- Synthesis and crystal structure of 2-[(3-bromo-phenylimino)methyl]phenol
-
A new Schiff base 2-[(3-bromo-phenylimino)methyl]phenol, derived from condensation of salicylaldehyde with m-bromoaniline, has been prepared and characterized by single crystal X-raydiffraction. Schiff base is in the monoclinic system, space group P21 with a = 3.928(14) ?, b = 10.590(4)?, c = 13.212(5)?, b = 97.360(4)?, Mr = 276.13, V = 545.1(3)?3, Dc = 1.682 g/cm3, Z = 2, μ = 3.745 mm-1, F(000) = 276, R = 0.0326, wR = 0.0455. The schiff base is stabilized by intermolecular C-H...O and p...p interaction and further linked into a 2D layer structure.
- Guo, Ya-Ning
-
-
Read Online
- Effect of substituents on the UV spectra of supermolecular system: Silver nanoparticles with bi-aryl Schiff bases containing hydroxyl
-
Effect of substituents on the ultraviolet (UV) spectra of supermolecular system involving silver nanoparticles (AgNPs) and Schiff bases was investigated. AgNPs and 49 samples of model compounds (MC), bi-aryl Schiff bases containing hydroxyl (XBAY, involving 4-OHArCH?NArY, 2-OHArCH?NArY, XArCH?NAr-4′-OH, and XArCH?NAr-2′-OH), were synthesized. The size of AgNPs was characterized by transmission electron microscopy (TEM), and the UV absorption spectra of AgNPs, XBAYs, and MC-AgNPs mixed solutions were measured, respectively. The results show that (1) the size of AgNPs is larger in MC-AgNPs solutions than that in AgNPs solution due to the distribution of MC molecules on the surface of AgNPs; (2) the UV absorption wavelength of XBAYs changes in the action of AgNPs and their wavelength shift exists limitation between XBAY and MC-AgNPs solutions; and (3) the wavelength shift limit of MC-AgNPs (λWSL) is influenced by the substituents X and Y and the position of hydroxyl OH. The wavenumber ΔνWSL of λWSL can be quantified by employing the excited-state substituent constant σexCC and Hammett constant σ of substituents X and Y. Comparing with the 4-OH, the 4′-OH makes the ΔνWSL a red shift, whereas the 2′-OH, comparing with the 2-OH, makes the ΔνWSL a blue shift.
- Cao, Chao-Tun,Cheng, Shimao,Zhang, Jingyuan,Cao, Chenzhong
-
-
- Copper-Catalyzed Asymmetric Annulation Reactions of Carbenes with 2-Iminyl- or 2-Acyl-Substituted Phenols: Convenient Access to Enantioenriched 2,3-Dihydrobenzofurans
-
We have developed a method for the highly diastereo- and enantioselective construction of 2,3-dihydrobenzofurans bearing tetrasubstituted carbon stereocenters by means of annulation reactions between carbenes and 2-iminyl- or 2-acyl-substituted phenols through catalysis by readily accessible copper(I)/bisoxazoline catalysts under mild conditions. These reactions feature a unique mechanism in which the copper catalyst serves a dual function: first it reacts with the diazo compound to generate a metal carbene, and second, upon formation of an oxonium ylide, it acts as a Lewis acid to activate the imine or ketone for diastereo- and enantioselective cyclization.
- Liang, Xin-Shen,Li, Rui-Dong,Wang, Xiao-Chen
-
supporting information
p. 13885 - 13889
(2019/08/26)
-
- Abnormal effect of hydroxyl on the longest wavelength maximum in ultraviolet absorption spectra for bis-aryl Schiff bases
-
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.
- Cao, Chao-Tun,Zhou, Wei,Cao, Chenzhong
-
-
- Synthesis and crystal structure of schiff base 2-[(3-Bromo-phenylimino) methyl]phenol and it's copper(II) complex
-
A new Schiff base 2-[(3-bromo-phenylimino)methyl]phenol (HL) (1), derived from condensation of salicylaldehyde with m-bromoaniline, and its copper(II) complex (2) [Cu2L4], have been prepared and characterized by single crystal X-ray diffraction. Schiff ba
- Zhang, Xin-Li
-
p. 3233 - 3237
(2014/07/22)
-