From Triplesalen to Triplesalophen: Ferromagnetic Interactions through Spin‐Polarization in a Trinuclear Ni<sup>II</sup> Triplesalophen Complex

Richthofen, Carl‐Georg Freiherr von; Stammler, Anja; Bögge, Hartmut; Glaser, Thorsten

doi:10.1002/ejic.201001018

Cited by 22 publications

(22 citation statements)

References 39 publications

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“…Upon heating at reflux, a red solid precipitated. The same behavior was found already for the reaction of H 6 baron Br with Ni(OAc) 2 · 4H 2 O . In contrast to the better solubility of H 6 kruse Br over the H 6 baron R ligands, the complex [(kruse Br )Ni II 3 ] is less soluble in non‐coordinating solvents than the complexes [(baron Br )Ni II 3 ].…”

Section: Resultssupporting

confidence: 79%

Increasing the π–π Interactions in Trinuclear Ni^II₃ Triplesalophen Complexes

Oldengott

Röhs

Stammler

et al. 2017

Zeitschrift anorg allge chemie

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The new triplesalophen ligand H 6 kruse Br was synthesized as a variation of the triplesalophen ligands H 6 baron R by replacing a phenyl by a methyl group at the terminal ketimine in order to allow closer contacts of trinuclear complexes due to less steric hindrance by the smaller methyl group. The ligand H 6 kruse Br was used to synthesize the trinuclear complex [(kruse Br )Ni II 3 ], which is insoluble in organic solvents despite the coordinating solvent pyridine. Recrystallization from pyridine results in the complex [(kruse Br ){Ni 2 (Ni(py) 2 )}], which was characterized by single-crystal X-ray diffraction. Two Ni II ions

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Section: Resultssupporting

confidence: 79%

Increasing the π–π Interactions in Trinuclear Ni^II₃ Triplesalophen Complexes

Oldengott

Röhs

Stammler

et al. 2017

Zeitschrift anorg allge chemie

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“…[25,56] The assignments of the NMR resonances in all products were supported by 2D COSY, HMBC, and HMQC NMR spectroscopic measurements and the numbering follows the numbering scheme depicted in Figures 1 (including all atoms S2) and 2 (including all atoms S7). The synthesis of H 2 carl Cl and H 6 baron R (R = Me, Cl, Br) has been published previously.…”

Section: Methodsmentioning

confidence: 99%

“…[56] The fine needles of [(baron Me )Ni 3 ]a could now be analyzed using a new singlecrystal X-ray diffractometer with Cu-K α radiation. Slow evaporation of the solvent resulted in the deposition of very fine needles of [(baron Me )-Ni 3 ]a.…”

Section: Synthesismentioning

confidence: 99%

“…Thus, recrystallization from pyridine or from reactions in pyridine directly results in trinuclear triplesalophen complexes with either no coordinated pyridine ([(baron Me )Ni 3 ]b and [(baron Cl )Ni 3 ]b), partial pyridine coordination [(baron Br ){Ni(py) 2 } 2 Ni], [56] or dimerized trinuclear complexes with further pyridine coordination ([(baron R ){Cu(py)} 2 Cu], R = Me, Cl, Br). Single crystals have been obtained from chloroform/n-butanol mixtures, however, these solid compounds are only soluble in pyridine, which is a coordinating solvent.…”

Section: Uv/vis Spectroscopymentioning

confidence: 99%

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Synthesis and Characterization of Trinuclear Ni^II₃ and Cu^II₃ Triplesalophen Complexes: Evaluation of Ligand Folding and Heteroradialene Formation and their Impact on the Magnetic Properties

et al. 2012

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The coordination chemistry of the triplesalophen ligands H 6 baron R (R = Me, Cl, Br) with Cu II and Ni II has been studied. The triplesalophen ligand system is an extension of the triplesalen ligand system and is composed of a bridging phloroglucinol ring with three meta-phenylene salophen coordination compartments. The completely sp 2 hybridized backbone of the triplesalophen ligands should favor a more planar molecular structure of the trinuclear complexes in comparison to the triplesalen complexes. Reaction of the ligands with the metal acetates in n-butanol/CHCl 3 provided the complexes [(baron Me )Ni 3 ]a, [(baron Cl )Ni 3 ]a, [(baron Br )-Ni 3 ]a, [(baron Me )Cu 3 ], [(baron Cl )Cu 3 ], and [(baron Br )Cu 3 ]. For the Ni II complexes, recrystallization from pyridine or performing the reaction in pyridine provided the compounds [(baron Me )Ni 3 ]b and [(baron Cl )Ni 3 ]b, whereas for the bromo derivative the complex [(baron Br ){Ni(py) 2 } 2 Ni] with one fourcoordinate and two six-coordinate Ni II ions have been obtained. In contrast, for the Cu II complexes, two [(baron R ){Cu(py)} 2 Cu] (R = Me, Cl, Br) units dimerize via [a] Lehrstuhl für Anorganische Chemie I, 5934bridging of a coordinated phenolate. The structural analysis reveals a strong tendency for π stacking of the trinuclear complexes resulting in a planarization of the complexes. The trinuclear triplesalophen complexes exhibit the four signatures of heteroradialene formation, which were extracted from single-crystal X-ray diffraction, NMR, FTIR, and UV/ Vis spectroscopy. Analysis of these experimental data with regard to the respective data of the free ligands H 6 baron R (R = Me, Cl, Br) and the mononuclear analogue H 2 carl Cl and its complexes [(carl Cl )Ni] and [(carl Cl )Cu] clearly demonstrates that the heteroradialene resonance structure, which has been established as the dominant resonance structure for the free ligands, still has a strong but smaller contribution in the trinuclear triplesalophen complexes. The magnetic properties demonstrate weak intramolecular ferromagnetic interactions mediated by the triplesalophen ligands in the trinuclear Cu II 3 complexes, which are experimentally difficult to determine due to intermolecular antiferromagnetic interactions of the same order of magnitude. molecular structures of the trinuclear Ni II 3 complexes [2] and the trinuclear Cu II 3 complexes [11] of the tert-butyl ligand H 6 talen tBu 2 exhibit a strong ligand folding along the central O-N vectors, resulting in overall bowl-shaped molecular structures. This ligand folding preorganizes the axial coordination sites of the metal salen subunits for the complementary binding of a hexacyanometallate. In combination with a strong tendency of two [(talen tBu 2 )M t 3 ] m+ complexes to dimerize due to van der Waals interaction of the tertbutyl phenyl groups, [12] a high driving force results for the formation of heptanuclear complexes [M t 6 M c ] n+ (= [{(talen tBu 2 )M t 3 } 2 {M c (CN) 6 }] n+ ) by the supramolecular assembly of two [(talen tBu ...

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“…Especially, prominent features in the 1700 -1400 cm −1 region cannot be explained by established assignments and trends derived for imineand/or salen-type ligands and complexes [46,47,49,51,63]. However, the realization that the π system of the central phloroglucinol backbone is heavily distorted toward a heteroradialene structure prompted us to ask whether these spectroscopic features may serve as a convenient method to evaluate the electronic structure of the ligand as well as of the complexes without high-resolution single-crystal diffraction data and NMR spectroscopy, which is not practicable for paramagnetic complexes.…”

Section: Introductionmentioning

confidence: 86%

Electronic and Molecular Structures of Heteroradialenes: A Combined Synthetic, Computational, Spectroscopic, and Structural Study Identifying IR Spectroscopy as a Simple but Powerful Experimental Probe

Richthofen

Feldscher

Lippert

et al. 2013

Zeitschrift Für Naturforschung B

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The vicinity of a hydrogen bond donor (O-H) and a hydrogen bond acceptor (C=O or C=N-R) in salicylaldehydes and ortho-Schiff bases results in significant structural variations compared to the monosubstituted derivatives that are reflected in the electronic structure and thus in the spectroscopic properties. This interplay between intramolecular hydrogen bonding and multicenter π-electron delocalization is the origin of the concept of resonance-assisted hydrogen bonding (RAHB). Herein, the complexity is extended from one hydrogen bond donor-acceptor pair in salicylaldehyde and ortho-Schiff bases to three hydrogen bond donor-acceptor pairs in 2,4,6-tricarbonyl-and 2,4,6-triimine-substituted phloroglucinols (1,3,5-trihydroxybenzene), respectively. To evaluate the changes in the molecular and electronic structures, we have performed a comprehensive computational, spectroscopic, and structural study starting from monosubstituted benzene derivatives as references over ortho-disubstituted derivates to the sixfold-substituted derivatives. Whereas in salicylaldehydes, ortho-Schiff bases, and 2,4,6-tricarbonyl-phloroglucinols the phenolic O-protonated tautomers represent the energy minima, the N-protonated tautomers represent the energy minima in 2,4,6-triiminephloroglucinols. The analysis provides a keto-enamine resonance structure with six exocyclic double bonds to be dominant for these species reminiscent of [6]radialenes, which were termed heteroradialenes. These heteroradialenes are non-aromatic alicycles. However, the predominance of this resonance structure does not represent a sudden change going from the 2,4,6-tricarbonyl-to the 2,4,6-triimine-phloroglucinols, but a gradual increase of analogous resonance structure contributions is observed even in salicylaldehyde and ortho-Schiff bases demonstrating some hetero-orthoquinodimethane character. These changes are, besides in the molecular structures, well reflected in the IR spectra, which can therefore be used as a simple tool to probe the electronic structures in these systems. Interruption of the delocalized π system supporting the intramolecular hydrogen bond, i. e. going from 2,4,6-triimine-to 2,4,6-triamine-substituted phloroglucinols, reestablishes an O-protonated aromatic phloroglucinol system.

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From Triplesalen to Triplesalophen: Ferromagnetic Interactions through Spin‐Polarization in a Trinuclear Ni^II Triplesalophen Complex

Cited by 22 publications

References 39 publications

Increasing the π–π Interactions in Trinuclear Ni^II₃ Triplesalophen Complexes

Increasing the π–π Interactions in Trinuclear Ni^II₃ Triplesalophen Complexes

Synthesis and Characterization of Trinuclear Ni^II₃ and Cu^II₃ Triplesalophen Complexes: Evaluation of Ligand Folding and Heteroradialene Formation and their Impact on the Magnetic Properties

Electronic and Molecular Structures of Heteroradialenes: A Combined Synthetic, Computational, Spectroscopic, and Structural Study Identifying IR Spectroscopy as a Simple but Powerful Experimental Probe

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From Triplesalen to Triplesalophen: Ferromagnetic Interactions through Spin‐Polarization in a Trinuclear NiII Triplesalophen Complex

Cited by 22 publications

References 39 publications

Increasing the π–π Interactions in Trinuclear NiII3 Triplesalophen Complexes

Increasing the π–π Interactions in Trinuclear NiII3 Triplesalophen Complexes

Synthesis and Characterization of Trinuclear NiII3 and CuII3 Triplesalophen Complexes: Evaluation of Ligand Folding and Heteroradialene Formation and their Impact on the Magnetic Properties

Electronic and Molecular Structures of Heteroradialenes: A Combined Synthetic, Computational, Spectroscopic, and Structural Study Identifying IR Spectroscopy as a Simple but Powerful Experimental Probe

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From Triplesalen to Triplesalophen: Ferromagnetic Interactions through Spin‐Polarization in a Trinuclear Ni^II Triplesalophen Complex

Increasing the π–π Interactions in Trinuclear Ni^II₃ Triplesalophen Complexes

Increasing the π–π Interactions in Trinuclear Ni^II₃ Triplesalophen Complexes

Synthesis and Characterization of Trinuclear Ni^II₃ and Cu^II₃ Triplesalophen Complexes: Evaluation of Ligand Folding and Heteroradialene Formation and their Impact on the Magnetic Properties