Formation of an asymmetrical ligand (H 3 L cyclic) via a metal-induced cyclization of symmetrical thiocarbohydrazone (H 4 L) in synthesizing an oxovanadium(IV) complex VO(HL cyclic)(EtOH)2

Deng, Yu‐Heng; Yang, Yingying; Zhang, Yajie; Yan, Qiaozhi; Liu, Juan

doi:10.1080/00958972.2012.673717

Cited by 5 publications

(3 citation statements)

References 21 publications

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“…Fits to the extended X-ray absorption fine structure (EXAFS) data revealed a coordination sphere composed of two shells: one at 1.60 Å, corresponding to the oxo ligand, and another at 2.05 Å (Figure S6 and Table S1–S3), corresponding to the protein and succinate ligands. The fitting analysis is consistent with previous structural characterization of vanadyl complexes − and notably similar to the first-sphere metrics obtained by EXAFS on the ferryl intermediate in TauD (shells at 1.62 and 2.05 Å) …”

Section: Resultssupporting

confidence: 89%

“…Both have +2 net charges resulting from bonding between the tetravalent metal cation and divalent oxide anion . Moreover, the metal–oxo bonds have similar lengths, ranging from 1.58 to 1.63 Å for octahedral vanadyl complexes with oxygen and nitrogen coordination − and from 1.61 to 1.64 Å for the ferryl intermediates in the Fe/2OG hydroxylase, TauD, and halogenases, CytC3 and SyrB2. ,, Importantly, the d 1 configuration of V IV gives the vanadyl ion an S = 1/2 ground state, which makes it EPR active and amenable to accurate determination of distances between vanadium and nearby magnetic nuclei by EPR methods.…”

Section: Introductionmentioning

confidence: 99%

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Vanadyl as a Stable Structural Mimic of Reactive Ferryl Intermediates in Mononuclear Nonheme-Iron Enzymes

Martinie¹,

Pollock²,

Matthews

et al. 2017

Inorg. Chem.

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The iron(II)- and 2-(oxo)glutarate-dependent (Fe/2OG) oxygenases catalyze an array of challenging transformations via a common iron(IV)-oxo (ferryl) intermediate, which in most cases abstracts hydrogen (H•) from an aliphatic carbon of the substrate. Although it has been shown that the relative disposition of the Fe–O and C–H bonds can control the rate of H• abstraction and fate of the resultant substrate radical, there remains a paucity of structural information on the actual ferryl states, owing to their high reactivity. We demonstrate here that the stable vanadyl ion [(VIV-oxo)2+] binds along with 2OG or its decarboxylation product, succinate, in the active site of two different Fe/2OG enzymes to faithfully mimic their transient ferryl states. Both ferryl and vanadyl complexes of the Fe/2OG halogenase, SyrB2, remain stably bound to its carrier protein substrate (L-aminoacyl-S-SyrB1), whereas the corresponding complexes harboring transition metals (Fe, Mn) in lower oxidation states dissociate. In the well-studied hydroxylase, taurine:2OG dioxygenase (TauD), the disposition of the substrate C–H bond relative to the vanadyl ion defined by pulse electron paramagnetic resonance methods is consistent with the crystal structure of the reactant complex and computational models of the ferryl state. Vanadyl substitution may thus afford access to structural details of the key ferryl intermediates in this important enzyme class.

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Section: Resultssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Vanadyl as a Stable Structural Mimic of Reactive Ferryl Intermediates in Mononuclear Nonheme-Iron Enzymes

Martinie¹,

Pollock²,

Matthews

et al. 2017

Inorg. Chem.

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“…One of the signals belonging to the two azomethine protons at 8.67 ppm in the spectrum of L shifted to 8.09 ppm after the formation of the complex. This indicates the coordination of one of the azomethine groups of L to the nickel(II) ion [24,29,30]. 1 H NMR spectrum of [Ni(L)(PPh 3 )] is given in Figure S2.…”

Section: Synthesis and Spectral Featuresmentioning

confidence: 99%

A New Nickel(II) Complex Derived From Bisthiocarbohydrazone: Synthesis, Characterization, Crystal Structure and Antioxidant Activity

KAYA

2023

Cumhuriyet Science Journal

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A new complex with composition [Ni(L)(PPh3)] (PPh3 = triphenylphosphine) was obtained from the reaction of 1,5-bis(salicylidene)thiocarbohydrazone (L) with an equimolar amount of [NiCl2(PPh3)2]. The complex was identified by FT-IR, 1H NMR and UV-Vis spectroscopic methods and elemental analysis. The solid state structure of [Ni(L)(PPh3)] was established by X-ray diffraction analysis. It was determined that the complex, whose nickel center has a distorted square planar configuration, crystallizes in the monoclinic space group I2/c. Bisthiocarbohydrazone (L) binds to the nickel center through its phenolate O, azomethine N and thioenolate S atoms in a dianionic tridentate mode. The antioxidant capacity of L and Ni(II) complex was examined using the CUPRAC (cupric reducing antioxidant capacity) method. Also, the DPPH (1,1-Diphenyl-2-picrylhydrazyl) method was used to test free radical scavenging activity of the compounds. Antioxidant activity results showed that L exhibited better activity than Ni(II) complex.

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Synthesis, characterization, crystal structure, DNA and human serum albumin interactions, as well as antiproliferative activity of a Cu(II) complex containing a Schiff base ligand formed in situ from the Cu(II)‐induced cyclization of 1,5‐bis(salicylidene)thiocarbohydrazide

Parsekar

Haldar

Antharjanam

et al. 2021

Applied Organom Chemis

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The reaction of Cu(OAc)2·H2O with o‐HOC6H4‐C(H)N‐NH‐C(S)‐NH‐NC(H)‐C6H4OH‐o in methanol resulted in the formation of a dinuclear Cu(II) complex [(o‐phen)Cu(HL)Cu(HL)] (1) in the solution where HL2− is a new O−NN− ligand ο−HOC6H4‐normalC()H=normalN‐normalN=truenormalC‐normalS‐normalCfalse(=normalN‐NH⎵false)‐C6H4OH−ο formed in situ from cyclization of the Schiff base and the isolated product was found to be a dimer of 1 forming a tetranuclear compound in solid due to axial coordination of bridging phenolate O− as revealed from X‐ray crystallography. Electronic spectroscopic study using calf thymus DNA as well as fluorescence quenching study of ethidium bromide bound DNA in presence of 1 showed intercalative DNA binding with Kb = 1.12 × 105 M−1 and Kapp = 8.80 × 105 M−1, respectively. This compound was found to be efficient in hydrolytic as well as oxidative DNA cleavage. The binding interaction between complex 1 and human serum albumin (HSA) was investigated using fluorescence emission, absorption, and molecular docking studies. 3D fluorescence studies revealed that HSA structure was altered at secondary and tertiary levels. The binding constant Ka value (~106 M−1) suggested a strong binding affinity of 1 to HSA, and the bimolecular quenching constant kq value (1013 M−1 s−1) suggested a static quenching mechanism operative in the quenching of the intrinsic fluorescence of the protein. Such high kq value may also be accounted by Förster resonance energy transfer (FRET) process. The distance r (3.22 nm) between donor HSA and acceptor complex 1 calculated from FRET theory suggested that they are close to each other. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay with human cervical cancer HeLa cells and human breast cancer MCF7 cells (IC50 = 2.2 and 1.2 μM, respectively) suggested remarkable in vitro anticancer activity of 1. Cell death in HeLa cells was induced via apoptosis as revealed from nuclear staining assays using Hoechst 33342 and acridine orange/propidium iodide dual staining, and apoptosis induction in HeLa cells happened through reactive oxygen species accumulation.

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Formation of an asymmetrical ligand (H ₃ L _cyclic) via a metal-induced cyclization of symmetrical thiocarbohydrazone (H ₄ L) in synthesizing an oxovanadium(IV) complex VO(HL _cyclic)(EtOH)₂

Cited by 5 publications

References 21 publications

Vanadyl as a Stable Structural Mimic of Reactive Ferryl Intermediates in Mononuclear Nonheme-Iron Enzymes

Vanadyl as a Stable Structural Mimic of Reactive Ferryl Intermediates in Mononuclear Nonheme-Iron Enzymes

A New Nickel(II) Complex Derived From Bisthiocarbohydrazone: Synthesis, Characterization, Crystal Structure and Antioxidant Activity

Synthesis, characterization, crystal structure, DNA and human serum albumin interactions, as well as antiproliferative activity of a Cu(II) complex containing a Schiff base ligand formed in situ from the Cu(II)‐induced cyclization of 1,5‐bis(salicylidene)thiocarbohydrazide

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