1,8-Naphthyridine, transition metal complexes

Finally, the structural characteristics of the 1,8-naphthyridines favour their behavior as bidentate and dinucleating ligands, thus leading to short metal-metal separations in late transition-metal complexes,24"26 and to the stabilization of mixed-valence complexes.27,28 The dinuclear ruthenium complex [ Ru(napy)(H20)2 (/i-Cl)(/i-0H)](C104)2 is a stable and active catalyst for the oxidation of alcohols and the epoxidation of alkenes, while its mononuclear precursor is much less active.29... 

Wang and Wong prepared the quinoline and 1,8-naphthyridine analogues, 518 and 519 of 74. The barriers in 518 and 519 are 109 and 108 kj mol, respectively. All barriers are suitable for separation of enantiomers by chiral HPLC (95T6941). Several transition metals complexes of 74, 518, and 519 were reported as well as their X-ray data. 

Intensily colored (near 450 nm) complexes involving Ruthenium (154) and 1,8-naphthyridine and its more basic derivative, 2,7-dimethyl-1,8-naphthyridine, have recently been described.105 The highly colored nature of these complexes has been ascribed to metal-to-ligand charge transfer transitions. 

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