Substituted m-phenylene bridges as strong ferromagnetic couplers for Cuii–bridge–Cuii magnetic interactions: new perspectives

Paital, Alok Ranjan; Mitra, Tamoghna; Ray, Debashis; Wong, Wing Tak; Ribas‐Ariño, Jordi; Novoa, Juan J.; Ribas, Joan; Aromı́, Guillem

doi:10.1039/b510074g

Cited by 66 publications

(36 citation statements)

References 10 publications

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“…The oxamate units of the ligand allow the coordination of a second metal ion to each unit, resulting in polynuclear complexes with interesting magnetic behavior [84e88]. The use of 1,3-diaminobenzenes bearing other N-substituents also resulted in dinuclear Cu II complexes with ferromagnetic interactions [89,90]. Especially interesting in the context of this account is the use of a m 3 -extended version with a 1,3,5-trisoxamate benzene bridging ligand, which allows the synthesis of a trinuclear Cu complex with a coupling constant of J ¼ þ5.8 cm À1 [91].…”

Section: Applications Of the Spin-polarization Mechanism To Transitiomentioning

confidence: 99%

Spin-polarization in 1,3,5-trihydroxybenzene-bridged first-row transition metal complexes

Glaser

Theil

Heidemeier

2008

Comptes Rendus. Chimie

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Section: Applications Of the Spin-polarization Mechanism To Transitiomentioning

confidence: 99%

Spin-polarization in 1,3,5-trihydroxybenzene-bridged first-row transition metal complexes

Glaser

Theil

Heidemeier

2008

Comptes Rendus. Chimie

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“…Tetradental Schiff base had been synthesized and characterized . Based on a combined theoretical–experimental study, substituted m‐phenylene ligands (m‐N‐Phi‐N) could act as tunable strong ferromagnetic couplers connecting Cu (II) ions …”

Section: Introductionmentioning

confidence: 99%

Synthesis, characterization of Schiff base metal complexes and their biological investigation

El‐Sonbati

Mahmoud

Mohamed

et al. 2019

Applied Organom Chemis

137

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A new Schiff base ligand named (E)‐2‐(((3‐aminophenyl)imino)methyl)phenol (HL) was prepared through condensation reaction of m‐phenylenediamine and 2‐hydroxybenzaldehyde in 1:1 molar ratio. The new ligand was characterized by elemental analysis and spectral techniques. The coordination behavior of a series of transition metal ions named Cr (III), Mn (II), Fe (III), Co (II), Ni (II), Cu (II), Zn (II) and Cd (II) with the newly prepared Schiff base ligand (HL) is reported. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental analyses, IR, UV–Vis, 1H NMR, mass, electronic spectra, magnetic susceptibility and conductivity measurements and further their thermal stability was confirmed by thermogravimetric analysis (TG). From IR spectra, it was observed that the ligand is a neutral tridentate ligand coordinates to the metal ions through protonated phenolic oxygen, azomethine nitrogen and nitrogen atom of NH2 group. The existence, the number and the position of the water molecules was studied by thermal analysis. The molecular structures of the Schiff base ligand (HL) and its metal complexes were optimized theoretically and the quantum chemical parameters were calculated. The synthesized ligand and its complexes were screened for antimicrobial activities against bacterial species (Staphylococcus aureus and Bacillis subtilis, (gram positive bacteria)), (Salmonella SP., Escherichia coli and Pseudomonas aeruginosa, (gram negative bacteria)) and fungi (Aspergillus fumigatus and Candida albicans). The complexes were found to possess high biological activities against different organisms. Molecular docking was used to predict the efficiency of binding between Schiff base ligand (HL) and both receptors of Escherichia coli (3 T88) and Staphylococcus aureus (3Q8U). The receptor of Escherichia coli (3 T88) showed best interaction with Schiff base ligand (HL) compared to receptor of Staphylococcus aureu (3Q8U).

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“…[22] Closely related ligand systems based on 1,3-di-and 1,3,5-triaminobenzenes that involve mostly ferromagnetic couplings have also been investigated. [51][52][53][54][55][56] To match the two necessary requirements for SMMs, namely large spin-multiplicity and large negative zero-field splitting with axial symmetry (E/D = 0), we designed the triplesalen ligand C (Scheme 1), [57] which combines the phloroglucinol bridging unit A for ferromagnetic couplings, and thus high-spin ground states, with the coordination environment of a salen ligand B, which is known to establish a pronounced magnetic anisotropy due to its strong ligand field in the basal plane. [58][59][60] A well-studied example of a similar system is the Jacobsen catalyst [(salen')Mn III Cl], [61] which is an Mn III (S = 2) species with a zero-field splitting, D, of around À2.5 cm À1 .…”

Section: Introductionmentioning

confidence: 99%

Trinuclear Copper Complexes with Triplesalen Ligands: Geometric and Electronic Effects on Ferromagnetic Coupling via the Spin‐Polarization Mechanism

Glaser

Heidemeier

Strautmann

et al. 2007

Chemistry A European J

145

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A series of trinuclear Cu(II) complexes with the tris(tetradentate) triplesalen ligands H(6)talen, H(6)talen(tBu(2) ), and H(6)talen(NO(2) ), namely [(talen)Cu(II) (3)] (1), [(talen(tBu(2) ))Cu(II) (3)] (2), and [(talen(NO(2) ))Cu(II) (3)] (3), were synthesized and their molecular and electronic structures determined. These triplesalen ligands provide three salen-like coordination environments bridged in a meta-phenylene arrangement by a phloroglucinol backbone. The structure of [(talen)Cu(II) (3)] (1) was communicated recently. The structure of the tert-butyl derivative [(talen(tBu(2) ))Cu(II) (3)] (2) was established in three different solvates. The molecular structures of these trinuclear complexes show notable differences, the most important of which is the degree of ligand folding around the central Cu(II)-phenolate bonds. This folding is symmetric with regard to the central phloroglucinol backbone in two structures, where it gives rise to bowl-shaped overall geometries. For one solvate two trinuclear triplesalen complexes form a supramolecular disk-like arrangement, hosting two dichloromethane molecules like two pearls in an oyster. The FTIR spectra of these complexes indicate the higher effective nuclear charge of Cu(II) in comparison to the trinuclear Ni(II) complexes by the lower C--O and higher C=N stretching frequencies. The UV/Vis/NIR spectra of 1-3 reflect the stronger ligand folding in the tert-butyl complex 2 by an intense phenolate-to-Cu(II) LMCT. This absorption is absent in 1 and is obscured by the nitro chromophore in 3. The more planar molecular structures cause orthogonality of the Cu(II) d(x(2)-y(2) ) orbital and the phenolate O p(z) orbital, which leads to small LMCT dipole strengths. Whereas 1 and 3 exhibit only irreversible oxidations, 2 exhibits a reversible one-electron oxidation at +0.26 V, a reversible two-electron oxidation at +0.59 V, and a reversible one-electron oxidation at +0.81 V versus Fc(+)/Fc. The one-electron oxidized form 2(+) is strongly stabilized with respect to reference mononuclear salen-like Cu complexes. Chemical one-electron oxidation of 2 to 2(+) allows the determination of its UV/Vis/NIR spectrum, which indicates a ligand-centered oxidation that can be assigned to the central phloroglucinol unit by analogy with the trinuclear Ni triplesalen series. Delocalization of this oxidation over three Cu(II)-phenolate subunits causes the observed energetic stabilization of 2(+). Temperature-dependent magnetic susceptibility measurements reveal ferromagnetic couplings for all three trinuclear Cu(II) triplesalen complexes. The trend of the coupling constants can be rationalized by two opposing effects: 1) electron-withdrawing terminal substituents stabilize the central Cu(II)-phenolate bond, which results in a stronger coupling, and 2) ligand folding around the central Cu(II)-phenolate bond opens a bonding pathway between the magnetic Cu(II) d(x(2)-y(2) ) orbital and the phenolate O p(z) orbital, which results in a stronger coupling. Density functional calculations indicate ...

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Substituted m-phenylene bridges as strong ferromagnetic couplers for Cuii–bridge–Cuii magnetic interactions: new perspectives

Abstract: Based on a combined theoretical-experimental study, we propose that substituted m-phenylene ligands (m-N-Phi-N) can act as tuneable strong ferromagnetic couplers connecting Cu(II) ions; a new complex presenting that bridge with J close to +15 cm(-1) has been suggested and synthesized.

Cited by 66 publications

References 10 publications

Spin-polarization in 1,3,5-trihydroxybenzene-bridged first-row transition metal complexes

Spin-polarization in 1,3,5-trihydroxybenzene-bridged first-row transition metal complexes

Synthesis, characterization of Schiff base metal complexes and their biological investigation

Trinuclear Copper Complexes with Triplesalen Ligands: Geometric and Electronic Effects on Ferromagnetic Coupling via the Spin‐Polarization Mechanism

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