Structural and Solution Characterization of Mononuclear Vanadium(IV) Complexes That Help To Elucidate the Active Site Structure of the Reduced Vanadium Haloperoxidases

Hamstra, Brent J.; Houseman, Andrew L. P.; Colpas, Gerard J.; Kampf, Jeff W.; LoBrutto, Russell; Frasch, Wayne D.; Pecoraro, Vincent L.

doi:10.1021/ic970284x

Cited by 117 publications

(97 citation statements)

References 42 publications

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“…However, in the 51 V NMR spectra of solutions containing 3 mm of V V and 6 mm of 1, a new signal at d~À577 ppm was detected in the pH range 5±9, indicating complex formation. With pyridoxamine, the 51 V NMR measurements with 3 mm V V and 12 mm of ligand did not show any complex formation in the same pH range. In the V V ±H 2 Rpyr 2 en system pH-potentiometry clearly indicated complex formation, and the stability constants given in Table 3 were obtained by the evaluation of the pH-metric titration data.…”

Section: Ligand Protonation By Ph-potentiometry and 1 H Nmr Spectroscmentioning

confidence: 79%

“…The aqueous V V ±H 2 Rpyr 2 en system was also studied by 2D 1 H NMR techniques, including COSY, NOESY, TOCSY, and ROESY, using the respective pulse sequences installed in the software of the NMR instrument. 51 V NMR acquisition parameters were: 33 kHz spectral width, 30 ms pulse width, 1 s acquisition time, and 10 Hz line broadening. The signal intensities of the NMR resonances were obtained using the program NUTS.…”

Section: Synthesis Of the Ligandsmentioning

confidence: 99%

“…However, no peaks are detected in the 51 V NMR below j À540 ppm j , which could suggest the presence of monooxovanadium(v) complexes. [25] Adding acid or base to decrease or increase the pH in the range 2±5, the observed NMR, EPR, and UV/Vis spectra show the same profile.…”

mentioning

confidence: 95%

“…EPR, 1 H, and 51 V NMR spectroscopies were used to provide detailed information for the rather complicated solution equilibria of these ligands with V IV O 2 + and V V O 2 + . Ab initio [13] and DFT [14] calculations were carried out and support the formation and identification of the isomers present in both systems, and help to explain the experimental data.…”

Section: Introductionmentioning

confidence: 99%

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N,N′‐Ethylenebis(pyridoxylideneiminato) and N,N′‐Ethylenebis(pyridoxylaminato): Synthesis, Characterization, Potentiometric, Spectroscopic, and DFT Studies of Their Vanadium(IV) and Vanadium(V) Complexes

Correia¹,

Pessoa²,

Duarte³

et al. 2004

Chemistry A European J

128

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The Schiff base N,N'-ethylenebis(pyridoxylideneiminato) (H 2 pyr 2 en, 1) was synthesized by reaction of pyridoxal with ethylenediamine; reduction of H 2 pyr 2 en with NaBH 4 yielded the reduced Schiff base N,N'-ethylenebis-(pyridoxylaminato) (H 2 Rpyr 2 en, 2); their crystal structures were determined by X-ray diffraction. The totally protonated forms of 1 and 2 correspond to H 6 L 4 + , and all protonation constants were determined by pH-potentiometric and Supporting information for this article is available on the WWW under http://www.chemeurj.org/ or from the author. Some additional X-ray data for 1, 2, 4, and 9 (SI-1); further discussion of IR spectra (

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Section: Ligand Protonation By Ph-potentiometry and 1 H Nmr Spectroscmentioning

confidence: 79%

Section: Synthesis Of the Ligandsmentioning

confidence: 99%

mentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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N,N′‐Ethylenebis(pyridoxylideneiminato) and N,N′‐Ethylenebis(pyridoxylaminato): Synthesis, Characterization, Potentiometric, Spectroscopic, and DFT Studies of Their Vanadium(IV) and Vanadium(V) Complexes

Correia¹,

Pessoa²,

Duarte³

et al. 2004

Chemistry A European J

128

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“…In recent studies, it was found that the investigation of ADA-metal chelates in solid state provides information about the chelating role of the divalent anion H 2 NCOCH 2 N(CH 2 COO ) 2 . Therefore, some mixedligand complexes of transitional metal ions with ADA as primary ligand and water molecule, imidazole and 2,2¢-bipyridine as secondary ligands have been reported [1,[4][5][6][7][8]. However, crystal structures of the mixed-ligand metal(II) complexes with ADA and 1,10-phenanthroline compound have not been studied so far.…”

Section: Discussionmentioning

confidence: 99%

Crystal structure of (phenanthroline-N,N′)-N-carbamoylmethyl-iminodiacetato- copper(II) dihydrate, [Cu(C6H8N2)(C12H8N2)] · 2H2O

Cheng¹,

Ma²,

Wang³

2006

Zeitschrift Für Kristallographie - New Crystal Structures

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Source of materialThe mixture of Cu(CH 3COO)2 · 5H2O (0.5 mmol, 0.100 g) and H 2ADA (1 mmol, 0.190 g; H2NCOCH2N(CH2COOH)2, N-carbamoylmethyl-iminodiacetic acid or named N-(2-acetamido)iminodiacetic acid) was stirred into 6 mL 50 % methanolic solution at room temperature, which was refluxed about 20 min. Then the pH was adjusted to approximately 6 with NaOH solid, and 4 mL 50 % methanolic solution of 1,10 phenanthroline (0.5 mmol, 0.100 g) was added. The reaction mixture was heated on a water bath for 6 h at 60°C and then filtered. The blue prismatic crystal was separated from the mother liquor by slow evaporation at room temperature after one week (yield 0.158 g, 65 %). Experimental detailsThe water H atoms were freely refined due to their importance in the hydrogen bonding. The other H atoms were added geometrically and refined using rigid body approximation. DiscussionChelation of ADA (the divalent anion of H2ADA) and metal(II) ions (such as Mg, Ca, Sr, Ba, Mn, Co, Ni, Cu, Zn, Cd, Hg, Pb etc.) in solution has been well researched for a long time [1]. H 2ADA acts as a polydentate ligand and presents a variety of coordination modes because of the presence of carbamoyl function and iminodiacetic group. It is not only a well-known chelating agent, but also used in biological buffers of pH 6.0-7.4 [2,3]. In recent studies, it was found that the investigation of ADA-metal chelates in solid state provides information about the chelating role of the divalent anion H 2 NCOCH 2 N(CH 2 COO ) 2 . Therefore, some mixedligand complexes of transitional metal ions with ADA as primary ligand and water molecule, imidazole and 2,2¢-bipyridine as secondary ligands have been reported [1,[4][5][6][7][8]. However, crystal structures of the mixed-ligand metal(II) complexes with ADA and 1,10-phenanthroline compound have not been studied so far. The asymmetric unit of the title crystal structure consists of a [Cu(ADA)(phen)] moiety and two hydrate water molecules (figure, top). The Cu(II) ion is five-coordinated (CuN 3 O 2 ) and the coordination polyhedron is a distorted trigonal bipyramid in which the divalent ADA anion acts as tridentate chelating ligand. The bond lengths of Cu1O1, Cu1O3 and Cu1N3 are 1.942(2) Å, 2.102(2) Å and 2.171(2) Å, respectively. The phen molecule serves as bidentate ligand chelating to the Cu(II) ion with Cu1N1 and CuN2 bond distances of 2.007(2) Å and 2.032(2) Å, respectively. It should be pointed out that the CuN (imino) and CuO (carboxyl) bonds are longer than those reported in other metal-ADA complexes [1,6,7], but remarkable close to nickel(II) complex [Ni(ADA)(bipy)(H 2 O)] · 4H 2 O (I) [8], which is probably due to steric hindrance of phen (or 2,2¢-bipyridine) weakening the bonding interaction of ADA with metal ions. The Cu(II) Z. Kristallogr.

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Synthetic Analogues for Oxovanadium(IV)–Glutathione Interaction: An EPR, Synthetic and Structural Study of Oxovanadium(IV) Compounds with Sulfhydryl‐Containing Pseudopeptides and Dipeptides

Tasiopoulos

Troganis

Evangelou

et al. 1999

Chemistry A European J

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(7) was prepared by the reaction of [VOCl 2 (thf) 2 ] with phen in a methanolic solution. The X-ray structure of 3 shows that the vanadium(iv) atom is ligated to a tridentate mpg 3À ligand at the S thiolato , N peptide and O carboxylato atoms. The X-ray structure of 7 is also reported. The optical, infrared, magnetic, electron paramagnetic resonance, and electrochemical properties of compounds 1 ± 5Ć H 3 OH and 7 were studied. Combination of the correlation plots of the EPR parameters g z versus A z , or the groundstate orbital population (b*) 2 versus A z , together with the additivity relationship, A z,calcd Sn i A zi /4, were shown to provide a powerful tool for probing the equatorial donor atoms in an oxovanadium(iv) compound and consequently in biomolecules. Thus, these methods provide valuable evidence for the assignment of the equatorial donor atoms for the V IV O 2 center of the V IV O 2 ± glutathione system at various pH values. Model NMR studies (interaction of vanadium(v) with H 3 mpg) showed that there is a possibility of vanadium(v) ligation to glutathione. The contribution of a deprotonated peptide(amide) nitrogen to A z is not a fixed quantity (it varies from 29 to 43 Â 10 À4 cm À1), but is influenced by the presence of the three other donor atoms in the equatorial plane and, in particular, their charge.

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Structural and Solution Characterization of Mononuclear Vanadium(IV) Complexes That Help To Elucidate the Active Site Structure of the Reduced Vanadium Haloperoxidases

Cited by 117 publications

References 42 publications

N,N′‐Ethylenebis(pyridoxylideneiminato) and N,N′‐Ethylenebis(pyridoxylaminato): Synthesis, Characterization, Potentiometric, Spectroscopic, and DFT Studies of Their Vanadium(IV) and Vanadium(V) Complexes

N,N′‐Ethylenebis(pyridoxylideneiminato) and N,N′‐Ethylenebis(pyridoxylaminato): Synthesis, Characterization, Potentiometric, Spectroscopic, and DFT Studies of Their Vanadium(IV) and Vanadium(V) Complexes

Crystal structure of (phenanthroline-N,N′)-N-carbamoylmethyl-iminodiacetato- copper(II) dihydrate, [Cu(C6H8N2)(C12H8N2)] · 2H2O

Synthetic Analogues for Oxovanadium(IV)–Glutathione Interaction: An EPR, Synthetic and Structural Study of Oxovanadium(IV) Compounds with Sulfhydryl‐Containing Pseudopeptides and Dipeptides

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