Year-end Sale % OFF 
Abstract
Various complexes of DHA with transition-metal cations are known for their antifungal properties. Here, four novel Zn and Cd complexes were prepared via the substitution of water by pyridine andg-picoline using Zn(DHA)2(H2O)2 (2) and Cd(DHA)2(H2O)2 (3) as starting materials. The products were characterized by IR, UV, elemental analysis, TGA and NMR techniques, including correlation times and intermolecular distance measurements using the NULL pulse sequence. The experimental data were compared to the molecular modeling results using DFT and the semiempirical method PM3, confirming that the pentacoordinated Zn complexes have bipyramidal geometry while the Cd complexes have the expected octahedral geometry. These results show that substitution of Zn by Cd leads to an important modification of the coordination structure, especially when strong ligands are involved.
Highlights
Many studies on complexes of transition metal ions with different ligands have been reported due to their importance in biochemical processes [1,2,3,4,5]
We carried out a differential scanning calorimetric (DSC) assay, in which complex 4 showed two endothermic transformations: one at 209 C (-33.94 Kcal/kg-1), corresponding to the pyridine loss and other at 270 C
Despite the inexistence of the octahedral complexes Zn(DHA)2(py)2 and Zn(DHA)2( -pic)2, we studied them by molecular modeling in order to compare their potential structural data with the respective bipyramidal complexes [2, 34,35,36]
Summary
Many studies on complexes of transition metal ions with different ligands have been reported due to their importance in biochemical processes [1,2,3,4,5]. Cadmium, which is environmentally dangerous [9] and widely used in industrial processes, is very toxic. Because 67Zn has a very low natural abundance (4.1%), possesses a low molar receptivity (2.9x10-3 relative to 1H) and a high quadrupolar moment (Q = 15.0 fm2), it is difficult to obtain 67Zn NMR spectra. Because of these properties, the exchange of Zinc for Cadmium has been used in solution and in the solid state to examine the metal complexation environment of zinc-containing biomolecules by 113Cd NMR [12,13,14]. It has been shown that Zn substitution for Cd leads to important changes in the coordination geometry of complexes with dehydroacetic acid [13,14,15]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
