3533-45-7

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• 58758-45-5 3-methoxy-2-(prop-2-yn-1-yloxy)benzaldehyde 
• 148-53-8 3-methoxy-2-hydroxybenzaldehyde 
• 7803-57-8 hydrazine hydrate 
• 1729-02-8 3-ethoxycarbonyl-8-methoxycoumarin 
• 3378-54-9 <2-Hydroxy-3-methoxy-benzyliden>-4-rhodan-anilin 

Relevant academic research and scientific papers

An integrated approach (synthetic, structural and biological) to the study of aroylhydrazone salts

The reaction of two methoxy substituted salinazid-based hydrazones, 4-methoxysalicylaldehyde isonicotinoyl hydrazone (L1) and 3-methoxysalicylaldehyde isonicotinoyl hydrazone (L2), with HCl, HBr, HNO3 and H2SO4 in methanol yielded salts of different stoichiometries (1:1 or 2:1) and/or polymorphic forms. In such a way, (HL1)+X- and (HL2)+X- salts, where X = Cl, Br, NO3, HSO4, as well as [H(L1)2]+Br- and (HL1)2+SO42- were obtained. The solid state properties and the propensity for transformation between different forms in solution were also investigated. The crystal structures of compounds (HL1)+Cl-, (HL1)+Br- (α and β), [H(L1)2]+Br-, (HL1)2+SO42-, (HL2)+Br-·MeOH and (HL2)+NO3- were solved by the single-crystal X-ray diffraction method while the structures of (HL1)+NO3- and (HL1)+HSO4- (α and β) were solved by the powder diffraction method. The details of anion binding with the isoniazid functionality are discussed. The aroylhydrazone salts were evaluated for cytotoxic activity in vitro. All compounds exhibited weak cytotoxicity against THP-1 and no cytotoxicity against HepG2 cells. In a preliminary antimicrobial screening assay, these compounds were not only active against antibiotic susceptible Gram-positive bacteria, but also exhibited antibacterial effects on a wide range of multidrug-resistant Gram-positive as well as multidrug resistant Gram-negative bacterial pathogens.

Linear 3d-4f compounds: synthesis, structure, and determination of the d-f magnetic interaction

A family of [RE2M2L2(BA)6] (RE = Gd, Tb, Dy, Y; M = Co, Ni, Cu, Zn; L = 1,2-bis(2-hydroxy-3-methoxybenzylidene)hydrazine; BA = benzoic acid) complexes were synthesized and structurally and magnetically characterized. The magnetic interactions between spin centers were systematically investigated. The interactions of M-M (M = Co, Ni and Cu) and Gd-Ni/Cu were extracted from the fitting of the experimental data of Y2M2 (M = Co, Ni and Cu) and Gd2M2 (M = Ni and Cu) derivatives, respectively. Furthermore, the Ln-M interactions were qualitatively analyzed by deducting the M-M coupling and the contribution of the crystal-field effects of the LnIII ion from the total magnetic susceptibility of Ln2M2 (Ln = Dy and Tb) compounds. In addition, complex [Dy2Zn2L2(BA)6] shows field induced single molecular magnet behavior profiting from the isolated anisotropic dysprosium ions.

Cascade detection of fluoride and bisulphate ions by newly developed hydrazine functionalised Schiff bases

Two hydrazine functionalized Schiff bases have been synthesized through the reaction between hydrazine and o-vanillin/salicylaldehyde compounds employing a green-chemical approach and characterized spectroscopically including XRD study. Crystal structure analysis reveals that both the chemosensors, N,N′-bis(o-vanilidine)hydrazine (P17) and N,N′-bis(salicylidene)hydrazine, (HARB) crystallize in monoclinic system with P21/n space group and exist in the locked forms through intramolecular H-bonding (~1.90 ?) between phenolic-OH and N atom of hydrazine. The chemosensors display excellent selectivity towards fluoride followed by bisulphate ions, over other potential competitor anions in acetonitrile. Binding stoichiometry of the individual chemosensor with F? is confirmed to be 1:1 and assessed with absorption study and 1H NMR analysis. Systematic DFT analysis reveals that the contribution of hydroxyl oxygen atoms to the HOMO increases sharply from the chemosensor to chemosensor–F? adduct (17% to 28%) leading to deprotonation of one hydroxyl group and consequently involvement in conjugation impeding the C=N isomerisation. Thus, the hydroxyl proton captured by F? restricts the C=N isomerisation as well as ICT character of both the chemosensors and confirms the cascade sensing mechanism for fluoride and bisulphate ions.

Synthesis, structure, and magnetic properties of heterometallic {Zn2Ln2} (Ln = Tb, Dy, Ho) compounds with parallelogram-like cores

This work presents the synthesis, structure, and magnetic properties of three tetranuclear heterometallic compounds with the chemical formula [Zn2Ln2(L)4Cl2]·xCH3CN·yCH3OH where Ln = Tb (1), Dy (2), and Ho (3) and the H2L ligand was 1,2-bis(2-hydroxy-3-methoxybenzylidene) hydrazine. Single-crystal X-ray analyses revealed that compounds 1-3 had similar coordination environments and structures. Direct current susceptibility measurements revealed that the χmT product decreased with decreasing temperature due most likely to either the thermal depopulation of the Stark sublevels of the TbIII, DyIII, and HoIII ions or antiferromagnetic coupling within the [Zn2Ln2] cores. Furthermore, compound 2 displayed a slow field-induced relaxation of magnetization. An energy barrier of ΔE/kB = 23.74 K and a pre-exponential factor of τ0 = 4.33 × 10-6 s were obtained by fitting the dynamic magnetic data to an Arrhenius rate law.

Highly fluorescent materials derived from ortho-vanillin: Structural, photophysical electrochemical and theoretical studies

Small-molecule organic fluorophores are highly in demand attributed to their extensive prospective in material and biomedical applications. Particularly, luminescent π-conjugated organic molecules that possess an efficient solid-state emission are excellent candidates for optoelectronic devices. Focusing on high demand of organic fluorophores, we herein report the synthesis of three organic fluorescent materials derived from o?vanillin, viz. an ester (F1), an azine (F2) and an azo dye (F3). Interestingly, F2 exhibited very intense luminescence in its aggregate phase due to the restriction in intra-molecular rotation (RIR), as demonstrated by solution thickening studies. Further, its Single Crystal X-ray Crystallography (SCXRD) study suggested the existence of various intra and inter molecular interactions and gave evidences for locked intra-molecular rotations of the benzene rings in the rigid conformation of the molecule. The bathochromic shift in fluorescence from solution to solid phase was confirmed by its thin-film emission spectrum, which evidences the formation of J-aggregates. The observed RIR, development of J-aggregates and high conjugation in F2 impart an excellent fluorescence in its aggregated state. Thin films of both F2 and F3 on ITO plates exhibited a bathochromic shift with a deep orange to red photoluminescence on UV excitation. Furthermore, the morphological characterization revealed the presence of clear dense grains in case of F2 and F3, while the DSC analysis indicated phase transitions of all the derivatives. As seen from dielectric measurement studies, the azo dye F3 exhibited the highest dielectric constant among the three derivatives. The electronic and photophysical data based on Density Functional Theory (DFT) and Time Dependent-DFT (TD-DFT) calculations are in agreement with the experimental results. All the above data clearly advocate that, the synthesized fluorophoric o?vanillin derivatives are excellent candidates for electro-optical devices.

Multifunctional luminescent magnetic cryocooler in a Gd5Mn2 pyramidal complex

Magnetic cooling is a highly efficient refrigeration technique with the potential of replacing expensive and rare helium-3 in the field of ultra-low temperature cooling. However, the visualization of a cryogen at an extremely low temperature and in a stro

A Copper-Benzotriazole-Based Coordination Polymer Catalyzes the Efficient One-Pot Synthesis of (N′-Substituted)-hydrazo-4-aryl-1,4-dihydropyridines from Azines

A series of new (N′-substituted)-hydrazo-4-aryl-1,4-dihydropyridines was successfully synthesized via a facile one-pot catalytic pathway utilizing azines and propiolate esters as starting materials and a one-dimensional copper benzotriazole-based coordination polymer as catalyst. In the absence of catalyst, the corresponding 5-substituted 4,5-dihydropyrazoles were formed in moderate to high yields. Fine-tuning of the catalysts allowed us to gain more insights regarding the plausible reaction mechanism. (Figure presented.).

Improvement in Titanium Complexes Bearing Schiff Base Ligands in the Ring-Opening Polymerization of L-Lactide: A Dinuclear System with Hydrazine-Bridging Schiff Base Ligands

A series of titanium (Ti) complexes bearing hydrazine-bridging Schiff base ligands were synthesized and investigated as catalysts for the ring-opening polymerization (ROP) of L-lactide (LA). Complexes with electron withdrawing or steric bulky groups reduced the catalytic activity. In addition, the steric bulky substituent on the imine groups reduced the space around the Ti atom and then reduced LA coordination with Ti atom, thereby reducing catalytic activity. All the dinuclear Ti complexes exhibited higher catalytic activity (approximately 10-60-fold) than mononuclear LCl-H-TiOPr2 did. The strategy of bridging dinuclear Ti complexes with isopropoxide groups in the ROP of LA was successful, and adjusting the crowded heptacoordinated transition state by the bridging isopropoxide groups may be the key to our successful strategy.

Unusual Aggregation/Gelation-Induced Phosphorescence of Propeller-Type Binuclear Platinum(II) Enantiomers

Three binuclear cyclometalated PtIIcomplexes, [(ppy)Pt(μ-SA)Pt(ppy)] (ppy = 2-phenylpyridine, SA: salicylaldehyde azine), have been synthesized and characterized. Owing to the blockage of the intramolecular rotation of the bridging SA ligands, all three complexes exhibit propeller-type enantiomers and aggregation-induced phosphorescence (AIP). Interestingly, one complex with –NEt2groups instead of long alkyl chains, amide, urea peptides, cholesterol, sugar, or steroidal groups was found to show strong phosphorescence enhancement gated by the gelation process. This unusual gelation behavior is rarely encountered, as the metallogel has no intermolecular hydrogen bonding or Pt–Pt interactions. We attribute the driving force of this gelation-induced phosphorescence (GIP) to the propeller-type structure, optimally balanced solubility of –NEt2groups, enantiomer-induced π–π stacking interactions, and strong multiple intermolecular H–C, H–O, and H–H interactions.

Ratiometric fluorescent pH probes based on aggregation-induced emission-active salicylaldehyde azines

A series of luminescent salicylaldehyde azines (SAs) containing different electron-accepting substituents (-NO2, -F, and -Cl), electron-donating substituents (-OMe and -NEt2), and a π-extended system (naphthalene ring) are prepared for the application of fluorescent pH probes. These SAs inheriting the aggregation-induced emission (AIE) features display strong blue, green, and red fluorescence with large Stokes shifts in water and solid medium. Combining the advantages of AIE and the chemical reactivity of phenol towards OH-/H+, most of the SAs can be used as ratiometric fluorescent pH probes with a broad pH range (2-14) in water and solid medium (test paper). Moreover, the inherent relationship between their chemical structures and AIE properties/pKa values (7.5-13.3) is studied, which provides unequivocal insights into the design of AIE-active dyes and their applications. This journal is