Schiff base complexes with different metals incorporating derivatives of 3,6‐di‐tert‐butylcarbazole

Abstract

Four new mononuclear complexes formed by the asymmetric azomethine ligand have been synthesized and characterized. Fe (III), Ga (III), Cu (II), and Co (II) ions were used as a central metal ion. The chelating ligand contains derivatives of 3,6-di-tert-butylcarbazole as a chromophor. The data of far FT-IR spectroscopy and mass spectrometry confirmed the formation of HC N bond and the coordination of metal ion through deprotonated oxygen and azomethine nitrogen. The X-ray powder analysis of polycrystalline complexes showed that the crystal cells of all complexes are triclinic, with unit cells containing four molecules each. The counter-ions are regularly embedded into the crystalline lattice. The conformation of the molecules of all complexes is elongated and symmetric. The thermal gravimetric analysis showed a high stability of all complexes above 200 C. The UV-Vis and fluorescence spectral data of the synthesized compounds were obtained in acetone, benzene, dichloromethane, chloroform, DMA, DMF, DMSO, and THF. The complexes show intensive π-π*, n-π*, and charge-transfer (CT) bands in the range from 200 to 400 nm in all solvents, whereas the ligand shows intensive π-π*, n-π* bands only. A strong red shift (21-31 nm) of the emission band maximum of the complexes is observed upon transition from nonpolar to polar solvents.

Hydrogen bonds-triggered differential extraction efficiencies for bifenthrin by three polymeric ionic liquids with varying anions based on FT-IR spectroscopy

“…As for the FT-IR spectra of PILs with varying anions, we focused on observation on the O-H stretching band at 3100-3700 cm À1 , C-H stretching band at 2700-3200 cm À1 , and B-F stretching band at 950-1152 cm À1 , respectively. [24][25][26] Based on changes in the above stretching bands, the H-bonding occurrence and reintegration information in PILs were deducted before and aer extraction.…”

Azomethine Fe3+ coordination compounds containing carbazole units: Synthetic approach, spectral characterization, and magnetic studies

“…In our previous works, we have synthesized different metal complexes bearing carbazole fragments only in the aldehyde part. 22,23 To extend a π-conjugated system, we introduced a carbazole fragment into the amine structure and increased the degree of branching. It is of interest to study a new dendrimeric multifunctional magnetic materials based on Fe complexes, which can demonstrate the existence of a SCO transition, that is, be in low spin (LS)/high spin (HS) states, which can be converted under external influence (temperature, irradiation, pressure, and magnetic field) or by ligand substitution.…”

“…Most previous investigations were devoted to Fe (II) spin‐crossover (SCO) complexes, while iron (III) coordination compounds have a wide range of advantages (e.g., structural, magnetic, photomagnetic, and relaxation). In our previous works, we have synthesized different metal complexes bearing carbazole fragments only in the aldehyde part 22,23 . To extend a π‐conjugated system, we introduced a carbazole fragment into the amine structure and increased the degree of branching.…”