Disubstituted-1,2,3-Triazoles as Monodentate N-Donor Ligands

In a final example, Osuka, Shinokubo, and coworkers have synthesized the 1,4-disubstituted-l,2,3-triazole appended Zn(II)-porphyrin, 15, and showed using NMR studies that it dimerizes in solution. X-ray crystallography confirmed that the dimerization is driven by coordination of the 1,4-disubstituted-l,2,3-triazole donor on one porphyrin to the Zn(ll) ion of the adjacent porphyrin (Fig. 5) [113]. As with the previously discussed Pd(II) and Re(I) complexes, the triazole unit interacts with the Zn(ll) ions through the N3 nitrogen. 

There are a number of other reported 1,4-disubstituted-l,2,3-triazole metal complexes in which monodentate binding is presumed [114—119]. None of these compounds have been structurally characterized, and as such, it is unknown whether the coordination is through the N2 or N3 nitrogen of the 1,2,3-triazole unit. However, on the basis of the previously discussed structurally characterized 

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