The complexes [Cu(samen)Cu(L)] and [Cu(samen)Ni(L)2] (Lbpy, phen) have been synthesized by the reaction of sodium N,N′-ethylenedisalicylamidatocuprate(II) pentahydrate (Na2- [Cu(samen)]·5H2O), a divalent metal ion, and 2,2′- dipyridyl or 1,10-phenanthroline. Cryomagnetic data for the CuCu complexes did not fit the Bleaney- Bowers equation; but the data did fit a modified Bleaney-Bowers equation with a large negative J and a significant negative θ, suggesting that a considerable magnetic interaction operates between essentially planar [Cu(samen)Cu(L)] molecules. The magnetisms of the CuNi complexes were well interpreted in terms of the susceptibility equation based on the Heisenberg model. An antiferromagnetic spin-exchange interaction (J= −13∼−14 cm−1) was suggested between the metal ions. 相似文献
The reaction of the macrocycles 1,4,7-tris (3,5-di-tert-butyl-2-hydroxy-benzyl)-1,4,7-triazacyclononane, L1H3, or 1,4,7-tris(3-tert-butyl-5-methoxy-2-hydroxy-benzyl)-1,4,7-triazacyclononane, L2H3, with Cu(ClO4)2·6H2O in methanol (in the presence of Et3N) affords the green complexes [CuII(L1H)] (1), [CuII(L2H)]·CH3OH (2) and (in the presence of HClO4) [CuII(L1H2)](ClO4) (3) and [CuII(L2H2)] (ClO4) (4). The CuII ions in these complexes are five-coordinate (square-base pyramidal), and each contains a dangling, uncoordinated pendent
arm (phenol). Complexes 1 and 2 contain two equatorially coordinated phenolato ligands, whereas in 3 and 4 one of these is protonated, affording a coordinated phenol. Electrochemically, these complexes can be oxidized by one electron,
generating the phenoxyl-copper(II) species [CuII(L1H)]+·, [Cu(L2H)]+·, [CuII(L1H2)]2+·, and [CuII(L2H2)]2+·, all of which are EPR-silent. These species are excellent models for the active form of the enzyme galactose oxidase (GO).
Their spectroscopic features (UV-VIS, resonance Raman) are very similar to those reported for GO and unambiguously show that
the complexes are phenoxyl-copper(II) rather than phenolato-copper(III) species.
Received: 10 February 1997 / Accepted: 7 April 1997 相似文献
Two Salen-type ligands (H2L1, 4,4′-dichloro-2,2′-[(1,3-propylene)dioxybis(nitrilomethylidyne)]diphenol and H2L2, 4,4′-dinitro-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol) and their corresponding complexes ({[CoL1(MeOH)]2(OAc)2Co} · 2MeOH and [CuL2]2) have been synthesized and characterized by element analyses, 1H NMR, FT-IR and UV-Vis spectra, TG-DTA and single crystal X-ray crystallography. Crystallographic data suggests the octahedral geometry for Co(II) complex and square-pyramidal geometry for Cu(II) complex. Furthermore, the fluorescence behavior of Cu(II) complex in DMSO is discussed. 相似文献
A novel oxalato-bridged rhenium(IV)-copper(II) compound, namely [ReIVBr4(μ-ox)CuII(bpy)2] (1), has been obtained by reacting (PPh4)2[ReBr4(ox)] with Cu(CF3SO3)2 and 2,2′-bpy in CH3CN, and its crystal structure determined by single-crystal X-ray diffraction. Intermolecular Br?Br interactions and nonbonding Cu?Br type contacts between the heterobimetallic dinuclear units lead to a two-dimensional supramolecular structure. Compound 1 behaves magnetically as a [ReIVCuII]2 tetranuclear species with weak antiferromagnetic interactions through the oxalato bridge and intermolecular Br?Br contacts. 相似文献
In order to systematically perform an experimental and theoretical study on DNA binding and photocleavage properties of transition
metal complexes of the type [M(L)2(L1)](PF6)n · xH2O (where M = Co(III) or Ni(II), L = 1,10-phenanthroline or 2.2′ bipryidine, L1 = Thiophene [2,3-b] quinoline (qt), n = 3 or 2 and x = 5 or 2) have been synthesized and characterized by elemental analysis, IR, 1H NMR, UV and magnetic susceptibility data. The DNA-binding properties of these complexes have been investigated with UV-Vis,
viscosity measurements, thermal denaturation and cyclic voltametric studies. It is experimentally found that all the complexes
are bound to DNA via intercalation in the order [Co(bpy)2(qt)](PF6)3 > [Co(phen)2(qt)](PF6)3 > [Ni(phen)2(qt)](PF6)2 > [Ni(bpy)2(qt)](PF6)2. The photocleavage studies with pUC19 DNA shows that all these complexes promoted the conversion of SC form to NC form in
absence of ‘inhibitors’. 相似文献
Mixed-ligand ruthenium(II) complexes of three photoactive ligands, viz., (E)-1-[2-(4-methyl-2-pyridyl)-4-pyridyl]-2-(1-naphthyl)-1-ethene (mppne), (E)-1-(9-anthryl)-2-[2-(4-methyl-2-pyridyl)-4-pyridyl]-1-ethene (mppae) and (E)-1-[2-(4-methyl-2-pyridyl)-4-pyridyl]-2-(1-pyrenyl)-1-ethene (mpppe), in which a 2,2′-bipyridyl unit is linked via an ethylinic linkage to either a naphthalene, an anthracene or a pyrene chromophore and three electroactive ligands, viz., 4-(4-pyridyl)-1,2-benzenediol (catpy), 5,6-dihydroxy-1,10-phenanthroline (catphen) and 1,2-benzenediol (cat), were synthesized in good to moderate yields. Complexes [Ru(bpy)2(mppne)]2+ (bpy is 2, 2′–bipyridyl), [Ru(bpy)2(mppae)]2+, [Ru(bpy)2(mpppe)]2+, [Ru(bpy)2(sq-py)]+, [Ru(bpy)2(sq-phen)]+ and [Ru(phen)2(bsq)]+ (phen is 1,10-phenanthroline) were fully characterized by elemental analysis, IR, 1H NMR, fast-atom bombardment or electron-impact mass, UV–vis and cyclic voltammetric methods. In the latter three complexes, the ligands catpy, catphen and cat are actually bound to the metal center as the corresponding semiquinone species, viz., 4-(4-pyridyl)-1,2-benzenedioleto(+I) (sq-py), 1,10-phenanthroline-5,6-dioleto(+I) (sq-phen) and 1,2-benzenedioleto(+I) (bsq), thus making the overall charge of the complexes formally equal to + 1 in each case. These three complexes are electron paramagnetic resonance active and exhibit an intense absorption band between 941 and 958 nm owing to metal-to-ligand charge transfer (MLCT, dRu→π*sq) transitions. The other three ruthenium(II) complexes containing three photoactive ligands, mppne, mppae and mpppe, exhibit MLCT (dRu→π*bpy ) bands in the 454–461-nm region and are diamagnetic. These can be characterized by the 1H NMR method. [Ru(bpy)2(mppne)]2+, [Ru(bpy)2(mppae)]2+ and [Ru(bpy)2(mpppe)]2+ exhibit redox waves corresponding to the RuIII/RuII couple along with the expected ligand (bpy and substituted bpy) based ones in their cyclic and differential pulse voltammograms (CH3CN, 0.1 M tetrabutylammonium hexafluorophosphate)—corresponding voltammograms of [Ru(bpy)2(sq-py)]+, [Ru(bpy)2(sq-phen)]+ and [Ru(phen)2(bsq)]+ are mainly characterized by waves corresponding to the quinone/semiquinone (q/sq) and semiquinone/1,2-diol (sq/cat) redox processes. The results of absorption and fluorescence titration as well as thermal denaturation studies reveal that [Ru(bpy)2(mppne)]2+ and [Ru(bpy)2(mppae)]2+ are moderate-to-strong binders of calf thymus DNA with binding constants ranging from 105 to 106 M−1. Under the identical conditions of drug and light dose, the DNA (supercoiled pBR 322) photocleavage activities of these two complexes follow the order:[Ru(bpy)2(mppne)]2+>[Ru(bpy)2(mppae)]2+, although the emission quantum yields follow the reverse order. The other ruthenium(II) complexes containing the semiquinone-based ligands are found to be nonluminescent and inefficient photocleavage agents of DNA. However, experiments shows that [Ru(bpy)2(sq)]+-based complexes oxidize the sugar unit and could be used as mild oxidants for the sugar moiety of DNA. Possible explanations for these observations are presented.Electronic Supplementary Material Supplementary material is available for this article at . 相似文献
A series of benzothiazole-substituted trisbipyridine ruthenium(II) analogues {[Ru(bpy)2(4,5′-bbtb)]2+, [Ru(bpy)2(5,5′-bbtb)]2+ and [Ru(bpy)2(5-mbtb)]2+ [bpy is 2,2′-bipyridine, bbtb is bis(benzothiazol-2-yl)-2,2′-bipyridine, 5-mbtb is 5-(benzothiazol-2-yl),5′-methyl-2,2′-bipyridine]}
have been prepared and compared with the complex [Ru(bpy)2(4,4′-bbtb)]2+ reported previously. From the UV–vis spectral studies, substitution at the 5-position of the bpy causes the ligand-centred
transitions to occur at considerably lower energy than for those with the functionality at the 4-position, while at the same
time causing the emission to be effectively quenched. However, substitution at the 4-position causes the metal-to-ligand charge
transfer to occur at lower energies. Fluorescent intercalator displacement studies indicate that the doubly substituted complexes
displace ethidium bromide from a range of oligonucleotides, with the greater preference shown for bulge and hairpin sequences
by the Λ enantiomer. Since the complexes only show small variation in the UV–vis spectra on the introduction of calf thymus
DNA and a small increase in fluorescence they do not appear to be intercalators, but appear to associate within one of the
grooves. All of the reported bisbenzothiazole complexes show reasonable cytotoxicity against a range of human cancer cell
lines.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
Many antitumor drugs act as topoisomerase inhibitors, and the inhibitions are usually related to DNA binding. Here we designed
and synthesized DNA-intercalating Ru(II) polypyridyl complexes Δ--[Ru(bpy)2(uip)]2+ and Λ-[Ru(bpy)2(uip)]2+ (bpy is 2,2′-bipyridyl, uip is 2-(5-uracil)-1H-imidazo[4,5-f][1,10]phenanthroline). The DNA binding, photocleavage, topoisomerase inhibition, and cytotoxicity of the complexes were studied.
As we expected, the synthesized Ru(II) complexes can intercalate into DNA base pairs and cleave the pBR322 DNA with high activity
upon irradiation. The mechanism studies reveal that singlet oxygen (1O2) and superoxide anion radical (O2•−) may play an important role in the photocleavage. The inhibition of topoisomerases I and II by the Ru(II) complexes has been
studied. The results suggest that both complexes are efficient inhibitors towards topoisomerase II by interference with the
DNA religation and direct topoisomerase II binding. Both complexes show antitumor activity towards HELA, hepG2, BEL-7402,
and CNE-1 tumor cells.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
A barbiturate derivative [1,5-dihydro-5-[5-pyrimidine-2,4(1H,3H)-dionyl]-2H-chromeno[2,3-d] pyrimidine-2,4(3H)-dione] (LH4) was allowed to react with 2,2′-bipyridyl-dinitrato-Copper(II)-dihydrate which provides two complexes, characterized as [Cu(bpy)(L1)]·3H2O () and [Cu(bpy)(L2)]·H2O (), where bpy = 2,2′-bipyridine, L1 = 5-hydroxy-hydurilic acid and L2 = alloxanic acid. In a separate reaction of LH4 with Cu(NO3)2·H2O another type of complex [Cu(LH3)2·(H2O)2]·4H2O () is formed. The complexes were characterized by single crystal X-ray crystallography, physicochemical and electrochemical studies. The interaction of complexes 1 and 3 with DNA was monitored using absorption and emission titrations as well as circular dichroism spectroscopy. The complexes were found to cleave supercoiled plasmid DNA to nicked circular and linear DNA. Complexes 1 and 3 were also tested against T-cell lymphoma (Dalton lymphoma DL) and showed significant cytotoxic activity with IC50 values of ~ 9.0 nM and 0.6 nM. 相似文献
Two new Zn(II) complexes containing guanidinium groups, [Zn(L1)Cl2](ClO4)2 · H2O · CH3OH (1) and [Zn(L2)Cl2](ClO4)2 · 0.5H2O (2), were synthesized and characterized (L1 = 5,5′-di[1-(guanidyl)methyl]-2,2′-bipyridyl bication and L2 = 6,6′-di[1-(guanidyl)methyl]-2,2′-bipyridyl bication). Both complexes are able to catalyze bis(p-nitrophenyl) phosphate (BNPP) hydrolysis efficiently. Obtained kinetic data reveal that both 1 and 2 show nearly 300- and 600-fold rate enhancement of BNPP hydrolysis, respectively, compared to their simple analogue without the guanidinium groups [Zn(bpy)Cl2] (bpy = 2,2′-bipyridy) (3). Enhanced acceleration for cleavage of BNPP could be attributed to cooperative interaction between the Zn(II) ion and the guanidinium groups by electrostatic interaction and H-bonding. Studies on inhibition of sequence-specific endonucleases (DraI and SmaI) by complexes show that 1 and 2 are able to recognize nucleotide sequence, -TTT^AAA-, and highly effectively cleave the plasmid DNA in the presence of hydrogen peroxide, while 3 has no specific binding to the DNA target sequences and only shows low DNA cleavage activity. 相似文献
A series of Rh(III) mixed ligand polypyridine type complexes have been prepared. Complexes of the form [Rh(L)2(L′)]n+, where n=2/3, L=2,2′-bipyridine (bpy)/1,10-phenanthroline (phen) and L′=3-(pyridin-2-yl)-1,2,4-triazole (Hpytr), 1-methyl-3-(pyridin-2-yl)-1,2,4-triazole (1M3pytr), 4-methyl-3-(pyridin-2-yl)-1,2,4-triazole (4Mpytr), 3,5-bis(pyridin-2-yl)-1,2,4-triazole (Hbpt), 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole (NH2bpt) and 3-(pyridin-2-yl)-5-phenyl-1,2,4-triazole (HPhpytr), have been prepared and their synthesis and characterisation are reported. Crystals of [Rh(bpy)2(Phpytr)](PF6)2 and [Rh(phen)2(NHbpt)](PF6)2 were obtained and their structures determined. Analysis of X-ray crystallographic data showed that coordination of the metal centre in [Rh(phen)2(NHbpt)](PF6)2 occurs via the amine moiety and a nitrogen of the pyridine ring. NMR studies illustrated that coordination to the NH2bpt ligand was also possible via a nitrogen of the triazole ring and the pyridine ring forming the complex [Rh(phen)2(NH2bpt)](PF6)3. The absorption and emission properties of the complexes studied were found to be π-π* in nature and preliminary evidence suggests that all complexes with the exception of [Rh(phen)2(NHbpt)](PF6)2 and [Rh(bpy)2(NHbpt)](PF6)2 are dual emitting at 77 K. 相似文献
Two mixed-ligand copper(II) complexes [{Cu(L1)(μ1,3-N3)}{Cu(L)(μ1,3-N3)(μ1,1-N3)}]n (1) [HL1 = 1-(N-ortho-hydroxyacetophenimino)-2,2-dimethyl-aminoethane; L = 2-(dimethylamino)-ethylamine] and [{Cu(L2)(μ1,3-N3)}{Cu(L)(μ1,3-N3)(μ1,1-N3)}]n (2) [HL2 = 1-(N-5-methoxy-ortho-hydroxyacetophenimino)-2,2-dimethyl-aminoethane] have been formed upon addition of aqueous solution of sodium azide to a methanolic solution of copper nitrate trihydrate and corresponding Schiff-base ligands. The ligands, HL1 and HL2 undergo partial hydrolysis of their imine bond during the course of reaction. Both the complexes contain single end-to-end (μ1,3) azido bridged 1D infinite chains (rail) which propagate parallel to the crystallographic b-axis; neighboring chains are interconnected by pairs through double asymmetric end-on (μ1,1) azido bridges (rung) to yield a ladder-like structure. In both complexes, rungs (end-on azido bridges) do not connect copper centers of the chains like in a regular ladder; instead they connect only the alternating copper sites of the 1D chain. In a chain the coordination environment around copper(II) ions are not the same: while the {Cu(L1)(μ1,3-N3)} and {Cu(L2)(μ1,3-N3)} moieties have a penta-coordinated copper(II) center, the copper(II) ion of the neighboring {Cu(L1)(μ1,3-N3)(μ1,1-N3)} or {Cu(L2)(μ1,3-N3)(μ1,1-N3)} moiety has an octahedral coordination environment. The variable temperature (2-300 K) magnetic susceptibility measurements showed that the magnetic interaction between the metal centers in complexes 1 and 2 is dominantly antiferromagnetic. The results of magnetic model are in good agreement with the experimental data. 相似文献
A series of complexes with the general formula [Fe(L)2]2+, where L represents the tridentating 6-(N-3,5-dimethylpyrazolyl)2,2′-bipyridine (L4); 6-(N-pyrazolyl-1-ylmethyl)-2,2′-bipyridine (L5); and 6-(N-3,5-dimethylpyrazolyl-1-ylmethyl)-2,2′-bipyridine (L6), were prepared and characterized. The room temperature solution magnetic susceptibility and redox properties of these compounds were investigated as a function of stepwise variation in the ligand structure. The Fe(III/II) couple was characterized by way of cyclic voltammetry using aprotic solvent conditions (acetonitrile) where each complex was observed to have reversible behavior. NMR methodology was used for measuring the magnetic susceptibilities where both [Fe(L4)2]2+ and Fe(L5)2]2+ exhibited diamagnetic low spin behavior; however, [Fe(L6)2]2+ measured a μeff of 4.1 Bohr-magnetons indicating spin equilibrium predominantly in the high spin state. 相似文献
Structural changes between [OsIIL3]2+ and [OsIIIL3]3+ (L: 2,2′-bipyridine; 1,10-phenanthroline) and molecular and electronic structures of the OsIII complexes [OsIII(bpy)3]3+ and [OsIII(phen)3]3+ are discussed in this paper. Mid-infrared spectra in the ν(bpy) and ν(phen) ring stretching region for [OsII(bpy)3](PF6)2, [OsIII(bpy)3](PF6)3, [OsII(phen)3](PF6)2, and [OsIII(phen)3](PF6)3 are compared, as are X-ray crystal structures. Absorption spectra in the UV region for [OsIII(bpy)3](PF6)3 and [OsIII(phen)3](PF6)3 are dominated by very intense absorptions (ε = 40 000-50 000 M−1 cm−1) due to bpy and phen intra-ligand π → π∗ transitions. In the visible region, relatively narrow bands with vibronic progressions of ∼1500 cm−1 appear, and have been assigned to bpy or phen-based, spin-orbit coupling enhanced, 1π → 3π∗ electronic transitions. Also present in the visible region are ligand-to-metal charge transfer bands (LMCT) arising from π(bpy) → t2g(OsIII) or π(phen) → t2g(OsIII) transitions. In the near infrared, two broad absorption features appear for oxidized forms [OsIII(bpy)3](PF6)3 and [OsIII(phen)3](PF6)3 arising from dπ-dπ interconfigurational bands characteristic of dπ5OsIII. They are observed at 4580 and 5090 cm−1 for [OsIII(bpy)3](PF6)3 and at 4400 and 4990 cm−1 for [OsIII(phen)3](PF6)3. The bpy and phen infrared vibrational bands shift to higher energy upon oxidation of Os(II) to Os(III). In the cation structure in [OsIII(bpy)3](PF6)3, the OsIII atom resides at a distorted octahedral site, as judged by ∠N-Os-N, which varies from 78.78(22)° to 96.61(22)°. Os-N bond lengths are also in general longer for [OsIII(bpy)3](PF6)3 compared to [OsII(bpy)3](PF6)2 (0.010 Å), and for [OsIII(phen)3](PF6)3 compared to [OsII(phen)3](PF6)2 (0.014 Å). Structural changes in the ligands between oxidation states are discussed as originating from a combination of dπ(OsII) → π∗ (bpy or phen) backbonding and charge redistribution on the ligands as calculated by natural population analysis. 相似文献
Pyrazole-3,5-dicarboxylate-bridged dinuclear ruthenium(II) and osmium(II) complexes of 2,2′-bipyridine of composition [(bpy)2Ru(pzdc)Ru(bpy)2](ClO4) · H2O (1) and [(bpy)2Os(pzdc)Os(bpy)2](ClO4) · H2O (2) have been obtained in high yield and have been separated to their homochiral (ΛΛ/ΔΔ) rac (1a, 2a) and heterochiral (ΛΔ/ΔΛ) meso (1b, 2b) diastereoisomers. The distinctive structural features of these diastereoisomers have been characterized by 1-D and 2-D 1H NMR spectroscopy. The X-ray crystal structure of rac-[(bpy)2Os(pzdc)Os(bpy)2](ClO4) · H2O (2a) has been determined. The electrochemical and electronic spectral studies have established that there remain difference in properties and hence difference in intermetallic communication between the diastereoisomeric forms in each case. 相似文献