Coordination modes of hydrazone and acyl-hydrazone ligands containing a pyridine group with the {Re(CO)3}+ fragment

Four acyl-hydrazones derived from 5-hydroxypicolinohydrazide and 4-hydroxybenzaldehyde (HL11), 2-fluoro-4-hydroxybenzaldehyde (HL12), 2,4-dihydroxybenzaldehyde (HL13) or 2-pyridinecarboxaldehyde (HL14) two hydrazones 2-hydrazino pyridine 4-dimethylaminobenzaldehyde (HL21) 4-diethylamino-2-hydroxybenzaldehyde (HL22) were synthesized their X-ray structures determined. Twelve rhenium(I) complexes of formula [ReX(HLn)(CO)3] (X = Cl, Br) obtained by treating these ligands with [ReX(CH3CN)2(CO)3], the some representative compounds determined diffraction. The coordination geometry around can be described as octahedral, three carbon atoms in a fac configuration, halogen atom nitrogen hydrazone chain group, respectively. carbonyl group acyl-hydrazone does not participate any HL11–HL14. mode all could established comparing IR 1H NMR spectra. Formation hydrazonate only proved possible derivatives HL22. A study corresponding single crystal showed presence dimer [Re2(L22)2(CO)6], which phenolate ligand partner coordinates to rhenium after deprotonation. This same is used bind at position released halide.