共查询到11条相似文献,搜索用时 0 毫秒
1.
Prof. Dr. Mohammed Enamullah Mohammad Mostafizur Rahman Mohammad Khairul Islam Dr. Dennis Woschko Prof. Dr. Christoph Janiak Prof. Dr. Gennaro Pescitelli 《ChemistryOpen》2022,11(7):e202200116
A family of bis[(R or S)-N-1-(Ar)ethylsalicylaldiminato-κ2N,O]-Δ/Λ-zinc(II) {Ar=C6H5 (ZnRL1 or ZnSL1), p-CH3OC6H4 (ZnRL2 or ZnSL2) and p-ClC6H4 (ZnRL3 or ZnSL3)} compounds was synthesized and investigated by multiple methods. They feature Λ/Δ-chirality-at-metal induction along the pseudo-C2 axis of the molecules. The chirality induction is quantitative in the solid state, explored by X-ray crystallography and powder X-ray diffraction (PXRD), where R or S-ligated complexes diastereoselectively yield Λ or Δ-configuration at the metal. On the other hand, Λ and Δ-diastereomers co-exist in solution. The Λ⇆Δ equilibrium is solvent- and temperature-dependent. Electronic circular dichroism (ECD) spectra confirm the existence of a diastereomeric excess of Λ-ZnRL1−3 or Δ-ZnSL1−3 in solution. DSC analysis reveals thermally induced irreversible phase transformation from a crystalline solid to an isotropic liquid phase. ECD spectra were reproduced by DFT geometry optimizations and time-dependent DFT (TD-DFT) calculations, providing ultimate proof of the dominant chirality atmetal in solution. 相似文献
2.
《应用有机金属化学》2017,31(10)
A novel tetradentate dianionic Schiff base ligand, N ,N ′‐bis(2‐carboxyphenylimine)‐2,5‐thiophenedicarboxaldhyde (H2L) and some first row d‐transition metal chelates (Co(II), Cu(II), Ni(II) and Zn(II)) were synthesized and characterized using various physicochemical and spectroscopic methods. The spectroscopic data suggested that the parent Schiff base ligand coordinates through both deprotonated carboxylic oxygen and imine nitrogen atoms. The free Schiff base and its metal chelates were screened for their antimicrobial activities for various pathogenic bacteria and fungi using the agar well diffusion method. The antibacterial and antifungal activities of all the newly synthesized compounds are significant compared to the standard drugs ciprofloxacin and nystatin. The antioxidant activities of the compounds were determined by reduction of 1,1‐diphenyl‐2‐picrylhydrazyl and compared with that of vitamin C as a standard. DNA binding ability of the novel Schiff base and its complexes was investigated using absorption spectroscopy, fluorescence spectroscopy, viscosity measurements and thermal denaturation. The obtained results clearly demonstrate that the binding affinity with calf thymus DNA follows the order: Cu(II) complex > Ni(II) complex > Zn(II) complex > Co(II) complex >H2L. Furthermore, the DNA cleavage activity of the newly synthesized ligand and its metal complexes was investigated using supercoiled plasmid DNA (pUC18) gel electrophoresis. 相似文献
3.
Lijuan Yang Wenqian Chen Yanmei Chen Wei Liu Tao Lei Lei Li Miaoshui Lin Jian Wu Yanyuan Cao Wu Li Prof. Dr. Yahong Li 《无机化学与普通化学杂志》2012,638(11):1833-1838
The reaction of the aryl‐oxide ligand H2L [H2L = N,N‐bis(3, 5‐dimethyl‐2‐hydroxybenzyl)‐N‐(2‐pyridylmethyl)amine] with CuSO4 · 5H2O, CuCl2 · 2H2O, CuBr2, CdCl2 · 2.5H2O, and Cd(OAc)2 · 2H2O, respectively, under hydrothermal conditions gave the complexes [Cu(H2L1)2] · SO4 · 3CH3OH ( 1 ), [Cu2(H2L2)2Cl4] ( 2 ), [Cu2(H2L2)2Br4] ( 3 ), [Cd2(HL)2Cl2] ( 4 ), and [Cd2(L)2(CH3COOH)2] · H2L ( 5 ), where H2L1 [H2L1 = 2, 4‐dimethyl‐6‐((pyridin‐2‐ylmethylamino)methyl)phenol] and H2L2 [H2L2 = 2‐(2, 4‐dimethyl‐6‐((pyridin‐2‐ylmethylamino)methyl)phenoxy)‐4, 6‐dimethylphenol] were derived from the solvothermal in situ metal/ligand reactions. These complexes were characterized by IR spectroscopy, elementary analysis, and X‐ray diffraction. A low‐temperature magnetic susceptibility measurement for the solid sample of 2 revealed antiferromagnetic interactions between two central copper(II) atoms. The emission property studies for complexes 4 and 5 indicated strong luminescence emission. 相似文献
4.
A new series of metal complexes containing Co(II), Pd(II), Fe(III) chloride and Cu(II) salts (chloride, bromide, sulphate and perchlorate) have been prepared with Schiff base ligand ( HL ). The synthesized compounds were elucidated using elemental analyses, spectral techniques, molar conductance, magnetic measurements and thermogravimetric studies. The analytical data established (1 M:1 L) stoichiometry for complexes ( 1 ), ( 2 ), ( 4 ), ( 6 ) and ( 7 ) as well as (1 M:2 L) and (2 M:3 L) stoichiometry for complexes ( 5 ) and ( 3 ), respectively. As a result, the ligand HL coordinates in complexes ( 1 ), ( 2 ), ( 4 ), ( 6 ) as a monobasic tridentate ONN moiety via the oxygen atom of the deprotonated phenolic OH, the nitrogen atoms of the azomethine and the imine group in pyrazolopyridine ring. While, it behaves as a neutral bidentate in complexes ( 3 , 7 ), chelates via oxygen and nitrogen atoms of enolic OH and azomethine groups. Also, in complex ( 5 ) Cu2+ ion binds via NO sits of two ligand molecules in its monobasic and neutral forms. The magnetic moment and electronic spectral data proposed octahedral structure for complexes ( 2 , 3 and 7 ) as well as triagonal bipyramidal and square pyramidal geometry for complexes ( 1 and 4 ), while, chelates ( 5 ) and ( 6 ) possess square planar geometry. TG/DTG studies confirmed the chemical formula for these complexes and established the thermal decomposition processes ended with the formation of metal or metal oxides contaminated with carbon residue. An axial electron spin resonance spectra were suggested for Cu(II) complexes pointing to 2B1g as a ground state with hyperfine structure for complex ( 4 ). In vitro antibacterial and antioxidant activities were performed for HL ligand and its metal complexes. The biological studies indicate that complex ( 3 ) has better antibacterial activity compared to the ligand and the other complexes. 相似文献
5.
《应用有机金属化学》2017,31(12)
The tetradentate Schiff base ligand (SB), N,N′‐bis‐(2‐mercaptophenylimine)‐2,5‐thiophenedicarboxaldehyde was prepared via condensation of 2,5‐thiophene‐dicarboxaldehyde with 2‐aminothiophenol in a 1:2 molar ratio by conventional method. Additionally, its Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized and fully characterized by elemental analysis, FT‐IR, 1H NMR, 13C NMR, UV–Vis, ESR, ESI‐mass, conductivity and magnetic susceptibility measurements. Spectral studies suggested that, the Schiff base coordinate metal ions through the azomethine N‐ and deprotonated thiol S‐ atoms. Based on UV–Vis absorption and magnetic susceptibility data, tetrahedral geometry was assigned for both Co(II) and Zn(II) complexes, whereas on the other hand, square planar geometry for both Ni(II) and Cu(II) complexes. The Schiff base and its metal complexes were screened for their in vitro antimicrobial activity by minimum inhibitory concentration (MIC) method. Free radical scavenging activity of the novel compounds was determined by elimination of 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radicals. In addition, the interactions of the free ligand and its complexes with calf thymus DNA (CT‐DNA) were explored using absorption, emission and viscosity measurements techniques. 相似文献
6.
Dr. Masahiro Ikeshita Sho Furukawa Takahiro Ishikawa Kana Matsudaira Prof.Dr. Yoshitane Imai Prof.Dr. Takashi Tsuno 《ChemistryOpen》2022,11(4)
The Front Cover shows the comparison of circularly polarized luminescence (CPL) properties of square planar platinum(II) complexes with different coordination geometries. Computational studies have revealed that the distortion of the coordination geometry is key to enhancement of the chiroptical responses of these compounds. More information can be found in the Research Article by Masahiro Ikeshita et al. 相似文献
7.
Mn(II), Co(II), Ni(II) and Cu(II) and N,N‐bis(3,5‐di‐tert‐butylsalicyidene)‐2,2‐dimethyle‐1,3‐diaminopropane complexes have been synthesized in Y zeolite cavity by the reaction of ion‐exchanged metal ions with the flexible ligand molecules. The host‐guest materials obtained have been characterized by elemental analysis, XRD, surface area, pore volume, TGA, FT‐IR and UV‐Vis techniques. Analysis of data indicates that formation of complexes in the pores Y zeolite without affecting the zeolite framework structure. Also, we report the oxidation of cyclohexanol catalyzed by host‐guest catalyst with tert‐buthyl hydrogen peroxide as oxygen donor. The activity of benzyl alcohol oxidation decreases in the series‐[Co(L)]/NaY > [Cu(L)]/NaY > [Mn(L)]/NaY > [Ni(L)]/NaY and the percent of product completely depend to catalyst. Zeolite complexes are stable enough to be reused and are suitable to be utilized as partial oxidation catalysts. 相似文献
8.
Ivan V. Smolyaninov Andrey I. Poddelsky Daria A. Burmistrova Yulia K. Voronina Nadezhda P. Pomortseva Vasiliy A. Fokin Ekaterina D. Tselukovskaya Ivan V. Ananyev Nadezhda T. Berberova Igor L. Eremenko 《Molecules (Basel, Switzerland)》2022,27(23)
A number of novel heteroligand Zn(II) complexes (1–8) of the general type (Ln)Zn(NN) containing O,N,O′-, O,N,S-donor redox-active Schiff bases and neutral N,N′-chelating ligands (NN) were synthesized. The target Schiff bases LnH2 were obtained as a result of the condensation of 3,5-di-tert-butyl-2-hydroxybenzaldehyde with substituted o-aminophenols or o-aminothiophenol. These ligands with combination with 2,2′-bipyridine, 1,10-phenanthroline, and neocuproine are able to form stable complexes upon coordination with zinc(II) ion. The molecular structures of complexes 4∙H2O, 6, and 8 in crystal state were determined by means of single-crystal X-ray analysis. In the prepared complexes, the redox-active Schiff bases are in the form of doubly deprotonated dianions and act as chelating tridentate ligands. Complexes 6 and 8 possess a strongly distorted pentacoordinate geometry while 4∙H2O is hexacoordinate and contains water molecule coordinated to the central zinc atom. The electrochemical properties of zinc(II) complexes were studied by the cyclic voltammetry. For the studied complexes, O,N,O′- or O,N,S-donor Schiff base ligands are predominantly involved in electrochemical transformations in the anodic region, while the N,N′-coordinated neutral nitrogen donor ligands demonstrate the electrochemical activity in the cathode potential range. A feature of complexes 5 and 8 with sterically hindered tert-butyl groups is the possibility of the formation of relatively stable monocation and monoanion forms under electrochemical conditions. The values of the energy gap between the boundary redox orbitals were determined by electrochemical and spectral methods. The parameters obtained in the first case vary from 1.97 to 2.42 eV, while the optical bang gap reaches 2.87 eV. 相似文献
9.
Mustafa Çelebier Ertan Şahin Nilgün Ancın Nurşen Altuntaş Öztaş Selma Gül Öztaş 《应用有机金属化学》2007,21(10):913-918
A series of neutral complexes, namely, [N‐(2‐hydroxy‐4‐nitrophenyl)‐3‐hydroxysalicylideneiminato]‐ diphenyltin(IV) ( Ia ), [N‐(2‐hydroxy‐4‐nitrophenyl)‐3‐methoxysalicylideneiminato]diphenyltin(IV) ( IIa ) and [N‐(2‐hydroxy‐4‐nitrophenyl)‐3‐ethoxysalicylideneiminato]diphenyltin(IV) ( IIIa ) were prepared by the reaction of diphenyltin dichloride on the corresponding Schiff bases. The Schiff bases were the reaction products of 2‐hydroxy‐4‐nitroaniline and appropriate salicylaldehydes. All the compounds were characterized by elemental analysis, 1H‐NMR, 13C‐NMR, IR and mass spectroscopy. Compound IIIa was also characterized by single crystal X‐ray diffraction and shows a C2NO2 coordination geometry nearly half‐way between a trigonal bipyramidal and square pyramidal arrangement. In the solid state, π? π interactions exist between the aniline fragments of neighbouring molecules. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
10.
Tamami Koshiyama Masako Kato 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(11):m446-m449
The title PtII complexes, viz. (2,2′‐bipyridine‐κ2N,N′)[(1R,2R)‐1,2‐diaminocyclohexane‐κ2N,N′]platinum(II) bis(hexafluorophosphate), [Pt(C6H14N2)(C10H8N2)](PF6)2, and [(1R,2R)‐1,2‐diaminocyclohexane‐κ2N,N′](1,10‐phenanthroline‐κ2N,N′)platinum(II) bis(hexafluorophosphate), [Pt(C6H14N2)(C12H8N2)](PF6)2, containing an aromatic α‐diimine and a non‐planar diaminocyclohexane, both form a ladder‐type structure, which is constructed via loose π–π stacking on the α‐diimine ligands and hydrogen bonding between the cyclic amines and the counter‐anions. In the former compound, there are two independent complex cations, both of which have a twofold axis through the Pt atom. 相似文献
11.
Polyol Metal Complexes. VIII. R,R-trans-Diaminocyclohexane-κN,N′ Methyl-β-D-xylopyranosid-2,3-ato-κO2,O3 Aqua Copper Dihydrate, [(R,R-chxn)(H2O)Cu(Me-β-D-Xylp2,3 H?2)] · 2 H2O, — a Copper Complex with a Twofold Deprotonated Xylose Derivative as a Ligand Methyl β-D-xylopyranoside forms a chelate complex with copper(II) ions in aqueous, alkaline solution after deprotonation at O-2 and O-3. In the blue crystals, CuII is further coordinated by R,R-trans-1,2-diaminocyclohexane and water; P21, a = 982.9(3), b = 705.8(5), c = 1 292.1(6) pm, β = 96.74(4)°, V = 890.2(8) · 106 pm3. The alkoxide-O-atoms act as acceptors in a hydrogen bond system, a typical feature of which is a homodromic helix of water molecules. 相似文献