A structural model for vanadyl–histidine interactions: structure determination of [VO(1-vinylimidazole)<sub>4</sub>Cl]Cl by a combination of X-ray crystallography and X-ray absorption spectroscopy

Calviou, Louise J.; Arber, Judith M.; Collison, David; Garner, C. David; Clegg, William

doi:10.1039/c39920000654

Cited by 22 publications

(20 citation statements)

References 17 publications

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“…We also performed the same analysis for some literature data, , and the results are included in Table . The resulting r values are in agreement with the X-ray determined V−N bond distances, ,− validating the indirect spin transfer mechanism. This analysis provides valuable insights into the origin of the good correlation between the HFC parameters and nitrogen types.…”

Section: Discussionsupporting

confidence: 78%

¹⁴N Coupling Parameters in Oxovanadium(IV)−Amine, −Imine, and −Isothiocyanate Complexes Studied by Electron Spin Echo Envelope Modulation Spectroscopy

Fukui¹,

Ohya-Nishiguchi²,

Kamada³

1997

Inorg. Chem.

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Electron spin echo envelope modulation (ESEEM) spectroscopy has been applied to several nitrogen-coordinated oxovanadium(IV) complexes. Results for two amine-nitrogen complexes, VO(edda) and VO(gly)2, two imine-nitrogen complexes, VO(salen) and VO(salophen), and one isothiocyanate complex, VO(NCS)4 2-, are presented. [H2edda = ethylenediamine-N,N‘-diacetic acid, gly- = glycinate, H2salen = N,N‘-bis(salicylidene)ethylenediamine, and H2salophen = N,N‘-bis(salicylidene)-o-phenylenediamine.] The 14N hyperfine coupling (HFC) and quadrupole coupling (NQC) parameters have been determined from computer simulation of the two-pulse and three-pulse ESEEM data recorded at some selected field positions. Resulting NQC parameters are e 2 qQ = 3.1 MHz (VO(edda)), 2.7 MHz (VO(gly)2), 2.4 MHz (VO(salen)), 2.6 MHz (VO(salophen), and 1.0 MHz (VO(NCS)4 2-). The isotropic HFC parameters, |A iso|, show a good correlation to the nitrogen type as 4.98 MHz (VO(edda)), 5.10 MHz (VO(gly)2), 5.83 MHz (VO(salen)), 5.78 MHz (VO(salophen)), and 7.47 MHz (VO(NCS)4 2-). The isotropic and anisotropic parts of the HFC parameters are analyzed in terms of the indirect spin transfer mechanism. The analysis has given good quantitative agreements, supporting the validity of this mechanism. According to the mechanism, the isotropic part of HFC depends essentially on two factors, the degree of the (negative) polarization of the nitrogen lone-pair sp n -hybrid orbital and the s orbital content of this orbital. The analysis has shown that the polarization is invariably around −1%. Thus, the good correlation can be attributed to the distinct difference of the s-orbital contents between nitrogen types.

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Section: Discussionsupporting

confidence: 78%

¹⁴N Coupling Parameters in Oxovanadium(IV)−Amine, −Imine, and −Isothiocyanate Complexes Studied by Electron Spin Echo Envelope Modulation Spectroscopy

Fukui¹,

Ohya-Nishiguchi²,

Kamada³

1997

Inorg. Chem.

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“…The V—O(sulfate) bond length of 2.1359(16) Å, is slightly longer than the V—O bond in [V (IV) O(acac) 2 ] (1.97 Å) 37. In complex 2, the V—Cl bond length (2.6501(12) Ǻ) is significantly longer those in examples of octahedral vanadium(IV) complexes with a chloride ligand trans - to V=O (2.465 Ǻ,38 2.468 Ǻ39) and suggests that this ligand is weakly bound. A CCDC search for similar vanadyl macrocyclic complexes with sulfate and chloride ligands in the 6 th axial position did not reveal any reported examples.…”

Section: Discussionmentioning

confidence: 88%

Oxovanadium(IV) Cyclam and Bicyclam Complexes: Potential CXCR4 Receptor Antagonists

Ross

Soares

Covelli³

et al. 2009

Inorg. Chem.

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Metal complexation can have a major influence on the antiviral and co-receptor binding properties of cyclam and bicyclam macrocycles. We report the synthesis of the vanadyl cyclam complexes [V (IV) O(cyclam)SO 4 ] (1) and [V (IV) O(cyclam)Cl]Cl -(2), and the analogous xylylbicyclam sulfato (3) and chlorido (4) complexes. The X-ray crystal structures of 1·1.33CH 3 OH and 2·CH 3 OH1.5H 2 O show short V=O bonds (1.6093(19) and 1.599(3) Å, respectively) with monodentate sulfate H-bonded to ring NH groups for 1, but a long V-Cl bond (2.650(12) Å) for 2. The solid-state structures of 3 and 4 were compared to those of 1 and 2 using vanadium K-edge EXAFS data. These suggested that complex 4 was oligomeric and contained bridging chlorido ligands. EPR studies suggested that the SO 4 2-(from 1) and Cl -(from 2) ligands are readily substituted by water in solution, whereas these remain partially bound for the V IV xylylbicyclam complexes 3 and 4. The vanadyl xylylbicyclam complexes were highly active against HIV-1 (III B ) and HIV-2 (ROD) strains with IC 50 values in the range 1-5 μM for 3 and 0.1-0.3 μM for 4; in contrast the vanadyl cyclam complexes 1 and 2 were inactive. The factors which contribute to the activity of these complexes are discussed. Studies of vanadyl cyclam docked into a model of the human CXCR4 coreceptor revealed that the coordination of vanadium to the carboxylate of Asp171 may be accompanied by H-bonding to the macrocycle and an attractive V=O··H interaction involving the backbone Trp195 α-carbon proton of CXCR4. In addition, hydrophobic interactions with Trp195 are present. Both ring configuration and the xylyl linker may play roles in determining the higher activity of the bicyclam complexes.

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“…The design of structural models of vanadate-dependent haloperoxidase enzymes (VHPO) [1][2][3][4][5][6][7][8][9][10][11] and the development of vanadium catalytic model systems for oxidations and oxygentransfer reactions, including the oxidative halogenation of organic substrates and oxidation of organic sulfides, [12][13][14][15][16][17][18] potentiated renewed interest in the coordination chemistry of vanadium complexes with polydentate ligands.…”

Section: Introductionmentioning

confidence: 99%

Vanadium complexes having [VO]2+, [VO]3+ and [VO2]+ cores with hydrazones of 2,6-diformyl-4-methylphenol: synthesis, characterization, reactivity, and catalytic potential

Maurya

Haldar

Kumar³

et al. 2013

Dalton Trans.

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The Schiff bases H3dfmp(L)2 obtained by the condensation of 2,6-diformyl-4-methylphenol and hydrazones [L = isonicotinoylhydrazide (inh), nicotinoylhydrazide (nah) and benzoylhydrazide (bhz)] are prepared and characterized. By reaction of [V(IV)O(acac)2] and the H3dfmp(L)2 in methanol the V(IV)O-complexes [V(IV)O{Hdfmp(inh)2}(H2O)] (1), [V(IV)O{Hdfmp(nah)2}(H2O)] (2) and [V(IV)O{Hdfmp(bhz)2}(H2O)] (3) were obtained. Upon their aerial oxidation in methanol [V(V)O(OMe)(MeOH){Hdfmp(inh)2}] (4), [V(V)O(OMe)(MeOH){Hdfmp(nah)2}] (5) and [V(V)O(OMe)(MeOH){Hdfmp(bhz)2}] (6) were isolated. In the presence of KOH, oxidation of 1-3 results in the formation of [V(V)O2{H2dfmp(inh)2}]n·5H2O (7), K[V(V)O2{Hdfmp(nah)2}] (8) and K[V(V)O2{Hdfmp(bhz)2}] (9). All compounds are characterized in the solid state and in solution, namely by spectroscopic techniques (IR, UV-Vis, EPR, (1)H, (13)C and (51)V NMR), and DFT is also used to calculate the V(IV) hyperfine coupling constants of V(IV)-compounds and (51)V NMR chemical shifts of several V(V)-species and assign them to those formed in solution. Single crystal X-ray analysis of [V(V)O(OMe)(MeOH){Hdfmp(bhz)2}] (6) and [V(V)O2{H2dfmp(inh)2}]n·5H2O (7) confirm the coordination of the ligand in the dianionic (ONO(2-)) enolate tautomeric form, one of the hydrazide moieties remaining non-coordinated. In the case of 7 the free N(pyridine) atom of the inh moiety coordinates to the other vanadium center yielding a polynuclear complex in the solid state. It is also demonstrated that the V(V)O2-complexes are catalyst precursors in the oxidative bromination of styrene by H2O2, therefore acting as functional models of vanadium dependent haloperoxidases. Plausible intermediates involved in the catalytic process are established by UV-Vis, (51)V NMR and DFT studies.

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A structural model for vanadyl–histidine interactions: structure determination of [VO(1-vinylimidazole)₄Cl]Cl by a combination of X-ray crystallography and X-ray absorption spectroscopy

Cited by 22 publications

References 17 publications

¹⁴N Coupling Parameters in Oxovanadium(IV)−Amine, −Imine, and −Isothiocyanate Complexes Studied by Electron Spin Echo Envelope Modulation Spectroscopy

¹⁴N Coupling Parameters in Oxovanadium(IV)−Amine, −Imine, and −Isothiocyanate Complexes Studied by Electron Spin Echo Envelope Modulation Spectroscopy

Oxovanadium(IV) Cyclam and Bicyclam Complexes: Potential CXCR4 Receptor Antagonists

Vanadium complexes having [VO]2+, [VO]3+ and [VO2]+ cores with hydrazones of 2,6-diformyl-4-methylphenol: synthesis, characterization, reactivity, and catalytic potential

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A structural model for vanadyl–histidine interactions: structure determination of [VO(1-vinylimidazole)4Cl]Cl by a combination of X-ray crystallography and X-ray absorption spectroscopy

Cited by 22 publications

References 17 publications

14N Coupling Parameters in Oxovanadium(IV)−Amine, −Imine, and −Isothiocyanate Complexes Studied by Electron Spin Echo Envelope Modulation Spectroscopy

14N Coupling Parameters in Oxovanadium(IV)−Amine, −Imine, and −Isothiocyanate Complexes Studied by Electron Spin Echo Envelope Modulation Spectroscopy

Oxovanadium(IV) Cyclam and Bicyclam Complexes: Potential CXCR4 Receptor Antagonists

Vanadium complexes having [VO]2+, [VO]3+ and [VO2]+ cores with hydrazones of 2,6-diformyl-4-methylphenol: synthesis, characterization, reactivity, and catalytic potential

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A structural model for vanadyl–histidine interactions: structure determination of [VO(1-vinylimidazole)₄Cl]Cl by a combination of X-ray crystallography and X-ray absorption spectroscopy

¹⁴N Coupling Parameters in Oxovanadium(IV)−Amine, −Imine, and −Isothiocyanate Complexes Studied by Electron Spin Echo Envelope Modulation Spectroscopy

¹⁴N Coupling Parameters in Oxovanadium(IV)−Amine, −Imine, and −Isothiocyanate Complexes Studied by Electron Spin Echo Envelope Modulation Spectroscopy