Vanadium-Induced Nucleophilic IPSO Substitutions in a Coordinated Tetrachlorosemiquinone Ring: Formation of the Chloranilate Anion as a Bridging Ligand

Chatterjee, Pabitra B.; Bhattacharya, Kaushik; Kundu, Nitya G.; Choi, Ki‐Young; Clérac, Rodolphe; Chaudhury, Muktimoy

doi:10.1021/ic801985g

Cited by 35 publications

(21 citation statements)

References 40 publications

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“…Efforts to generate benzosemiquinonoid-containing transition metal complexes with a nuclearity of greater than one have resulted in numerous dinuclear compounds, including those containing metal centers bridged by derivatives of 2,5-dihydroxy-1,4-benzoquinonoids [172][173][174][175][176][177][178][179][180][181][182][183][184][185][186][187][188][189], bis(pyrazolyl)benzoquinonoids [190][191][192][193], bis(phosphine)benzoquinonoids [194,195], bis(amino) benzoquinonoids [196][197][198][199][200][201][202], and bis(amino)diiminobenzoquinonoids [86,[203][204][205][206]. Indeed, the radical form of these ligands has shown enhanced magnetic coupling compared to their non-radical redox isomers [174,180,182].…”

Section: Benzosemiquinonoid Radical-bridged Single-molecule Magnetsmentioning

confidence: 99%

Radical ligand-containing single-molecule magnets

Demir

Jeon

Long

et al. 2015

Coordination Chemistry Reviews

522

386

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Section: Benzosemiquinonoid Radical-bridged Single-molecule Magnetsmentioning

confidence: 99%

Radical ligand-containing single-molecule magnets

Demir

Jeon

Long

et al. 2015

Coordination Chemistry Reviews

522

386

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“…Since the first observation of a strong magnetic interaction between paramagnetic metal ions and the H 2 An x− (x = 3, 1) radical species, reported by Gatteschi et al [48] several types of metal complexes ranging from finite discrete homoleptic and heteroleptic mononuclear systems to extended homoleptic and heteroleptic polymeric systems showing a large variety of peculiar crystal structures and physical properties, have been obtained so far [7,[49][50][51][52][53][54][55][56][57][58][59][60]. Valence Tautomerism is an essential phenomenon in anilato-based systems [29,[61][62][63][64] and it has been observed for the first time by Sato et al [64] in the heteroleptic dinuclear complex, [(CoTPA) 2 (H 2 An)](PF 6 ) 3 , (TPA = tris(2-pyridylmethyl)amine) that exhibits a valence tautomeric transition with a distinct hysteresis effect (13 K) around room temperature and photoinduced valence tautomerism under low temperature.…”

Section: Substituentmentioning

confidence: 99%

Recent Advances on Anilato-Based Molecular Materials with Magnetic and/or Conducting Properties

et al. 2017

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Abstract:The aim of the present work is to highlight the unique role of anilato-ligands, derivatives of the 2,5-dioxy-1,4-benzoquinone framework containing various substituents at the 3 and 6 positions (X = H, Cl, Br, I, CN, etc.), in engineering a great variety of new materials showing peculiar magnetic and/or conducting properties. Homoleptic anilato-based molecular building blocks and related materials will be discussed. Selected examples of such materials, spanning from graphene-related layered magnetic materials to intercalated supramolecular arrays, ferromagnetic 3D monometallic lanthanoid assemblies, multifunctional materials with coexistence of magnetic/conducting properties and/or chirality and multifunctional metal-organic frameworks (MOFs) will be discussed herein. The influence of (i) the electronic nature of the X substituents and (ii) intermolecular interactions i.e., H-Bonding, Halogen-Bonding, π-π stacking and dipolar interactions, on the physical properties of the resulting material will be also highlighted. A combined structural/physical properties analysis will be reported to provide an effective tool for designing novel anilate-based supramolecular architectures showing improved and/or novel physical properties. The role of the molecular approach in this context is pointed out as well, since it enables the chemical design of the molecular building blocks being suitable for self-assembly to form supramolecular structures with the desired interactions and physical properties.Keywords: benzoquinone derivatives; molecular magnetism; multifunctional molecular materials; spin-crossover materials; metal-organic frameworks General IntroductionThe aim of the present work is to highlight the key role of anilates in engineering new materials with new or improved magnetic and/or conducting properties and new technological applications. Only homoleptic anilato-based molecular building blocks and related materials will be discussed. Selected examples of para-/ferri-/ferro-magnetic, spin-crossover and conducting/magnetic multifunctional materials and MOFs based on transition metal complexes of anilato-derivatives, on varying the substituents at the 3,6 positions of the anilato moiety, will be discussed herein, whose structural features or physical properties are peculiar and/or unusual with respect to analogous compounds reported in the literature up to now. Their most appealing technological applications will be also reported.

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“…1,7–11 The major method for characterization of metal complexes with redox active ligands in the solid state is X-ray crystallography. 9,10,12–15 Solution characterization is often done using electrochemistry, UV- vis spectroscopy and EPR spectroscopy. 8–10,15 Another characterization method used less frequently for such complexes in solution is multinuclear NMR spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

“…9,10,12–15 Solution characterization is often done using electrochemistry, UV- vis spectroscopy and EPR spectroscopy. 8–10,15 Another characterization method used less frequently for such complexes in solution is multinuclear NMR spectroscopy. 16 Solid state methods commonly used include FTIR spectroscopy, 12,15,17 but a need exists for alternative characterization methods of these metal complexes with redox active ligands particularly in cases when the material is not crystalline.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Noninnocent Metal Complexes Using Solid-State NMR Spectroscopy: o-Dioxolene Vanadium Complexes

et al. 2011

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51V solid-state NMR (SSNMR) studies of a series of non-innocent vanadium(V) catechol complexes have been conducted to evaluate the possibility that 51V NMR observables, quadrupolar and chemical shift anisotropies, and electronic structures of such compounds can be used to characterize these compounds. The vanadium(V) catechol complexes described in these studies have relatively small quadrupolar coupling constants, which cover a surprisingly small range from 3.4 to 4.2 MHz. On the other hand, isotropic 51V NMR chemical shifts cover a wide range from −200 ppm to 400 ppm in solution and from −219 to 530 ppm in the solid state. A linear correlation of 51V NMR isotropic solution and solid-state chemical shifts of complexes containing non-innocent ligands is observed. These experimental results provide the information needed for the application of 51V SSNMR spectroscopy in characterizing the electronic properties of a wide variety of vanadium-containing systems, and in particular those containing non-innocent ligands and that have chemical shifts outside the populated range of −300 ppm to −700 ppm. The studies presented in this report demonstrate that the small quadrupolar couplings covering a narrow range of values reflect the symmetric electronic charge distribution, which is also similar across these complexes. These quadrupolar interaction parameters alone are not sufficient to capture the rich electronic structure of these complexes. In contrast, the chemical shift anisotropy tensor elements accessible from 51V SSNMR experiments are a highly sensitive probe of subtle differences in electronic distribution and orbital occupancy in these compounds. Quantum chemical (DFT) calculations of NMR parameters for [VO(hshed)(Cat)] yield 51V CSA tensor in reasonable agreement with the experimental results, but surprisingly, the calculated quadrupolar coupling constant is significantly greater than the experimental value. The studies demonstrate that substitution of the catechol ligand with electron donating groups results in an increase in the HOMO-LUMO gap and can be directly followed by an upfield shift for the vanadium catechol complex. In contrast, substitution of the catechol ligand with electron withdrawing groups results in a decrease in the HOMO-LUMO gap and can directly be followed by a downfield shift for the complex. The vanadium catechol complexes were used in this work because the 51V is a half-integer quadrupolar nucleus whose NMR observables are highly sensitive to the local environment. However, the results are general and could be extended to other redox active complexes that exhibit similar coordination chemistry as the vanadium catechol complexes.

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Vanadium-Induced Nucleophilic IPSO Substitutions in a Coordinated Tetrachlorosemiquinone Ring: Formation of the Chloranilate Anion as a Bridging Ligand

Cited by 35 publications

References 40 publications

Radical ligand-containing single-molecule magnets

Radical ligand-containing single-molecule magnets

Recent Advances on Anilato-Based Molecular Materials with Magnetic and/or Conducting Properties

Characterization of Noninnocent Metal Complexes Using Solid-State NMR Spectroscopy: o-Dioxolene Vanadium Complexes

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