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1.
Creaven BS Czeglédi E Devereux M Enyedy ÉA Foltyn-Arfa Kia A Karcz D Kellett A McClean S Nagy NV Noble A Rockenbauer A Szabó-Plánka T Walsh M 《Dalton transactions (Cambridge, England : 2003)》2010,39(45):10854-10865
The coordination modes of copper(II) complexes of Schiff base-derived coumarin ligands, which had previously shown good anti-Candida activity, were investigated by pH-potentiometric and UV-Vis spectroscopic methods. These studies confirmed the coordination mode of the ligands to be through the N of the imine and deprotonated phenol of the coumarin-derived ligand in solution. In addition, the more active complexes and their corresponding ligands were investigated in the presence of copper(II) in liquid and frozen solution by ESR spectroscopic methods. A series of secondary amine derivatives of the Schiff base ligands, were isolated with good solubility characteristics but showed little anti-Candida activity. However, cytotoxicity studies of the secondary amines, together with the copper complexes and their corresponding ligands, against human colon cancer and human breast cancer cells identified the chemotherapeutic potential of these new ligands. 相似文献
2.
Suning Wang 《Journal of Cluster Science》1995,6(4):463-484
Copper complexes with aminoalcoholato ligands have attracted much attention recently because of their potential applications in ceramic materials. This review deals with polynuclear copper (II) complexes containing bidentate and triden-tate aminoalcoholato ligands. The focus of this article is on the synthesis, structure, and magnetic properties of polynuclear copper (II) complexes obtained recently by our group. Some relevant work reported previously by other researchers is also included.Dedicated to Professor Jiaxi Lu on the occasion of his 80th birthday. 相似文献
3.
Three trinuclear zinc(II)/nickel(II) complexes with two pentadentate ligands, N-p-nitrobenzoylsalicylhydrazidate (H3-p-nbzshz) and N-o-nitrobenzoylsalicylhydrazidate (H3-o-nbzshz) have been synthesized and characterized by X-ray crystallography. The complex [Zn3(p-nbzshz)2(C5H5N)4]n (1) molecule exhibits a one-dimensional wave-like chain structure resulting from the linkage of phenolate oxygen donor atoms of the ligands between neighboring motifs. The two nickel(II) complexes, Ni3(p-nbzshz)2(C5H5N)4 (2) and Ni3(o-nbzshz)2(C3H7NO)2(C2H6O)2 (3) are trinuclear complexes in which three nickel(II) centers exhibit alternating square-planar and octahedral geometries. Complex 2 exhibits a curved Ni3 metal arrangement with a Ni(1)–Ni(2)–Ni(3) angle of 62.36°, while the three nickel atoms in complex 3 are strictly linear with an angle of 180°. 相似文献
4.
Seidler-Egdal RK Nielsen A Bond AD Bjerrum MJ McKenzie CJ 《Dalton transactions (Cambridge, England : 2003)》2011,40(15):3849-3858
Capillary electrophoresis (CE) and electrospray ionisation (ESI) mass spectra of aqueous solutions of manganese(II) complexes of the monoanions of the pentadentate ligands N-methyl-N'-carboxymethyl-N,N'-bis(2-pyridylmethyl)ethane-1,2-diamine (mcbpen(-)) and N-benzyl-N'-carboxymethyl-N,N'-bis(2-pyridylmethyl)ethane-1,2-diamine (bcbpen(-)), show the presence of a mixture of closely related Mn(II) species, assigned to the mono, di-, tri- and poly-cationic complexes [Mn(II)(L)(H(2)O)](n)(n+), L = mcbpen(-) or bcbpen(-) with n = 1, 2, 3, etc. In solution, these complexes are reversibly oxidized by tert-butyl hydrogen peroxide (TBHP), (NH(4))(2)[Ce(NO(3))(6)], Ce(ClO(4))(4), oxone and [Ru(bipy)(3)](3+) to form metastable (t(?) = min to h) higher valent (hydr)oxide species, showing a collective maximum absorbance at 430 nm. The same species can be produced by [Ru(bipy)(3)](2+)-mediated photooxidization in the presence of an electron acceptor. TBHP oxidation of the complexes, in large excesses of the TBHP, is concurrent with an O(2) evolution with turnovers of up to 1.5 × 10(4) mol of O(2) per mol of [Mn] and calculated rate constants from two series of experiments of 0.039 and 0.026 mol[O(2)] s(-1) M(-2). A 1:1 reaction of TBHP with [Mn] is rate determining and the resultant species is proposed to be the mononuclear, catalytically competent, [Mn(IV)(O)(mcbpen)](+). At very close m/z values [Mn(III)(OH)(mcbpen)](+), [Mn(2)(III/IV)(O)(2)(mcbpen)(2)](+) and [Mn(IV)(2)(O)(2)(mcbpen)(2)](2+) are detected by ESI MS and CE when the concentration of TBHP is comparable to or lower than that of [Mn]. These are conditions that occur post catalysis and these species are derived from [Mn(IV)(O)(mcbpen)](+) through condensation reactions. 相似文献
5.
A pair of novel C3-epimeric sugar-derived ligands (glycoligands) with a neutral N4O donor set was synthesized. Copper(II) complexes of both ligands were obtained and characterized by X-ray crystallography. Cyclic voltammetry, electron paramagnetic resonance, and UV-vis spectroscopies showed similar electronic properties. Mirror-image CD spectra were obtained for the Cu(II) d-d band, indicating an enantiomeric character of the coordination sphere, which has been rationalized structurally. This example shows the possible predetermination of stereochemistry for complexes by ligands based on a glycoscaffold. 相似文献
6.
Summary Copper(II) salts were reacted with two diamino-dithioether ligands, i.e. 1,3-di(o-aminophenylthio)propane (abbreviated H2L1) and 1,2-di(o-aminophenylthio)xylene (abbreviated H2L2). Mixtures of copper(I) and copper(II) complexes were obtained with Cl– and ClO
4
–
counterions. The major products were the copper(I) complexes, which were obtained pure after recrystallisation from MeCN-MeOH. The ligands lose two protons from the amine functions to form copper(I) complexes of general formula [CuL]X, where X = ClO
4
–
or Cl–. The complexes were oxidised to [CuL]X2 with H2O2 in DMF. Cu(NO3)2 on the other hand gave [CuH2LNO3]NO3. 相似文献
7.
Lei Shen Meng Jie Cao Fei Fei Zhang Qi Wu Li Yang Zhao Yi Ming Lu Qiao Yun Li Gao Wen Yang Bo Wei Jian Hua Zou 《Transition Metal Chemistry》2016,41(2):125-131
Reactions of three tetrazole carboxylate ligands, namely 5-(4-pyridyl)tetrazole-2-acetic acid (Hpytza), 1,3,5-tris(tetrazol-5-yl)benzene-N2,N2′,N2″-triacetic acid (H3tzpha) and 5-aminotetrazole-1-propanoic acid (Hatzpa) with Mn(NO3)2·6H2O in the presence of KOH afforded three new complexes, [Mn(pytza)2] (1), [Mn3(tzpha)2(H2O)12]·2CH3OH·10H2O (2) and [Mn(atzpa)2(H2O)2] (3), respectively. These complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Complex 1 displays a three-dimensional network while 2 and 3 show one-dimensional chains. Furthermore, the luminescence properties of these complexes were investigated at room temperature in the solid state. 相似文献
8.
Jing-Yun Wu Hui-Fang Chen Yu-Chen Jao Sheng-Ming Huang Tien-Wen Tseng Shie-Ming Peng 《Journal of solid state chemistry》2011,184(7):1740-1748
Two Cd(HBimc)-based isomers, [Cd(HBimcN)(HBimcT)(H2O)]·3.5H2O·EtOH (1a·3.5H2O·EtOH, H2Bimc=1H-benzimidazole-5-carboxylic acid) and [Cd(HBimcN)(HBimcT)(H2O)] (1b), and two Cu(HMBimc)-based coordination polymers, [Cu(HMBimcN)2(H2O)]·1/2H2O (2·1/2H2O, H2MBimc=2-methyl-1H-benzimidazole-5-carboxylic acid) and [Cu(HMBimcT)2]·2THF·H2O (3·2THF·H2O), were self-assembled from Cd(ClO4)2·6H2O/H2Bimc and Cu(ClO4)2·6H2O/H2MBimc systems, respectively. Compound 1a adopts a ladder-like chain structure, comprised of a hydrogen-bond-stabilized Cd2(HBimcN)2-metallocyclic stair and a 1D straight -(Cd-HBimcT)n- edge, whereas compound 1b exhibits a 2D (4,4)-rhombus layered structure, intercrossed by 1D -(Cd-HBimcN)n- chains and -(Cd-HBimcT)n- chains. Compound 2 shows a 1D double-stranded wave-like chain from two single-stranded wave-like -(Cu-HMBimcN)n- chains and compound 3 adopts a 2D (4,4)-topological layer structure, intercrossed by subunits of 1D -(Cu-HMBimcT)n- chains. Interestingly, a pair of tautomeric HBimc building blocks—normal (N or HBimcN) and tautomer (T or HBimcT)—is simultaneously included in the structures of 1a and 1b, whilst the N- and T-configured HMBimc building blocks are present as separate entities in Cu species, 2 and 3, respectively. The existence of only a tautomer (T) mode of the benzimidazolecarboxylate-based ligand in a Cu(II) network is observed for the first time. 相似文献
9.
Urmila Pal Chaudhuri Lei Yang Laura R. Whiteaker Arunendu Mondal Matthew R. Fultz Douglas R. Powell Robert P. Houser 《Polyhedron》2007,26(18):5420-5431
Mononuclear copper(II) complexes of a family of pyridylmethylamide ligands HL, HLMe, HLPh, HLMe3 and HLPh3, [HL = N-(2-pyridylmethyl)acetamide; HLMe = N-(2-pyridylmethyl)propionamide; HLPh = 2-phenyl-N-(2-pyridylmethyl)acetamide; HLMe3 = 2,2-dimethyl-N-(2-pyridylmethyl)propionamide; HLPh3 = 2,2,2-triphenyl-N-(2-pyridylmethyl)acetamide], were synthesized and characterized. The reaction of copper(II) salts with the pyridylmethylamide ligands yields complexes [Cu(HL)2(OTf)2] (1), [Cu(HLMe)2](ClO4)2 (2), [Cu(HL)2Cl]2[CuCl4] (3), [Cu(HLMe3)2(THF)](OTf)2 (4), [Cu(HLMe3)2(H2O)](ClO4)2 (5a and 5b), [Cu(HLPh3)2(H2O)](ClO4)2 (6), [Cu(HL)(2,2′-bipy)(H2O)](ClO4)2 (7), and [Cu(HLPh)(2,2′-bipy)(H2O)](ClO4)2 (8). All complexes were fully characterized, and the X-ray structures vary from four-coordinate square-planar, to five-coordinate square-pyramidal or trigonal-bipyramidal. The neutral ligands coordinate via the pyridyl N atom and carbonyl O atom in a bidentate fashion. The spectroscopic properties are typical of mononuclear copper(II) species with similar ligand sets, and are consistent their X-ray structures. 相似文献
10.
Yoshiyuki Kani Shigeru Ohba Sayo Ito Yuzo Nishida 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(6):e233-e235
The four title CuII compounds are chloro[(2‐furylmethyl)bis(2‐pyridylmethyl)amine‐N,N′,N′′]copper(II) perchlorate, [CuCl(C17H17N3O)]ClO4, (I), chloro{2‐[bis(2‐pyridylmethyl)amino]ethanolato‐N,N′,N′′,O}copper(II) hemi[tetrachlorocopper(II)], [CuCl(C14H17N3O)][CuCl4]1/2, (II), chloro[(2‐morpholinoethyl)bis(2‐pyridylmethyl)amine‐N,N′,N′′,N′′′]copper(II) perchlorate, [CuCl(C18H24N4O)]ClO4, (III), and chloro[(2‐piperidinylethyl)bis(2‐pyridylmethyl)amine‐N,N′,N′′,N′′′]copper(II) hexafluorophosphate, [CuCl(C19H26N4)]PF6, (IV). They have tripodal potentially tetradentate ligands. In (I), the O atom of the furan moiety weakly coordinates to the Cu atom at a distance of 2.750 (3) Å. 相似文献
11.
Dees A Zahl A Puchta R Hommes NJ Heinemann FW Ivanović-Burmazović I 《Inorganic chemistry》2007,46(7):2459-2470
Seven-coordinate manganese(II) complexes [Mn(L)(H2O)2]2+, where L represents an equatorial pentadentate macrocyclic ligand with five nitrogen donor atoms, were studied with regard to their acid-base properties, water-exchange rate constants, and corresponding activation parameters (DeltaH, DeltaS, and DeltaV). Three of the studied complexes without imine bonds in the macrocyclic ligand are proven superoxide dismutase (SOD) mimetics. Their water-exchange parameters were compared with those of the imino groups containing complex [Mn(L1)(Cl)2] (dichloro-2,13-dimethyl-3,6,9,12,18-pentaazabicyclo[12.3.1]-octadeca-1(18),2,12,14,16-pentaenemanganese(II)), which does not show SOD activity. In addition the X-ray crystal structure of a new complex, dichloro-2,6-bis[1-(2-(N-methylamino)ethylimino)ethyl]pyridine-manganese(II) [Mn(L2)(Cl)2], which is the acyclic analog of [Mn(L1)(Cl)2], is reported. Stability constants of the complexes and the pKa values of the ligands were measured by potentiometric titration. The titrations of [Mn(L1)(H2O)2]2+ and [Mn(L2)(H2O)2]2+ led to complicated species distribution curves because of their ligands containing imine bonds. Water exchange was measured by temperature- and pressure-dependent 17O NMR techniques. In addition to the measurements on [Mn(EDTA)(H2O)]2- and its derivatives, this is the only study of water exchange on seven-coordinate manganese complexes. The water exchange rate constants vary between 1.6 x 107 s-1 and 5.8 x 107 s-1 at 25 degrees C and are mainly controlled by the pi-acceptor abilities of the ligands. The exchange rate constant of the diaqua-1,4,7,10,13-pentaazacyclopentadecanemanganese(II) [Mn([15]aneN5)(H2O)2]2+ complex seems to be even higher but could not be exactly determined. On the basis of the obtained activation parameters, the exchange mechanism of the studied seven-coordinate manganese(II) complexes follows a dissociative pathway (Id mechanism). DFT calculations (UB3LYP/LANL2DZp) were performed to obtain the energy required for the dissociation of the coordinated water molecule, that is, the energy difference between the starting seven-coordinate complex and a six-coordinate intermediate. The results have been discussed in terms of the catalytic mechanism of the proven SOD mimetics. 相似文献
12.
New copper(II) complexes of general formula, Cu(ONS)B (ONS = the di-negatively charged Schiff base, S-benzyl-β-N-(2-hydroxyphenyl) methylendithiocarbazate; B = pyridine, 2,2′-dipyridyl or 1,10-phenanthroline) have been synthesized and characterised by magnetic and spectroscopic measurements. The complex, Cu(ONS)py is four-coordinate and square-planar. Magnetic and spectroscopic data support a five-coordinate, presumably, a trigonal-bipyramidal structure for the [Cu(ONS)dipy] and (Cu(ONS)phen] complexes 相似文献
13.
R. N. Patel K. K. Shukla Anurag Singh M. Choudhary D. K. Patel Juan Niclós-Gutiérrez Duane Choquesillo-Lazarte 《Transition Metal Chemistry》2009,34(2):239-245
Abstract Two new nickel(II) complexes, namely [Ni(BPSE)](BF4) 1, and [Ni (5-BST)CH3OH]ClO4
2 [BPSE = 2-benzoylpyridinesalicylidene ethylenediamine, 5-BST = 5-bromosalicylidene-tris(2-aminoethyl)amine] have been synthesized
and characterized using various physico-chemical methods. The magnetic and spectroscopic data indicate a distorted square
planar geometry for complex 1, while complex 2 is assigned a distorted octahedral geometry. Complex 1 crystallized in the triclinic space group P-1. Complex 2 adopts an octahedral geometry with space group symmetry P 21/n. The superoxide dismutase activity of these complexes has been measured.
Graphical Abstract This paper describes three new nickel (II) complexes viz; [Ni(BPSE)](BF4) 1, [Ni(BSE)] 2 and [Ni (5-BST) CH3OH] ClO4 3 [BPSE
= 2-benzoylpyridine salicyledene-ethylenediamine, BSE = bis(salicylaldehyde) ethylenediamine, 5-BST = 5-bromosalicyledene-tris(2-amino
ethyl) amine]. The magnetic and spectroscopic data indicate a distorted square planar geometry for complex 1 and 2, while
the comlplex 3 is assigned a distorted octahedral geometry. Superoxide dismutase activity of these complexes have also been
measured.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
14.
Fry FH Spiccia L Jensen P Moubaraki B Murray KS Tiekink ER 《Inorganic chemistry》2003,42(18):5594-5603
Copper(II) complexes of three bis(tacn) ligands, [Cu(2)(T(2)-o-X)Cl(4)] (1), [Cu(2)(T(2)-m-X)(H(2)O)(4)](ClO(4))(4).H(2)O.NaClO(4) (2), and [Cu(2)(T(2)-p-X)Cl(4)] (3), were prepared by reacting a Cu(II) salt and L.6HCl (2:1 ratio) in neutral aqueous solution [T(2)-o-X = 1,2-bis(1,4,7-triazacyclonon-1-ylmethyl)benzene; T(2)-m-X = 1,3-bis(1,4,7-triazacyclonon-1-ylmethyl)benzene; T(2)-p-X = 1,4-bis(1,4,7-triazacyclonon-1-ylmethyl)benzene]. Crystals of [Cu(2)(T(2)-m-X)(NPP)(mu-OH)](ClO(4)).H(2)O (4) formed at pH = 7.4 in a solution containing 2 and disodium 4-nitrophenyl phosphate (Na(2)NPP). The binuclear complexes [Cu(2)(T(2)-o-XAc(2))(H(2)O)(2)](ClO(4))(2).4H(2)O (5) and [Cu(2)(T(2)-m-XAc(2))(H(2)O)(2)](ClO(4))(2).4H(2)O (6) were obtained on addition of Cu(ClO(4))(2).6H(2)O to aqueous solutions of the bis(tetradentate) ligands T(2)-o-XAc(2) (1,2-bis((4-(carboxymethyl)-1,4,7-triazacyclonon-1-yl)methyl)benzene and T(2)-m-XAc(2) (1,3-bis((4-(carboxymethyl)-1,4,7-triazacyclonon-1-yl)methyl)benzene), respectively. In the binuclear complex, 3, three N donors from one macrocycle and two chlorides occupy the distorted square pyramidal Cu(II) coordination sphere. The complex features a long Cu...Cu separation (11.81 A) and intermolecular interactions that give rise to weak intermolecular antiferromagnetic coupling between Cu(II) centers. Complex 4 contains binuclear cations with a single hydroxo and p-nitrophenyl phosphate bridging two Cu(II) centers (Cu...Cu = 3.565(2) A). Magnetic susceptibility studies indicated the presence of strong antiferromagnetic interactions between the metal centers (J = -275 cm(-1)). Measurements of the rate of BNPP (bis(p-nitrophenyl) phosphate) hydrolysis by a number of these metal complexes revealed the greatest rate of cleavage for [Cu(2)(T(2)-o-X)(OH(2))(4)](4+) (k = 5 x 10(-6) s(-1) at pH = 7.4 and T = 50 degrees C). Notably, the mononuclear [Cu(Me(3)tacn)(OH(2))(2)](2+) complex induces a much faster rate of cleavage (k = 6 x 10(-5) s(-1) under the same conditions). 相似文献
15.
The coordination properties of three heterofunctional phosphine oxide ligands, 2-methylpyridyldiphenylphosphine oxide (L1), phenylphosphino-bis-2-methylpyridine oxide (L2) and phenylphosphino-bis-2-methylpyridine N,N′,P-trioxide (L3) with Cu(II) is described. The X-ray crystal structures of the compounds display a distorted octahedral geometry, which exhibit Jahn–Teller distortions. In compounds 1 and 2, the L1 and L2 ligands react with Cu(BF4)2 in a 2:1 ligand to metal ratio, respectively, with the BF4 anions interacting with the metal center. L3 reacts with Cu(BF4)2 in 1:1 and 2:1 ligand/metal ratios to form compounds 3 and 4, respectively. Addition of either 2,2′-bipyridine or 4,4′-bipyridine to reaction solutions containing Cu(BF4)2 and L3 produces a discrete molecule (5) and a polymeric structure (7), respectively. The reaction of both bipyridines in the presence of Cu(BF4)2 and L3 gives rise to a discrete molecule (6) characterized by two octahedral coppers interconnected by the 4,4′-bipyridine. The electrochemical and photophysical properties of all compounds were investigated by cyclic voltammetry (CV) and UV–Vis, as they exhibited no emission or excitation in fluorimetric experiments. 相似文献
16.
The coordination chemistries of the potential tetradentate ligands N,N'-bis(3,5-di-tert-butyl-2-hydroxyphenyl)ethylenediamine, H4[L1], the unsaturated analogue glyoxal-bis(2-hydroxy-3,5-di-tert-butylanil), H2[L2], and N,N'-bis(2-hydroxy-3,5-di-tert-butylphenyl)-2,2-dimethylpropylenediamine, H4[L3], have been investigated with nickel(II), palladium(II), and copper(II). The complexes prepared and characterized are [Ni(II)(H3L1)2] (1), [Ni(II)(HL2)2].5/8CH2Cl2 (2), [Ni(II)(L3**)] (3), [Pd(II)(L3**)][Pd(II)(H2L3) (4), and [Cu(II)(H2O)(L4)] (5), where (L4)2- is the oxidized diimine form of (L3)4- and (L3**)2- is the bis(o-iminosemiquinonate) diradical form of (L3)4-. The structures of compounds 1-5 have been determined by single crystal X-ray crystallography. In complexes 1 and 2, the ligands (H3L1)- and (HL2)- are tridentate and the nickel ions are in an octahedral ligand environment. The oxidation level of the ligands is that of an aromatic o-aminophenol. 1 and 2 are paramagnetic (mu(eff) approximately 3.2 mu(B) at 300 K), indicating an S = 1 ground state. The diamagnetic, square planar, four-coordinate complexes 3 and [Pd(II)(L3**)] in 4 each contain two antiferromagnetically coupled o-iminobenzosemiquinonate(1-) pi radicals. Diamagnetic [Pd(II)(H2L3)] in 4 forms an eclipsed dimer via four N-H.O hydrogen bonding contacts which yields a nonbonding Pd.Pd contact of 3.0846(4) A. Complex 5 contains a five-coordinate Cu(II) ion and two o-aminophenolate(1-) halves in (L4)2-. The electrochemistries of complexes 3 and 4a ([Pd(II)(L3**)] of 4) have been investigated, and the EPR spectra of the monocations and -anions are reported. 相似文献
17.
W. -K. Dong Sh. -Sh. Gong Y. -X. Sun J. -F. Tong J. Yao 《Journal of Structural Chemistry》2011,52(5):1018-1024
Two new linear CuII complexes [Cu(L1)2] (I) (HL1 = (E)-3,5-dichloro-2-hydroxy benzaldehyde O-methyl oxime) and [Cu(L2)2] (II) (HL2 = (E)-3,5-dichloro-2-hydroxy benzaldehyde O-ethyl oxime) are synthesized and characterized by elemental analysis, IR, UV-Vis, and X-ray diffraction methods. X-ray crystallographic
analyses indicate that complexes I and II have a similar structure consisting of one CuII ion and two L− units. In the complexes, the CuII ion lying on an inversion centre is four-coordinated in a trans-CuN2O2 square planar geometry by two phenolate O and two oxime N atoms from two symmetry-related N,O-bidentate oxime-type ligands.
However, the crystal structure of the two complexes is different: complex I forms an infinite three-dimensional supramolecular network structure through intermolecular hydrogen bonding and π...π interaction,
while complex II forms an infinite one-dimensional supramolecular structure through intermolecular hydrogen bonds. 相似文献
18.
19.
Secondary coordination sphere controlled reversible geometry reorganisations in copper(II) complexes
Reversible geometry reorganisations are demonstrated by cis-3,5-diamino-trans-hydroxycyclohexane (cis,trans-DAHC) copper(ii) fluoride complexes, with the concentration of water in the mother liquor controlling interconversion between blue crystals of 5-coordinate syn-[Cu(DAHC)(2)F](F).2CH(3)OH.H(2)O and red crystals of 4-coordinate anti-[Cu(DAHC)(2)](F)(2).2H(2)O. 相似文献
20.
《Polyhedron》1999,18(8-9):1355-1362
New symmetrical 2,6-bis{N-[2-(2-benzimidazolyl)-phenyl]iminomethyl}-4-methylphenol (L1) and unsymmetrical 2-N-[2-(2-benzimidazoyl)phenyl]iminomethyl-6-[(4-methylpiperazin-1-yl)-methyl]-4-methylphenol (L2) binucleating ligands have been synthesized. Complexation of these ligands with Cu(II) perchlorate and appropriate sodium salt offered the binuclear copper(II) complexes, [Cu2L(X)](ClO4)2, (X=Cl, OH and OAc 1–6). Their spectral, electrochemical and magnetic properties have been studied. Two distinct reduction peaks were observed at negative potentials. The electrochemical data shows that the complexes of L2 undergo reduction at less negative potential (E1pc=−0.15 to −0.25 V, E2pc=−0.45 to −0.65 V) when compared to the complexes of L1 (E1pc=−0.45 to −0.58 V, E2pc=−1.07 to −1.103 V). A variable temperature magnetic study on the complexes of the ligand L1 showed strong antiferromagnetic coupling between the copper atoms (−2J=285–295 cm−1), in contrast, the complexes of the ligand L2 showed weak antiferromagnetic interaction (−2J=60–85 cm−1). Electron spin resonance (ESR) spectra (RT) of the complexes of ligand L1 showed no signal and the complexes of ligand L2 showed a broad feature. 相似文献