Synthesis, structure and properties of new triiron(III) complexes: Phosphodiester cleavage and antioxidant activity

Phosphate Triester Hydrolysis by Mononuclear Iron(III) Complexes: The Role of Benzimidazole in the Second Coordination Sphere

“…[49] The amino groups on the side chain could shift the λ max values of 2 and 3, compared to 1, due to its interaction with the phenolate ring, simulating a withdrawing effect. [23] All bands have λ max comparable with other iron(III) complexes described in the literature [23,32,38,48] (Table 1). TD-DFT calculations were performed based on the previously discussed optimized ground state geometries to confirm these attributions and obtain further information on the excited state configurations (Table S7).…”

“…The general vibrational profile in infrared (FTIR) spectra for complexes 1-3 is quite similar to their respective ligands (Figure S10 and Table S3), with shifts and distinct intensity upon coordination with the metallic center and the ClÀ O stretch for 2 and 3, related to the counterion. [32,35,38,48] The presence of the protonated amine, suggested for 3 is also corroborated by the large band in 3185 cm À 1 , which is not present in the HL 3 spectrum. [50] For 1, all bands agree with those described in the first reported characterization.…”

“…[53][54][55] These isomer shift values are similar to those found for complexes with a rich nitrogenoxygen environment. [32,[53][54][55] The quadrupole splitting (DE Q Þ of doublets corresponding to samples 2 and 3 are 0.695 mm s -1 and 0.733 mm s -1 , respectively. These values are compatible with those found for high-spin Fe 3 + in complexes with similar surroundings.…”

“…For PÀ O bond hydrolysis specifically, purple acid phosphatases (PAPs) bioinspired compounds have gained the attention of chemists over the last three decades. [22][23][24][25][26][27][28][29][30][31][32] Structurally similar to PTE, PAPs can be found in several sources, ordinarily in their Fe III M II form (M II = Zn, Mn or Fe). [33,34] For PAP mimetics, iron-based complexes typically exhibited superior catalytic results.…”

“…[33,34] For PAP mimetics, iron-based complexes typically exhibited superior catalytic results. [25,26,32,35] While this metal acidity generates more efficient nucleophiles under milder conditions (pH 5 to 7), [36] the M II metal is responsible for substrate coordination and for helping to reach optimal conditions to promote hydrolysis. [37] However, these reactions can work even with mononuclear compounds if the complex presents an available position to interact with the substrate and another to promote hydrolysis.…”