title: C-C coupling of N-heterocycles at the fac-Re(CO)(3) fragment: synthesis of pyridylimidazole and bipyridine ligands.
abstract: A new family of cationic rhenium tricarbonyl complexes with either two N-alkylimidazole (N-RIm) and one pyridine (Py) ligand, or two pyridine and one N-RIm ligand, [Re(CO)3 (N-RIm)(3-x) (Py)x ](+) , has been prepared. The reaction of these complexes with a strong base, followed by an oxidant, selectively afforded 2,2'-pyridylimidazole complexes as the result of intramolecular dehydrogenative CC coupling reactions. For tris(pyridine) complexes [Re(CO)3 (Py)3 ](+) the reaction pattern upon a deprotonation/oxidation sequence is maintained, which allows the generation of complexes with 2,2'-bipyridine ligands. In the particular combination of two different types of pyridine ligand in the cationic fac-Re(CO)3 complexes only the cross-coupling products with asymmetric 2,2'-bipyridine ligands were obtained; the homocoupling products were not observed.
authors.affiliation: Departamento de Química Orgánica e Inorgánica, Universidad de Oviedo, Julián Clavería, 8, 33006 Oviedo (Spain).
authors.forename: Maialen Espinal
authors.initials: ME
authors.lastname: Viguri
authors.forename: Julio
authors.initials: J
authors.lastname: Pérez
authors.forename: Lucía
authors.initials: L
authors.lastname: Riera
mesh_terms: D018360:Crystallography, X-Ray; D007093:Imidazoles / Q000138:chemical synthesis* / Q000737:chemistry; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry; D012211:Rhenium / Q000737:chemistry*
chemical_list: D007093:Imidazoles; D008024:Ligands; D011725:Pyridines; D012211:Rhenium
keywords: CC coupling; imidazoles; organometallic compounds; pyridines; rhenium