Cd(ΙΙ) and Mn(ΙΙ) complexes of a new hexadentate Schiff base ligand derived from an asymmetric tripodal tetraamine and 2-pyridinecarboxaldehyde

Two new compounds, [CdL22pyfp(NO3)](ClO4) (1) and [MnL22pyfpCl](ClO4) (2), were prepared by the template condensation of a previously known ligand, (L22py), and 2-pyridinecarboxaldehyde in the presence of Cd(NO3)2 · 4H2O or MnCl2 · 4H2O in equimolar ratios. The resulting compounds were characterized by elemental analysis, IR and single crystal X-ray diffraction, and by NMR in the case of the Cd(II) complex. The Cd(II) ion is in an eight-coordinate environment that is best described as a distorted dodecahedron. The environment around the Mn(II) ion may be described as a distorted pentagonal bipyramid. The 1H NMR spectrum of the cadmium complex shows the signal of the imine proton to have two satellites (3J = 44.4 Hz) with intensities of 1:6:1 due to coupling with the neighboring 111/113Cd atom. The electronic spectra of both complexes, as well as the ligand, is explained on the basis of TD-DFT calculations.

Graphical abstractTwo new complexes were prepared by the template condensation of a previously known ligand, (L22py), and 2-pyridinecarboxaldehyde in the presence of Cd(NO3)2 · 4H2O or MnCl2 · 4H2O in equimolar ratios. The resulting compounds were characterized by elemental analysis, IR and single crystal X-ray diffraction, and by NMR in the case of the Cd(II) complex.Figure optionsDownload full-size imageDownload as PowerPoint slide