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1.
《Arabian Journal of Chemistry》2014,7(4):509-517
The binuclear Schiff base complexes are formed newly using different transition metals at their stable oxidation state as Cu(II), Ni(II), and VO(II). 3,3′,4,4′-tetraminobiphenyl and 2-aminobenzaldehyde were condensed to form a new Schiff base ligand having an two N4 group responsible for better chelating to the metal centers. The ligand and their complexes have been established by analytical, spectral and electrochemical data. The interaction studies of the complexes with CT-DNA were carried out using cyclic voltammetry, viscosity measurements and fluorescence spectroscopy. The free ligand and their metal complexes were screened for their antimicrobial activities against the following species: Klebsiella pneumoniae, Escherichia coli and Staphylococcus aureus. A comparative study of minimum inhibitory concentration (MIC) values of the Schiff base and its complexes indicate that the metal complexes exhibit higher antibacterial activity than the free ligand. 相似文献
2.
Chemical and Structural Stability of Zirconium‐based Metal–Organic Frameworks with Large Three‐Dimensional Pores by Linker Engineering
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Dr. Suresh B. Kalidindi Dr. Sanjit Nayak Dr. Michael E. Briggs Dr. Susanna Jansat Dr. Alexandros P. Katsoulidis Dr. Gary J. Miller Dr. John E. Warren Dr. Dmytro Antypov Dr. Furio Corà Dr. Ben Slater Dr. Mark R. Prestly Dr. Carlos Martí‐Gastaldo Prof. Matthew J. Rosseinsky 《Angewandte Chemie (International ed. in English)》2015,54(1):221-226
The synthesis of metal–organic frameworks with large three‐dimensional channels that are permanently porous and chemically stable offers new opportunities in areas such as catalysis and separation. Two linkers (L1=4,4′,4′′,4′′′‐([1,1′‐biphenyl]‐3,3′,5,5′‐tetrayltetrakis(ethyne‐2,1‐diyl)) tetrabenzoic acid, L2=4,4′,4′′,4′′′‐(pyrene‐1,3,6,8‐tetrayltetrakis(ethyne‐2,1‐diyl))tetrabenzoic acid) were used that have equivalent connectivity and dimensions but quite distinct torsional flexibility. With these, a solid solution material, [Zr6O4(OH)4(L1)2.6(L2)0.4]?(solvent)x, was formed that has three‐dimensional crystalline permanent porosity with a surface area of over 4000 m2 g?1 that persists after immersion in water. These properties are not accessible for the isostructural phases made from the separate single linkers. 相似文献
3.
Stefanie Griesbeck Matthias Ferger Corinna Czernetzi Dr. Chenguang Wang Dr. Rüdiger Bertermann Dr. Alexandra Friedrich Dr. Martin Haehnel Dr. Daniel Sieh Dr. Masayasu Taki Prof. Dr. Shigehiro Yamaguchi Prof. Dr. Todd B. Marder 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(32):7679-7688
The stability of tetracationic triarylboranes in dilute aqueous solution was investigated by tuning the steric demand of the linker in a (para-(N,N,N-trimethylammonio)xylyl)2B–(linker)–B(para-(N,N,N-trimethylammonio)xylyl)2 structure. With increasing steric bulk of the linker, namely 1,4-phenylene, 2,2′′′-(3,3′′′-dimethyl)-5,2′:5′,2′′:5′′,5′′′-quaterthiophene, 9,10-anthracenylene, and 4,4′′′-(5′-(3,5-dimethylphenyl))(5′′-(3′′′,5′′′-dimethylphenyl))-2′,2′′-bithiophene, the stability of the compounds increased. The anthracene-based chromophore, compound 3M is water-stable for at least 48 h, is nontoxic to cells and exhibits an exceedingly high fluorescence quantum yield of 0.86 in water making it an ideal candidate for confocal live-cell imaging of lysosomes. 相似文献
4.
Dr. Jens Langer Mathias Köhler Dr. Helmar Görls Prof. Dr. Matthias Westerhausen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(11):3154-3161
A general procedure was developed for the synthesis of diarylcalcium complexes by addition of KOtBu to arylcalcium iodides in THF. Intermediate arylcalcium tert‐butanolate dismutates immediately leading to insoluble tert‐butanolate precipitates of calcium. Depending on the steric demand and denticity of additional neutral aliphatic azabases, mononuclear or dinuclear complexes trans‐[Ca(α‐Naph)2(thf)4] ( 1 ), [Ca(β‐Naph)2(thf)4] ( 2 ), [Ca(Tol)2(tmeda)]2 ( 3 ), [Ca(Ph)2(tmeda)]2 ( 4 ), [Ca(Ph)2(pmdta)(thf)] ( 5 ), [Ca(hmteta)(Ph)2] ( 6 ), and [Ca([18]C‐6)(Ph)2] ( 7 ) were isolated (Naph=naphthyl; meda=N,N,N′,N′‐tetramethylethylenediamine; pmdta= N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine; hmteta=N,N,N′,N′′,N′′′,N′′′‐hexamethyltriethylenetetramine). The Ca?C bond lengths vary between 250.8 and 263.5 pm, the ipso‐carbon atoms show low‐field‐shifted resonances in the 13C NMR spectra. 相似文献
5.
Joseph A. Letizia Dr. Scott Cronin Rocio Ponce Ortiz Dr. Antonio Facchetti Dr. Mark A. Ratner Prof. Tobin J. Marks Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(6):1911-1928
Electron‐transporting organic semiconductors (n‐channel) for field‐effect transistors (FETs) that are processable in common organic solvents or exhibit air‐stable operation are rare. This investigation addresses both these challenges through rational molecular design and computational predictions of n‐channel FET air‐stability. A series of seven phenacyl–thiophene‐based materials are reported incorporating systematic variations in molecular structure and reduction potential. These compounds are as follows: 5,5′′′‐bis(perfluorophenylcarbonyl)‐2,2′:5′,‐ 2′′:5′′,2′′′‐quaterthiophene ( 1 ), 5,5′′′‐bis(phenacyl)‐2,2′:5′,2′′: 5′′,2′′′‐quaterthiophene ( 2 ), poly[5,5′′′‐(perfluorophenac‐2‐yl)‐4′,4′′‐dioctyl‐2,2′:5′,2′′:5′′,2′′′‐quaterthiophene) ( 3 ), 5,5′′′‐bis(perfluorophenacyl)‐4,4′′′‐dioctyl‐2,2′:5′,2′′:5′′,2′′′‐quaterthiophene ( 4 ), 2,7‐bis((5‐perfluorophenacyl)thiophen‐2‐yl)‐9,10‐phenanthrenequinone ( 5 ), 2,7‐bis[(5‐phenacyl)thiophen‐2‐yl]‐9,10‐phenanthrenequinone ( 6 ), and 2,7‐bis(thiophen‐2‐yl)‐9,10‐phenanthrenequinone, ( 7 ). Optical and electrochemical data reveal that phenacyl functionalization significantly depresses the LUMO energies, and introduction of the quinone fragment results in even greater LUMO stabilization. FET measurements reveal that the films of materials 1 , 3 , 5 , and 6 exhibit n‐channel activity. Notably, oligomer 1 exhibits one of the highest μe (up to ≈0.3 cm2 V?1 s?1) values reported to date for a solution‐cast organic semiconductor; one of the first n‐channel polymers, 3 , exhibits μe≈10?6 cm2 V?1 s?1 in spin‐cast films (μe=0.02 cm2 V?1 s?1 for drop‐cast 1 : 3 blend films); and rare air‐stable n‐channel material 5 exhibits n‐channel FET operation with μe=0.015 cm2 V?1 s?1, while maintaining a large Ion:off=106 for a period greater than one year in air. The crystal structures of 1 and 2 reveal close herringbone interplanar π‐stacking distances (3.50 and 3.43 Å, respectively), whereas the structure of the model quinone compound, 7 , exhibits 3.48 Å cofacial π‐stacking in a slipped, donor‐acceptor motif. 相似文献
6.
Natarajan Raman Arumugam Sakthivel Ramaraj Jeyamurugan 《Central European Journal of Chemistry》2010,8(1):96-107
Few novel binuclear Schiff base metal complexes [M2LCl3], where M = Cu(II) and Zn(II); L= 2,6-bis-({2-[(3-hydroxy-4-nitrobenzylidene)amino]ethylimino}methyl)-4-methylphenol (BHEM),
2,6-bis-({2-[(3,4-dimethoxybenzylidene)amino]ethylimino} methyl)-4-methylphenol (BDEM) and 2,6-bis-({2-[(2,3,5-trichlorobenzylidene)amino]ethylimino}methyl)-4-methylphenol
(BTEM), have been synthesized and characterized by analytical and spectral data. The data suggest that BHEM/BDEM/BTEM ligands
afford square-pyramidal/distorted square-pyramidal geometry on metalation with Zn(II)/Cu(II). The binding behaviour of these
complexes with DNA has been investigated using electronic absorption spectroscopy as well as viscosity and voltammetric measurements;
the results show that they interact with DNA through intercalating way. From the DNA cleavage study of these complexes, investigated
by gel electrophoresis, we found that they efficiently cleave supercoiled pUC19 DNA in the presence of a reducing agent (3-mercaptopropionic
acid) and on irradiation with UV light of 360 nm wavelength. The mechanism reveals that singlet oxygen (1O2) plays a significant role in the photo cleavage. The superoxide dismutase (SOD) mimetic activity of the synthesized complexes
demonstrates that most of the complexes have promising SOD-mimetic activity. The antimicrobial study indicates that the complexes
inhibit the growth of bacteria and fungi more than the free ligands. 相似文献
7.
Yoel Tsur Harold H. Levine Moshe Levy 《Journal of polymer science. Part A, Polymer chemistry》1974,12(7):1515-1529
Polybenzimidazoles were prepared in poly(phosphoric acid) from isophthalic, m- and p-phenylene diacetic, succinic, adipic, suberic, and sebacic acids and 3,3′-diaminobenzidine, 3,3′,4,4′-tetraaminodiphenyl ether and 3,3′,4,4′-tetraaminodiphenylmethane. The thermal, mechanical, and bonding properties were studied. A 3:1 copolymer of isophthalic and m-phenylenediacetic acid with 3,3′-diaminobenzidine showed the best results as far as isothermal oxidation resistance and thermal and processing characteristics. 相似文献
8.
Yong Dou Lu Yang Lan Qin Yunhui Dong Zhen Zhou Daopeng Zhang Suna Wang 《Acta Crystallographica. Section C, Structural Chemistry》2020,76(6):616-624
The solar photocatalysis of water splitting represents a significant branch of enzymatic simulation by efficient chemical conversion and the generation of hydrogen as green energy provides a feasible way for the replacement of fossil fuels to solve energy and environmental issues. We report herein the self‐assembly of a CoII‐based metal–organic framework (MOF) constructed from 4,4′,4′′,4′′′‐(ethene‐1,1,2,2‐tetrayl)tetrabenzoic acid [or tetrakis(4‐carboxyphenyl)ethylene, H4TCPE] and 4,4′‐bipyridyl (bpy) as four‐point‐ and two‐point‐connected nodes, respectively. This material, namely, poly[(μ‐4,4′‐bipyridyl)[μ8‐4,4′,4′′,4′′′‐(ethene‐1,1,2,2‐tetrayl)tetrabenzoato]cobalt(II)], [Co(C30H16O8)(C10H8N2)]n, crystallized as dark‐red block‐shaped crystals with high crystallinity and was fully characterized by single‐crystal X‐ray diffraction, PXRD, IR, solid‐state UV–Vis and cyclic voltammetry (CV) measurements. The redox‐active CoII atoms in the structure could be used as the catalytic sites for hydrogen production via water splitting. The application of this new MOF as a heterogeneous catalyst for light‐driven H2 production has been explored in a three‐component system with fluorescein as photosensitizer and trimethylamine as the sacrificial electron donor, and the initial volume of H2 production is about 360 µmol after 12 h irradiation. 相似文献
9.
Honeycomb‐like Ordered Assembly of DNA Induced by Flexible Binuclear Ruthenium(II)–Polypyridyl Complexes
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Sushma B. Singh Prof. Dr. Avinash S. Kumbhar Dr. Ayesha Khan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(44):15760-15771
A series of binuclear ruthenium(II)–polypyridyl complexes of the type [Ru2(N‐N)4(BPIMBp)]4+, in which N‐N is 2,2′‐bipyridine (bpy; 1 ), 1,10‐phenanthroline (phen; 2 ), dipyrido[3,2‐d:2′,3‐f] quinoxaline (dpq; 3 ), dipyrido[3,2‐a:2′,3′‐c] phenanzine (dppz; 4 ), and 1,4′‐bis[(2‐pyridin‐2‐yl)‐1H‐imidazol‐1‐yl)methyl]‐1,1′‐biphenyl (BPIMBp) is a bridging ligand, have been synthesized and characterized. These complexes are charged (4+) cations and flexible due to the ?CH2 group of the bridging ligand and possess terminal ligands with variable intercalative abilities. The interaction of complexes 1 – 4 with calf thymus DNA (CT‐DNA) was explored by using UV/Vis absorption spectroscopy, steady‐state emission, emission quenching with K4[Fe(CN)6], ethidium bromide displacement assay, Hoechst displacement assay, and viscosity measurements and revealed a groove‐binding mode for all the complexes through a spacer and an intercalative mode for complexes 3 and 4 . A decrease in the viscosity of DNA revealed bending and coiling of DNA, an initial step toward aggregation. Interestingly, a distinctive honeycomb‐like ordered assembly of the DNA–complex species was visualized by fluorescence microscopy in the solution state. The use of SEM and AFM confirmed the disordered self‐organization of the DNA–complex adduct on evaporation of the solvent. The small orderly nanosized DNA aggregates were confirmed by means of circular dichroism, dynamic light scattering (DLS), and TEM. These complexes are moderately cytotoxic against three different cell lines, namely, MCF‐7, HeLa, and HL‐60. 相似文献
10.
Dr. Konstantin Drandarov Dr. Ioannis Tiritiris Olga Wassiljew Prof. Dr. Hans‐Ullrich Siehl Prof. Dr. Willi Kantlehner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(23):7224-7228
A method for the preparation of the first acetylenedicarboxamidinium salt from a bis‐orthoamide derivative of acetylenedicarboxyclic acid has been established. The salt reacted with cyclopentadiene and furan at room temperature to give bicyclic [4+2]‐cycloaddition products. The solid compounds were characterized by solution NMR spectroscopy and by single‐crystal X‐ray diffraction. Quantum‐chemical calculations of the isolated N,N,N′,N′,N′′,N′′,N′′′,N′′′‐octamethyl‐acetylene‐bis(carboxamidinium) ion showed very good agreement with the spectroscopic and diffraction data. 相似文献
11.
Catalytic Water Oxidation by Ruthenium(II) Quaterpyridine (qpy) Complexes: Evidence for Ruthenium(III) qpy‐N,N′′′‐dioxide as the Real Catalysts
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Yingying Liu Dr. Siu‐Mui Ng Dr. Shek‐Man Yiu Dr. William W. Y. Lam Xi‐Guang Wei Dr. Kai‐Chung Lau Prof. Tai‐Chu Lau 《Angewandte Chemie (International ed. in English)》2014,53(52):14468-14471
Polypyridyl and related ligands have been widely used for the development of water oxidation catalysts. Supposedly these ligands are oxidation‐resistant and can stabilize high‐oxidation‐state intermediates. In this work a series of ruthenium(II) complexes [Ru(qpy)(L)2]2+ (qpy=2,2′:6′,2′′:6′′,2′′′‐quaterpyridine; L=substituted pyridine) have been synthesized and found to catalyze CeIV‐driven water oxidation, with turnover numbers of up to 2100. However, these ruthenium complexes are found to function only as precatalysts; first, they have to be oxidized to the qpy‐N,N′′′‐dioxide (ONNO) complexes [Ru(ONNO)(L)2]3+ which are the real catalysts for water oxidation. 相似文献
12.
P. G. Pronkin A. S. Tatikolov V. I. Sklyarenko V. A. Kuz’min 《High Energy Chemistry》2006,40(6):403-409
Using the flash photolysis method, the spectral and kinetic characteristics of triplet states of a number of meso-substituted thiacarbocyanine dyes (3,3′-diethyl-9-methoxythiacarbocyanine iodide, 3,3′,9-triethylthiacarbocyanine iodide, 3,3′-diethyl-9-methylthiacarbocyanine iodide, and 3,3′-diethyl-9-thiomethylthiacarbocyanine iodide) were studied, and the rate constants of triplet quenching by a stable nitroxyl radical, iodide ion, and oxygen were determined in solutions and in complexes with DNA. The results obtained show the formation of two types of dye-DNA complexes: formed by binding of the dye in the groove of a DNA molecule and by intercalation of the dye between base pairs. The complexation creates steric hindrances upon quenching of the triplet states of the ligands and causes great differences between the rate constants of the quenching processes. 相似文献
13.
Brendan Twamley Ned J. Hardman Philip P. Power 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(11):e514-e515
The sterically encumbered terphenyl halides 2′‐chloro‐2,2′′,4,4′′,6,6′′‐hexaisopropyl‐1,1′:3′,1′′‐terphenyl, C36H49Cl, (I), 2′‐bromo‐2,2′′,4,4′′,6,6′′‐hexaisopropyl‐1,1′:3′,1′′‐terphenyl, C36H49Br, (II), and 2′‐iodo‐2,2′′,4,4′′,6,6′′‐hexaisopropyl‐1,1′:3′,1′′‐terphenyl, C36H49I, (III), crystallize in space group Pnma. They are isomorphous and isostructural with a plane of symmetry through the centre of the molecule. The C–halide bond distances are 1.745 (3), 1.910 (4) and 2.102 (6) Å for (I)–(III), respectively. 相似文献
14.
Cerium‐Based M4L4 Tetrahedra as Molecular Flasks for Selective Reaction Prompting and Luminescent Reaction Tracing
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Yang Jiao Dr. Jian Wang Dr. Pengyan Wu Liang Zhao Dr. Cheng He Jing Zhang Prof. Chunying Duan 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(8):2224-2231
The application of metal–organic polyhedra as “molecular flasks” has precipitated a surge of interest in the reactivity and property of molecules within well‐defined spaces. Inspired by the structures of the natural enzymatic pockets, three metal–organic neutral molecular tetrahedral, Ce‐TTS, Ce‐TNS and Ce‐TBS (H6TTS: N′,N′′,N′′′‐nitrilotris‐4,4′,4′′‐(2‐hydroxybenzylidene)‐benzohydrazide; H6TNS: N′,N′′,N′′′‐nitrilotris‐6,6′,6′′‐(2‐hydroxybenzylidene)‐2‐naphthohydrazide; H6TBS: 1,3,5‐ phenyltris ‐4,4′,4′′‐(2‐hydroxybenzylidene)benzohydrazide), which exhibit different size of the edges and cavities, were achieved through self‐assembly by incorporating robust amide‐containing tridentate chelating sites into the fragments of the ligands. They acted as molecular flasks to prompt the cyanosilylation of aldehydes with excellent selectivity towards the substrates size. The amide groups worked as trigger sites and catalytic driven forces to achieve efficient guest interactions, enforcing the substrates proximity within the cavity. Experiments on catalysts with the different cavity radii and substrates with the different molecular size demonstrated that the catalytic performance exhibited enzymatical catalytic mechanism and occurred in the molecular flask. These amides were also able to amplify guest‐bonding events into the measurable outputs for the detection of concentration variations of the substrates, providing the possibility for metal–organic hosts to work as smart molecular flasks for the luminescent tracing of catalytic reactions. 相似文献
15.
Sebastian Amthor David Hernández-Castillo Dr. Boris Maryasin Phillip Seeber Alexander K. Mengele Prof. Dr. Stefanie Gräfe Prof. Dr. Leticia González Prof. Dr. Sven Rau 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(68):16871-16878
The substitution behavior of the monodentate Cl ligand of a series of ruthenium(II) terpyridine complexes (terpyridine (tpy)=2,2′:6′,2′′-terpyridine) has been investigated. 1H NMR kinetic experiments of the dissociation of the chloro ligand in D2O for the complexes [Ru(tpy)(bpy)Cl]Cl ( 1 , bpy=2,2’-bipyridine) and [Ru(tpy)(dppz)Cl]Cl ( 2 , dppz=dipyrido[3,2-a:2′,3′-c]phenazine) as well as the binuclear complex [Ru(bpy)2(tpphz)Ru(tpy)Cl]Cl3 ( 3 b , tpphz=tetrapyrido[3,2-a:2′,3′-c:3′′,2′′-h:2′′′,3′′′-j]phenazine) were conducted, showing increased stability of the chloride ligand for compounds 2 and 3 due to the extended π-system. Compounds 1 – 5 ( 4 =[Ru(tbbpy)2(tpphz)Ru(tpy)Cl](PF6)3, 5 =[Ru(bpy)2(tpphz)Ru(tpy)(C3H8OS)/(H2O)](PF6)3, tbbpy=4,4′-di-tert-butyl-2,2′-bipyridine) are tested for their ability to run water oxidation catalysis (WOC) using cerium(IV) as sacrificial oxidant. The WOC experiments suggest that the stability of monodentate (chloride) ligand strongly correlates to catalytic performance, which follows the trend 1 > 2 > 5 ≥ 3 > 4 . This is also substantiated by quantum chemical calculations, which indicate a stronger binding for the chloride ligand based on the extended π-systems in compounds 2 and 3 . Additionally, a theoretical model of the mechanism of the oxygen evolution of compounds 1 and 2 is presented; this suggests no differences in the elementary steps of the catalytic cycle within the bpy to the dppz complex, thus suggesting that differences in the catalytic performance are indeed based on ligand stability. Due to the presence of a photosensitizer and a catalytic unit, binuclear complexes 3 and 4 were tested for photocatalytic water oxidation. The bridging ligand architecture, however, inhibits the effective electron-transfer cascade that would allow photocatalysis to run efficiently. The findings of this study can elucidate critical factors in catalyst design. 相似文献
16.
N. Raman R. Jeyamurugan A. Sakthivel L. Mitu 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2010,75(1):88-97
Novel Schiff base Cu(II), Ni(II), Co(II) and Zn(II) complexes have been designed and synthesized using the macrocyclic ligand derived from the condensation of diethylphthalate with Schiff base, obtained from benzene-1,2-diamine and 3-benzylidene-pentane-2,4-dione. The ligand and its complexes have been characterized by analytical and spectral techniques. DNA binding properties of these complexes have been investigated by UV–vis, viscosity measurements, cyclic voltammetric and differential pulse voltammogram studies. The intrinsic binding constants for Co(II), Ni(II), Cu(II) and Zn(II) complexes are 1.6 × 106, 1.8 × 106, 2.0 × 106 and 1.5 × 106 M?1 respectively which are obtained from electronic absorption experiment. Control DNA cleavage experiments using pUC19 supercoiled (SC) DNA and minor groove binder (distamycin) suggest the major groove binding tendency for the synthesized complexes. In the presence of a reducing agent like 3-mercaptopropionic acid (MPA), the synthesized complexes show chemical nuclease activity under dark reaction condition. The complexes also show efficient photo-induced DNA cleavage activity on irradiation with a monochromatic UV light of 360 nm in the presence of inhibitors. Control experiments show inhibition of cleavage in the presence of singlet oxygen quencher like sodium azide and enhancement of cleavage in D2O, suggesting the formation of singlet oxygen as a reactive species in a type-II process. 相似文献
17.
R. Prabu A. Vijayaraj R. Suresh R. Shenbhagaraman V. Kaviyarasan V. Narayanan 《Journal of the Iranian Chemical Society》2014,11(3):825-837
A series of binuclear copper(II) complexes of N-functionalized cyclam derivatives has been prepared by the Schiff base condensation of 1,8-[bis(3-formyl-2-hydroxy-5-methyl)benzyl]-l,4,8,11-tetraazacyclo-tetradecane (PC-a), 1,8-[bis(3-formyl-2-hydroxy-5-bromo)benzyl]-l,4,8,11-tetraazacyclo-tetradecane (PC-b) with appropriate aliphatic diamines, and copper(II) perchlorate. All the complexes were characterized by elemental, FT-IR, UV–Vis, ESI and ESR spectral analysis. The room temperature magnetic moment studies depicts the presence of an antiferromagnetic interaction in the binuclear complexes, which is also observed from the broad ESR spectra with a g value of 2.10–2.11. Variable-temperature magnetic susceptibility study of the complex [Cu2L2a](ClO4)2 shows that the calculated ?2J value is 219 cm?1, which conveys a spin–spin interaction between the two copper(II) ions. The catechol oxidation and hydrolysis of 4-nitrophenylphosphate were carried out by using the complexes as a catalyst. All the above metal complexes were screened for antimicrobial and human pathogenic fungal activity. The binding of the complexes to calf thymus DNA (CT-DNA) has been investigated with UV–Vis and fluorescence spectroscopy. All complexes display significant cleavage property of circular plasmid pBR322 DNA into linear form. Spectral, electrochemical, magnetic and catalytic studies support the distortion of the copper ion geometry that arises as the macrocyclic ring size increases. 相似文献
18.
《Journal of Coordination Chemistry》2012,65(24):4380-4397
Schiff base mixed-ligand copper complexes [CuL1(phen)Cl2], [CuL1(bipy)Cl2], [Cu(L1)2Cl2], [Cu(L2)2Cl2], [CuL2(bipy)Cl2], and [CuL2(phen)Cl2] (where L1?=?4-[3,4-dimethoxy-benzylidene]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazole-3-one; L2?=?4-[3-hydroxy-4-nitro-benzylidene]-1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazole-3-one; phen?=?1,10-phenanthroline; and bipy?=?2,2′-bipyridine) have been synthesized and characterized. Their DNA-binding properties have been studied by electronic absorption spectra, viscosity, and electrochemical measurements. The absorption spectral and viscosity results suggest that the copper(II) complexes bind to DNA via partial intercalation. The addition of DNA resulting in the decrease of the peak current of the copper(II) complexes indicates their interaction. Interaction between the complexes and DNA has also been investigated by submarine gel electrophoresis. The copper complexes cleave supercoiled pUC19 DNA to nicked and linear forms through hydroxyl radical and singlet oxygen in the presence of 3-mercaptopropionic acid as the reducing agent. These copper complexes promote the photocleavage of pUC19 DNA under irradiation at 360?nm. Mechanistic study reveals that singlet oxygen is likely to be the reactive species responsible for the cleavage of plasmid DNA by the synthesized complexes. The in vitro antimicrobial study indicates that the metal chelates have higher activity against the bacterial and fungal strains than the free ligands. 相似文献
19.
《Journal of Coordination Chemistry》2012,65(13):2378-2387
New iron(III) and cobalt(III) complexes, [Fe(2,2′-dpdtc)3], [Fe(3,3′-dpdtc)3], [Co(2,2′-dpdtc)3], and [Co(3,3′-dpdtc)3] (dpdtc?=?dipicolyldithiocarbamate) have been synthesized and their molecular structures and spectroscopic properties determined. The 2,2′- and 3,3′-dpdtc ligands have four donors, S, S′, N, and N′. These complexes are insoluble in water, but soluble in acidic solution. Crystal structures of these metal complexes reveal that the central metal ions have MS6 (M?=?Fe and Co) octahedral structures and all dipicolyl groups do not coordinate. 相似文献
20.
Synthesis,crystal structures,DNA binding and cleavage properties and protein binding activities of three mononuclear cobalt(II) complexes
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Qian Sun Jing Lu Jun‐Ling Li Lin Jiang Wen Gu Xin Liu Jin‐Lei Tian Shi‐Ping Yan 《应用有机金属化学》2014,28(4):259-266
Three new mononuclear cobalt(II) complexes containing ligands with extended planar quinoxaline moieties, {dipyrido[3,2‐a:2′,3′‐c]phenazine (dppz) or dipyrido[3,2‐d:2′,3′‐f]quinoxaline (dpq)}, viz. [Co(dppz)(acac)2] · CH3OH ( 1 ), [Co(dpq)(tfnb)2] ( 2 ) and [Co(dpq)(dbm)2] ( 3 ), where acac = acetylacetonate, tfnb = benzoyltrifluoroacetone and dbm = dibenzoylmethane, have been synthesized and structurally characterized as octahedral complexes. The binding ability of the complexes with calf thymus (CT)‐DNA has been investigated by spectroscopic and viscosity measurements. Results indicate that all complexes bind to CT‐DNA via intercalative mode, and the DNA binding affinity of dppz complex 1 is apparently stronger than that of dpq complexes 2 and 3 . Furthermore, DNA photocleavage experiments indicate that these complexes are efficient DNA cleaving agents in UV‐A (365 nm) and hydroxyl radical (HO·), singlet oxygen (1O2) and superoxide anion (1O2?) serve as the major cleavage active species. In addition, interaction of the complexes with bovine serum albumin (BSA) was investigated using UV ? visible and fluorescence methods, which indicated that all complexes could quench the intrinsic fluorescence of BSA in a static quenching process. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献