Influence of substituents on the structure of Schiff bases Cu(II) complexes
Abstract
The relationship between molecular conformation and substituent effects of salicylaldehyde Schiff-base Cu(II) complexes was explored. For this study, eight samples of the complexes Cu(Sal-X)2 (X = OMe, Me, H, F, Cl, Br, CF3 and CN) were obtained by reaction of Cu(OAc)2 with Schiff base ligands (Sal-X) derived from Salicydaldehyde, and their crystal structures were characterized by the X-ray diffraction technique. The QSPR methods were employed to achieve deeper insight into geometry structure of Cu(Sal-X)2. The results show that the main geometrical parameters of Cu(Sal-X)2 are dominated by the substituents on the aniline ring. That is, the dihedral angle τ1 between the Cu-O-N plane and O-Cdbnd N plane increases with the increase of electron-donating effect and electron-withdrawing effect of substituents, whereas the electronic effect of substituents has the opposite effect on τ2, which is the dihedral angle between the aniline ring plane and C-N-Cu plane. Moreover, the bond length LCu-N decreases with growing excited-state parameter σccex of substituents which enhances the energy of C-N bond.
- Publication:
-
Journal of Molecular Structure
- Pub Date:
- June 2020
- DOI:
- 10.1016/j.molstruc.2020.127916
- Bibcode:
- 2020JMoSt120927916X
- Keywords:
-
- Copper complexes crystal;
- Substituent effect;
- Dihedral angle;
- QSPR;
- Bond length