Synthesis, EPR study and photophysical properties of a mononuclear Fe(III) Schiff base complex functionalized by 3,6-di-tert-butyl-carbazole moieties

Dendritic Iron(III) Carbazole Complexes: Structural, Optical, and Magnetic Characteristics

“…The corresponding spectra are shown in Figure 2 . The absorption profiles are similar for all compounds, and mimic the behavior of a previously studied [ 36 ] complex containing the same magnetoactive core and two 3,6-di- tert -butyl-carbazole moieties on the ligand periphery. An intense absorption band in the UV region (~240 nm) is characteristic of intraligand (IL) transitions.…”

“…Upon excitation at 350 nm, the compounds exhibit an intense dual fluorescence with two emission bands centered at ~445 and ~485 nm. Thus, the increase in the number of carbazole-based photoactive fragments in the molecular structure of the complex results in a double-band emission (with maxima at 445 and 485 nm), in contrast to the single emission pattern (with a maximum at 449 nm) observed for a complex functionalized by only two carbazole moieties ( λ exc = 345 nm) [ 36 ].…”

“…To rationalize the experimental observations, the electronic absorption spectrum calculations were carried out via time-dependent DFT. According to our previous studies [ 36 , 37 ], the cationic complex may adopt either a meridional ( a ) or a facial ( b ) isomeric form ( Figure 3 ), wherein ( a ) the N -ethyl- N -(2-aminoethyl)salicylaldiminate (salEen) ligand moieties are not bent and adopt a meridional coordination mode, or ( b ) they are bent and form a coordination core with an O−Fe−O axis and two N−Fe−N(H) axes, i.e., the two N- or the two N(H)-donor atoms are cis to one another ( Figure 3 ). Note that a facial trans -counterpart with the O−Fe−O, N−Fe−N, and N(H)−Fe−N(H) axes is the most energetically unfavorable isomeric form and, therefore, its formation is highly unlikely.…”

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.…”