Mn(II) and Cd(II) macrocyclic Schiff base complexes with a single pendant coordinating 2-pyridylmethyl arm: Synthesis, X-ray crystal structure and NMR studies

Abstract

Six new macrocyclic Schiff base complexes were prepared by the template condensation of two tripodal ligands and with 2-[2-(2-formyl phenoxy)ethoxy] benzaldehyde and 2-[3-(2-formyl phenoxy)propoxy]benzaldehyde in the presence of Cd(NO 3 )·4H 2 O or MnCl 2 in equimolar ratios. The resulting compounds were characterized by IR spectroscopy, elemental analysis and mass spectrometry in all cases and by X-ray and NMR in the case of all Cd(II) complexes. The cyclocondensation reaction of N-(2-pyridylmethyl)-N-(2-aminoethyl)-1,2-diaminoethane, L 22py , with both 2-[2-(2-formyl phenoxy)ethoxy] benzaldehyde and 2-[3-(2-formyl phenoxy)propoxy]benzaldehyde, and reaction of N-(2-pyridylmethyl)-N-(2-aminoethyl)-1,3-diaminopropane, L 33py , with 2-[2-(2-formyl phenoxy)ethoxy] benzaldehyde in the presence of equimolar amounts of Cd(II) or Mn(II) metal ions is reported. The resulting compounds [CdL 1 Cl](ClO 4 )·1/2CH 3 CN ( 1 ), [MnL 1 Cl](ClO 4 ) ( 2 ), [CdL 2 (NO 3 )](ClO 4 )·CH 3 CN ( 3 ), [MnL 2 Cl]ClO 4 ( 4 ), [CdL 3 Cl](ClO 4 )·H 2 O ( 5 ) and [MnL 3 Cl]ClO 4 ( 6 ) were characterized by IR spectroscopy, elemental analysis and mass spectrometry in all cases and by X-ray and NMR in the case of the Cd(II) complexes. X-ray single crystal structure analysis of a selected single crystal of compound ( 1 ) showed that it contains two cations ( A ) and ( B ), [CdL 1 Cl] + , with similar N 4 OCl donor sets. In contrast, the results of microanalysis, NMR and mass spectra showed that in the bulk sample, there are two different cations [CdL 1 Cl] + and [CdL 1 (NO 3 )] + in the ratio of 4–1, respectively. X-ray crystal structure determination of other cadmium complexes, ( 3 ) and ( 5 ), confirmed that in addition to the expected macrocylic ligand with a N 4 O 2 donor set, the NO 3 - and Cl − anions are coordinated to the central metal ion, respectively.