Synthesis, X-ray structure, and DFT studies of five- and eight-coordinated Cd(II) complexes with s-triazine N-pincer chelate

Abstract

The synthesis and spectral characterizations of [CdLCl2] (1) and [CdL(NO3)2(H2O)] (2) pincer complexes of the s-triazine core ligand (L), 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-methoxy-1,3,5-triazine), are presented. Complexes 1 and 2 have five- and eight-coordinated Cd(II) ions, respectively, where L acts as a neutral tridentate N-chelate. The coordination sphere is completed by two coordinated Cl– anions in 1 and with one water molecule and two bidentate nitrate anions in 2. The neutral complex units of 1 and 2 are packed by the polar Cl…H and O…H hydrogen bonds, respectively. Using Hirshfeld analysis, the percentages of these contacts are 24.5% and ∼36.8%, respectively. Both complexes showed some anion-π stacking interactions. Thermogravimetric analysis showed that 1 is thermally more stable than 2. The orbital-orbital interactions included in the Cd-Cl, Cd-O, and Cd-N coordinate bonds were analyzed using DFT calculations. The calculated NMR results correlated very well with the experimental data.