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1.
The crystal structures, magnetic properties, and catalase-like activities of assymmetric dinuclear manganese(III, III) complexes, [Mn2III, III(spa)2(μ-Me3CCO2)(Me3CCO2)(CH3OH)] ( 1 ) and [Mn2III, III(vpa)2(μ-Me3CCO2)(Me3CCO2)(CH3OH)] ( 2 ), (H2spa = 3-salicyclideneamino-1-propanol, H2vpa = O-vanillin), were reported. The crystal structures of complexes 1 and 2 consist of the same discrete asymmetric coordination environment of dinuclear clusters, where the two manganese atoms are bridged by two alkoxo oxygens of the spa or vpa ligands and one bidentate carboxylate ion, whereas an additional oxygen atom of monodentate carboxylate coordinated to the first metal ion, and the second metal ion was coordinated by one oxygen atom of the solvent CH3OH. Magnetic investigations (2–300 K) reveal an intramolecular antiferromagnetic spin exchange interaction with axial-field splittings: J = ?12.3 cm?1 (D = ?0.10 cm?1) and J = ?13.3 cm?1 (D = ?0.15 cm?1) for complexes 1 and 2 , respectively. The complexes should show catalase-like activity for H2O2 disproportionation in CH3OH solvent at 25° with rate constants of k = 6.35 dm3moI?1s?1 and 6.20 dm3mol?1s?1 for complexes 1 and 2 , respectively.  相似文献   

2.
Three novel Schiff base cadmium(II) complexes, derived from the end‐on (μ‐1,1‐N3) azide or end‐to‐end (μ‐1,3‐NCS) thio cyanate bridges and similar tridentate Schiff base ligands, have been synthesized under similar synthetic procedures and their crystal structures determined by X‐ray diffraction methods. They are the dinuclear double end‐on azide‐bridged [Cd2(L1)2(N3)2(μ‐1,1‐N3)2] ( 1 ), the dinuclear double end‐on azide‐bridged [Cd2(L2)2(N3)2(μ‐1,1‐N3)2] ( 2 ), and the dinuclear double end‐to‐end thiocyanate‐bridged [Cd2(L3)2(NCS)2(μ1,3‐NCS)2] ( 3 ), where L1, L2 and L3 are three similar tridentate Schiff bases obtained by condensation of 2‐pyridylaldehyde with N,N‐diethylethane‐1,2‐diamine, of 2‐pyridylaldehyde with N‐isopropylethane‐1,2‐diamine, and of 2‐pyridylaldehyde with N,N‐dimethylpropane‐1,3‐diamine, respectively. Each cadmium(II) centre in the complexes is in a distorted octahedral coordination. There is a crystallographic inversion centre in each of the complexes. The similar small ligands used as the secondary ligands in the preparation of the cadmium(II) complexes with similar Schiff bases can result in similar structures.  相似文献   

3.
Four new complexes of [Cu(bpm)(ox)(H2O)] ( 1 ), [Cu(tpd)(dca)(H2O)] ( 2 ), [Cu(bppz)(N3)2] ( 3 ), and [Cu(bpm)21,3‐N3)(N3)] ( 4 ) (bpm = 2,2′‐bipyrimidine, bppz = 2,3‐bis(2‐pyridyl)pyrazine, tpd = 4‐terpyridone, dca = dicyanamide, ox = oxalate) have been prepared and characterized by X‐ray single‐crystal analysis and variable‐temperature magnetic measurements. Compounds 1–4 are essentially mononuclear Cu(II) complexes. However, in complex 1 , Cu(II) it was found that intermolecular hydrogen bonding through between H2O and ox formed 1‐D chain structure. In complex 2 it was found that the hydrogen bonding between H2O and tpd of the next molecule led to for a binuclear Cu(II) complex. In complex 3 , two nitrogen atoms, one of the pyridyl group of bppz and one of N3? ligands, are weakly coordinated to neighbor Cu(II) ion thus leading to formation of a 1‐D chain structure. In complex 4 , one nitrogen atom of terminated N3? is weakly coordinated to the neighbor Cu(II) site to form a 1‐D polymeric structure. The magnetic susceptibility measurements indicate that complex 1 and 4 exhibit a weak antiferromagnetic interaction whereas a ferromagnetic coupling has been established for complexes 2 and 3 .  相似文献   

4.
Three novel complexes, namely [Zn(CuL)(pzdc)]2 · 5H2O ( 1 ), [Zn(NiL)(pzdc)]2 · 5H2O ( 2 ), and [Gd2(pzdc)2(NiL)6](ClO4)2 · 6H2O ( 3 ) (CuL and NiL, H2L = 2, 3‐dioxo‐5, 6, 14, 15‐dibenzo‐1, 4, 8, 12‐tetraazacyclo‐pentadeca‐7, 13‐dien and H2pzdc = pyrazine‐2, 3‐dicarboxylic acid) were synthesized and structurally determined. Complexes 1 and 2 are tetranuclear [ZnII2MII2] (M = Ni ( 1 ), Cu ( 2 ), respectively) molecules including both oxamide and pzdc2– bridges. The structure of compound 3 consists of pyrazine‐2, 3‐dicarboxylate and oxamido‐bridged, and is arranged in different butterfly‐like octanuclear molecules. The magnetic susceptibility data of 3 were analyzed.  相似文献   

5.
Two new metal complexes [Zn( L1 )]n ( 1 ) and [Cd3( L2 )2Cl2(H2O)6]n ( 2 ) (H2 L1 = 1,5‐bis(tetrazol‐5‐yl)‐3‐oxapentane, H2 L2 = bis(tetrazol‐5‐yl)methane) have been synthesized and characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction analysis. Complex 1 was a 2‐D sheet constructed by L1 and Zn(II) center, further assembled to form a three‐dimensional (3‐D) supramolecular networks through weak hydrogen‐bonding interactions. In the complex 2 , there were two unequivalent Cd(II) centers, and some of ligands L2 adopted chelate coordination mode, and others adopted bridge coordination mode linking the Cd1 center and simultaneously bridging the Cd2 center, the Cl anions adopted μ2 bridging mode, ligands L2 and the Cl anions linked the Cd(II) centers to form a 3‐D supramolecular networks.  相似文献   

6.
Two tetranuclear manganese complexes, [NaMnIIMn3III4‐O2–)(HL)3(SCN)4] ( 1 ) and [NaMnIIMn3III4‐O2–)(HL)3Cl4][NaMnIIMn3III4‐O2–)(HL)3Cl3(H2O)]ClO4 · 3.5H2O ( 2 ) were obtained from the reaction of manganese perchlorate with a quadridentate Schiff base ligand, 3‐(2‐hydroxybenzylideneamino)propane‐1, 2‐diol (H3L) derived from condensation of 2‐hydroxybenzaldehyde with 3‐amino‐1, 2‐propanediol, as well as the coligand KSCN or NaCl under basic conditions. Single‐crystal X‐ray studies reveal that those two complexes all have a mixed‐valent tetrahedral core, which contains an apical MnII ion and three basal MnIII ions situated in the [Mn34‐O2–)]7+ equilateral triangle plane. Fitting of the magnetic susceptibility data to the theoretical χmT vs. T expression, revealed that the presence of only antiferromagnetic interactions between the central metal atoms in 1 , while both antiferromagnetic and ferromagnetic interactions are present in 2 .  相似文献   

7.
Blue crystals of Cu2(phen)2(H2O)2(C5H6O4)2 were obtained from a CH3OH–H2O solution containing CuCl2, 1,10‐phenanthroline (phen), glutaric acid and Na2CO3. The crystal structure (monoclinic, P21/c (no. 14), a = 10.271(1), b = 10.595(1), c = 15.585(1) Å, β = 107.105(3)°, Z = 2, R = 0.0328, wR2 = 0.1027 for 3376 observed reflections (F ≥ 2σ(F ) out of 3728 unique reflections) is built up of dinuclear Cu2(phen)2(H2O)2(C5H6O4)2 complex molecules centered at inversion centers. The Cu atoms are square‐pyramidally coordinated by two nitrogen atoms of one bidentate chelating phen ligand and three oxygen atoms from two bridging glutarate anions and one axial water molecule (d(Cu–N) = 2.018(2), 2.024(2) Å; basal d(Cu–O) = 1.949(2), 1.956(2) Å; axial d(Cu–O) = 2.382(2) Å). Through the π‐π stacking interactions extending in a direction, the complex molecules are interlinked into 2 D layers parallel to the ac plane. The resultant 2 D layers are held together by hydrogen bonds between water molecules and uncoordinated carboxyl oxygen atoms.  相似文献   

8.
ZnCl2(NIT‐pPy) 1 , (NIT‐pPy = 2‐(4‐pyridyl)‐4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazolyl‐1‐oxyl‐3‐oxide) crystallizes in the orthorhombic space group Pnn2 with the cell parameters a = 9.4083(9), b = 39.686(3), c = 7.4417(14) Å. ZnCl2(NIT‐6M‐oPy) 2 , (NIT‐6M‐oPy = 2‐(6‐methyl‐2‐pyridyl)‐4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazolyl‐1‐oxyl‐3‐oxide) crystallizes in the monoclinic space group Pn with a = 7.377(2), b = 19.096(4), c = 11.853(2) Å, β = 95.65(3)°. The temperature dependence magnetic susceptibility of complex 1 revealed an intermolecular ferromagnetic exchange interaction. A simple spin‐polarization model has been used to justify the observed ferromagnetic exchange interaction between the spins of the radical NO group in complex 2 .  相似文献   

9.
The reactions of CuX2 (X = Cl, Br) with dipinodiazafluorenes yielded four new complexes [CuX2L1]2 (X = Cl (1), Br (2), L1 = (1R,3R,8R,10R)-2,2,9,9-Tetramethyl-3,4,7,8,9,10-hexahydro-1H-1,3:8,10-dimethanocyclopenta [1,2-b:5,4-b’]diquinolin-12(2H)-one) and [(CuX2)2L2]n (X = Cl (3), Br (4), L2 = (1R,3R,8R,10R,1’R,3’R,8’R,10’R)-2,2,2’,2’,9,9,9’,9’-Octamethyl-1,1’,2,2’,3,3’,4,4’,7,7’,8,8’,9,9’,10,10’-hexadecahydro-1,3:1’,3’:8,10:8’,10’-tetramethano-12,12’-bi(cyclopenta [1,2-b:5,4-b’]diquinolinylidene). The complexes were characterized by IR and EPR spectroscopy, HR-ESI-MS and elemental analysis. The crystal structures of compounds 1, 2 and 4 were determined by X-ray diffraction (XRD) analysis. Complexes 1–2 have a monomeric structure, while complex 4 has a polymeric structure due to additional coordinating N,N sites in L2. All complexes contain a binuclear fragment {Cu2(μ-X)2×2} (X = Cl, Br) in their structures. Each copper atom has a distorted square-pyramidal coordination environment formed by two nitrogen atoms and three halogen atoms. The Cu-Nax distance is elongated compared to Cu-Neq. The EPR spectra of compounds 1–4 in CH3CN confirm their paramagnetic nature due to the d9 electronic configuration of the copper(II) ion. The magnetic properties of all compounds were studied by the method of static magnetic susceptibility. For complexes 1 and 2, the effective magnetic moments are µeff ≈ 1.87 and 1.83 µB (per each Cu2+ ion), respectively, in the temperature range 50–300 K, which are close to the theoretical spin value (1.73 µB). Ferromagnetic exchange interactions between Cu(II) ions inside {Cu2(μ-X)2X2} (X = Cl, Br) dimers (J/kB ≈ 25 and 31 K for 1 and 2, respectively) or between dimers (θ′ ≈ 0.30 and 0.47 K for 1 and 2, respectively) were found at low temperatures. For compounds 3 and 4, the magnetic susceptibility is well described by the Curie–Weiss law in the temperature range 1.77–300 K with µeff ≈ 1.72 and 1.70 µB for 3 and 4, respectively, and weak antiferromagnetic interactions ≈ −0.4 K for 3 and −0.65 K for 4). Complexes 1–4 exhibit high catalytic activity in the oxidation of alkanes and alcohols with peroxides. The maximum yield of cyclohexane oxidation products reached 50% (complex 3). Based on the data on the study of regio- and bond-selectivity, it was concluded that hydroxyl radicals play a decisive role in the oxidation reaction. The initial products in reactions with alkanes are alkyl hydroperoxides.  相似文献   

10.
RbMnO2 was prepared via the azide/nitrate route. Stoichiometric mixtures of the precursers (Mn2O3, RbN3 and RbNO3) were heated in a special regime up to 600 °C and annealed at this temperature for 30 h in specially designed silver crucibles. Single crystals have been grown by annealing a 1:1 mixture of Rb2O and MnOx at 585 °C for 1200 h. According to the crystal structure determination Mn3+ is in a square‐pyramidal coordination by oxygen. These [MnO5] units form double chains extending along the crystallographic c‐axis. RbMnO2 shows Curie‐Weiss behaviour down to ~ 100 K. A fit of the susceptibility data yields an average value of the magnetic moment (per manganese atom) of μeff = 5.33 μB, and θp = –820 K. At 50 K and low field strength onset of ferromagnetic order due to spin canting has been observed.  相似文献   

11.
Two new isostructural complexes, [Mn3(L)6(bipy)2] ( 1 ) and [Co3(L)6(bipy)2] ( 2 ) (L = 2,4‐dichlorobenzoate, bipy = 2, 2′‐bipyridine) were synthesized under the hydrothermal conditions and characterized by single‐crystal X‐ray diffraction, IR spectroscopy, EA (elemental analysis), and magnetic measurements. The two complexes are found to contain a trinuclear (M3) unit that opens up a possibility of being magnetic materials. The magnetic measurements reveal that 1 exhibits the antiferromagnetic exchange interaction between metal ions and 2 presents a weak ferromagnetic interactions between the CoII ions.  相似文献   

12.
Two manganese phosphonates Mn2[{(O3PCH2)2NHR}(H2O)F]·H2O (R = ?C6H11 (1) , ?CH2C5H4N (2) ) have been synthesized by hydrothermal reaction and characterized by single–crystal X–ray diffraction as well as with infrared spectroscopy, elemental analysis and thermogravimetric analysis. The two isomorphous compounds feature layered structures in ab plane, in which the tetramers comprised of two MnO4F2 and two MnO5F polyhedra are cross–linked via phosphonate oxygen atoms to form MnII phosphonate layers. The organic groups of the ligands are orientated toward the interlayer space.  相似文献   

13.
A new dumbbell‐type 4,4′‐bipy‐bridged dinuclear copper(II) complex, [Cu2(4,4′‐bipy)L2(H2O)2](ClO4)4 · 8CH3OH · 10H2O, where L = 1‐[bis(3‐aminopropyl)amino]‐2‐ propanol and bipy = bipyridine, has been synthesized and characterized, X‐ray crystallographic analysis shows that the [Cu2(4,4′‐bipy)L2(H2O)2]4+ cations and water molecules generate layer structures extending parallel to bc planes through hydrogen bonding interactions of O–H ··· O and C–H ··· O. The layers are also connected by hydrogen bonding interactions involving methanol, water, and perchlorate anions. These interactions lead to the formation of rectangular channels of 12.3 Å × 6.0 Å along the crystallographic c axis. Perchlorate anions fill in each channel in a sandwich‐like packing mode, they are joined with the adjacent layers by water heptamers. Magnetic susceptibility measurements show that the magnetic exchange interaction is weak although it has a regular π‐type electron transfer pathway. Furthermore, the electrochemical and thermogravimetric properties of the complex were also investigated.  相似文献   

14.
Three new phenolate oxygen bridged transition metal complexes [Zn3(HL1)33‐CH3O)]·(ClO4)2(H2O)3 ( 1 ), [Ni2(HL1)21,1‐N3)(o‐vanillin)]·H2O ( 2 ), [Ni3(HL2)2(PhCOO)2(PhCOOH)2(EtOH)2] ( 3 ) have been synthesized by metal ions and potentially multidentate Schiff base ligands (H2L1 = 2‐((1‐hydroxy‐2‐methylpropan‐2‐ylimino) methyl)‐6‐methoxyphenol; H3L2 = (E)‐1‐((2‐hydroxy‐3‐methoxy‐benzylidene)amino)ethane‐1,2‐diol). All the three complexes 1 , 2 , and 3 have been characterized by elemental analysis, FT‐IR spectroscopy, and single‐crystal X‐ray diffraction studies. Crystal structures reveal that complex 1 is a trinuclear incomplete cubane‐like zinc cluster whereas complex 2 is a dinuclear nickel complex bridged by azide, and compound 3 is a trinuclear nickel complex. The luminescent property for complex 1 and magnetic behaviors for complexes 2 and 3 have been investigated.  相似文献   

15.

The title complex [K{Cu(acen)}3]2[Co(NCS)4]·1/4CH3OH (acen = acetylacetonethylenediamine anion) has been prepared and characterized. Single-crystal x-ray analysis reveals that the complex crystallizes in space group P I with a = 11.442(2), b = 15.098(3), c = 28.500(4) Å, α = 82.77(1), β = 83.58(1), γ = 85.07(1)°. The crystal consists of the complex [K{Cu(acen)}3]+ cations, [Co(NCS)4]2? anions and methanol molecules. Three [Cu(acen)] molecules function as bridging ligands through phenolic O atoms to one K+ to give the tetranuclear [K{Cu(acen)}3]+ cation. Each copper(II) atom in the cation is in a square-planar geometry, being coordinated by two oxygen atoms and two nitrogen atoms from a quadridentate acen ligand. The cobalt(II) atom is coordinated by four nitrogen atoms of thiocyanate ligands, forming a deformed tetrahedral environment. The IR and UV-Vis spectra have also been investigated.  相似文献   

16.
Two heterospin complexes [Cu(NIT3Py)(cda)H2O] · H2O ( 1 ) and [Cu(NIT2Py)(cda)H2O] · H2O · CH3OH ( 2 ) with CuII ions and pyridyl‐substituted nitronyl nitroxide radicals (NITxPy = 2‐(x′‐pyridyl)‐4,4,5,5‐tetramethyl‐imidazoline‐1‐oxyl‐3‐oxide, x = 3, 2; H2cda = 4‐hydroxy‐pyridine‐2,6‐dicarboxylic acid) were synthesized and characterized structurally and magnetically. The single crystal structures show that the two complexes are both two‐spin complexes, in which the different radicals make the two complexes have different hydrogen bonding interactions to form 2D and 1D supramolecular network for complexes 1 and 2 , respectively. The magnetic measurements indicate that complexes 1 and 2 both exhibit antiferromagnetic interactions between CuII and radicals.  相似文献   

17.
Reaction of the ligand 1,3-bis(2′-benzimidazolylimino)isoindoline with manganese(II) chloride in acetonitrile/methanol leads to the novel mononuclear manganese(II) complex 1,3-bis(2′-benzimidazolylimino)isoindolinedichloro manganese(II) [Mn(bimindH)Cl2], which has been characterized by various techniques such as elemental analysis, IR, UV–Vis, ESR spectroscopy, and X-ray diffraction. The ligand bimindH was synthesized by fusing phthalonitrile and 2-aminobenzimidazole at high temperature until ammonia evolution ceased. The catalase-like activity of the complex was tested in propionitrile, and it proved to be active in the dihydrogen peroxide dismutation. Based on kinetic studies the reaction is first-order in relation to both the complex and hydrogen peroxide.  相似文献   

18.
The reaction of cadmium salts with various amounts of the tridentate NS2‐chelating ligands 1‐(2‐mercapto‐acetophenone)‐4‐triphenylmethylthiosemicarbazone (H2L1) and 1‐(5‐mercapto‐3‐methyl‐1‐phenylpyrazole‐4‐carboxaldehyde)‐4‐triphenyl‐methylthiosemicarbazone (H2L2) in the presence of bases like N‐methylimidazole (N–MeIm), pyridine (py) or triethylamine (Et3N) provided a series of novel mono‐, di‐, tri‐ and heptanuclear cadmium complexes. They are of the general formulas [CdL1(N–MeIm)]2 ( 1 ), [CdL1(py)]2 ( 2 ), [CdL2(N–MeIm)]2 ( 3 ), [CdL2(py)3] · 0.25 C6H14 · 0.5 py ( 4 ), [Et3NH]2[Cd3L ] · 7 MeOH ( 5 ), [Et3NH]2[Cd3L ] ( 6 ) and [Et3NH]2[Cd7L ] · 14 MeOH ( 7 ). The compounds were characterized by elemental analysis, IR‐ and 1H‐NMR‐spectroscopy. Single‐crystal X‐ray structure analyses are reported for the complexes 2 , 4 , 5 and 7 . While 2 has a dimeric structure where each cadmium ion is pentacoordinated in a N2S3‐environment, 4 consists of a monomeric cadmium center with distorted octahedral N4S2‐coordination. The complexes 5 and 7 exhibit new structural types for tri‐ and heptanuclear cadmium compounds. It is shown that sulfur bridging might proceed via arylthiolates, iminothiolates or even both functions of the ligand. Aggregation is influenced by various factors like solvents, counterions and ligand properties.  相似文献   

19.
邢婧  周荫庄 《化学进展》2009,21(6):1199-1206
以酰腙为配体钒的单核、双核配合物因其结构丰富、生物活性多样而引起广泛关注。目前该领域新配合物的合成、表征和生物活性的研究甚为活跃。本文回顾了近年来钒酰腙配合物的研究状况,主要从以下三个方面进行综述:(1)钒酰腙配合物的合成方法;(2)此类配合物的配位模式;(3)一些单、双核钒酰腙配合物抗变形虫,抗肿瘤,类胰岛素,抑制Na+, K+-ATP酶,与DNA作用的生物活性。文中着重阐述了钒酰腙化合物的结构和生物活性之间的关系。此外,还提出了钒酰腙配合物研究领域的不足之处并对其今后发展方向进行了展望。  相似文献   

20.
含锰的过渡金属配合物以其独特的分子结构 ,在功能材料方面显示出潜在的应用价值 [1~ 4 ] .此外 ,锰在许多生物体系中扮演着重要活性反应中心的角色 .例如在光合作用光系统 ( PS )中水氧化中心( WOC)的锰簇合物、含锰过氧化氢酶 ( Mn Catalase)、含锰超氧化物歧化酶 ( Mn SOD  相似文献   

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