The Fe(III) complexes with a doubly deprotonated polydentate acylhydrazone: crystal structure of the first diamagnetic mu-oxo-diiron(III) complex
Abstract
The synthesis of two Fe(III) complexes with a doubly deprotonated polydentate of the acylhydrazone class is described. The first complex was obtained by hydrolyzing the previously synthesized high-spin pentagonal-bipyramidal (PBP) [Fe(Hdapsox)Cl-2] (H(2)dapsox = 2',2"'-(2,6-pyridindiyldiethylidene)dioxamohydrazide); the second was obtained by a template synthesis in a base medium starting from iron(III) chloride, 2,6-diacetylpyridine (dap) and semioxamazide (sox) (in a 1:1:2 molar ratio). Hydrolysis, during which the semioxamazide amide group changed into a carboxyl group, resulted in the mu -oxo-diiron(III) complex [Fe(dapoamh)(H2O)(2)O . 3H(2)O (H(2)dapoamh = dioxo-2,6-pyridinediylbis(ethylidyne-1-hydrazinyl-2-ylidene)diacetic acid) with a doubly deprotonated acylhydrazone that retained its PBP geometry. The [Fe(dapsox)Cl].H2O complex obtained in the latter case has a square-pyramidal geometry with an asymmetrically coordinated, but still doubly deprotonated dapsox as a tetradentate.... The structure of the [Fe(dapoamh)(H2O)(2)O . 3H(2)O complex determined by single-crystal X-ray analysis in this work represents the first mu -oxo-dimer of a PBP geometry with an acyclic polydentate. This is also the first diamagnetic Cl-oxo-diiron(III) complex ever obtained; this not only points to the super-exchange interaction over an ore-oxygen, but also to a significant interaction between the two low-spin Fe(III) ion d-orbitals. Based on the EPR spectra, it has been established that the monomer [Fe(dapsox)Cl].H2O complex is among the rare Fe(III) complexes with an intermediate spin state S = 3/2, and that a temperature decrease causes it to change to a low-spin complex, i.e. it demonstrates a cross-over (S = 3/2 reversible arrow S = 1/2). Further characterization has been done by IR and UV-VIS spectroscopy, and also by measuring the magnetic momentum at 293, 195 and 77 K. The results of this work, as well as of the previously synthesized Cu(II), Co(II) and Ni(II) complexes with H(2)dapsox, Hdapsox(-) and dapsox(2-), have led us to the conclusion that the doubly deprotonated acylhydrazone ligand has a considerably stronger field than its neutral or monoanionic forms. (C) 2001 Elsevier Science B.V. All rights reserved.
Keywords:
Fe(III) complexes / X-ray crystal structures / mu-oxo-diiron(III) complexes / diamagnetic dimersSource:
Inorganica Chimica Acta, 2001, 313, 1-2, 109-119Publisher:
- Elsevier Science Sa, Lausanne
DOI: 10.1016/S0020-1693(00)00377-7
ISSN: 0020-1693
WoS: 000167206900014
Scopus: 2-s2.0-0035952187
Collections
Institution/Community
Hemijski fakultet / Faculty of ChemistryTY - JOUR AU - Bacchi, Alessia AU - Ivanović-Burmazović, Ivana AU - Pelizzi, G AU - Anđelković, Katarina K. PY - 2001 UR - https://cherry.chem.bg.ac.rs/handle/123456789/450 AB - The synthesis of two Fe(III) complexes with a doubly deprotonated polydentate of the acylhydrazone class is described. The first complex was obtained by hydrolyzing the previously synthesized high-spin pentagonal-bipyramidal (PBP) [Fe(Hdapsox)Cl-2] (H(2)dapsox = 2',2"'-(2,6-pyridindiyldiethylidene)dioxamohydrazide); the second was obtained by a template synthesis in a base medium starting from iron(III) chloride, 2,6-diacetylpyridine (dap) and semioxamazide (sox) (in a 1:1:2 molar ratio). Hydrolysis, during which the semioxamazide amide group changed into a carboxyl group, resulted in the mu -oxo-diiron(III) complex [Fe(dapoamh)(H2O)(2)O . 3H(2)O (H(2)dapoamh = dioxo-2,6-pyridinediylbis(ethylidyne-1-hydrazinyl-2-ylidene)diacetic acid) with a doubly deprotonated acylhydrazone that retained its PBP geometry. The [Fe(dapsox)Cl].H2O complex obtained in the latter case has a square-pyramidal geometry with an asymmetrically coordinated, but still doubly deprotonated dapsox as a tetradentate. The structure of the [Fe(dapoamh)(H2O)(2)O . 3H(2)O complex determined by single-crystal X-ray analysis in this work represents the first mu -oxo-dimer of a PBP geometry with an acyclic polydentate. This is also the first diamagnetic Cl-oxo-diiron(III) complex ever obtained; this not only points to the super-exchange interaction over an ore-oxygen, but also to a significant interaction between the two low-spin Fe(III) ion d-orbitals. Based on the EPR spectra, it has been established that the monomer [Fe(dapsox)Cl].H2O complex is among the rare Fe(III) complexes with an intermediate spin state S = 3/2, and that a temperature decrease causes it to change to a low-spin complex, i.e. it demonstrates a cross-over (S = 3/2 reversible arrow S = 1/2). Further characterization has been done by IR and UV-VIS spectroscopy, and also by measuring the magnetic momentum at 293, 195 and 77 K. The results of this work, as well as of the previously synthesized Cu(II), Co(II) and Ni(II) complexes with H(2)dapsox, Hdapsox(-) and dapsox(2-), have led us to the conclusion that the doubly deprotonated acylhydrazone ligand has a considerably stronger field than its neutral or monoanionic forms. (C) 2001 Elsevier Science B.V. All rights reserved. PB - Elsevier Science Sa, Lausanne T2 - Inorganica Chimica Acta T1 - The Fe(III) complexes with a doubly deprotonated polydentate acylhydrazone: crystal structure of the first diamagnetic mu-oxo-diiron(III) complex VL - 313 IS - 1-2 SP - 109 EP - 119 DO - 10.1016/S0020-1693(00)00377-7 ER -
@article{ author = "Bacchi, Alessia and Ivanović-Burmazović, Ivana and Pelizzi, G and Anđelković, Katarina K.", year = "2001", abstract = "The synthesis of two Fe(III) complexes with a doubly deprotonated polydentate of the acylhydrazone class is described. The first complex was obtained by hydrolyzing the previously synthesized high-spin pentagonal-bipyramidal (PBP) [Fe(Hdapsox)Cl-2] (H(2)dapsox = 2',2"'-(2,6-pyridindiyldiethylidene)dioxamohydrazide); the second was obtained by a template synthesis in a base medium starting from iron(III) chloride, 2,6-diacetylpyridine (dap) and semioxamazide (sox) (in a 1:1:2 molar ratio). Hydrolysis, during which the semioxamazide amide group changed into a carboxyl group, resulted in the mu -oxo-diiron(III) complex [Fe(dapoamh)(H2O)(2)O . 3H(2)O (H(2)dapoamh = dioxo-2,6-pyridinediylbis(ethylidyne-1-hydrazinyl-2-ylidene)diacetic acid) with a doubly deprotonated acylhydrazone that retained its PBP geometry. The [Fe(dapsox)Cl].H2O complex obtained in the latter case has a square-pyramidal geometry with an asymmetrically coordinated, but still doubly deprotonated dapsox as a tetradentate. The structure of the [Fe(dapoamh)(H2O)(2)O . 3H(2)O complex determined by single-crystal X-ray analysis in this work represents the first mu -oxo-dimer of a PBP geometry with an acyclic polydentate. This is also the first diamagnetic Cl-oxo-diiron(III) complex ever obtained; this not only points to the super-exchange interaction over an ore-oxygen, but also to a significant interaction between the two low-spin Fe(III) ion d-orbitals. Based on the EPR spectra, it has been established that the monomer [Fe(dapsox)Cl].H2O complex is among the rare Fe(III) complexes with an intermediate spin state S = 3/2, and that a temperature decrease causes it to change to a low-spin complex, i.e. it demonstrates a cross-over (S = 3/2 reversible arrow S = 1/2). Further characterization has been done by IR and UV-VIS spectroscopy, and also by measuring the magnetic momentum at 293, 195 and 77 K. The results of this work, as well as of the previously synthesized Cu(II), Co(II) and Ni(II) complexes with H(2)dapsox, Hdapsox(-) and dapsox(2-), have led us to the conclusion that the doubly deprotonated acylhydrazone ligand has a considerably stronger field than its neutral or monoanionic forms. (C) 2001 Elsevier Science B.V. All rights reserved.", publisher = "Elsevier Science Sa, Lausanne", journal = "Inorganica Chimica Acta", title = "The Fe(III) complexes with a doubly deprotonated polydentate acylhydrazone: crystal structure of the first diamagnetic mu-oxo-diiron(III) complex", volume = "313", number = "1-2", pages = "109-119", doi = "10.1016/S0020-1693(00)00377-7" }
Bacchi, A., Ivanović-Burmazović, I., Pelizzi, G.,& Anđelković, K. K.. (2001). The Fe(III) complexes with a doubly deprotonated polydentate acylhydrazone: crystal structure of the first diamagnetic mu-oxo-diiron(III) complex. in Inorganica Chimica Acta Elsevier Science Sa, Lausanne., 313(1-2), 109-119. https://doi.org/10.1016/S0020-1693(00)00377-7
Bacchi A, Ivanović-Burmazović I, Pelizzi G, Anđelković KK. The Fe(III) complexes with a doubly deprotonated polydentate acylhydrazone: crystal structure of the first diamagnetic mu-oxo-diiron(III) complex. in Inorganica Chimica Acta. 2001;313(1-2):109-119. doi:10.1016/S0020-1693(00)00377-7 .
Bacchi, Alessia, Ivanović-Burmazović, Ivana, Pelizzi, G, Anđelković, Katarina K., "The Fe(III) complexes with a doubly deprotonated polydentate acylhydrazone: crystal structure of the first diamagnetic mu-oxo-diiron(III) complex" in Inorganica Chimica Acta, 313, no. 1-2 (2001):109-119, https://doi.org/10.1016/S0020-1693(00)00377-7 . .