1761-56-4Relevant articles and documents
Synthesis, structure, and magnetic properties of a tetradecanuclear manganese complex
Huang, Siang-Hua,Jhan, Siang-Yu,Yang, Chen-I,Tsai, Hui-Lien
, p. 245 - 251 (2013)
A new [Mn14(μ4-O)4(μ3-OH) 4(L)4(O2CPh)14(OMe) 2]·2CH2Cl2 (1·2CH 2Cl2) cluster, where H2L = N-salicylidene-o- aminophenol, was synthesized by reacting the [Mn6O2(O 2CPh)10(DMF)4] precursor with tridentate ligands. The structure of the tetradecanuclear complex features a [Mn II6MnIII8(μ4-O) 4(μ3-OH)4]24+ core which is comprised of a non-planar rod-like [MnII2Mn III6(μ4-O)4(μ3-OH) 2]12+ unit, with both sides bonded in the form of a [MnII2MnIII(μ3-OH)]6+ triangle. Direct current (dc) magnetic susceptibility measurements of the complex indicate the existence of intramolecular antiferromagnetic interactions between the metal ions, with a ground state of S = 2. The complex exhibits frequency-dependent out-of-phase signals in alternating current (ac) magnetic susceptibility measurements, suggesting slow magnetic relaxations.
Heterometallic octanuclear REIII3NiII 5 (RE = DyIII, GdIII and YIII) clusters with slow magnetic relaxation for the dysprosium derivative
Wang, Huiyu,Ke, Hongshan,Lin, Shuang-Yan,Guo, Yang,Zhao, Lang,Tang, Jinkui,Li, Yun-Hui
, p. 5298 - 5303 (2013)
Reactions of rare earth benzoate and nickel perchlorate with a Schiff-base ligand, 2-([(2-hydroxyphenyl)imino]methyl) phenol (H2L), in the presence of triethylamine yielded three heterobimetallic octanuclear clusters of general formula [RE3Ni5L5(PhCOO) 3(μ3-OH)5(μ3-OCH 3)(CH3OH)4(H2O)]·xCH 3OH·yH2O (RE = DyIII, x = 4, y = 4 (1), RE = GdIII, x = 5, y = 4 (2), RE = YIII, x = 5, y = 3 (3)). Single-crystal X-ray diffraction reveals that the metal core of each cluster consists of two distorted [RE2Ni2O4] cubane-like moieties and a heterobimetallic triangular [RE2NiO 2] unit, with RE ions arranged in a typical triangular fashion. Variable-temperature solid state magnetic susceptibilities of these complexes were measured in the temperature range 2-300 K and the results indicate that an overall ferromagnetic interaction among the metal ions is operative for compounds 2 and 3. Under zero external field, the Dy3Ni5 compound shows a frequency dependence of the out-of-phase (χ′′) signals, which indicates slow relaxation of the magnetization.
DNA binding and cytotoxicity of two Cu(II) complexes containing a Schiff base ligand along with 1,10-phenanthroline or imidazole as a coligand
Koley, Manjuri K.,Parsekar, Sidhali Uday,Duraipandy, Natarajan,Kiran, Manikantan Syamala,Varghese, Babu,Manoharan, Periakaruppan T.,Koley, Aditya P.
, p. 211 - 221 (2018)
We report the synthesis, characterization and biological activities of the compounds [CuL(o-phen)] (1) and [CuL(Imz)] (2), (H2L = o-HOC6H4C(H)=NC6H4OH-o, o-phen = 1,10-phenanthroline, and Imz = imidazole). Both the compounds 1 and 2 have been characterized by X-ray crystallography. A four-line EPR pattern originating from the interaction of the unpaired electron with the central 63/65Cu nucleus (I = 3/2) with Aiso values of 7.3 and 8.5 mT, respectively for 1 and 2 in DMF at RT suggests their monomeric nature in solution. These compounds undergo irreversible oxidation–reduction. Biological studies show intercalative DNA binding and remarkable cell cytotoxicity as well as anticancer activity. IC50 values of 1 and 2 for the human lung cancer A549 cell line (0.67 and 0.59 μM, respectively) and for the breast cancer MCF7 cell line (6.30 and 8.88 μM, respectively) are found to be very promising. Compounds 1 and 2 appear to be more potent for the human lung cancer A549 cell line than some anticancer drugs tested for this cell line. Most importantly, 1 and 2 are found to be remarkably less toxic for the human lung embryonic normal cell line L132 as evident from the cell viabilities in presence of these two compounds.
Salicylimine-based fluorescent chemosensor for aluminum ions and application to bioimaging
Kim, Soojin,Noh, Jin Young,Kim, Ka Young,Kim, Jin Hoon,Kang, Hee Kyung,Nam, Seong-Won,Kim, So Hyun,Park, Sungsu,Kim, Cheal,Kim, Jinheung
, p. 3597 - 3602 (2012)
In this study, an assay to quantify the presence of aluminum ions using a salicylimine-based receptor was developed utilizing turn-on fluorescence enhancement. Upon treatment with aluminum ions, the fluorescence of the sensor was enhanced at 510 nm due to formation of a 1:1 complex between the chemosensor and the aluminum ions at room temperature. As the concentration of Al 3+ was increased, the fluorescence gradually increased. Other metal ions, such as Na+, Ag+, K+, Ca2+, Mg2+, Hg2+, Mn2+, Co2+, Ni 2+, Cu2+, Zn2+, Cd2+, Pb 2+, Cr3+, Fe3+, and In3+, had no such significant effect on the fluorescence. In addition, we show that the probe could be used to map intracellular Al3+ distribution in live cells by confocal microscopy.
N-(2-Hydroxyphenyl)salicylaldimine
Elerman, Yalcin,Elmali, Ayhan,Atakol, Orhan,Svoboda, Ingrid
, p. 2344 - 2346 (1995)
The title compound, 2-(salicylideneaminophenol, C13H11NO2, a potential tridentate ligand, has two crystallographically independent molecules in the asymmetric unit, one of which is disordered.Intramolecular hydrogen bonds occur between the pairs of atoms O(16) and N(8) , and O(1) and O(16) , the H atoms essentially being bonded to the O atoms.
Oxo-bridged bis oxo-vanadium(V) complexes with tridentate Schiff base ligands (VOL)2O (L = SAE, SAMP, SAP): Synthesis, structure and epoxidation catalysis under solvent-free conditions
Cordelle, Cindy,Agustin, Dominique,Daran, Jean-Claude,Poli, Rinaldo
, p. 144 - 149 (2010)
The dinuclear V(V) complexes (VOL)2O (L = SAE (1), SAMP (2), SAP (3)) have been synthesized from VO(acac)2 and the corresponding tridentate ligands LH2 in methanol under reflux conditions and subsequent air oxidation in organic solvent. They have been characterized by IR and NMR spectroscopy, by thermogravimetric analysis, and by single crystal X-ray diffraction for 1 and 2. DFT calculations were carried out for a better understanding of the vibrational pattern, principally the V-O related vibrations. Complex [VO(SAP)]2O (3) catalyzes the epoxidation of cyclooctene by TBHP in water in the absence of any added solvent with good selectivity.
Degradation of organic pollutants in waters by a water-insoluble iron(III) Schiff base complex
Song, Quan,Ma, Wan-Hong,Jia, Man-Ke,Johnson, David,Huang, Ying-Ping
, p. 70 - 76 (2015)
To degrade organic pollutants in water with hydrogen peroxide (H2O2) under visible light (λ ≥ 420 nm), a novel water-insoluble iron Schiff base complex, iron(III)-bis-salicylaldehyde-o-aminophenol (Fe-SAP), was prepared and characterized using NMR, MS, IR, and UV-Vis spectroscopy. Rhodamine B (RhB) and salicylic acid were used as probes to characterize the photocatalytic system. High catalytic activity of Fe-SAP was observed over a wide range of pH values from 3 to 9. Scavenging studies of reactive oxygen species (ROS) and ESR experiments indicate that the primary ROS from photocatalytic conversion of H2O2 is 1O2, rather than .OH. To date, there have been few reports on the generation of 1O2 by iron organic complexes for the oxidative decomposition of organics. The catalyst stability and reusability are good, most likely because the water-insoluble Fe-SAP is able to reduce the damage to its organic ligands by .OH. Given these favorable characteristics, Fe-SAP exhibits excellent potential for practical application in removing refractory organic pollutants and pollutants of emerging concern from water and wastewater.
Tridentate ONS vs. ONO salicylideneamino(thio)phenolato [MoO2L] complexes for catalytic solvent-free epoxidation with aqueous TBHP
Wang, Weili,Vanderbeeken, Thibaut,Agustin, Dominique,Poli, Rinaldo
, p. 26 - 30 (2015)
Comparison of molybdenum precatalysts with salicylideneaminothiophenolato (SATP; a tridentate ONS ligand) and salicylideneaminophenolato (SAP; a tridentate ONO ligand) in the solvent-free epoxidation of cyclooctene with aqueous TBHP yields better activity for the former. The DFT study of the catalytic cycle shows that the SATP catalyst follows the same pathway recently established for the SAP analogue and with a slightly smaller activation barrier in agreement with the experimental results.
Spectrophotometric and conductometric study of the complexation of N-salicylidene-2-aminophenol with Cu2+in methanol + 1,4-dioxane binary solutions
Biswas, Rashmidipta,Brahman, Dhiraj,Sinha, Biswajit
, p. 1263 - 1277 (2015)
The complexation reaction between N-salicylidene-2-aminophenol, abbreviated as SAP, with the Cu2+ was studied in binary mixtures of methanol and 1,4-dioxane using conductometric and spectrophotometric methods at different temperatures. The stability constants (Kf) for the 1:1 complex, Cu2+- -SAP, were calculated from computer fitting of the absorbance and molar conductance data against various mole ratios (cM:cL or cL:cM) in different binary solvent mixtures. A non-linear behaviour was observed for the variation of log Kf for the complex against the solvent composition. Various thermodynamic parameters (Δ H, ΔS and ΔG) for the formation of the Cu2+-SAP complex were determined from the temperature dependence of the stability constants (Kf). The overall results showed that the complexation reaction is entropy driven and is affected by the nature and composition of the mixed solvents.
Experimental and theoretical investigation of ground state intramolecular proton transfer (GSIPT) in salicylideneaniline Schiff base derivatives in polar protic medium
Das, Bijoya,Chakraborty, Amrita,Chakraborty, Shamik
, (2020)
Ground state intramolecular proton transfer process has been comprehensively investigated in three salicylideneaniline Schiff base derivatives (SB1, SB2, and SB3) using experimental and theoretical methods. It has been confirmed that all the three Schiff base molecules in the ground electronic state exist in the enol form in non-polar and polar aprotic solvents. Keto form is being populated by the polar protic solvent through ground state intramolecular proton transfer (GSIPT) process. Ground state equilibrium between the enol and keto tautomers for SB1 and SB3 is mainly governed by the proton donating ability of the solvent. Ground state equilibria between the enol and keto tautomers of SB2 which is a positional isomer of SB3 is governed by the polarity and proton donating ability of the solvents. Excited state intramolecular proton transfer (ESIPT) process is also evidenced in all the three Schiff base molecules. Theoretical calculations at the B3LYP/cc-pVDZ level in the gas phase and in different solvents using polarisable continuum model (PCM) have failed to establish the GSIPT process. Microsolvation of individual enol and keto conformers has been investigated considering upto three solvent molecules. The energetics of the individual conformers together with the corresponding transition state have been calculated. It has been confirmed that the keto conformer is more stable compared to the enol conformer in microsolvated cluster of three methanol molecules. Lowering of activation energy for the enol to keto tautomerisation in the presence of methanol also supports the experimental observation for GSIPT process. TDDFT/B3LYP/cc-pVDZ single point calculations for microsolvated clusters of enol and keto form of the Schiff base molecules exhibit an excellent agreement with the experimentally obtained absorption spectra. Difference in spectral nature of the Schiff base molecules has been explained using natural bond orbital (NBO) analysis. Quantum theory of atoms in molecules (QTAIM) has also been utilised to understand the GSIPT process in detail.
