Azolyl complexes synthesis

Anion displacement of halides with azolyl anions is one common route to azolyl complexes. One example of such a synthesis is shown in Equation 4.21. In other cases, azolyl complexes have been prepared by proton transfer between the free azole and a metal alkox-ide or hydroxide. An example involving the synthesis of palladium-azolyl complexes is shown in Equation 4.22. In some rare cases, reactions of pyrrole and d early metal alkyls also lead to the formation of a metal-nitrogen bond via o-bond metathesis, as shown in Equation 4.23. Finally, several late-transition-metal-azolyl complexes possessing accompanying hydride Hgands have been prepared by N-H activation of pyrrole and other azoles. 

Retrosynthetically, preparation of N-azolyl 2,6-bis(imino)pyridyl metal complexes as precatalysts for polymerization involves (i) synthesis of N-amino azoles, (ii) condensation of 2,6-diacetylpyridine with two equivalents of N-amino azole, and (iii) complexation of die appropriate transition metal halide with the terdentate ligands. The latter two reactions present no real challenge and are more or less analogous to fhe published preparation of N-aryl 2,6-bis(imino)pyridyl complexes [13], and fhe more demanding synthesis of N-amino-azoles was covered in a preceding section. 

Song Y-H, Chiu Y-C, Chi Y, Chou P-T, Cheng Y-M, Un C-W, Lee G-H, Carty AJ (2008) Synthesis, characterization, and photophysical properties of luminescent gaUittm and indium complexes constructed using tridentate 6-azolyl-2,2 -bipyridine chelates. Organometallics... 

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