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1.
The stability constants of the mixed-ligand complexes formed between Cu(Arm)2+, where Arm = 2,2′-bipyridine (Bpy) or 1,10-phenanthroline (Phen), and the monoanion or the dianion of 9-[2-(phosphonomethoxy)ethyl]-2-aminopurine (PME2AP), a structural isomer of the antivirally active 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA), were determined by potentiometric pH titrations in aqueous solution at 25 °C and I = 0.1 M (NaNO3). Detailed stability constant comparisons reveal that in the monoprotonated ternary Cu(Arm)(H;PME2AP)+ complexes the proton is at the phosphonate group and that stacking between Cu(Arm)2+ and H(PME2AP) plays a significant role. The ternary Cu(Arm)(PME2AP) complexes are considerably more stable than the corresponding Cu(Arm)(R-PO3) species, where represents a phosph(on)ate ligand with a group R that is unable to participate in any kind of interaction within the complexes. The increased stability is attributed to intramolecular stack formation in the Cu(Arm)(PME2AP) complexes and also, to a smaller extent, to the formation of 5-membered chelates involving the ether-oxygen present in the residue of PME2AP2−. This latter interaction was previously quantified by studying ternary Cu(Arm)(PME) complexes (PME2− = dianion of (phosphonomethoxy)ethane), which can form the 5-membered chelates but where no intramolecular ligand-ligand stacking is possible. Application of these results allows a quantitative analysis of the intramolecular equilibria involving three structurally different Cu(Arm)(PME2AP) species; e.g., about 5% of the Cu(Bpy)(PME2AP) system exist with the metal ion solely coordinated to the phosphonate group, 15% as a 5-membered chelate involving the ether-oxygen atom of the residue, and 80% with an intramolecular π-π stack between the purine moiety of PME2AP2− and the aromatic rings of Bpy. Finally, comparison of the stacking properties of PME2AP2− and PMEA2− in their ternary complexes reveals that stacking is somewhat more pronounced in the Cu(Arm)(PMEA) than in the Cu(Arm)(PME2AP) species. Speculatively, this reduced stacking intensity, together with a different hydrogen-bonding pattern, could well lead to a different positioning of the 2-aminopurine moiety (compared to the adenine residue) in the active site cavity of nucleic acid polymerases and thus be responsible for the reduced antiviral activity of PME2AP compared with that of PMEA.  相似文献   

2.
Mixed ligand complexes: [Co(L)(bipy)] · 3H2O (1), [Ni(L)(phen)] · H2O (2), [Cu(L)(phen)] · 3H2O (3) and [Zn(L)(bipy)] · 3H2O (4), where L2− = two -COOH deprotonated dianion of N-(2-benzimidazolyl)methyliminodiacetic acid (H2bzimida, hereafter, H2L), bipy = 2,2′ bipyridine and phen = 1,10-phenanthroline have been isolated and characterized by elemental analysis, spectral and magnetic measurements and thermal studies. Single crystal X-ray diffraction studies show octahedral geometry for 1, 2 and 4 and square pyramidal geometry for 3. Equilibrium studies in aqueous solution (ionic strength I = 10−1 mol dm−3 (NaNO3), at 25 ± 1 °C) using different molar proportions of M(II):H2L:B, where M = Co, Ni, Cu and Zn and B = phen, bipy and en (ethylene diamine), however, provides evidence of formation of mononuclear and binuclear binary and mixed ligand complexes: M(L), M(H−1L), M(B)2+, M(L)(B), M(H−1L)(B), M2(H−1L)(OH), (B)M(H−1L)M(B)+, where H−1L3− represents two -COOH and the benzimidazole N1-H deprotonated quadridentate (O, N, O, N), or, quinquedentate (O, N, O, N, N) function of the coordinated ligand H2L. Binuclear mixed ligand complex formation equilibria: M(L)(B) + M(B)2+ ? (B)M(H−1L)M(B)+ + H+ is favoured with higher π-acidity of the B ligands. For Co(II), Ni(II) and Cu(II), these equilibria are accompanied by blue shift of the electronic absorption maxima of M(II) ions, as a negatively charged bridging benzimidazolate moiety provides stronger ligand field than a neutral one. Solution stability of the mixed ligand complexes are in the expected order: Co(II) < Ni(II) < Cu(II) > Zn(II). The Δ log KM values are less negetive than their statistical values, indicating favoured formation of the mixed ligand complexes over the binary ones.  相似文献   

3.
Two new neutral, binuclear CuIICuII bis(oxamato) complexes with the formula [Cu2(opba)(pmdta)(MeOH)] · 1/2MeOH · dmf (3) and [Cu2(nabo)(pmdta)(MeOH)] (4), with opba = o-phenylene-bis(oxamato), nabo = 2,3-naphthalene-bis(oxamato), pmdta = N,N,N′,N″,N″-pentamethyldiethylenetriamine and dmf = dimethylformamide have been synthesized and their crystal structures have been determined. The structure of 3 consists of dimeric [Cu2(opba)(pmdta)(MeOH)] entities, joined together by mutual intermolecular Cu?O contacts of the Cu2+ ion of one [Cu(opba)]2− complex fragment and one carboxylate atom of the oxamato group of a second [Cu(opba)]2− complex fragment. The structure of 4 consists of neutral binuclear complexes joined together by hydrogen bonds and π-π interactions, giving rise to an unique supramolecular 1D-chain. The magnetic properties of 3 and 4 were studied by susceptibility measurements versus temperature. For the intramolecular J parameter, identical values of (−114 ± 2) cm−1 (3) and (−112 ± 2) cm−1 (4) were obtained.  相似文献   

4.
Combined pH-metric, UV-Vis, 1H NMR and EPR spectral investigations on the complex formation of M(II) ions (M=Co, Ni, Cu and Zn) with N-(2-benzimidazolyl)methyliminodiacetic acid (H2bzimida, hereafter H2L) in aqueous solution at a fixed ionic strength, I=10−1 mol dm−3, at 25 ± 1 °C indicate the formation of M(L), M(H−1L) and M2(H−1L)+ complexes. Proton-ligand and metal-ligand constants and the complex formation equilibria have been elucidated. Solid complexes, [M(L)(H2O)2] · nH2O (n=1 for M = Co and Zn, n=2 for M = Ni) and {Cu (μ-L) · 4H2O}n, have been isolated and characterized by elemental analysis, spectral, conductance and magnetic measurements and thermal studies. Structures of [Ni(L)(H2O)2] · 2H2O and {Cu(μ-L) · 4H2O}n have been determined by single crystal X-ray diffraction. The nickel(II) complex exists in a distorted octahedral environment in which the metal ion is coordinated by the two carboxylate O atoms, the amino-N atom of the iminodiacetate moiety and the pyridine type N-atom of the benzimidazole moiety. Two aqua O atoms function as fifth and sixth donor atoms. The copper(II) complex is made up of interpenetrating polymeric chains of antiferromagnetically coupled Cu(II) ions linked by carboxylato bridges in syn-anti (apical-equatorial) bonding mode and stabilized via interchain hydrogen bonds and π-π stacking interactions.  相似文献   

5.
The proligands PicMe-AaR (PicMe = methoxipicolyl-5-amide, where the amide substituent is an amino acid AaR = HisH, HisMe, IleH, IleMe, TrpH, TrpMe, HTyrEt, tBuTyrMe, HThrMe, tBuThrMe) and the complexes [VO(Pic-AaR)2] have been synthesised and characterised. A detailed EPR study of the VO2+/Pic-His systems in water revealed the predominance of the complex [VO(Pic-His)H2O] in the pH range 2-6, with tridentate coordination of Pic-His via the picolinate moiety and imidazole-Nδ. Speciation analyses of the binary systems VO2+/Pic-Aa (Aa = His, Ile, Trp) and the ternary systems VO2+/Pic-Aa/B (Aa = His, Ile; B = citrate (cit), lactate (lac), phosphate) showed a predominance of the ternary complexes [VO(Pic-Aa)(cit/lac)] and [VO(Pic-Aa)(cit/lac)OH] in the physiological pH regime. If, in addition, human serum albumin (HAS) and apotransferrin (Tf) are present, with all of the low and high molecular mass constituents in their blood serum concentrations, about two thirds of VO2+ is bound to the protein, while there is still a sizable amount of ternary complex [VO(Pic-Aa)(cit/lac)] present (about 1/4 for Pic-His and 1/3 for Pic-Ile) when the vanadium(IV) concentration is relatively high; at lower concentrations Tf is the predominant binder. Insulin-mimetic studies for VO2+/Pic-Aa (Aa = His, Ile, Tyr and Trp), based on a lipolysis assay with rat adipocytes, provided IC50 values of 0.41(1) for VO2+/Pic-His and VO2+/Pic-Ile, which compares with 0.87(17) for VOSO4.  相似文献   

6.
The macrocyclic symmetrical and a series of unsymmetrical binuclear copper(II) complexes have been synthesized by using mononuclear complex [CuL] [3,3′-((1E,7E)-3,6-dioxa-2,7-diazaocta-1,7-diene-1,8-diyl)bis(3-formyl-5-methyl-2-diolato)copper(II)]. Another compartment of the [CuL] have been condensed with various diamines like 1,2-bis(aminooxy)ethane (L1), 1,2-diamino ethane(L2a), 1,3-diamino propane(L2b), 1,4-diamino butane(L2c), 1,2-diamino benzene(L2d), 1,8-diamino naphthalene(L2e) and characterized by elemental, spectroscopic, and X-ray crystallographic methods. The influence of the coordination geometry and the ring size of the binucleating ligands on the electronic, redox, magnetic, catecholase activity, DNA binding and cleavage properties have been studied. The molecular structures of the symmetrical binuclear complex [Cu2L1(H2O)2](ClO4)2 (1) and unsymmetrical binuclear complex [Cu2L2b(ClO4)(H2O)]ClO4 (2b) were determined by X-ray crystallography. Both of them were discrete binuclear species in which each Cu(II) ions are in distorted square pyramid. The Cu?Cu distances vary from 3.0308 (2b) to 3.0361 Å (1). Electrochemical studies evidenced that two quasi-reversible one electron-transfer reduction waves −0.91 to −1.01 V, −1.26 to −1.55 V) for binuclear complexes are obtained in the cathodic region. Cryomagnetic investigation of the binuclear complexes reveals a weak antiferromagnetic spin exchange interaction between the Cu(II) ions within the complexes (−2J = 104.4-127.5 cm−1). The initial rate (Vin) for the oxidation of 3,5-di-tert-butylcatechol to o-quinone by the binuclear Cu(II)complexes are in the range 3.6 × 10−5 to 7.3 × 10−5 Ms−1. The binuclear Cu(II) complexes are avid binders to calf thymus DNA. The complexes display significant oxidative cleavage of circular plasmid pBR322 DNA in the presence of mercaptoethanol using the singlet oxygen as a reactive species. The aromatic diamine condensed macrocyclic ligands of copper(II) complexes display better DNA interaction and significant chemical nuclease activity than the aliphatic diamine condensed macrocyclic Cu(II) complexes.  相似文献   

7.
Ternary systems of Cu(II) with phosphocreatine (PCr) and the polyamines (PAs), ethylenediamine (en), 1,3-diaminopropane (tn), putrescine (Put), spermidine (Spd), and spermine (Spm), were investigated in aqueous solution through potentiometry, ultraviolet-visible, EPR and Raman spectroscopy. The binary complex CuPCr was also studied by Raman spectroscopy, and the calculation of the minimum stabilization energy was done assuming this molecule in aqueous solution. The stability constants of the CuPCrPA ternary complexes were determined by potentiometry (T = 25 °C, I = 0.1 mol L− 1, KNO3). The stability order determined was CuPCrSpm > CuPCrSpd > CuPCren > CuPCrtn > CuPCrPut, the same order of the corresponding binary complexes of Cu(II) with these polyamines. The evaluation of intramolecular PA-PCr interactions in protonated and deprotonated species of ternary complexes was carried out using the equation Δlog K = log βCuPCrPAHq + p − (log βCuPAHq + log βCuPCrHp). All of the CuPCrPA ternary complexes have a square planar structure and are bonded to PCr through the nitrogen atom of the guanidine group and the oxygen atom of the phosphate group, and to the PAs through two nitrogen atoms of the amine groups. The structure of the complex CuPCrSpm is planar with distortion towards tetrahedral. Calculation of the minimum stabilization energy for the CuPCr and CuPCrenH complexes confirmed the proposed coordination mode.  相似文献   

8.
The stability constants and the thermodynamic parameters of the formation of the binary complexes of trivalent Am3+, Cm3+ and Eu3+ with CDTA and of their ternary complexes with CDTA + IDA were determined by solvent extraction measurements in aqueous solutions of I = 6.60 m (NaClO4) at temperatures of 0-60 °C. The endothermic enthalpy and the positive entropy values reflect the significant effects of cation dehydration and of the rigidity of the ligand structure in the formation of these complexes. TRLFS and NMR (1H and 13C) data provided information on the structure of the ternary complexes in solution. The size and rigidity of CDTA affect the binding mode of IDA in the complexation of M(CDTA)(IDA)(H2O)3− and M(CDTA)(IDA)3− in which IDA has a bidentate coordination mode in the former and a tridentate coordination mode in the latter.  相似文献   

9.
Some copper(I) complexes of the type [Cu(L)(dppe)]X (1-4) [where L = (3-trifluoromethylphenyl)pyridine-2-ylmethylene-amine; dppe = 1,2-bis(diphenylphosphino)ethane; X = Cl, CN, ClO4 and BF4] have been synthesized by the condensation of 3-aminobenzotrifluoride with 2-pyridinecarboxaldehyde followed by the reaction with CuCl, CuCN, [Cu(MeCN)4]ClO4 and [Cu(MeCN)4]BF4 in presence of dppe. The complexes 1-4 were then characterized on the basis of elemental analysis, IR, UV-Vis and 1H NMR spectral studies. The representative complex of the series 4 has been characterized by single crystal X-ray diffraction which reveal that in complex the central copper(I) ion assumes the irregular pseudo-tetrahedral geometry. The catalytic activity of the complexes was tested and it was found that all the complexes worked as effective catalyst in the amination of aryl halide.  相似文献   

10.
Two new binuclear copper complexes, [Cu2(oxpn)(bpy)(pic)(H2O)](pic) (1) and [Cu2(oxpn)(Me2bpy)(pic)](pic) (2) [H2oxpn = N,N′-bis(3-aminopropyl)oxamide; Hpic = 2,4,6-trinitrophenol; bpy = 2,2′-bipyridine; Me2bpy = 4,4′-dimethyl-2,2′-bipyridine], have been synthesized and characterized by elemental analyses, conductivity measurements, IR, UV-visible spectroscopy and single crystal X-ray analyses. Both complexes have similar molecular structures. In complex 1, the central two Cu(II) atoms are bridged by cis-oxpn2− with the Cu1-Cu2 separation of 5.221 Å and the polyhedron of each copper atom is a square-pyramid. Similarly, complex 2 is a cis-oxpn2−-bridged binuclear complex with the Cu1-Cu2 separation of 5.196 Å. Cu1(II) central atom situated in a tetrahedral geometry is four-coordinated and Cu(II) atom situated in a square-pyramidal geometry is five-coordinated. Hydrogen bonding interactions and π-π stacking interactions link the binuclear copper complex 1 or 2 into a 2D infinite network. The antibacterial assays indicate that the two complexes showed better activities than their ligands. The interactions of the two binuclear complexes with herring sperm DNA (HS-DNA) have been studied by UV absorption titration, fluorescence titration and viscosity measurements. The results suggest that the two binuclear complexes bind to HS-DNA via an intercalative mode.  相似文献   

11.
Ternary Cu(II) complexes [Cu(II)(saltrp)(B)] (1,2), (saltrp = salicylidene tryptophan, B = 1,10 phenathroline (1) or 2,2′ bipyridine (2)) were synthesized and characterized. Complex 2 was structurally characterized by single crystal X-ray crystallography. The molecular structure shows a distorted square pyramidal coordination geometry (CuN3O2) in which the ONO donor Schiff base is bonded to the Cu(II) in the basal plane. The N,N donor heterocyclic base displays an axial-equatorial binding mode. CT-DNA binding studies revealed that the complexes show good binding propensity (Intrinsic binding constant, Kb = 3.32 × 105 M−1 for 1 and Kb = 3.10 × 105 M−1 for 2). The catalytic role of these complexes in the oxidative and hydrolytic cleavage of DNA was studied in detail. Complex 1 binds and cleaves DNA more efficiently as compared to 2. From the kinetic experiments, rate constants for the hydrolysis of phosphodiester bond of DNA backbone were determined as 1.94 h−1 and 1.05 h−1 for 1 and 2 respectively. It amounts to (2.93-5.41) × 107 fold rate enhancement compared to uncatalyzed double stranded DNA, which is impressive as compared to related Cu(II) Schiff base complexes.  相似文献   

12.
The mixed-ligand complex formation in the systems Hg2+-Edta4−-L (L = Cys2−, Met) has been studied by means of calorimetry, pH-potentiometry and NMR spectroscopy in aqueous solution at 298.15 K and the ionic strength of I = 0.5 (KNO3). The thermodynamic parameters of formation of the HgEdtaL, HgEdtaHL and (HgEdta)2L complexes have been determined. The most probable coordination mode for the complexone and the amino acid in the mixed-ligand complexes is discussed.  相似文献   

13.
Three novel ternary copper(II) complexes, [Cu2(phen)2(l-PDIAla)(H2O)2](ClO4)2·2.5H2O (1), [Cu4(phen)6(d,l-PDIAla)(H2O)2](ClO4)6·3H2O (2) and [Cu2(phen)2(d,l-PDIAla)(H2O)](ClO4)2·0.5H2O (3) (phen = 1,10-phenanthroline, H2PDIAla = N,N’-(p-xylylene)di-alanine acid) have been synthesized and structurally characterized by single-crystal X-ray crystallography and other structural analysis. Spectrometric titrations, ethidium bromide displacement experiments, CD (circular dichroism) spectral analysis and viscosity measurements indicate that the three compounds, especially the complex 3, strongly bind to calf-thymus DNA (CT-DNA). The intrinsic binding constants of the ternary copper(II) complexes with CT-DNA are 0.89 × 105, 1.14 × 105 and 1.72 × 105 M−1, for 1, 2 and 3, respectively. Comparative cytotoxic activities of the copper(II) complexes are also determined by acid phosphatase assay. The results show that the ternary copper(II) complexes have significant cytotoxic activity against the HeLa (Cervical cancer), HepG2 (hepatocarcinoma), HL-60 cells (myeloid leukemia), A-549 cells (pulmonary carcinoma) and L02 (liver cells). Investigations of antioxidation properties show that all the copper(II) complexes have strong scavenging effects for hydroxyl radicals and superoxide radicals.  相似文献   

14.
A new ligand, N,N′-dibenzylethane-1,2-diamine (L) and its four transition metal(II) complexes, ML2(OAc)2 · 2H2O (M = Cu, Ni, Zn, Co), have been synthesized and characterized by elemental analysis, mass spectra, molar conductivity, NMR and IR. Moreover, the crystals structure of Cu(II) and Ni(II) complexes characterized by single crystal X-ray diffraction showed that the complexes have a similar molecular structure. Ni(II) has an regular octahedral coordination environment complexes, but typical Jahn Teller effect influenced Cu(II) in an elongated octahedral environment. The interaction between complexes and calf thymus DNA were studied by UV and fluorescence spectra measure, which showed that the binding mode of complexes with DNA is intercalation. Under physiological pH condition, the effects of Cu(OAc)2L2 · 2H2O and Ni(OAc)2L2 · 2H2O on human serum albumin were examined by fluorescence. The results of spectroscopic measurements suggested that the hydrophobic interaction is the predominant intermolecular force. The enthalpy change ΔH0 and the entropy change ΔS0 of Cu(OAc)2L2 · 2H2O and Ni(OAc)2L2 · 2H2O were calculated to be −11.533 kJ mol−1 and 46.339 J mol−1 K−1, −11.026 kJ mol−1 and 46.396 J mol−1 K−1, respectively, according to the Scatchard’s equation. The quenching mechanism and the number of binding site (n ≈ 1) were also obtained from fluorescence titration data.  相似文献   

15.
The interaction of copper complexes of (−)-epicatechin gallate (ECG) and (−)-epigallocatechin gallate (EGCG) with calf thymus DNA (ct-DNA) was investigated by UV-visible (UV-Vis), fluorescence and circular dichroism along with melting studies. It was observed that both copper complexes quench the fluorescence intensity of ethidium bromide bound ct-DNA upon binding, resulting in a ground state complex formation by a static quenching process. The binding constants evaluated from fluorescence data were supported by the UV-Vis study. The values ranged from 0.84 to 1.07 × 105 M−1 and 1.14 to 1.04 × 105 M−1 for Cu(II)-ECG and Cu(II)-EGCG, respectively for the temperature range 21-42 °C with two binding sites. Thermodynamic parameters obtained are suggestive of the involvement of different modes of interaction during binding for each complex although both were found to be intercalating in nature. Circular dichroism studies and variations in the melting temperature reveal unwinding of the ct-DNA helix with conformational changes due to binding.  相似文献   

16.
The oxidative addition reactions between two different [Ir(cod)(LL′)] complexes (LL′ = hpt and AnMetha) and iodomethane was kinetically investigated. The rate of oxidative addition was determined as 2.2(2) × 10−2 and 2.69(6) × 10−2 M−1 s−1 for [Ir(cod)(hpt)] and [Ir(cod)(AnMetha)] in nitromethane respectively. The large negative entropy of activation for the above-mentioned reactions in different solvents clearly point to an associative mechanism. An intrinsic volume of activation of −30.5(3) and −28(3) cm3 mol−1 was determined for [Ir(cod)(hpt)] and [Ir(cod)(AnMetha)], respectively. A linear transition state with large charge separation and central ion contraction due to oxidation, contributes to the negative volume of activation.  相似文献   

17.
The stability and the associated thermodynamic parameters of the binary and the ternary complexes of trivalent Am, Cm, and Eu with IDA and with EDTA + IDA, were determined by using a solvent extraction technique for aqueous solutions of I = 6.60 m (NaClO4) at temperatures of 0-60 °C. The endothermic enthalpy and the positive entropy reflect the significant effect of dehydration in the formation of these complexes at high ionic strength. TRLFS and NMR (1H and 13C) data helped to establish the structure of the ternary complexes in solution. In the ternary complex M(EDTA)(IDA)3−, EDTA binds via four carboxylates and two nitrogens, and IDA via two carboxylates and one nitrogen to the central Eu3+.  相似文献   

18.
Adduct formation of ternary Pt(II) complexes composed of an amino acid and an aromatic diimine, [Pt(A)(DA)] (A = glycinate (Gly), alaninate (Ala), valinate, or arginine (Arg); DA = 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen)), with flavin mononucleotide (FMN) and anthraquinone-2-sulfonate (AQS) were investigated by spectroscopic, X-ray diffraction, and electrochemical methods. The Pt(II) complexes formed 1:1 [Pt(A)(DA)]-FMN adducts by stacking with the aromatic moiety of FMN, and the stability constants, log K, for the systems with [Pt(A)(phen)] (A = Gly, Ala, and Arg) and [Pt(Arg)(bpy)] were determined to be 2.83(8)-3.42(6) from 1H NMR spectra at 25 °C in D2O (I = var.). The structure of the adduct [Pt(Ala)(phen)](AQS) (1) was determined by X-ray analysis to involve a π-π stacking interaction between coordinated phen and AQS with the distance of 3.400(7) Å and a hydrogen bond between the sulfonate moiety of AQS and the amino group of coordinated Ala. Cyclic voltammetry of the 1:1 [Pt(A)(DA)]-FMN systems in a phosphate buffer (pH 7.0) showed that the potentials, E1/2, for the two-electron redox process of FMN shifted to higher values by 18-31 mV as compared with the value for free FMN.  相似文献   

19.
The substitution behaviour of [PtCl(R)(COD)] (R = Me and Fc) complexes, by the stepwise addition of phosphine ligands, L (L = PPh3, PEt3 and P(NMe2)3), were investigated in situ by 1H and 31P NMR spectroscopy. Addition of less than two equivalents of the phosphine ligand results in the formation of dimeric molecules with the general formula trans-[Pt(R)(μ-Cl)(L)]2 for the sterically demanding systems where R = Me/L = P(NMe2)3 and R = Fc/L = PEt3, PPh3 and P(NMe2)3 while larger quantities resulted in cis- and trans mixtures of mononuclear complexes being formed. In the case of the relatively small steric demanding, strongly coordinating, PEt3 ligand the trans-[PtCl(R)(PEt3)2] mononuclear complexes were exclusively observed in both cases. The crystal structures of the two substrates, [PtCl(R)(COD)] (R = Me or Fc), as well as the cis-[PtCl(Fc)(PPh3)2] substitution product are reported.  相似文献   

20.
The synthesis, structural characterization and magnetic property of two new coordination polymers [Cu(pyz)(μ-CH3CO2)4]n (1) and [Cu(pyz)(μ-CCl3CO2)4]n (2) (pyz = pyrazine) are reported. Here, the carboxylato bridged two dinuclear copper(II) complexes are linked through pyrazine giving a 1-D alternating chain. The magnetic property of the complexes indicates a significant difference originated from the introduction of electron withdrawing substituent on the bridging dicarboxylate. Complex 1 exhibits strong antiferromagnetic interactions with J = −344.61 cm−1, whereas 2 exhibits comparatively less strong antiferromagnetic coupling with J = −238.53 cm−1.  相似文献   

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