3230-43-1Relevant academic research and scientific papers
A DFT and experimental study of the spectroscopic and hydrolytic degradation behaviour of some benzylideneanilines
Nelson, Peter N.,Robertson, Tahjna I.
, (2021/10/12)
The spectroscopic and hydrolytic degradation behaviour of some N-benzylideneanilines are investigated experimentally and theoretically via high quality density function theoretical (DFT) modelling techniques. Their absorption and vibrational spectra, accurately predicted by DFT calculations, are highly dependent on the nature of the substituents on the aromatic rings, hence, though some of their spectroscopic features are similar, energetic differences exist due to differences in their electronic structures. Whereas the o-hydroxy aniline derived adducts undergo hydrolysis via two pathways, the most energetically economical of which is initiated by a fast enthalpy driven hydration, over a conservative free energy (ΔG?) barrier of 53 kJ mol?1, prior to the rate limiting entropy controlled lysis step which occurs via a conservative barrier of ca.132 kJ mol?1, all other compounds hydrolyse via a slower two-step pathway, limited by the hydration step. Barriers heights for both pathways are controlled primarily by the structure and hence, stability of the transition states, all of which are cyclic for both pathways.
Synthesis, spectroscopic characterization, computational studies, theoretical investigation of NLO properties and antibacterial activities of mixed ligand complexes of Co(II) and Cu(II)
Anjum, Afreen,Jaiswal, Nitesh,Kumar, Manoj,Modanawal, Vishnu Kumar,Paswan, Sikandar,Srivastava, Shekhar
, (2022/01/14)
The reaction of Schiff base 2-(4-(dimethylamino)benzylideneamino)phenol (DBAP) and diethylenetriamine/ethylenediamine with cobalt(II) and copper(II) metal ion in equimolar ratio afforded mixed ligand complexes [M(DBAP)(L)Cl(H2O)n] (1
Synthesis, characterization and antioxidant activity of nickel(ii) schiff base complexes derived from 4-(dimethylamino)benzaldehyde
Nawaz, Nighat,Ahmad, Irshad,Darwesh, Nizam M.,Wahab, Amjad,Ur Rahman, Sadeeq,Sajid, Abdul,Khan, Farhan A.,Khan, Sher B.,Patching, Simon G.,Uddin, Kamal
, p. 238 - 242 (2021/01/20)
Nickel(II) complexes of the following Schiff base ligands derived from 4-(dimethylamino)benzaldehyde were synthesised: (Z)-1-(4-(dimethylamino)benzylideneamino)propan-1-ol through condensation with 1-amino-propan-1-ol, (N1E,N2E)-Nsu
Oxidative NHC Catalysis for the Generation of Imidoyl Azoliums: Synthesis of Benzoxazoles
Patra, Atanu,James, Anjima,Das, Tamal Kanti,Biju, Akkattu T.
, p. 14820 - 14826 (2019/01/03)
N-Heterocyclic carbene (NHC)-catalyzed intramolecular cyclization of aldimines generated from 2-amino phenols and aromatic aldehydes leading to the synthesis of 2-arylbenzoxazoles under mild conditions is presented. The reaction proceeds via the generation of the aza-Breslow intermediates from imines and NHC, which under oxidative conditions form the key imidoyl azoliums and a subsequent intramolecular cyclization furnishes the product. The reaction tolerates a broad range of functional groups, and the products are formed in generally good yields.
Understanding difficulties of irregular number-membered ring transition states for intramolecular proton transfer in excited state
Qin, Xiaozhuan,Ding, Ge,Wang, Zhenqiang,Gong, Yulong,Gao, Fang,Zhang, Shengtao,Luo, Ziping,Li, Hongru
supporting information, p. 403 - 410 (2017/01/03)
This study presents a variety of organic dyes with similar molecular structures that could undergo intramolecular proton transfer in excited states via five-, six- and seven-number-membered ring transition states, respectively. In addition, the dyes without proton transfer segments are also synthesized to use as references. X-ray single crystal diffraction, NMR spectra as well as UV/visible spectra suggests the presence of internal hydrogen bond with different strength in the target dyes. The steady and transient fluorescence measurements demonstrate occurrence of excited state intramolecular proton transfer via a six number-membered ring transition state. In contrast, it cannot be processed through five- and seven-number-membered ring transition states of the studied dyes. The molecular geometry optimization of the studied dyes reveals fundamental factors for the difficulties of intramolecular proton transfer in excited states via five- and seven-number-membered ring transition states.
Abnormal effect of hydroxyl on the longest wavelength maximum in ultraviolet absorption spectra for bis-aryl Schiff bases
Cao, Chao-Tun,Zhou, Wei,Cao, Chenzhong
, (2017/09/19)
Two sets of bis-aryl Schiff bases that contain 4(or 4′)-OH and 2(or 2′)-OH were synthesized. The first set consists of 4-HOArCH=NArY and XArCH=NArOH-4′, and the second set consists of 2-HOArCH=NArY and XArCH=NArOH-2′. Their ultraviolet absorption spectra were measured and investigated. A very interesting phenomenon was observed by analyzing their wave number νmax (cm?1) of longest wavelength maximum λmax (nm) of ultraviolet. Compared with the change regularity of the νmax of XArCH=NArY (where the X and Y excluded OH), the 4′-position hydroxyl (4′-OH) and 2′-position hydroxyl (2′-OH) have abnormal performance. The details are the following: the 4′-OH contributes an additional red shift to the νmax of XArCH=NArOH-4′ (λmax increase), whereas the 2′-OH contributes an additional blue shift to the νmax of XArCH=NArOH-2′ (λmax decrease). In addition, there are ortho steric effects of all 2-OH and 2′-OH on the νmax for 2-HOArCH=NArY and XArCH=NArOH-2′, and the ortho steric effect contributes a red shift to their νmax. These experimental facts can provide an important theoretical reference for us using aryl Schiff base compounds as optical materials and performing the molecular design.
Preparation, spectroscopic investigation and biological activity of new mixed ligand chelates
Alassbaly, Faten Suliman,El-Ajaily, Marei Mailoud,Ben-Gweirif, Salha Faraj,Maihub, Abdussalam Ali
, p. 1034 - 1042 (2015/01/30)
Preparation and investigation of new Co(II), Ni(II), Zn(II) and Cr(III) chelates with mixed ligands including Schiff base (L1) formed from the condensation of 4-dimethylaminobenzaldehyde with 2-aminophenol and anthranilic acid (L2) w
A small molecule that displays marked reactivity toward copper-versus zinc-amyloid-β implicated in Alzheimer's disease
Savelieff, Masha G.,Liu, Yuzhong,Senthamarai, Russell R.P.,Korshavn, Kyle J.,Lee, Hyuck Jin,Ramamoorthy, Ayyalusamy,Lim, Mi Hee
supporting information, p. 5301 - 5303 (2014/05/06)
Alzheimer's disease (AD) is a complex, multifactorial, neurodegenerative disease that poses tremendous difficulties in pinpointing its precise etiology. A toolkit, which specifically targets and modulates suggested key players, may elucidate their roles i
Photoprotective activity of resveratrol analogues
Polonini, Hudson Caetano,Lima, Larissa Lavorato,Goncalves, Karla Mara,Do Carmo, Antonio Marcio Resende,Da Silva, Adilson David,Raposo, Nadia Rezende Barbosa
, p. 964 - 968 (2013/04/10)
Resveratrol is a promising agent for protecting human skin from UV radiation and to reduce the occurrence of cutaneous malignancies. We describe the photoprotective activity of six resveratrol analogues using the diffuse transmittance technique to determine the SPF and the protection against UVA radiation. The analogues presented a varied profile of photoprotection, the SPF ranging from 2 to 10 and the UVAPF from 0 to 9. Among the six compounds tested, the protection against UVB sunrays provided by compound B was more significant than the protection provided by resveratrol; compounds C, D, E and F show photoprotection similar to resveratrol.
Antioxidant activities and transition metal ion chelating studies of some hydroxyl Schiff base derivatives
Zhang, Ye,Zou, Biqun,Wang, Kai,Pan, Yingming,Liang, Hong,Yi, Xianghui,Wang, Hengshan
experimental part, p. 1341 - 1346 (2012/08/27)
Several hydroxyl Schiff base (HSB) compounds (1-10) with good radical scavenging activity (RSA) were designed. Compounds 6, 7, and 10 showed better RSAs than the common synthetic antioxidant 2,6-diterbutyl- 4-methylphenol (BHT) in DPPH and ABTS assays. To probe whether these HSB compounds may exert their antioxidant effect through transition metal ion chelation, the copper and ferrous chelating abilities of them were investigated. It was found by fluorescence quenching spectra that the binding constants Ka were in the range of 0.85×103-7.30×104 M-1. Further study was carried out by the complexation of a representative compound 5 with ferrous ion in mass spectrum. A 2:1 5-ferrous complex was readily formed in a methanol-water solution (v:v, 8:2), which confirmed that the chelation happened when the HSB compounds were treated with transition metal ions. The above results indicated that the transition metal ion chelation play an important role in their antioxidant abilities. Springer Science+Business Media, LLC 2011.
