- Synthesis, spectroscopic characterization and in vitro studies of new heteroleptic copper (II) complexes derived from 2-hydroxy napthaldehyde Schiff's bases and N, N donor ligands: Antimicrobial, DNA binding and cytotoxic investigations
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A series of eight new copper (II) complexes of types [Cu(HL1)(B)] (4a-4d) and [Cu(HL2)(B)] (4e-4h), where HL1 is N-(2-hydroxy-1-naphthalidene)-2-aminophenol, HL2 is N-(2-hydroxy-1-naphthylidene)-2-mercaptoaniline and B is N, N donor ligands viz bipyridyl (bpy), 1,10-phenanthroline (phen), dipyridoquinoxaline (dpq) and dipyridophenazine (dppz) have been synthesized and characterized by elemental analysis as well as by spectroscopic techniques (IR, UV, ESI mass and EPR spectra). The DNA-binding properties of these copper complexes (4a-4h) have been investigated by electronic absorption, viscosity measurements and docking analyses. The results obtained indicated that the complexes get bonded with DNA via an intercalation binding mode with an intrinsic binding constant, Kb (1.116 ± 0.21 to 7.227 ± 0.21) × 104 M-1. The antimicrobial activity assays with the Schiff's bases and their heteroleptic copper (II) complexes of 4a and 4b exhibited profound activity against gram positive bacteria, gram negative bacteria and fungi. Further, complexes 4d and 4h displayed significant cytotoxicity when examined in vitro on a panel of cancerous cell line - human liver cancer cell line - HepG-2 cells (IC50 = 40.82 and 29.74 μg/ml).
- Kiran, Tummalapalli,Prasanth, Vuppalapati Giri,Balamurali,Vasavi,Munusami, Punnagai,Sathiyanarayanan, Kulathu Iyer,Pathak, Madhvesh
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- UV–vis spectral property of a multi-hydroxyl Schiff-base derivative and its colorimetric response to some special metal ions
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A multi-hydroxyl Schiff-base derivative, N-2′-hydroxyl-1′-naphthyl methylene-2-amino phenol (HNMAP), was synthesized and characterized by FTIR, 1H NMR and UV–vis spectroscopy. It was noted to find there was great effect for solvent and pH on the UV–vis spectroscopy of HNMAP. Especially, some metal ions could make its UV–vis spectra changed regularly with different time-resolved effects. For example, a real-time and multi-wavelength response to Fe2+ at 520 nm, 466 nm and 447 nm and a quite slow one about 26 min to Fe3+ at 447 nm and 466 nm, respectively. Under the optimized conditions, the changes in the corresponding absorption intensities at above wavelengths were in proportion to cFe 2+ or cFe 3+ during respectively partitioned linear ranges, which realized to quantitatively detect Fe2+ or Fe3+ with a large linear range more than two orders of magnitude. A 1:1 complex mode for HNMAP-Fe2+ and 1:2 for HNMAP-Fe3+ were proposed from UV–vis spectral titration and Job's plot. HNMAP would be a potential sensor for colorimetric detection of Fe2+ and Fe3+ in practice.
- Xing, Lin,Zheng, Xiaoyu,Sun, Wenyu,Yuan, Hua,Hu, Lei,Yan, Zhengquan
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- Three novel Ni(II), VO(II) and Cr(III) mononuclear complexes encompassing potentially tridentate imine ligand: Synthesis, structural characterization, DNA interaction, antimicrobial evaluation and anticancer activity
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Three novel Cr(III),VO(II) and Ni(II) imine complexes derived from the condensation of 2-aminophenol (AP) with 2-hydroxynaphthaldehyde (HN) were synthesized. The prepared HNAP imine ligand and its complexes were investigated via various physicochemical tools. The results suggest that the parent ligand behaves as a dibasic tridentate ONO ligand, when coordinated to Cr(III) in octahedral and to Ni(II) in tetrahedral geometry. In the case of VO(II), it coordinates in distorted square pyramidal geometry. Also, the prepared compounds were screened for their antimicrobial activities against pathogenic bacteria, Escherichia coli (?ve), Bacillus subtilis (+ve) and Staphylococcus aureus (+ve), and some types of fungi, Aspergillus niger, Candida glabrata and Trichophyton rubrum. The results indicate that the complexes show a stronger antimicrobial efficiency compared to the pro-ligand. The interaction of the prepared complexes with calf thymus DNA was investigated using spectral, viscosity and gel electrophoresis measurements. The obtained results clearly demonstrate that the binding affinity with calf thymus DNA follows the order HNAPCr > HNAPV > HNAPNi. The cytotoxic activity of the prepared compounds on human colon carcinoma cells (HCT-116 cell line), hepatic cellular carcinoma cells (HepG-2cell line) and breast carcinoma cells (MCF-7cell line) was examined. From these results it is found that the investigated complexes have potent cytotoxicity against growth of carcinoma cells compared to the corresponding imine pro-ligand.
- Abdel-Rahman, Laila H.,Abu-Dief, Ahmed M.,Basha, Maram,Hassan Abdel-Mawgoud, Azza A.
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- π-Conjugated molecules identified for reversible and visual detection of F? in aqueous: Effect of heterocycle unit on sensing performance
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To illustrate the impact of molecular structure, especially heterocycle unit, on the sensing performance, two kinds of π-conjugated molecules containing aromatic heterocyclic (Dye 1) and aromatic ring (Dye 2) were identified and compared each other. Even with similar structures, they possessed quite different spectral and colorimetric responses to F?, Cl?, Br?, I?, NO3 ?, HSO4 ?, H2PO4 ?, ClO4 ? and CH3COO?, etc. The reason might result from the difference in withdraw-electron ability of aromatic and heterocyclic rings, which would lead to different acidity of active H in the target π-conjugated molecules. In acidic aqueous, Dye 1 expressed a reversible ratiometric-colorimetric response to F?, accompanying with a visual color change from bright yellow to purple, a nice linear range of 2.0–35.0 × 10?6 mol/L and a low detection limit of 1.60 × 10?7 mol/L. While Dye 2 did not react with any anion due to its weak acidity of active hydrogen. Under the optimized conditions, Dye 1 was successfully applied for colorimetric or naked-eye detection of F? in environmental water, tea and toothpaste samples with RSD ≤ 3.1%. The recognition mechanism for Dye 1 to F? was confirmed to be deprotonation one with a 1:1 binding stoichiometry.
- Yan, Zhengquan,Wang, Cong,Tang, Yulian,Zhu, Yanjie,Cao, Qianying,Yang, Tianran,Hu, Lei
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- Spectroscopic and computational study of a naphthalene derivative as colorimetric and fluorescent sensor for bioactive anions
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The anion recognition property of a naphthalene based receptor (L) was investigated by naked-eye, UV-Vis, fluorescence, 1H NMR and computational methods. The receptor L showed fluoride selective naked-eye detectable colorimetric and UV-Vis spectral changes over other tested anions due to the formation of hydrogen bonding complex in 1:1 stoichiometry and/or deprotonation between fluoride and the receptor. Interestingly, the fluorescence of L was quenched by fluoride but enhanced by acetate.
- Sharma, Darshna,Sahoo, Suban K.,Bera, Rati Kanta,Kamal, Raj
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- A "turn-on" fluorescent chemosensor for aluminum ion and cell imaging application
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A simple and efficient fluorescent chemosensor for Al3 + is reported in the paper. The chemosensor is obtained by dehydration reaction of 2-hydroxy-1-naphthaldehyde and 2-aminophenol. The chemosensor has high selectivity and sensitivity for Al3 + and displays fluorescence "off-on" switch signal. The detection limit of the chemosensor for Al3 + can reach 1.0 × 10- 7 M in DMSO/H2O (1:9, v/v) solution. The mass spectra and Job's plot analysis confirm the 1:1 stoichiometry between chemosensor and Al3 +. Potential utilization of the probe as an intracellular sensor of Al3 + in human cancer (HiSa) cells is also examined by confocal fluorescence microscopy.
- Guo, Ailing,Zhu, Ruitao,Ren, Yuehong,Dong, Jinlong,Feng, Liheng
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- The arginine detection and cytotoxicity of fluorescent probes based on naphthalene derivatives
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From a biological point of view, Schiff base probes containing fluorescent groups are chemically modified to provide an effective method for the detection of amino acids. According to this method, three molecular probes containing Schiff base and hydroxyl group have been designed and synthesized. UV-Vis and fluorescent data indicated that compound 2 showed strong sensitivity and high selectivity for arginine (Arg) among normal twenty kinds of amino acids. In addition, compound 2 displayed high combining ability with Arg and low cytotoxicity in MCF-7 cell from 0 to 150?μg/mL. The above results showed the synthesized probes also can be used a biosensor for the Arg detection in vivo.
- Shang, Xuefang,Li, Congshu,Li, Jie,Chen, Yanmei,Chen, Hongli,Wang, Tianyun
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- Synthesis, characterization, DFT study and antioxidant activity of (2-hydroxynaphthalen-1-yl) methyl 2-hydroxyphenyl amino phosphonic acid
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New molecule α-aminophosphonate namely (2-hydroxynaphthalen-1-yl) methyl 2-hydroxyphenyl amino phosphonic acid (HMHP) was synthesized by condensation based on 2-amino phenol and 2-hydroxy naphthaldehyde. During the reaction, imine intermediate namely 2-hydroxyphenyl imino naphthalen-2-ol (HIN) was formed before adding acid phosphorous to the reaction mixture. It can be confirmed the concept of Kabachinik-Fields reaction, which it's perform the attachment of phosphorus atom to the carbon atom of imine function. Both compounds were identified using IR, 1H, 13C and 31P NMR spectroscopic techniques. The evaluation of the antioxidant activity of HMHP and HIN was investigated by utilizing several in vitro assays: scavenging activity against DPPH radical and H2O2 non radical, β-carotene/linoleic acid against linoleic peroxidation, reducing power against ferric oxidation and phosphomolybdate (TAC) against molybdate ion oxidation. Results indicate that HMHP reflects greater antioxidant potency compared to HIN in most tests, where it is apt to offer the hydrogen radical very well at IC50 (37.64 ± 1.43) in DPPH test. For the other tests the inhibition percent at 50 % are relatively closed between them. Except the H2O2 scavenging, while HIN exhibited excellent activity at IC50 (24.7306 ± 0.71785). The quantum chemical calculations were performed using density functional theory (DFT) to study the effects of the transfer electronic and proton transfer on the antioxidant activities of the synthesized compounds. Also, theoretical FT-IR was calculated. The experimental results are in comfort with those calculated theoretically.
- Chafaa, Salah,Chafai, Nadjib,Djenane, Meriem,Ghedjati, Samira,Houas, Noudjoud,Kitouni, Siham
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- Reinforcement of ‘imine-hydroxyl chelation pocket’ by encapsulating into the β-CD cavity for the sterically protective detection of Al3+
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The effect of encapsulating a schiff base probe; o-phenolnaphthylimine (pni) into β-cyclodextrin (β-CD) and its impact on the detection of Al3+ was investigated using the spectrofluorometric technique. The impact of imine moiety and the neighbouring hydroxyl groups of pni in the sensing of Al3+ were assessed through the experimental and computational procedure. The role of ‘imine-hydroxyl chelation pocket’ of pni in the detection of Al3+ was estimated, correlated and demonstrated. FTIR, NMR and mass spectral techniques were used for the investigations in solid state. Stoichiometry of the complexes was estimated using UV–visible and fluorescence spectral techniques in liquids state. Molecular modeling and steric maps were obtained using 3D structural data of compounds. Linearity range, LOD and LOQ were estimated from the selectivity and sensitivity studies. The proposed work demonstrates the impact of additional binding centers that has to be considered while designing a chemosensor for metal cations.
- Bharathi, A.,Chakravarty, Sujay,Krishnan, M. Murali,Parinamachivayam, G.,Premkumar, K.,Ragavendran, V.,Sivakumar, K.,Stalin, T.
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- Condensation product of 2-hydroxy-1-napthaldehyde and 2-aminophenol: Selective fluorescent sensor for Al3+ ion and fabrication of paper strip sensor for Al3+ ion
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The condensation product of 2-hydroxy-1-napthaldehyde and 2-aminophenol (L), in 1:1 (v/v) CH3OH:H2O acts as selective fluorescent sensor for Al3+. The fluorescence intensity of L at emission wavelength 517 nm, when excited with 360 nm photons, increases on interaction with Al3+ by ca. 7-fold. Under UV lamp, L shows light yellow fluorescence on interaction with Al3+ visible to bare eyes. Metal ions – Na+, K+, Ca2+, Mg2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Pb2+, Cd2+ and Hg2+do not interfere. The increase in fluorescence intensity is due to the quenching of photoinduced electron transfer (PET) process prevailing in L. The fluorescent and UV/Visible spectral data analysis showed a 1:1 complexation between L and Al3+ with logβ = 4.532 (β = binding constant) and detection limit 10?5 M. DFT and TDDFT calculations also confirm 1:1 interaction between L and Al3+. L has been successfully applied in fluorescent imaging of Al3+ in live rat L6 myoblasts cells and as paper strip fluorescent sensor for Al3+ in aqueous medium.
- Sarma, Smita,Bhowmik, Ananya,Sarma, Manas Jyoti,Banu, Sofia,Phukan, Prodeep,Das, Diganta Kumar
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- Compound with aggregation-induced emission function and preparation method and application thereof
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The invention relates to a compound with an aggregation-induced emission function, the chemical structure of the compound is shown as a general formula I, 2-hydroxy-1-naphthaldehyde and 2-aminothiophenol (or 2-aminophenol) react in organic solvents to obtain Schiff base structure intermediates; and recrystallizing and purifying are carried out to obtain the intermediate, and the intermediate is reacted with an oxidant in an organic solvent to obtain the compound with the aggregation-induced emission function. Further the compound is modified to obtain series of functionalized aggregation-induced emission compounds. The synthesis method of the compounds is simple, the reaction conditions are mild, the synthesis is easy, the post-treatment operation is convenient, the yield is high, and theheating reaction shortens the reaction time. The obtained aggregation-induced emission compound has an excited state intramolecular proton transfer effect. Intramolecular weak acting force hydrogen bonds exist between hydroxyl hydrogen atoms on a naphthalene ring and nitrogen atoms on an ortho-benzothiazole ring, an excited state intramolecular proton transfer effect is achieved, and large Stokesshift is shown.
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Paragraph 0071; 0072
(2021/03/13)
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- Half-sandwich ruthenium complexes with Schiff base ligands bearing a hydroxyl group: Preparation, characterization and catalytic activities
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Three half-sandwich ruthenium(II) complexes with hydroxyl group functionalized Schiff-base ligands [Ru(p-cymene)LCl] (2a-2c) have been synthesized and characterized. All ruthenium complexes were fully characterized by 1H and 13C NMR spectra, mass spectrometry and infrared spectrometry. The molecular structure of ruthenium complex 2c was confirmed by single-crystal X-ray diffraction methods. Furthermore, these half-sandwich ruthenium complexes were found to exhibit high catalytic activity for nitro compounds reduction using NaBH4 reducing agent in the presence of cetyltrimethylammonium bromide (CTAB) in water at room temperature.
- Jia, Wei-Guo,Wang, Zhi-Bao,Zhi, Xue-Ting
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- V(V)-Schiff base species induce adipogenesis through structure-specific influence of genetic targets
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Vanadium has been known to exhibit numerous functions in biological systems, projecting exogenous activity linked to regulatory roles in cell metabolism and insulin mimesis. Poised to probe into the vanadium adipogenic potential, reflecting on efficient anti-diabetic drugs, research was launched in our labs to pursue the (a) synthesis of diversely structured Schiff base ligands, as vanadium chelating binders, containing a variably configured o-vanillin core with a specified common organic o-aminophenol tether, (b) synthesis of a family of well-defined soluble vanadium-Schiff base compounds, bearing the above mentioned Schiff ligands (and in one case 4,4'-bipyridine), (c) study of their toxicity profile and adipogenic activity in 3T3-L1 fibroblasts toward mature adipocytes, and (d) determination of molecular biological targets linked to the vanadium-induced cell differentiation process, thereby unravelling factors impacting signaling pathways influencing insulin mimesis. The results suggest that (a) all emerging vanadospecies contain V(V) mononuclear centers bound to Schiff bases (and 4,4'-bipyridine), (b) a welldefined (solid-state and solution) physicochemical profile of all species justifies their selection in biological studies, (c) the vanadium toxicity profile is strongly related to the form of V(V) (complexed forms, substrate-ligand nature), (d) there is a structure-specific behavior of vanadium influencing adipogenesis, and (e) molecular target loci are also influenced by vanadoforms in a structure-specific fashion, thereby collectively projecting an interwoven role of factors emanating from vanadium and impacting cell differentiation and insulin mimetic activity. The so far accrued knowledge constitutes the basis for further development of biomarker-driven structure-specific vanadodrugs, contributing through insulin biomimicry to therapeutic technologies in Diabetes mellitus.
- Tsave,Halevas,Yavropoulou,Yovos,Hatzidimitriou,Psycharis,Ypsilantis,Stathi,Salifoglou
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supporting information
p. 17872 - 17890
(2019/12/30)
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- Design, synthesis, and characterization of an Fe(ii)-polymer of a redox non-innocent, heteroatomic, polydentate Schiff's base ligand: negative differential resistance and memory behaviour
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In the present work, the unique negative differential resistance (NDR) and memory effect of an organic-metallic hybrid polymer based on the self-assembly of Fe(ii)-ions preceded by the synthesis of a newly designed multidentate Schiff's base ligand has been reported. The polymerization process was closely monitored in an absorbance study using a UV-vis spectrophotomer. The presence of sharp isosbestic points and saturation of absorbance at 1?:?1 ligand to metal concentration confirmed the stepwise growth of the polymer. A model monomer Fe-complex was also developed based on the model ligand, with the aim of understanding the properties of the polymer in a better way by comparative study but surprisingly both ligand and model ligand coordinate in a different fashion with the same Fe(ii)-metal ions under similar reaction conditions, though both of them have identical binding sites. It has been found that the monomer model complex is paramagnetic while the metallopolymer is diamagnetic in nature. FESEM images of thin films of the polymer revealed the presence of homogeneously distributed interparticulate mesopores which was further confirmed by surface area analysis. A long single strand of the polymer was found on the HOPG surface by AFM study. The cyclic voltammetry study indicated that both conjugated ligand and metallopolymers are electrochemically active. The bistable memory behaviour of the device fabricated on ITO has shown a negative differential resistance effect along with good RAM and ROM behaviour, showing the potential of this novel polymer as memristor.
- Oberoi, Deepa,Dagar, Parveen,Shankar, Uday,Vyas, Giriraj,Kumar, Anil,Sahu, Satyajit,Bandyopadhyay, Anasuya
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supporting information
p. 19090 - 19100
(2018/11/26)
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- Hydroxyl-containing half-sandwich rutheniumcoordination compound, preparation method and method for reducing nitrobenzene compound into aniline compound
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The invention discloses a hydroxyl-containing half-sandwich rutheniumcoordination compound, a preparation method and a method for reducing nitrobenzene compounds into aniline compounds. A structure of the hydroxyl-containing half-sandwich rutheniumcoordination compound is as shown by formula (I), where X is halogen and R is H, hydrocarbonyl of C1 to C6 or halogen. By adopting the method, the high-yield half-sandwich rutheniumcoordination compound can be prepared under mild conditions, and the half-sandwich rutheniumcoordination compound can reduce nitrobenzene compounds into aniline compounds under mild conditions.
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Paragraph 0049; 0050; 0051; 0052; 0053
(2017/06/02)
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- Triphenylphosphinopalladium(II) complexes with ONO-donor ligands: syntheses, structures and catalytic applications in C?C cross-coupling reactions
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Reactions of 1-((2-hydroxy-5-R-phenylimino)methyl)naphthalen-2-ols (H2Ln, n?=?1–3 for R?=?H, Me, Cl, respectively) with [Pd(PPh3)2Cl2] and Et3N in toluene under reflux produced three new mononuclear square-planar palladium(II) complexes with the general formula [Pd(Ln)(PPh3)] (1, R?=?H; 2, R?=?Me; 3, R?=?Cl). All the complexes were characterized using elemental analysis, solution conductivity and various spectroscopic (infrared, UV–visible and NMR) measurements. Molecular structures of 1, 2, 3 were confirmed using single-crystal X-ray diffraction analysis. In each complex, the fused 5,6-membered chelate rings forming phenolate-O, azomethine-N and naphtholate-O donor (Ln)2? and the PPh3 form a square-planar ONOP coordination environment around the metal centre. Infrared and NMR spectroscopic features of 1, 2, 3 are consistent with their molecular structures. Electronic spectra of the three complexes display several strong primarily ligand-centred absorption bands in the range 322–476?nm. All the complexes were found to be effective catalysts for carbon–carbon cross-coupling reactions of arylboronic acids with aromatic and heteroaromatic aldehydes to form the corresponding diaryl ketones. Copyright
- Prabhu, Rupesh Narayana,Babu, G. Narendra,Pal, Samudranil
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- Fluorescent aluminum chelate complexes as modified precursors for nano-structured alumina
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A series of new mononuclear heteroleptic derivatives of aluminum(III), {[(CH3COCHCOCH3)AlL] (1 and 4)}, {[(C6H5COCHCOC6H5)AlL] (2, 5, and 7)}, and {[(C9H6NO)AlL] (3 and 6)}, have been synthesized by reacting Al(OPri)3 with tridentate Schiff base H2Lx (H2L1?=?C13H10BrNO2; H2L2?=?C14H13NO3; H2L3?=?C17H13NO2) and β-diketone/8-hydroxyquinoline (β-diketone?=?acetylacetone/dibenzoylmethane) in 1 : 1 : 1 stoichiometry using anhydrous benzene and ethanol. All the complexes were characterized by elemental analysis, FTIR, and NMR (1H and 13C) spectral studies. Molecular structures obtained from single-crystal XRD of aqua 1 (1a) and DMSO coordinated 2 (2a) authenticate their existence. Further, nanostructured α-alumina was synthesized from 1 by well-established sol–gel method and was characterized by powder XRD, TEM, and EDX analyses.
- Prasanth, Vuppalapati Giri,Rathore, Ravindranath S.,Pathak, Madhvesh,Sathiyanarayanan, Kulathu Iyer
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p. 983 - 996
(2017/02/26)
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- Towards a global greener process: from solvent-less synthesis of molybdenum(vi) ONO Schiff base complexes to catalyzed olefin epoxidation under organic-solvent-free conditions
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Nine Schiff base ligands derived from o-hydroxyaldehydes (2-hydroxybenzaldehyde, 2-hydroxy-3-methoxybenzaldehyde, 2-hydroxy- 1-naphthaldehyde) and nine corresponding dioxomolybdenum(vi) complexes, cis-[MoO2L(CH3OH)] or cis-[MoO2L(CH3OH)]·CH3OH and dinuclear [MoO2L]2, have been prepared using the conventional solution-based method as well as mechanochemically, by liquid assisted grinding (LAG). All products have been characterised by means of IR spectroscopy, thermal analyses and also by powder and five molybdenum complexes by single crystal X-ray diffraction. The crystal structure analysis of mononuclear complexes reveal distorted octahedral Mo(vi) coordination by ONO donor atoms from a dianionic tridentate Schiff base ligand, two oxido oxygen atoms from the MoO22+ moiety and an oxygen atom from the MeOH molecule trans to the oxido oxygen atom. Due to the trans effect of the oxido oxygen atom, Mo-O(MeOH) is the longest bond distance within the Mo coordination sphere and it expected to be the point of maximum reactivity of the complexes. All complexes have been studied as pre(catalysts) for the epoxidation of cis-cyclooctene, cyclohexene and (R)-limonene using aqueous tert-butyl peroxide (TBHP) as the oxidant and in the absence of an organic solvent.
- Cindri?, Marina,Pavlovi?, Gordana,Katava, Robert,Agustin, Dominique
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supporting information
p. 594 - 602
(2017/02/05)
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- A novel approach toward the synthesis of some new tridentate Schiff bases from anil-like compounds
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A novel method was developed for synthesizing a series of new tridentate Schiff base ligands starting from hydroxynaphthyl pyrimidinyl amines with o-phenylenediamines or o-aminophenol or 2-amino-3-hydroxy-pyridine in the presence of formic acid catalyst under solvent-free conditions. In these reactions [1+1], the condensation product as half-unit ligand was obtained. Moreover, the reaction of hydroxynaphthylmethylene pyrimidinyl amines with 3,4-diaminopyridine and 1,8-naphthalenediamine leads to the formation of C2-naphthylated imidazopyridine and dihydropyrimidine, respectively. The attractive features of this protocol are use of an inexpensive catalyst, operational simplicity, short reaction times, easy handling, and good yields.
- Bagheri, Fatemeh,Olyaei, Abolfazl
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p. 1111 - 1119
(2016/11/09)
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- Influence of Tuned Linker Functionality on Modulation of Magnetic Properties and Relaxation Dynamics in a Family of Six Isotypic Ln2 (Ln = Dy and Gd) Complexes
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A coordination complex family comprising of six new dinuclear symmetric lanthanide complexes, namely, [Ln2(Lx)2(L′)2(CH3OH)2]·yG (H2Lx: three related yet distinct Schiff-base linkers; x = 1-3, according to the nomenclature of the Schiff-base linker employed herein. HL′: 2,6-dimethoxyphenol. yG refers to crystallographically assigned guest solvent species in the respective complexes; y = number of solvent molecules; LnIII = Dy/Gd) were isolated employing a mixed-ligand strategy stemming out of a strategic variation of the functionalities introduced among the constituent Schiff-base linkers. The purposeful introduction of three diverse auxiliary groups with delicate differences in their electrostatic natures affects the local anisotropy and magnetic coupling of LnIII ion-environment in the ensuing Ln2 dinuclear complexes, consequentially resulting into distinctly dynamical magnetic behaviors among the investigated new-fangled family of isotypic Ln2 complexes. Among the entire family, subtle alterations in the chemical moieties render two of the Dy2 analogues to behave as single molecule magnets, while the other Dy2 congener merely exhibits slow relaxation of the magnetization. The current observation marks one of the rare paradigms, wherein magnetic behavior modulation was achieved by virtue of the omnipresent influence of subtly tuned linker functionalities among the constituent motifs of the lanthanide nanomagnets. To rationalize the observed difference in the magnetic coupling, density functional theory and ab initio calculations (CASSCF/RASSI-SO/POLY-ANISO) were performed on all six complexes. Subtle difference in the bond angles leads to difference in the J values observed for Gd2 complexes, while difference in the tunnel splitting associated with the structural alterations lead to variation in the magnetization blockade in the Dy2 complexes.
- Mukherjee, Soumya,Lu, Jingjing,Velmurugan, Gunasekaran,Singh, Shweta,Rajaraman, Gopalan,Tang, Jinkui,Ghosh, Sujit K.
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p. 11283 - 11298
(2016/11/17)
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- Hepta-coordinated heteroleptic derivatives of zirconium(IV): Synthesis, structural characterization and ring opening polymerization of ε-caprolactone
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A series of new hepta-coordinated heteroleptic derivatives of zirconium(IV) of the types [(CH3COCHCOCH3)2ZrL] (1, 3, 5 and 7) and [(C6H5COCHCOC6H5)2ZrL] (2, 4, 6 and 8) (L?=?a dianionic [ONO]-tridentate ancillary ligand) was synthesized quantitatively by reacting Zr(OPri)4·PriOH with the tridentate Schiff's base ligands H2Lx(H2L1?=?C13H11NO2; H2L2?=?C13H10BrNO2; H2L3?=?C14H13NO3; H2L4?=?C17H13NO2) and β-diketones (acetylacetone/dibenzoylmethane) in a 1:1:2 stoichiometry using dry benzene and ethanol as solvents. All these newly synthesized solid derivatives were fairly soluble in common organic solvents. They were characterized by elemental analyses, FTIR and NMR (1H and13C) spectral studies. Single crystal XRD data of complexes 1, 2, 3 and 5 indicated the hepta-coordination and monomeric nature of these complexes. Furthermore, all these derivatives were tested for the ring opening polymerization of ε-caprolactone. The dibenzoylmethane derivatives were inactive in polymerizing ε-caprolactone unlike the acetylacetonate complexes. The molecular weight and polydispersity index values of polycaprolactone were obtained by GPC analysis. Kinetic studies for the rate of polymerization of ε-caprolactone by these catalytically active zirconium(IV) complexes authenticated the first order dependence of the polymerization rate on the monomer concentration. Among these, complex 3, with an electronegative bromine atom on the Schiff's base moiety, exhibited the best catalytic activity with a conversion of >95% in 2?h.
- Vuppalapati, Giri Prasanth,Rathore, Ravindranath S.,Pathak, Madhvesh,Kulathu Iyer, Sathiyanarayanan
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p. 163 - 171
(2016/09/28)
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- DETERGENTS OR CLEANING AGENTS CONTAINING A BLEACH-ENHANCING TRANSITION METAL COMPLEX WHICH IS OPTIONALLY PRODUCED IN SITU
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The aim of the invention is to improve the cleaning power of detergents and cleaning agents, especially with regard to bleachable stains, while avoiding any damage to the textile treated with said detergents and cleaning agents. For this purpose, a bleach catalyst in the form of a complex of Fe—, Mo—, Mn— and/or W with a ligand having a skeleton of formula (I) is used.
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Page/Page column 9-10
(2012/10/23)
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- Nitridoosmium(VI) Complexes for Treatment of Cancer
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The invention relates to nitridoosmium complexes and methods of using these compounds as treatments for cancer.
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Page/Page column 9
(2011/10/10)
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- Sulfanilamide copper(II) chelates with 2-[(2-Hydroxyphenyl-imino)methyl] phenolom and 1-[(2-Hydroxyphenylimino)-methyl]naphthalen-2-ol
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2-[(2-Hydroxyphenylimino)methyl]phenol (H2L1) and 1-[(2-hydroxyphenylimino)methyl]naphthalen- 2-ol (H2L2) reacted with copper(II) acetate hydrate and sulfanilamide (Sf1), sulfathiazole (Sf2), sulfaethidole (Sf3), sulfadiazine (Sf4), and sulfadimidine (Sf5) in ethanol to give mixed-ligand copper chelates with the composition Cu(Sf1-5)(L 1-2) . nH2O (n = 1, 2). All these complexes are monomeric. Salicylaldehyde imines (H2L1 and H2L 2) behave as doubly deprotonated tridentate O,N,O ligands, whereas sulfanilamides (Sf1-5) are unidentate ligands. Thermolysis of the synthesized complexes includes dehydration at 70-90°C, followed by complete thermal decomposition (290-380°C). The complexes [Cu(Sf1)(L 1)] . 2H2O and [Cu(Sf3)(L1)] . H2O at a concentration of 10-4 M inhibited growth and reproduction of 100% of human myeloid leukemia cells (HL-60). The inhibitory effect was 90 and 75%, respectively, at a concentration of 10-5 M, whereas no antitumor activity was observed at a concentration of 10-6 M. Pleiades Publishing, Ltd., 2010.
- Gulya,Tsapkov,Poirier,Aruksandei,Pakhontsu
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experimental part
p. 1351 - 1354
(2011/02/27)
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