1761-61-1Relevant articles and documents
Vanadium(V) complexes of some bidentate hydrazone ligands and their bromoperoxidase activity
Adak, Piyali,Ghosh, Bipinbihari,Pakhira, Bholanath,Sekiya, Ryo,Kuroda, Reiko,Chattopadhyay, Shyamal Kumar
, p. 135 - 143 (2017)
Dinuclear methoxy bridged complexes of vanadium, [VO(μ-OMe)(OMe)(L)]2(1–3) have been synthesized from the reaction of VOSO4·H2O with triethylamine and the respective hydrazone ligand. The compounds have been characterized by spectroscopic methods and determination of single crystal X-ray structure of one of them (1). DFT and TD-DFT calculations were used to understand the electronic structures of the complexes and their electronic spectra respectively. Though the dimeric complexes are stable in the solid state, the ESI-MS spectra as well as1H NMR spectra of the complexes suggest that in solution the monomeric forms of the complexes are the major species. The V(V) complexes in DMF were used to catalyze the oxidative bromination of salicylaldehyde, in aqueous H2O2/KBr in the presence of HClO4at room temperature. The complexes show exceptionally high bromoperoxidase activity with salicylaldehyde as a model substrate to produce 5-bromo salicylaldehyde in good yield and high TOF and TON. Therefore, these complexes behave as functional models of vanadate dependent bromoperoxidase enzyme.
Novel D-π-A dye sensitizers of polymeric metal complexes based on Cd(II) with salicylaldehyde and diaminomaleonitrile: Synthesis, characterization, and photovoltaic performance for dye-sensitized solar cells
Hu, Jiaomei,Jin, Xueliang,Peng, Dahai,Xie, Qiufang,Liu, Ye,Liao, Yanlong,Zhu, Chunxiao,Zhong, Chaofan
, p. 8327 - 8342 (2015)
Being a key component of dye-sensitized solar cells, dye sensitizer and its synthesis and application have been extensively researched. In this paper, four novel polymeric metal complexes as dye sensitizers based on Cd(II) with salicylaldehyde and diaminomaleonitrile were functionally designed and synthesized. These dyes use poly(p-phenylenevinylene) or bithiophene phenylenevinylene as electron donor, Cd(II) complex unit as electron acceptor, and ethylenic bond as π linker. They were characterized by FT-IR, 1H NMR, gel permeation chromatography, and elemental analysis. Their thermal, photophysical, electrochemical, and photovoltaic properties were also investigated by thermogravimetric analysis, differential scanning calorimetry, C-V curves, and J-V curves. All four polymeric metal complexes exhibited some photovoltaic performances. The dyes containing bithiophene (P2, P4) exhibited higher power conversion efficiency (PCE) values than the corresponding polymers without thiophene unit (P1, P3). Dual-core cadmium polymeric metal complexes showed higher PCE than mononuclear cadmium complexes by comparing P4 with P2 as well as P3 with P1. The highest PCE of compound P4 reached 2.07 % (J sc = 4.22 mA/cm2, V oc = 0.71 mV, and FF = 69.1 %) under simulate AM 1.5G solar irradiation.
Efficient one-pot synthesis of ethyl [2-(2H-Chromene-3yl)-4-oxo-L,3- thiazolidin-3-yl]acetates
Reddy, S. Satyanarayana,Krupadanam, G. L. David
, p. 1305 - 1311 (2010)
Ethyl [2-(2H-chromene-3yl)-4-oxo-1,3-thiazolidin-3yl]acetates (6a-e) were synthesized in a single pot by the reaction of 2H-3-chromenecarbaldehydes (3a-e), glycine ethyl ester hydrochloride (4), and mercaptoacetic acid (5) in diisopropylethylamine/benzene under refluxing conditions in a Dean-Stark trap.
Heterogeneous Catalytic Oxidative Bromination and Oxidation of Thioethers By Vanadium(IV) Oxido Complex of Benzoylacetone and Effect of Solid Supports
Kesharwani, Neha,Chaudhary, Nikita,Haldar, Chanchal
, p. 3562 - 3581 (2021)
Vanadium(IV) oxido complex of 1-Phenyl-1,3-butanedione [VIVO(bzac)2] (1) was prepared, characterized, and heterogenized onto APTMS modified graphene oxide, as well as imidazole modified polystyrene beads. Graphene oxide supported complex GO-APTMS-[VIVO(bzac)2] (2) and polymer anchored complex PS-im-[VIVO(bzac)2] (3) were used for the oxidative bromination of a number of small organic molecules and oxidation of a series of thioethers. Both 2 and 3 evolve as excellent heterogeneous catalysts. The nature of solid support does not impact substrate conversion (%) during the oxidative bromination of salicylaldehyde, phenol, or styrene, whereas it influences the substrate conversion (%) as well as the product selectivity (%) during the oxidation of thioethers. Graphic Abstract: [Figure not available: see fulltext.]
Copper(II) N, N, O-Chelating Complexes as Potential Anticancer Agents
Pe?a, Quim,Sciortino, Giuseppe,Maréchal, Jean-Didier,Bertaina, Sylvain,Simaan, A. Jalila,Lorenzo, Julia,Capdevila, Mercè,Bayón, Pau,Iranzo, Olga,Palacios, òscar
, p. 2939 - 2952 (2021)
Three novel dinuclear Cu(II) complexes based on a N,N,O-chelating salphen-like ligand scaffold and bearing varying aromatic substituents (-H, -Cl, and -Br) have been synthesized and characterized. The experimental and computational data obtained suggest that all three complexes exist in the dimeric form in the solid state and adopt the same conformation. The mass spectrometry and electron paramagnetic resonance results indicate that the dimeric structure coexists with the monomeric form in solution upon solvent (dimethyl sulfoxide and water) coordination. The three synthesized Cu(II) complexes exhibit high potentiality as ROS generators, with the Cu(II)/Cu(I) redox potential inside the biological redox window, and thus being able to biologically undergo Cu(II)/Cu(I) redox cycling. The formation of ROS is one of the most promising reported cell death mechanisms for metal complexes to offer an inherent selectivity to cancer cells. In vitro cytotoxic studies in two different cancer cell lines (HeLa and MCF7) and in a normal fibroblast cell line show promising selective cytotoxicity for cancer cells (IC50 about 25 μM in HeLa cells, which is in the range of cisplatin and improved with respect to carboplatin), hence placing this N,N,O-chelating salphen-like metallic core as a promising scaffold to be explored in the design of future tailor-made Cu(II) cytotoxic compounds.
Mono- and dinuclear oxidovanadium(v) complexes of an amine-bis(phenolate) ligand with bromo-peroxidase activities: Synthesis, characterization, catalytic, kinetic and computational studies
Debnath, Mainak,Dolai, Malay,Pal, Kaberi,Bhunya, Sourav,Paul, Ankan,Lee, Hon Man,Ali, Mahammad
, p. 2799 - 2809 (2018)
The mono- and dinuclear oxidovanadium(v) complexes [VVO(L1)(Cl)] (1) and [L1VVO(μ2-O)VO(L1)] (2) of ONNO donor amine-bis(phenolate) ligand (H2L1) were readily synthesized by the reaction between H2L1 and VCl3.(THF)3 or VO(acac)2 in MeOH or MeCN, respectively, and then characterized through mass spectroscopy, 1H-NMR and FTIR techniques. Both the complexes possess distorted octahedral geometry around each V centre. Upon the addition of 1 equivalent or more acid to a MeCN solution of complex 1, it immediately turned into the protonated form, which might be in equilibrium as: [L1ClVVOH]+ ? [L1ClVV-OH]+ (in the case of [L1ClVVOH]+ oxo-O is just protonated, whereas in [L1ClVV-OH]+ it is a hydroxo species), with the shift in λmax from 610 nm to 765 nm. Similar was the case for complex 2. The complexes 1 and 2 could efficiently catalyze the oxidative bromination of salicylaldehyde in the presence of H2O2 to produce 5-bromo salicylaldehyde as the major product with TONs of 405 and 450, respectively, in the mixed solvent system (H2O:MeOH:THF = 4:3:2, v/v). The kinetic analysis of the bromide oxidation reaction indicated a first-order mechanism in the protonated peroxidovanadium complex and a bromide ion and limiting first-order mechanism on [H+]. The evaluated kBr and kH values were 5.78 ± 0.20 and 11.01 ± 0.50 M-1 s-1 for complex 1 and 6.21 ± 0.13 and 20.14 ± 0.72 M-1 s-1 for complex 2, respectively. The kinetic and thermodynamic acidities of the protonated oxido species of complexes 1 and 2 were pKa = 2.55 (2.35) and 2.16 (2.19), respectively, which were far more acidic than those reported by Pecoraro et al. for peroxido-protonation instead of oxido protonation. On the basis of the chemistry observed for these model compounds, a mechanism of halide oxidation and a detailed catalytic cycle are proposed for the vanadium haloperoxidase enzyme and these were substantiated by detailed DFT calculations.
Syntheses and characterization of monobasic tridentate Cu(II) Schiff-base complexes for efficient oxidation of 3,5-di-: tert -butylcatechol and oxidative bromination of organic substrates
Kumari, Sweta,Mahato, Arun Kumar,Maurya, Abhishek,Singh, Vijay Kumar,Kesharwani, Neha,Kachhap, Payal,Koshevoy, Igor O.,Haldar, Chanchal
, p. 13625 - 13646 (2017)
Two monomeric copper complexes [CuII(sal-ppzH)Cl2] (1) and [CuII(hyap-ppzH)Cl2] (2) were synthesized by reacting CuCl2·2H2O with the monobasic tridentate Schiff-base ligands [Hsal-ppz] (I) and [Hyap-ppz] (II) (derived by reacting 1-(2-aminoethyl) piperazine with salicylaldehyde and 2-hydroxyacetophenone) respectively. Elemental analysis, IR, UV-Vis, 1H NMR and 13C NMR data confirm the structures of the ligands and those of the complexes. Both complexes are monomeric in nature in the solid state and in solution as well. Single crystal XRD data suggest a distorted square pyramidal geometry for 1 crystallized in the P1 space group. DFT studies established a similar molecular structure for 2. The synthesized metal complexes [CuII(sal-ppzH)Cl2] (1) and [CuII(hyap-ppzH)Cl2] (2) successfully catalyzed the oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) in methanol in the presence of H2O2 with high Kcat values of 1.182 × 104 mmol h-1 and 2.880 × 104 mmol h-1, respectively. [CuII(sal-ppzH)Cl2] (1) and [CuII(hyap-ppzH)Cl2] (2) were also anchored into the polymeric matrix of chloromethylated polystyrene and were analyzed by TGA, atomic absorption spectroscopy (AAS), EPR, scanning electron microscopy (SEM) as well as energy dispersive X-ray (EDX) analysis. The polymer grafted metal complexes were used as catalyst precursors in the oxidative bromination of salicylaldehyde in the presence of H2O2, KBr and HClO4. Under optimized reaction conditions, both catalysts show nearly quantitative oxidative bromination of salicylaldehyde, with the order of % products formed being 5-bromosalicylaldehyde > 3,5-dibromosalicylaldehyde > 3-bromosalicylaldehyde. Plausible reactive species involved in the catalytic cycle are identified by UV-Vis spectroscopy, pH metric titration, ESI-MS, EPR and DFT studies.
The one pot synthesis salicylaldehyde prepared by reactive grinding with derivative phenol and paraformaldehyde in absence magnesium methoxide
Balali, Ebrahim,Shameli, Abolghasem,Naeimi, Hoseein,MehdiGhanbari, Mohammad
, p. 1611 - 1614 (2013)
The formylation phenols are mono-formylated using a mixture of paraformaldehyde, Mg(OMe)2, by reactive grinding. In all cases but one, only one regioisomer of the salicylaldehyde is obtained in good to high yield.
Synthesis and characterization of Azo schiff bases and their β-lactam derivatives
Shinde, Anil H.,Patil
, p. 1520 - 1524 (2020)
Azo salicylaldehyde (I5) was synthesized by reaction of 5-bromo-salicylaldehyde with diazonium salt of 4-nitroaniline by diazotization method. Thus, synthesized azoaldehyde was treated with variable 2-aminobenzothiazoles (I6a-f) to synthesize the Schiff bases (I7a-f). The β-lactam derivatives (I8a-f) were also synthesized. All the newly synthesized compounds were characterized by TLC, UV-visible and FT-IR techniques.
Dioxovanadium(V) complexes of ONO donor ligands derived from pyridoxal and hydrazides: Models of vanadate-dependent haloperoxidases
Maurya, Mannar R.,Agarwal, Shalu,Bader, Cerstin,Rehder, Dieter
, p. 147 - 157 (2005)
[VO(acac)2] reacts with H2L [H2L are the hydrazones H2pydx-inh (I), H2pydx-nh (II), or H 2pydx-bhz (III); pydx = pyridoxal, inh = isonicotinohydrazide, nh = nicotinohydrazide, bhz = benzohydrazide] in dry methanol to yield the oxovanadium(IV) complexes [VOL] (H2L = I: 1; H2L = II: 4) or [VO(pydx-bhz)]. These complexes, when exposed to air, convert into the corresponding dioxovanadium(V) complexes [VO2HL] (H2L = I: 2; H2L = II: 5; H2L = III: 7). Aqueous solutions of vanadate and the ligands at pH = 7.5 give rise to the formation of [K(H 2O)3][VO2(pydx-inh)] (3), [K(H 2O)2][VO2(pydx-nh)] (6) and [K(H 2O)2][VO2(pydx-bhz)] (8). Treatment of 6 and 8 with H2O2 generates the oxo(peroxo)vanadium complexes [VO(O2)L] (H2L = II: 9; H2L = III: 10). Complexes 9 and 10 are capable of transferring an oxo group to PPh3. Acidification of 8 with HCl afforded a hydroxo(oxo) complex. The crystal and molecular structures of ligand I and complex 3 have been solved by single-crystal X-ray diffraction. In the anion 3, the vanadium atom is in a distorted tetragonal-pyramidal environment (τ = 0.23). The K+ ion is coordinated to four water molecules (two of which bridge to a neighbouring K+ ion), the pyridine nitrogen atom of an isonicotinic moiety, the equatorial oxo group of the VO2+ fragment, and the alcoholic group of the pyridoxal moiety, which links adjacent layers in the three-dimensional lattice network. In the presence of KBr/H2O 2, the anionic complexes 3, 6 and 8 catalyse the oxidative bromination of salicylaldehyde in water to 5-bromosalicylaldehyde in ca. 40% yields with ca. 87% selectivity. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
