Tuning the redox properties of a 1-D supramolecular array via selective deprotonation of coordinated imidazoles around a Mn(II) center

Hammes, Brian S.; Damiano, Bryan J.; Tobash, Paul H.; Hidalgo, Melanie J.; Yap, Glenn P. A.

doi:10.1016/j.inoche.2005.03.010

Cited by 11 publications

(2 citation statements)

References 14 publications

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“…While the distortion is most prevalent in [Fe(bpp) 2 ] 2+ chemistry, it also occurs in high-spin iron(II) complexes of other tris -heterocyclic ligands, − and in related complexes of high-spin iron(III), − manganese(II), − cobalt(II), − and zinc(II). − In high-spin iron(II) complexes, the distortion electronically resembles a Jahn–Teller distortion of a 5 E ground state (in D 2d symmetry), which is favored in complexes of tridentate ligands with a narrow bite angle. , However, distortion also occurs in complexes with an orbital singlet ground state. In that case, the absence of a ligand field stabilization energy makes their coordination geometry more susceptible to deformations induced by crystal packing.…”

Section: Introductionmentioning

confidence: 99%

A Survey of the Angular Distortion Landscape in the Coordination Geometries of High-Spin Iron(II) 2,6-Bis(pyrazolyl)pyridine Complexes

Capel Berdiell,

Michaels,

Munro

et al. 2024

Inorg. Chem.

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Reaction of 2,4,6-trifluoropyridine with sodium 3,4dimethoxybenzenethiolate and 2 equiv of sodium pyrazolate in tetrahydrofuran at room temperature affords 4-(3,4-dimethoxyphenylsulfanyl)-2,6-di(pyrazol-1-yl)pyridine (L), in 30% yield. The iron(II) complexes [FeL 2 ][BF 4 ] 2 (1a) and [FeL 2 ][ClO 4 ] 2 (1b) are high-spin with a highly distorted six-coordinate geometry. This structural deviation from ideal D 2d symmetry is common in highspin [Fe(bpp) 2 ] 2+ (bpp = di{pyrazol-1-yl}pyridine) derivatives, which are important in spin-crossover materials research. The magnitude of the distortion in 1a and 1b is the largest yet discovered for a mononuclear complex. Gas-phase DFT calculations at the ω-B97X-D/6-311G** level of theory identified four minimum or local minimum structural pathways across the distortion landscape, all of which are observed experimentally in different complexes. Small distortions from D 2d symmetry are energetically favorable in complexes with electron-donating ligand substituents, including sulfanyl groups, which also have smaller energy penalties associated with the lowest energy distortion pathway. Natural population analysis showed that these differences reflect greater changes to the Fe−N{pyridyl} σ-bonding as the distortion proceeds, in the presence of more electron-rich pyridyl donors. The results imply that [Fe(bpp) 2 ] 2+ derivatives with electron-donating pyridyl substituents are more likely to undergo cooperative spin transitions in the solid state. The high-spin salt [Fe(bpp) 2 ][CF 3 SO 3 ] 2 , which also has a strong angular distortion, is also briefly described and included in the analysis.

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Section: Introductionmentioning

confidence: 99%

A Survey of the Angular Distortion Landscape in the Coordination Geometries of High-Spin Iron(II) 2,6-Bis(pyrazolyl)pyridine Complexes

Capel Berdiell,

Michaels,

Munro

et al. 2024

Inorg. Chem.

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“…A literature survey on the chemistry of H 2 dimpy showed the use of this molecule and its derivatives, via alkylation or deprotonation, in the modulation of redox and spectroscopic properties of Co, Mn, Ni, Ru and Fe complexes (Carina et al, 1998;Fuchs et al, 2010;Hammes et al, 2005;Savchuk et al, 2017;Stupka et al, 2004), and in the preparation of catalysts based on different metal centres, for example, ruthenium(II) complexes for H/D exchange between hydrocarbons (Hashiguchi et al, 2010) and for condensation of benzyl alcohol (Li et al, 2018), copper(II) complexes for atom-transfer radical polymerization (Ratier de Arruda et al, 2017) and cobalt(III) complexes for water oxidation (Rigsby et al, 2012). Reports on gold(III) complexes as anticancer agents (Zou et al, 2013) and organoplatinum(II) complexes with charge-carrier mobility and thermo-and vapour-luminescence properties (Che et al, 2011) were also found in the literature.…”

Section: Introductionmentioning

confidence: 99%

Analysis of solvent-accessible voids and proton-coupled electron transfer of 2,6-bis(1H-imidazol-2-yl)pyridine and its hydrochloride

et al. 2019

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The crystal structures of the solid form of solvated 2,6‐bis(1H‐imidazol‐2‐yl)pyridine (H2dimpy) trihydrate, C11H9N5·3H2O·[+solvent], I, and its hydrate hydrochloride salt 2‐[6‐(1H‐imidazol‐2‐yl)pyridin‐2‐yl]‐1H‐imidazol‐3‐ium chloride trihydrate, C11H10N5+·Cl−·3H2O, II, are reported and analysed in detail, along with potentiometric and spectrophotometric titrations for evaluation of the acid–base equilibria and proton‐coupled electron‐transfer reactions. Compound I crystallizes in the high‐symmetry trigonal space group P3221 with an atypical formation of solvent‐accessible voids, as a consequence of the 32 screw axis in the crystallographic c‐axis direction, which are probably occupied by uncharacterized disordered solvent molecules. Additionally, the trihydrated chloride salt crystallizes in the conventional monoclinic space group P21/c without the formation of solvent‐accessible voids. The acid–base equilibria of H2dimpy were studied by potentiometric and spectrophotometric titrations, and the results suggest the formation of H3dimpy+ (pKa1 = 5.40) and H4dimpy2+ (pKa2 = 3.98), with the electrochemical behaviour of these species showing two consecutive irreversible proton‐coupled electron‐transfer reactions. Density functional theory (DFT) calculations corroborate the interpretation of the experimental results and support the assignment of the electrochemical behaviour.

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Synthesis, Structures, and Reactivities of Pincer‐Type Ruthenium Complexes Bearing Two Proton‐Responsive Pyrazole Arms

Yoshinari

Tazawa

Kuwata

et al. 2012

Chemistry An Asian Journal

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A new metal-ligand bifunctional, pincer-type ruthenium complex [RuCl(L1-H(2))(PPh(3))(2)]Cl (1; L1-H(2)=2,6-bis(5-tert-butyl-1H-pyrazol-3-yl)pyridine) featuring two proton-delivering pyrazole arms has been synthesized. Complex 1, derived from [RuCl(2)(PPh(3))(3)] with L1-H(2), underwent reversible deprotonation with potassium carbonate to afford the pyrazolato-pyrazole complex [RuCl(L1-H)(PPh(3))(2)] (2). Further deprotonation of 1 and 2 with potassium hexamethyldisilazide in methanol resulted in the formation of the bis(pyrazolato) complex [Ru(L1)(MeOH)(PPh(3))(2)] (3). Complex 3 smoothly reacted with dioxygen and dinitrogen to give the side-on peroxo complex [Ru(L1)(O(2))(PPh(3))(2)] (4) and end-on dinitrogen complex [Ru(L1)(N(2))(PPh(3))(2)] (5), respectively. On the other hand, the reaction of [RuCl(2)(PPh(3))(3)] with less hindered 2,6-di(1H-pyrazol-3-yl)pyridine (L3-H(2)) led to the formation of the dinuclear complex [{RuCl(2)(PPh(3))(2)}(2)(μ(2)-L3-H(2))(2)] (6), in which the pyrazole-based ligand adopted a tautomeric form different from L1-H(2) in 1 and the central pyridine remained uncoordinated. The detailed structures of 1-6 were determined by X-ray crystallography.

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Tuning the redox properties of a 1-D supramolecular array via selective deprotonation of coordinated imidazoles around a Mn(II) center

Cited by 11 publications

References 14 publications

A Survey of the Angular Distortion Landscape in the Coordination Geometries of High-Spin Iron(II) 2,6-Bis(pyrazolyl)pyridine Complexes

A Survey of the Angular Distortion Landscape in the Coordination Geometries of High-Spin Iron(II) 2,6-Bis(pyrazolyl)pyridine Complexes

Analysis of solvent-accessible voids and proton-coupled electron transfer of 2,6-bis(1H-imidazol-2-yl)pyridine and its hydrochloride

Synthesis, Structures, and Reactivities of Pincer‐Type Ruthenium Complexes Bearing Two Proton‐Responsive Pyrazole Arms

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