Thermal stability and crystallographic characterization of mononuclear Ni(II) and heterodinuclear Ni(II)-Co(II) complexes of the reduced ONNO type Schiff base
Journal of Thermal Analysis and Calorimetry, cilt.151, sa.3, ss.2127-2139, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 151 Sayı: 3
- Basım Tarihi: 2026
- Doi Numarası: 10.1007/s10973-026-15321-w
- Dergi Adı: Journal of Thermal Analysis and Calorimetry
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, Index Islamicus, INSPEC
- Sayfa Sayıları: ss.2127-2139
- Anahtar Kelimeler: Ni-Co Heterodinuclear complex, ONNO type Schiff base, Reduced Schiff bases, Thermogravimetry
- Ankara Üniversitesi Adresli: Evet
Özet
In this study, the ONNO type Schiff base ligand N, N’-bis(2-hydroxyphenylidene)-1,3-propanediamine (LH2) was reduced and converted into a tetradentate phenolic amine ligand, N, N′-bis(2-hydroxybenzyl)-1,3-diaminopropane (LHH2). First, a mononuclear [NiLHCl(DMF)]2(DMF) complex (I) was obtained with the reduced ligand in dimethylformamide (DMF). CoCl2 was then added to the complex I to give the heterodinuclear [NiLHCoCl2(DMF)2] complex (II). The complexes were characterized by elemental analysis, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and single-crystal X-ray diffraction (XRD). The XRD analysis of complex I revealed that one phenolic oxygen persisted in its coordinated phenol form, while the charge of Ni(II) was observed to be neutralized by a chloride ion and a phenolate ion. The Ni(II) center ion in the complex exhibited octahedral coordination, being surrounded by two phenolic oxygens, two aminic nitrogens, an oxygen from a DMF molecule, and a chloride ion. In complex II, the Ni(II) ion was coordinated by two phenolic oxygens, two aminic nitrogen, and two DMF oxygens. The Co(II) ion was found to have a tetrahedral coordination sphere with two phenolate oxygens and two chloride ions. Thermogravimetric analysis demonstrated distinct thermal behaviors for mononuclear and heterodinuclear complexes. The mononuclear complex exhibited stability up to 210 °C and an exothermic reaction at 510 °C in an oxygen atmosphere, resembling energetic materials. The heterodinuclear complex showed higher thermal stability and a distinct decomposition pathway, influenced by Co(II) coordination. These findings highlight the significance of heterometallic coordination in thermal properties and controlled decomposition applications. (Figure presented.)