Synthesis, Spectroscopic, Thermal and Catalytic Properties of Four New Metal (II) Complexes with Selected N- and O-Donor Ligands

Abstract

Four solid compounds with formulae: Co(OAc)2(Im)·H2O (I), Ni(OAc)2(Im)1.5·2H2O (II), Cu2(OAc)4(Im) (III) and Zn(OAc)2(Im)·H2O (IV) (where: Im = 1H-Imidazole) were prepared and characterized by chemical and elemental analysis, powder X-ray diffraction patterns and FTIR spectroscopy. Catalytic properties of each complex for styrene oxidation reaction were investigated. Furthermore, thermal properties of compounds were studied using the TG-DTG and DSC techniques under dry air atmosphere. Additionally, volatile thermal decomposition and fragmentation products were also investigated using the TG-FTIR spectra in air.

Synthesis, Spectroscopic, Thermal, and Catalytic Properties of Eight New Complexes of Metal(II) Formates or Propionates with Imidazole; Relationship between the Carbon Chain Length and Catalytic Activity

“…The FTIR spectra of synthesized complexes prove their purity and allow establishing the manner in which carboxylate anions and imidazole bind the metal cation. All analyses have been performed in a manner analogous to the previously studied compounds [ 25 ].…”

“…Table 12 and Figure 8 present conversion degrees for eight described compounds (M(II) formate or propionate complexes with imidazole) as well as for four previously studied compounds [ 25 ] (M(II) acetate complexes with imidazole). In case of studied compounds, the main product of oxidation is carbon dioxide.…”

“…Catalytic properties have been studied in the liquid-phase styrene oxidation reaction. Reactions were carried out in 50-mL round-bottom flasks with the molar ratio of reagents being the same as in the previous part of the study [ 25 ]: C 2 H 3 N:H 2 O 2 :C 8 H 8 = 1:1:1. The reaction mixture was stirred in a water bath at 60 °C and refluxed.…”

“…The molar ratio of metal cation and imidazole was determined based on the formulas of the complexes synthesized in our previous study [ 25 ]. This data is presented in Table 1 .…”

“…In one our previously published articles, we reported the synthesis, spectroscopic, thermal, and catalytic properties of four new M(II) acetate (where M = Co, Ni, Cu, Zn) complexes with imidazole [ 25 ]. Apart from experimental methods, such compounds can also be studied using computational techniques [ 26 , 27 , 28 ].…”