Abstract
Two histidinehydroxamic acid derivatives ( N-methyl-histidinehydroxamic acid, N-Me-Hisha and Z-histidinehydroxamic acid, Z-Hisha) have been synthesized and their complexation with Cu 2+-, Ni 2+- and Zn 2+-ions has been studied by using pH-potentiometric, UV–Vis, CD, 1H NMR, EPR and ESI-MS methods. Both of the two new derivatives contain one donor atom less compared to the histidinehydroxamic acid (Hisha). In the case of N-Me-Hisha the hydroxamate-N as donor is eliminated, while the coordination of the amino- N of Z-Hisha is not possible at all. With the ambidentate N-Me-Hisha, the histamine-type coordination mode is favoured if the metal ion is Ni 2+ and the bis-[NH 2,N imid] complex is the most stable in this system. The mixed type, [NH 2,N imid] + [O,O], coordination mode dominates in the Cu 2+- N-Me-Hisha complexes, while different low stability mono-chelated linkage isomers are formed with Zn 2+. With Z-Hisha (having poor water solubility) hydroxamate-type coordination mode predominates in low stability complexes in the Ni 2+ and Zn 2+ containing systems. Interestingly, the interaction with Cu 2+ is very strong and results in the formation of a high stability 12-MC-4 type metallacrown with involvement of 5-membered and 7-membered chelates.
Sign-in/Register to access full text options 
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.
