Synthesis and characterization of catalytically active Ni(II) complexes with bis(phenol)diamine ligands

Jafari, Zahra (author), Safaei, Elham (author), Wojtczak, Andrzej (author), Zeinalipour-Yazdi, Constantinos D. (author), Kozlevčar, Bojan (author), Jagličić, Zvonko (author)

A novel N,N’-dimethylethylenediamine derivative of substituted bis(phenol)diamine ligands, namely 2-(tert-butyl)-4-methylphenol in H$_2$L$^1$, was synthesized by a convenient green procedure. Nickel)II) complex [NiL$^1$] 1 has been synthesized and characterized by various methods along with crystal structure determined. Ni(II) coordination center in a mononuclear complex is surrounded by two phenolate oxygen atoms and two amine nitrogen atoms of the ligand in a square planar arrangement. The magnetic susceptibility of the title complex indicates a paramagnetic behavior above 150 K, while strong ferromagnetism below 100 K. Furthermore, the cyclic voltammetry studies show two ligand-centered oxidation of the phenolate groups to phenoxyl radical and the metal-centered reduction of Ni(II) to Ni(0). The Glaser coupling reaction of phenylacetylene was also studied. A strong catalytic activity at room T in THF solvent is observed for 1 in the presence of zinc powder as a reducing agent. A full conversion rate was achieved after 7 h at 25 °C. The DFT analysis corroborates with the square-planar NiO$_2$N$_2$ chromophore of 1 being reduced in catalytically active Ni(0) by applied Zn. The calculated Gibbs free energy of the reaction leading to the formation of the substrate Ni-complex is favorable endothermic. Most of the data for 1 were obtained also for the very similar previously reported [NiL$^2$] 2, with 2,4- di tert-butylphenol in H$_2$L$^2$, which were than compared.

• Language: English
• Keywords: bisphenoldiamine, nickel complexes, Glaser reaction, coupling of phenylacetylene, ferromagnetism, green procedure
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FKKT - Faculty of Chemistry and Chemical Technology; FGG - Faculty of Civil and Geodetic Engineering
• Publication status: Published
• Publication version: Author Accepted Manuscript
• Year: 2025
• Number of pages: 8 str.
• Numbering: Vol. 574, art. 122353
• PID: 20.500.12556/RUL-161611
• UDC: 546.742:547.415.1
• ISSN on article: 0020-1693
• DOI: 10.1016/j.ica.2024.122353
• COBISS.SI-ID: 207250179
• Publication date in RUL: 12.09.2024

Record is a part of a journal

• Title: Inorganica Chimica Acta
• Shortened title: Inorg. Chim. Acta
• Publisher: Elsevier
• ISSN: 0020-1693
• COBISS.SI-ID: 25620736

Licences

• License: CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
• Link: http://creativecommons.org/licenses/by-nc-nd/4.0/
• Description: The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.

Secondary language

• Language: Slovenian
• Keywords: bisfenoldiamini, nikljevi kompleksi, Glaserjeva reakcija, sklopitev fenilacetilena, feromagnetizem, zeleni postopek