Inorg. Chem. 1997, 36, 629-636. 

An interesting new bridged complex, [Ru(TDBOHPP) L a L] (type H) in which the bridge L a L is 4,4 -azopyridine, has been studied in the search for molecular switches [217]. Protonation of the polymer induces partial oxidation of the Ru(II) to Ru(III) at the expense of the azo groups which are reduced to hydrazo species. Along with the formation of the Ru(II)-Ru(III) mixed valence compound a NIR intervalence band is switched on . The chemistry of these complexes is further complicated by the phenolic hydroxy groups in the porphyrin ligand which can also be deprotonated and oxidized. 

The constants for H-bridging complex formation between D-glucose, cellobiose, xylose, and phenol as models for cellulose and different 0-basic dipolar molecules such as N-methyl-caprolactam HMPA, and DMSO in chloroform and ethanol have been determined. Evidence of hydrogen bonding in D-fructose as shown in (28) has been obtained from variable temperature high field n.m.r. spectroscopy. The preponderance of the -furanose form in DMSO is attributed to this feature. The kinetics of the tautomeric equilibria were studied. 

As expected, assembly of the phenolate-bridged non-symmetric dinuclear metal core readily takes place, as is illustrated for the dicopper(II)complex 28 (figure 4).32... 

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