103886-91-5Relevant articles and documents
Ruthenium (II) complexes of NO ligands: Synthesis, characterization and application in transfer hydrogenation of carbonyl compounds
?alik, Hatice Selvi,Ispir, Esin,Karabuga, ?emistan,Aslantas, Mehtet
, p. 122 - 129 (2016)
New Schiff base ligands including azo group such as (4-((E)-(4-ethylphenyl)diazenyl)-2-((E)-(phenylimino)methyl)phenol 2, 4-((E)-(4-ethylphenyl)diazenyl)-2-((E)-(naphthalen-1-ylimino)methyl)phenol 3, 2-((E)-(benzylimino)methyl)-4-((E)-(4-ethylphenyl)diazenyl)phenol 4 and azo group-free ligand (E)-2-((benzylimino)methyl)phenol 8 and their ruthenium complexes 5-7 and 9 with [RuCl2(p-cymene)] were synthesized and characterized by spectroscopic techniques including 1H and 13C NMR, FT-IR and UV-Vis. According to the UV-visible, IR and NMR data, the Ru (II) complexes 5-7 and 9 are formed by the coordination of N, O atoms of the ligands. Molecular structures of the complex 7 and complex 9 were determined by single crystal X-ray diffraction studies. These Ruthenium (II) complexes 5-7 and 9 were used as catalysts for the transfer hydrogenation of a series of ketones and benzaldehyde in 2-propanol. Following the comparison of complex 9 with the other three azo containing complexes 5-7, it was observed that azo group has got remarkable increasing effect on the catalytic activity. The results showed that the complex 5 is efficient than the other Ru (II) complexes.
A spectroscopic study of proton transfer and photochromism in N-(2-hydroxybenzylidene)aniline
Lewis, J. W.,Sandorfy, C.
, p. 1738 - 1746 (1982)
The infrared spectral characteristics of N-(2-hydroxybenzylidene)aniline, its deuterium substituted analogue, N-(2-hydroxybenzylidene)-m-toluidine, and their photoproducts have been investigated.The infrared spectrum of a low temperature polycrystalline film of N-(2-hydroxybenzylidene)aniline exhibits new absorption bands at 3380, 1646, 1537, 1502, 1319, and 1310 cm-1 upon irradiation at 365 nm.Likewise, the spectrum of the m-toluidine derivative exhibits new absorption bands at 3320,1650, 1535, 1503, 1321, 1310, and 995 cm-1 upon irradiation at 365 nm.These new data, in conjunction with the newly acquired data on the hydrochloride and deuterochloride of the title compound, indicate that the photoproduct is a zwitterion, not an ortho-quinone.It is also inferred that the photoproduct exists in a conformation which is cis about the central carbon-nitrogen double bond.
Factors determining tautomeric equilibria in Schiff bases
Flores-Leonar, Martha,Esturau-Escofet, Nuria,Méndez-Stivalet, José M.,Marín-Becerra, Armando,Amador-Bedolla, Carlos
, p. 600 - 605 (2011)
Schiff bases derived from o-hydroxyaldehydes present keto and enol tautomeric forms; the relative equilibrium between these two tautomers depending on the particular aldehyde the Schiff bases is derived from. Thus benzaldehyde produces a stable enol tauto
GROUND- AND EXCITED-STATE PROTOTROPIC TAUTOMERISM IN ANILS OF AROMATIC α-HYDROXYALDEHYDES STUDIED BY ELECTRONIC ABSORPTION, FLUORESCENCE AND 1H AND 13C NMR SPECTROSCOPIES AND SEMI-EMPIRICAL CALCULATIONS
Alarcon, Sergio H.,Olivieri, Alejandro C.,Cravero, Raquel M.,Labadie, Guillermo,Gonzalez-Sierra, Manuel
, p. 713 - 720 (1995)
Proton transfer processes in both the ground and excited states in anils of aromatic α-hydroxyaldehydes (salicylaldehyde, 2-hydroxynaphthalene-1-carbaldehyde and the novel 10-hydroxyphenanthrene-9-carbaldehyde) have been studied by a combination of spectroscopic techniques.Solution 1H and 13C NMR is used to establish the position of the tautomeric equilibria.UV-visible absorption and fluorescence spectral data help to characterize the existence, in all cases, of excited-state intramolecular proton transfer (ESIPT) phenomena.Semi-empirical calculations involving full geometry optimization and calculation of heats of formation for the ground state (AM1) and vertical excitation energies and oscillator strengths (INDO/S) are in agreement with the experimental observations.
The evaluation of the role of C-H?F hydrogen bonds in crystal altering the packing modes in the presence of strong hydrogen bond
Kaur, Gurpreet,Singh, Sandhya,Sreekumar, Amritha,Choudhury, Angshuman Roy
, p. 154 - 169 (2016)
Interactions involving fluorine is an area of contemporary research. To unravel the importance of weak C-H?F hydrogen bonds and C-H?π interactions in organic compounds in the presence of strong hydrogen bond, a series of N-benzylideneanilines with simultaneously hydroxyl (-OH) and fluorine substitutions were synthesized for structural analysis. These compounds have been studied through experimental single crystal X-ray diffraction analysis and computational methods (Gaussian09 and AIM2000). The hydroxyl group present in all the molecules were found to form strong O-H?N hydrogen bond, but the spatial arrangement of the molecules connected by this hydrogen bond have been found to be controlled by the weak C-H?F and C-H?O hydrogen bonds, weak C-H?π and π?π interactions. This manuscript illustrates the importance of several weaker interactions in altering the packing modes in the presence of strong hydrogen bonds.
LiBF4-catalyzed formation of fused pyrano- and furanobenzopyrans
Yadav,Reddy,Madhuri, Ch,Sabitha, G,Jagannadh, B,Kumar,Kunwar
, p. 6381 - 6384 (2001)
Lithium tetrafluoroborate efficiently catalyzes an unusual cyclization of o-hydroxybenzaldimines with 2,3-dihydrofuran and 3,4-dihydro-2H-pyran at ambient temperature to afford a class of new pyrano- and furanobenzopyran derivatives in excellent yields with high diastereoselectivity.
Blue Highly Fluorescent Boranil Derived From Anil Ligand: Synthesis, Characterization, Experimental and Theoretical Evaluation of Solvent Effect on Structures and Photophysical Properties
Agren, Soumaya,Chaabene, Marwa,Allouche, Abdul-Rahman,Ben Chaabane, Rafik,Lahcinie, Mohamed,Baouab, Mohamed Hassen V
, (2020)
In this study, we report the design and the synthesis of a Schiff base; Anil and its corresponding Boron Difluoride complexe; Boranil. The synthesis procedure was carried out adopting new, optimized reaction conditions. The Boranil dye presents the advantage to be emissive in solution. 1H and 19F NMR along with FTIR confirmed both compound's structure. To gain a better understanding of the solvatochromic behavior of Anil and Boranil, the dependence of the absorption spectra on the solvent's polarity was studied in depth. Thus, UV–Vis spectroscopy was performed in five selected solvents. In addition to the solvent's polarity effect, the influence of BF2 moiety introduction on the molecule's photophysical properties was also evaluated. When examining different absorption spectra, we found that the title fluorescent dye exhibited weak solvatochromic (11 nm in THF) as well as a slight redshift broader and relatively more structured absorption spectra after complexation. Besides, we investigate the obtained key structure–property relationships through DFT and TD-DFT calculations using a 6–311++ G (d, p) basis set. Quantum chemical calculations allowed confirming proposed structures and understanding their electronic structure in larger details. Theoretical results also showed good agreement with the experimental findings. Finally, the frontier molecular orbitals were investigated to illustrate the pi-conjugation and charge transfer effect.
Mixed Tri- and Bi-dentate Schiff-base Complexes of Technetium(V) and Rhenium(V). The Crystal Structure of N-(2-Oxidophenyl)salicylideneiminato-NOO')oxo(8-quinolinolato-NO)technetium(V)
Mazzi, Ulderico,Refosco, Fiorenzo,Tisato, Francesco,Bandoli, Giuliano,Nicolini, Marino
, p. 1623 - 1628 (1986)
Six-co-ordinate complexes of technetium(V) and rhenium(V) containing the MO3+ core with tri- and bi-dentate Schiff-base ligands were synthesized and characterized.The complexes with general formula 1)L) 1/sup
Chemical fixation of CO2 into cyclic carbonates by azo-containing Schiff base metal complexes
Ikiz, Mesut,Ispir, Esin,Aytar, Emine,Ulusoy, Mahmut,Karabu?a, ?emistan,Aslanta?, Mehmet,?elik, ?mer
, p. 7786 - 7796 (2015)
Two new ligands containing a -NN- group, 4-((E)-(4-bromophenyl)diazenyl)-2-((E)-(phenylimino)methyl)phenol (L1H, 2), 4-((E)-(4-bromophenyl)diazenyl)-2-((E)-((4-ethylphenyl)imino)methyl)phenol (L2H, 3) and their metal complexes were synthesized. The synthesized metal complexes were used as catalysts for the chemical fixation of CO2 into cyclic carbonates using epoxides which were used as both substrate and solvent. According to analytical, UV-visible and IR data, the metal complexes are formed by coordination of the N and O atoms of the ligands and the metal:ligand ratio was found to be 1:2 for all the complexes. The TG and DTA results showed that these complexes had good thermal stability. The molecular structures of ligand 2 (L1H) and its ZnII complex 4 (Zn(L1)2) were determined by single crystal X-ray diffraction studies. After choosing the most active catalyst (Zn(L1)2, 4), optimization studies were performed by changing various parameters. Ionic liquids have been found to have a positive effect and showed the most active performance with (bmim)PF6 + Zn(L1)2 (4) as a binary catalytic system.
Influence of bond fixation in benzo-annulated N-salicylideneanilines and their ortho-C(=O)X derivatives (X = CH3, NH2, OCH 3) on tautomeric equilibria in solution
Gawinecki, Ryszard,Kuczek, Agnieszka,Kolehmainen, Erkki,Osmialowski, Borys,Krygowski, Tadeusz M.,Kauppinen, Reijo
, p. 5598 - 5607 (2007)
(Chemical Equation Presented) 1H, 13C, and 15N NMR spectra show that an ortho-C(=O)X group present in the molecules of N-salicylideneanthranilamide (X = NH2), methyl N-salicylideneanthranilate (X = OCH3), N-salicylidene-o- aminoacetophenone (X = CH3), and their benzo analogues have only a minor effect on the tautomeric OH/NH-equilibrium in solution. Only two of three possible tautomers were detected Lability of the absent form was proved by theoretical calculations. Calculated energies show that the enolimino form (OH) is less stable than the enaminone (NH) form only for dibenzo-annulated N-salicylideneanilines. The population of each species in the tautomeric mixture was found to be inversely proportional to its energy. Application of the geometry-based aromaticity index HOMA shows that the effectiveness of the π-electron delocalization in different rings in the molecule depends mostly on the position of benzoannulation. Both the NH...O and N...HO hydrogen bonds present in the NH and OH tautomers respectively, increase the aromaticity of the quasirings H-O-C=C-C=N and O=C-C=C-N-H and decrease the aromatic character of the fused benzene ring. These results seem to be reliable when N-salicylideneanilines studied are compared with naphthalene and their benzo-annulated derivatives i.e., phenanthrene, anthracene, and triphenylene. An analysis of the effectiveness of π-electron delocalization confirms that in all cases studied, the OH form is more stable. Although the HOMA values and calculated energies are not a criterion that allows determination of the dominating tautomer, both of these parameters correctly show the effect of changes in the molecular topology on tautomeric preferences.
