Rhenium(V) Complexes Containing Mono- and Tridentate Imido Ligands: Crystal Structures, Spectroscopic Results and DFT Optimization

Rhenium(V) complexes containing the [ReX(PPh 3 ) 2 ] 4+ (X = Br, I) moiety were studied. The reaction of N-(2-aminophenyl)salicylideneimine (H3pna) with trans-[ReOBr3(PPh3)2] produced the complex salt [Re(pna)Br(PPh3)2]0.5Br.0.5(ReO4) (1), in which the tridentate ligand pna is coordinated via a doubly  deprotonated nitrogen (as an imide), an imino nitrogen and a deprotonated phenolate oxygen atom. The reaction of trans-[ReO(OEt)I 2 (PPh 3 ) 2 ] with two equivalents of 2-aminophenol (H3ap) in ethanol led to the isolation of the ‘2+1’ complex salt [Re(Hap)(H 2 ap)I(PPh 3 ) 2 ]I (2) in good yield. TheHapligand is coordinated  monodentately via the doubly deprotonated imido nitrogen, and H2ap is chelated bidentately through the neutral amino nitrogen and a deprotonated phenolate oxygen atom. The crystal structures of 1 and 2 were determined by X-ray single crystal diffraction. Spectroscopic results and DFT calculations are also reported. KEYWORDS : Rhenium(V), tridentate imido, ‘2 + 1’ coordination, X-ray crystal structures, DFT.