Zn(II) curcuminate complexes with 2,2'-bipyridine and carboxylates

Grabner, Sabina (author), Modec, Barbara (author)

Two novel zinc(II) compounds with curcuminate (abbreviated as cur$^−$), [Zn(CH$_3$COO) (cur)(bpy)](1)·CH$_3$OH·2H$_2$O (bpy = 2,2′-bipyridine) and [Zn(PhCOO)(cur)(bpy)] (2)·CH$_3$OH, have been synthesized and characterized. Their composition has been determined by single-crystal X-ray structure analysis. Complexes 1 and 2 are similar: in both a five-fold coordination environment of zinc(II) consists of a monodentate carboxylate, a chelating bidentate 2,2′-bipyridine, and curcuminate, which is bound via a deprotonated 1,3-dione moiety. In 1, 2,2′-bipyridine nitrogen atoms and curcuminate oxygen atoms form the base of a square pyramid, whereas the acetate oxygen occupies its apex. The O$_3$N$_2$ donor set in 2 defines a polyhedron which more closely resembles a trigonal bipyramid. The packing in the crystal lattices of both compounds is governed by hydrogen-bonds. Complexes 1 and 2 display higher stability than curcumin in buffered media at pH = 7.0, however, the degradation of coordinated cur$^−$ is comparable to that of yellow pigment curcumin (curH) when the pH is raised to 7.2. Both complexes 1 and 2 in DMSO exhibit fluorescence with Stokes shifts of 5367 and 4634 cm$^{−1}$, respectively.

• Language: English
• Keywords: curcumin, Zn(II) complexes, stability, crystal structures
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Publication status: Published
• Publication version: Version of Record
• Year: 2019
• Number of pages: 20 str.
• Numbering: Vol. 24, iss. 14, art. 2540
• PID: 20.500.12556/RUL-132833
• UDC: 546.47:547.979.4
• ISSN on article: 1420-3049
• DOI: 10.3390/molecules24142540
• COBISS.SI-ID: 1538287299
• Publication date in RUL: 04.11.2021

Record is a part of a journal

• Title: Molecules
• Shortened title: Molecules
• Publisher: MDPI
• ISSN: 1420-3049
• COBISS.SI-ID: 18462981

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 11.07.2019

Secondary language

• Language: Slovenian
• Keywords: kurkumin, cink, Zn(II) kompleksi, stabilnost, kristalne strukture

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P1-0134
• Name: Kemija za trajnostni razvoj