2H-Azirines as ligands: Synthesis and structural characterization of (2H-3-arene-azirine)ReI(CO)3Br complexes

The synthesis and structural characterization of four 2H-azirine rhenium(I) complexes are described. Stabilization of the highly reactive and strained 3-arene-2H-azirine ligand through N-coordination to the transition metal is observed. The reaction of [Re(CO)3(THF)2Br] with 3-arene-2H-azirine ligands (az) in THF at −20 °C in a 1:2 molar ratio afforded the neutral bis-azirine complexes [Re(CO)3(az)2Br] (az = NCH2CC6H4R; R = –H, –Me, –Cl, –Br). After purification, all complexes have been fully characterized. The molecular structures of the novel rhenium(I) complexes exhibit slightly distorted octahedral coordination geometries around the metal centers with cis-bonded az ligands.