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1.
Li Xu Yang-Yin Xie Nan-Jing Zhong Zhen-Hua Liang Juan He Hong-Liang Huang Yun-Jun Liu 《Transition Metal Chemistry》2012,37(2):197-205
Two ruthenium(II) polypyridyl complexes, namely [Ru(phen)2(DMDPPZ)](ClO4)2
1 (phen = 1,10-phenanthroline, DMDPPZ = 3,6-dimethyldipyrido[3,2-a:2′,3′-c]phenazine) and [Ru(dmp)2(DMDPPZ)](ClO4)2
2 (dmp = 2,9-dimethyl-1,10-phenanthroline), have been synthesized and characterized. The DNA-binding properties of the complexes
were investigated by spectrophotometric methods, viscosity measurements, and photoactivated cleavage studies. The DNA-binding
constants for complexes 1 and 2 have been determined as 8.78 (±0.94) × 105 M−1 (s = 3.02) and 1.26 (±0.35) × 105 M−1 (s = 1.69), respectively. The results suggest that these complexes bind to calf thymus DNA through intercalation. When irradiated
at 365 nm, the complexes promote the photocleavage of pBR322 DNA, and complex 1 cleaves DNA more effectively than complex 2 under comparable experimental conditions. The cytotoxicities of complexes 1 and 2 have been evaluated by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) method. Complex 2 shows higher anticancer potency than complex 1 against four tumor cell lines. The apoptosis-inducing activity was assessed by acridine orange/ethidium bromide staining
assay, and the antioxidant activities of these complexes against hydroxyl radical were also explored. 相似文献
2.
Cheng-Hui Zeng Yun-Jun Liu Zheng-Zheng Li Zhen-Hua Liang Hong-Liang Huang Fu-Hai Wu 《Transition Metal Chemistry》2010,35(6):731-736
Two new ruthenium(II) polypyridyl complexes, [Ru(dmp)2(maip)](ClO4)2
1 (maip = 2-(3-aminophenyl)imizado[4,5-f][1,10]phenanthroline and [Ru(dmp)2(paip)](ClO4)2
2 (paip = 2-(4-aminophenyl)imidazo[4,5-f][1,10]phenanthroline, dmp = 2, 9-dimethyl-1,10-phenanthroline) have been synthesized and characterized.
The DNA-binding behaviors of complexes 1 and 2 were studied by viscosity measurements, thermal denaturation, and absorption titration. The results show that the two complexes
intercalate between the base pairs of DNA. The DNA-binding constants K
b for complexes 1 and 2 were determined to be 3.23 ± 0.16 × 104 M−1 (s = 0.97) and 4.34 ± 0.65 × 104 M−1 (s = 1.13). The cytotoxicity of these complexes has been evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium
bromide) assay. The IC50 values are 35.70, 41.04, 55.25 and 37.50 for complex 1 and 37.02, 103.08, 130.07 and 37.80 for complex 2 against BEL-7402, C-6, HepG-2 and MCF-7 cell lines, respectively. The antioxidant activity against hydroxyl radical (OH•)
was also investigated. 相似文献
3.
Shanmugam Sreedaran Kuppannan Shanmuga Bharathi Aziz Kalilur Rahiman Raju Prabu Raman Jagadesh Nanjian Raaman Vengidusamy Narayanan 《Transition Metal Chemistry》2009,34(1):33-41
A series of trinuclear Cu(II) complexes have been prepared by Schiff base condensation of 1,8-[bis(3-formyl-2-hydroxy-5-methyl)benzyl]-l,4,8,11-tetraazacyclotetradecane
and 1,8-[bis(3-formyl-2-hydroxy-5-bromo)benzyl]-l,4,8,11-tetraazacyclotetradecane with aromatic and aliphatic diamines, Cu(II)
perchlorate and triethylamine. The complexes were characterized by elemental and spectroscopic analysis. Electrochemical studies
of the complexes in DMF solution show three irreversible one-electron reduction processes around Epc
1 = −0.73 to −0.98 V, Epc
2 = −0.91 to −1.20 V and Epc
3 = −1.21 to −1.33 V. ESR spectra and magnetic moments of the trinuclear Cu(II) complexes show the presence of antiferromagnetic
coupling. The rate constants for hydrolysis of 4-nitrophenylphosphate by the Cu(II) complexes are in the range of 3.33 × 10−2 to 7.58 × 10−2 min−1. The rate constants for the catecholase activity of the complexes fall in the range of 2.67 × 10−2 to 7.56 × 10−2 min−1. All the complexes were screened for antifungal and antibacterial activity. 相似文献
4.
Wen-Kui Dong Gang Wang Shang-Sheng Gong Jun-Feng Tong Yin-Xia Sun Xiong-Hou Gao 《Transition Metal Chemistry》2012,37(3):271-277
Two new Cu(II) complexes, [Cu(L1)2] (1) and [Cu(L2)2] (2) (HL1 = (E)-3-bromo-5-chloro-2-hydroxy benzaldehyde O-methyl oxime; HL2 = (E)-3-bromo-5-chloro-2-hydroxy benzaldehyde O-ethyl oxime), have been synthesized and characterized by physicochemical and spectroscopic methods. X-ray crystallographic
analyses show that complexes 1 and 2 have similar structures, consisting of one Cu(II) atom and two L− units. In both complexes, the Cu(II) atom, lying on an inversion center, 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 ligands. Moreover,
both complexes form an infinite three-dimensional supramolecular structure involving intermolecular C–H···Br hydrogen bonds
and π···π stacking interactions between the metal chelate rings and aromatic rings. Substituent effects in the two complexes
are discussed. 相似文献
5.
Adisorn Ratanaphan Tidarat Nhukeaw Pornvichai Temboot Kanidtha Hansongnern 《Transition Metal Chemistry》2012,37(2):207-214
A bidentate ligand, 5-chloro-2-(phenylazo)pyridine (Clazpy), and its two polypyridyl ruthenium(II) complexes, [Ru(Clazpy)2bpy]Cl2·7H2O (1) and [Ru(Clazpy)2phen]Cl2·8H2O (2), were synthesized and characterized. The DNA-binding properties of these complexes with DNA, the breast cancer susceptibility
gene 1 (BRCA1), and the pBIND plasmid DNA were probed by photocleavage, electronic absorption titration, ethidium bromide quenching, and
thermal denaturation. Both complexes were found to bind to the BRCA1 fragment through the intercalative mode into the base pairs of DNA, and the DNA-binding constants (Kb) for 1 and 2 were 7.0 × 104 M−1 and 5.1 × 105 M−1, respectively. In addition, both complexes enhanced the single-stranded cleavage of the plasmid DNA. Under comparable experimental
conditions, 2 cleaved DNA more effectively than 1, in a dose–response manner. The data indicated that the binding affinity of these two complexes to DNA was dependent on the
aromatic planarity and hydrophobicity of the intercalative polypyridyl ligand. 相似文献
6.
Nikolay Kaloyanov Mihail Neykov Diana W. Wesselinova Georgi D. Dimitrov 《Central European Journal of Chemistry》2012,10(4):1034-1041
Novel heavy metal complexes: Sr(5-NH2-phen)4(NO3)(OH)(H2O)2 (1) (synthesized via a static self-assembly process) and Sn(phen)(NO3)(OH)(H2O) (2), Sn(5-NH2-phen)(OH)(Cl)(H2O) (3), Pb(5-NH2-phen)(NO3)2(H2O) (4) (obtained via metal competitive reactions under mild conditions) were reported. The coordination compounds were characterized by elemental
analysis, FTIR-spectroscopy and FAB-mass spectrometry. Their cytotoxicity was measured by MTS-test towards human tumour (MDA-MB-231,
HT-29, HeLa, HepG2) and non-tumour diploid (Lep-3) cell lines. The most pronounced cytotoxic effect on all cancer lines showed
1 and 4 at their high concentrations as well as 1 at its lower ones (≤ 4×10−2 mg). Therefore, strontium complex of 5-amino-o-phenanthroline (1) exhibited the widest antitumour spectrum activity, having no toxicity to non-tumour cells at quantities ≤ 4×10−2 mg. The computed EC50 values of 1–4 against MDA-MB-231, HT-29, HeLa, HepG2 varied from 1.40×10−3 to 6.31×10−6 M. Towards Lep-3 substances 2–4 showed IC50 7.52×10−4 − 0.44 M. Substance 1 possess EC50=1.26×10−7 M to the non-tumour cells.
相似文献
7.
Yan‐Ping Zhang Yue Li Guan‐Cheng Xu Jin‐Yu Li Hua‐Ying Luo Jin‐Yao Li Li Zhang Dian‐Zeng Jia 《应用有机金属化学》2019,33(3)
Two new complexes, namely [Cu6L6] ( 1 ) and [Zn(HL)2] ( 2 ) (H2L = N‐(1‐phenyl‐3‐methyl‐4‐propenylidene‐5‐pyrazolone)‐2‐furancarboxylic acid hydrazide), have been synthesized and characterized. Single crystal X‐ray analysis indicates that complex 1 has a hexanuclear structure and complex 2 exhibits a mononuclear structure. The DNA/bovine serum albumin (BSA) binding properties of complexes 1 and 2 were investigated by absorption spectroscopy and fluorescence quenching. Both complexes could effectively intercalate to DNA with calculated quenching constants of 2.6 × 105 and 1.25 × 105 M?1, respectively. The quenching mechanism of the intrinsic fluorescence of BSA by the complexes was found to be a static one. The cytotoxicities of 1 and 2 were investigated in two human tumor cell lines, human esophageal cancer cells (Eca‐109) and cervical cancer cells (HeLa). Complex 1 exhibits higher antitumor activity than 2 . Furthermore, 1 can inhibit HeLa cells by inducing apoptosis and G0/G1 phase cell cycle arrest. All results demonstrate that 1 and 2 both have DNA/BSA binding capacity and antitumor activity. 相似文献
8.
Thathan Premkumar Subbiah Govindarajan 《Journal of Thermal Analysis and Calorimetry》2010,100(2):725-732
The new hydrazinium lanthanide metal complexes of 2-pyrazinecarboxylic acid (HpyzCOO) of the formulae (N2H5)2[Ln(pyzCOO)5] · 2H2O (1), where Ln = La or Ce and (N2H5)3[Ln(pyzCOO)4(H2O)] · 2NO3 (2), where Ln = Pr, Nd, Sm or Dy have been synthesized and characterized by physico-chemical methods. The IR absorption bands
of N–N stretching at 960 cm−1 unambiguously prove the existence of N2H5
+ ions. The bonding parameters β, b1/2, % δ and η, have been calculated from the electronic spectroscopic (hypersensitive) bands of Pr(III) and Nd(III) complexes.
All the complexes undergo endothermic followed by exothermic decomposition to leave the respective metal oxides as the end
products. However, the DTA of the complexes 2 demonstrate rather sharp peak than the complexes 1, owing to overwhelming exothermicity, which may be due to the loss of both hydrazine and nitrate moieties in the same step.
The X-ray powder diffraction studies reveal the existence of isomorphism among the member complexes. 相似文献
9.
Four pyridinecarboxamide iron dicyanide building blocks and one Mn(III) compound have been employed to assemble cyanide-bridged
heterometallic complexes, resulting in a series of trinuclear cyanide-bridged FeIII–MnII complexes: {[Mn(DMF)2 (MeOH)2][Fe(bpb)(CN)2]2}·2DMF (1), {[Mn(MeOH)4][Fe(bpmb)(CN)2]2}·2MeOH·2H2O (2), {[Mn(MeOH)4][Fe(bpdmb)(CN)2]2}·2MeOH·2H2O (3) and {[Mn(MeOH)4][Fe(bpClb)(CN)2]2}·4MeOH (4) (bpb2− = 1,2-bis(pyridine-2-carboxamido)benzenate, bpmb2− = 1,2-bis(pyridine-2-carboxamido)-4-methyl-benzenate, bpdmb2− = 1,2-bis(pyridine-2-carboxamido)-4,5-dimethyl-benzenate, bpClb2− = 1,2-bis(pyridine-2-carboxamido)-4-chloro-benzenate). Single-crystal X-ray diffraction analysis shows their similar sandwich-like
structures, in which the two cyanide-containing building blocks act as monodentate ligands through one of their two cyanide
groups to coordinate the Mn(II) center. Investigation of the magnetic properties of these complexes reveals antiferromagnetic
coupling between the neighboring Fe(III) and Mn(II) centers through the bridging cyanide group. A best fit to the magnetic
susceptibilities of complexes 1 and 3 gave the magnetic coupling constants J = −1.59(2) and −1.32(4) cm−1, respectively. 相似文献
10.
Hérica A. Magosso Natália Fattori Leliz T. Arenas Yoshitaka Gushikem 《Cellulose (London, England)》2012,19(3):913-923
This work describes for the first time the synthesis and characterization of new promising materials based on cellulose (Cel)
and cellulose acetate (Celac), previously modified with aluminum oxide (CelAl and CelacAl) and post functionalized with 1,4-diazabicyclo
[2.2.2] octane-n-propyltrimethoxysilane chloride (SiDbCl2), resulting the chemically modified hybrid materials CelAl/SiDbCl2 and CelacAl/SiDbCl2. The materials have shown to be useful in the adsorption of CuCl2 from ethanol, presenting high effective adsorption capacity. In the adsorption process, the copper ions diffuse into the
solid solution interface and are retained as anionic complexes CuCl3− or CuCl42−. An expressive effective adsorption capacity tQ, as well as the stability constants β1 and β2, were found for both adsorbents: (a) CelAl/DbCl2: tQ = 0.33 × 10−3 mol g−1, log β1 = 4.23 (±0.04) and log β2 = 6.99 (±0.03); (b) CelacAl/DbCl2: tQ = 0.48 × 10−3 mol g−1, log β1 = 5.1 (±0.1) and log β2 = 8.3 (±0.1). Both adsorbent materials are potentially useful in the pre-concentration and further analysis of Cu(II) present
in trace amounts in ethanol, extensively used as an automotive fuel in Brazil. Regeneration of the adsorbents requires a very
simple procedure consisting in their immersion in aqueous solution which causes the immediate release of the Cu(OH2)n2+ species to the solution phase. 相似文献
11.
The electrode characteristics and selectivities of PVC-based thiocyanate selective polymeric membrane electrode (PME) incorporating
the newly synthesized zinc complex of 6,7:14,15-Bzo2-10,11-(4-methylbenzene)-[15]-6,8,12,14-tetraene-9,12-N2-1,5-O2 (I
1
) and zinc complex of 6,7:14,15-Bzo2-10,11-(4-methylbenzene)-[15]-6,14-diene-9,12-dimethylacrylate-9,12-N2-1,5-O2 (I
2
) are reported here. The best response was observed with the membrane having a composition of I2:PVC:o-NPOE:HTAB in the ratio of 6:33:59:2 (w/w; milligram). This electrode exhibited Nernstian slope for thiocyanate ions over working concentration range of 4.4 × 10−7 to 1.0 × 10−2 mol L−1 with detection limit of 2.2 × 10−7 mol L−1. The performance of this electrode was compared with coated graphite electrode (CGE), which showed better response characteristics
w.r.t Nernstian slope 59.0 ± 0.2 mV decade−1 activity, wide concentration range of 8.9 × 10−8 to 1.0 × 10−2 mol L−1 and detection limit of 6.7 × 10−8 mol L−1. The response time for CGE and PME was found to be 8 and 10 s, respectively. The proposed electrode (CGE) was successfully
applied to direct determination of thiocyanate in biological and environmental samples and also as indicator electrode in
potentiometric titration of SCN− ion. 相似文献
12.
Ming-Li Liu Jian-Min Dou Da-Cheng Li Da-Qi Wang Jian-Zhong Cui 《Transition Metal Chemistry》2012,37(1):117-124
The thiosemicarbazide and hydrazide Cu(II) complexes, [Cu3L21(py)4Cl2] (1), [Cu(HL2)py] (2) and [Cu(HL3)py] (3), (H2L1 = 1-picolinoylthiosemicarbazide, H3L2 = N′-(2-hydroxybenzylidene)-3-hydroxy-2-naphthohydrazide, H3L3 = 2-hydroxy-N′-((2-hydroxy-naphthalen-1-yl)methylene)benzohydrazide) have been prepared and characterized through physicochemical and spectroscopic
methods as well as X-ray crystallography. Complex 1 has a centrosymmetric structure with –N–N– bridged Cu3 skeleton. Neighboring molecules are linked into a 3D supermolecular framework by π–π stacking interactions, N–H···Cl and
C–H···Cl hydrogen bonds. Complexes 2 and 3 have similar planar structures but different dimers formed by concomitant Cu···N and Cu···O interactions, respectively. Solvent
accessible voids with a volume of 391 ?3 are included in the structure of complex 2, indicating that this complex is a potential host candidate. Thermogravimetric analysis shows that the three complexes are
stable up to 100 °C. 相似文献
13.
Xian W. Huang Wen T. Zhu Jia C. Zhang Guo J. Su 《Monatshefte für Chemie / Chemical Monthly》2012,35(6):101-107
Abstract
Two new Co(II) complexes [Co(ipH)2(bdipH)]2+ and [Co(8-HQ)2(bdipH)] (ipH = imidazo[4,5-f][1,10]phenanthroline, bdipH = 2-(benzo[d][1,3]dioxol-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline, 8-HQ = 8-hydroxyquinoline) were synthesized and characterized in detail by elemental analysis, IR, and UV–Vis spectroscopic techniques. The effects of pH on the UV–Vis absorption and emission spectra of the complex were studied. The interaction of the two complexes with calf thymus DNA was explored by using viscosity measurements, electronic absorption titration, competitive binding experiments, and cyclic voltammetry. The experimental results show that complex [Co(ipH)2(bdipH)]2+ exhibits pH-sensitive emission, the two complexes can bind to DNA in an intercalation mode, and the DNA binding affinity of complex [Co(ipH)2(bdipH)]2+ (K b = 2.11 × 105 M−1) is greater than that of complex [Co(8-HQ)2(bdipH)] (K b = 1.76 × 105 M−1). The results show that the size and shape of the ancillary ligand have significant effects on the binding affinity of DNA and complexes. 相似文献14.
Complexation of U(VI), Ce(III) and Nd(III) with acetohydroxamic acid in perchlorate aqueous solution
Dong-Yong Chung Eun-Kyoung Choi Eil-Hee Lee Kwang-Wook Kim 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(2):315-319
Complexes of UO2
2+, Ce3+ and Nd3+ (M) with acetohydroxamic acid (AHA or L) in an aqueous solution have been investigated by the pH-spectral titration method
at 25 °C in an aqueous medium of 1.0 M NaClO4 ionic strength. Cerium(III) and neodymium(III) form [ML]2+, [ML2]+, [ML3] complexes with acetohydroxamic acid, while in case of UO2
2+ form [UO2L]+, [UO2L2] complexes with acetohydroxamic acid. Data processing with SQUAD program calculates the best values for the stability constants
from pH-spectrophotometric titration data. The protonation constant obtained was pK1 = 9.15 ± 0.04 at 25 °C. The stability constants for acetohydroxamic acid with UO2
2+, Ce3+ and Nd3+ were β1 = 7.22 ± 0.011, β2 = 14.89 ± 0.018 for UO2
2+ and β1 = 5.05 ± 0.062, β2 = 10.60 ± 0.076, β3 = 16.23 ± 0.088 for Ce3+ and β1 = 5.90 ± 0.028, β2 = 12.22 ± 0.038, β3 = 18.58 ± 0.042 for Nd3+, respectively. 相似文献
15.
Mark A. W. Lawrence Sonia E. Thomas Paul T. Maragh Tara P. Dasgupta 《Transition Metal Chemistry》2011,36(5):553-563
The kinetics of the intra-molecular electron transfer of an adduct of l-ascorbic acid and the [Fe3IIIO(CH3COO)6(H2O)3]+ cation in aqueous acetate buffer was studied spectrophotometrically, over the ranges 2.55 ≤ pH ≤ 3.74, 20.0 ≤ θ ≤ 35.0 °C,
at an ionic strength of 0.50 and 1.0 mol dm−3 (NaClO4). The reaction of l-ascorbic acid and the complex cation involves the rapid formation of an adduct species followed by a slower reduction in
the iron centres through consecutive one-electron transfer processes. The final product of the reaction is aqueous iron(II)
in acetate buffer. The proposed mechanism involves the triaqua and diaqua-hydroxo species of the complex cation, both of which
form adducts with l-ascorbic acid. At 25 °C, the equilibrium constant for the adduct formation was found to be 86 ± 15 and 5.8 ± 0.2 dm3 mol−1 for the triaqua and diaqua-hydroxo species, respectively. The kinetic parameters derived from the rate expression have been
found to be: k
0 = (1.12 ± 0.02) × 10−2 s−1 for the combined spontaneous decomposition and k
1 = (4.47 ± 0.06) × 10−2 s−1 (ΔH
1‡ = 51.0 ± 2.3 kJ mol−1, ΔS
1‡ = −100 ± 8 J K−1 mol−1), k
2 = (4.79 ± 0.38) × 10−1 s−1 (ΔH
2‡ = 76.5 ± 0.8 kJ mol−1, ΔS
2‡ = 6 ± 3 J K−1 mol−1) for the triaqua and diaqua-hydoxo species, respectively. 相似文献
16.
From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Mg2+(aq) + 1·Sr2+(nb) ⇆ 1·Mg2+(nb) + Sr2+(aq) taking place in the two-phase water–nitrobenzene system (1 = beauvericin; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K
ex (Mg2+, 1·Sr2+) = 0.0 ± 0.1. Further, the stability constant of the 1·Mg2+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C as log βnb (1·Mg2+) = 9.1 ± 0.2. By using quantum mechanical DFT calculations, the most probable structures of the non-hydrated 1·Mg2+ and hydrated 1·Mg2+·3H2O complex species were predicted. 相似文献
17.
Diacetylplatinum(II) complexes [Pt(COMe)2(N^N)] (N^N = bpy, 3a; 4,4′-t-Bu2-bpy, 3b) were found to undergo oxidative addition reactions with organyl halides. The reaction of 3a with methyl iodide and propargyl bromide led to the formation of the cis addition products (OC-6-34)-[Pt(COMe)2(R)X(bpy)] (R = Me, X = I, 4a; CH2C≡CH, X = Br, 4k). Analogous reactions of 3a with ethyl iodide, benzyl bromide, and substituted benzyl bromides, 3-(bromomethyl)pyridine, 2-(bromomethyl)thiophene, allyl
bromide, and cyclohex-2-enyl bromide led to exclusive formation of the trans addition products (OC-6-43)-[Pt(COMe)2(R)X(bpy)] (X = I, R = Et, 4b; X = Br, R = CH2C6H5, 4c; CH2C6H4(o-Br), 4d; CH2C6H4(p-COOH), 4e; CH2-3-py (3-pyridylmethyl), 4f; CH2-2-tp (2-thiophenylmethyl), 4g; CH2CH=CH2, 4h; c-hex-2-enyl (cyclohex-2-enyl), 4i). All complexes 4 were characterized by microanalysis, 1H and 13C NMR and IR spectroscopy. Additionally, complexes 4a, 4f, and 4g were characterized by single-crystal X-ray diffraction analyses. Reactions of 3a and 3b with o-, m- and p-bis(bromomethyl)benzene, respectively, led to the formation of dinuclear platinum(IV) complexes [{Pt(COMe)2Br(N^N)}2-{μ-(CH2)2C6H4}] (5). These complexes were characterized by microanalysis, IR spectroscopy, and depending on their solubility by 1H and 13C NMR spectroscopy, too. A single-crystal X-ray diffraction analysis of complex [{Pt(COMe)2Br(bpy)}2{μ-m-(CH2)2C6H4}] (5b) confirmed its dinuclear composition. The solid-state structures of 4a, 4f, 4g, and 5b are discussed in terms of C–H···O and O–H···O hydrogen bonds as well as π–π stacking between aromatic rings. 相似文献
18.
Hongmei Shi Shipeng Liu Shigang Shen Shuying Huo Weijun Kang 《Transition Metal Chemistry》2009,34(8):821-826
Kinetics of oxidation of dl-pipecolinate by bis(hydrogenperiodato)argentate(III) complex anion, [Ag(HIO6)2]5−, has been studied in aqueous alkaline medium in the temperature range of 25–40 °C. The oxidation kinetics is first order
in the silver(III) and pipecolinate concentrations. The observed second-order rate constant, decreasing with increasing [periodate]
is virtually independent of [OH−]. α-Aminoadipate as the major oxidation product of pipecolinate has been identified by chromatographic analysis. A reaction
mechanism is proposed that involves a pre-equilibrium between [Ag(HIO6)2]5− and [Ag(HIO6)(H2O)(OH)]2−, a mono-periodate coordinated silver(III) complex. Both Ag(III) complexes are reduced in parallel by pipecolinate in rate-determining
steps (described by k
1 for the former Ag(III) species and k
2 for the latter). The determined rate constants and their associated activation parameters are k
1 (25 °C) = 0.40 ± 0.02 M−1 s−1, ∆H
1≠ = 53 ± 2 kJ mol−1, ∆S
1≠ = −74 ± 5 J K−1 mol−1 and k
2 (25 °C) = 0.64 ± 0.02 M−1 s−1, ∆H
2≠ = 41 ± 2 kJ mol−1, ∆S
2≠ = −110 ± 5 J K−1 mol−1. The time-resolved spectra, a positive dependence of the rate constants on ionic strength of the reaction medium, and the
consistency of pre-equilibrium constants derived from different reaction systems support the proposed reaction mechanism. 相似文献
19.
Chao Xu Jing-Jing Zhang Taike Duan Quan Chen Qian-Feng Zhang 《Journal of Cluster Science》2010,21(4):813-823
Abstract
Reaction of the [Me4N]2[Cd(SPh-4-Me)4] with two equivalents of [M(PPh3)2NO3] afforded the neutral linear trinuclear complexes [Cd(μ-SPh-4-Me)4{M(PPh3)2}2] (M = Cu 1, Ag 2) in which two [M(PPh3)2]+ fragments chelate with the opposite edges of a tetrahedral [Cd(SPh-4-Me)4]2− moiety via the sulfur atoms of the Me-4-PhS− species. Treatment of [Sn(SPh)4] with two equivalents of [Ag(PPh3)2NO3] gave the neutral linear trinuclear complex [Sn(μ-SPh)6(AgPPh3)2] (3) that is composed of a central distorted SnS6 octahedron sharing two opposite planes with two slightly distorted AgS3P tetrahedrons. Complexes 2 and 3 are air and optically stable. Their nonlinear optical absorption and refraction were investigated under the same conditions. The nonlinear optical absorption and refraction of complex 2 were determined to be α 2 = 3.11 × 10−11 m/W and n 2 = 4.15 × 10−12 esu, respectively. The nonlinear optical absorption and refraction of complex 3 were determined to be α 2 = 8.36 × 10−11 m/W and n 2 = 1.47 × 10−11 esu, respectively. 相似文献20.
Wen-Kui Dong Jun-Feng Tong Yin-Xia Sun Jian-Chao Wu Jian Yao Shang-Sheng Gong 《Transition Metal Chemistry》2010,35(4):419-426
Two new mono- and dinuclear Cu(II) complexes, namely [CuL1]·0.5H2O (1) and [(Cu2(L2)2)(DMF)]·0.5DMF (2) (H2L1 = 1,2-bis{[(Z)-(3-methyl-5-oxo-1-phenyl-1H-pyrazolidin-4(4H)-yl)(phenyl)]methylene-aminooxy}ethane; H2L2 = 1,3-bis{[(Z)-(3-methyl-5-oxo-1-phenyl-1H-pyrazolidin-4(4H)-yl)(phenyl)] methyleneaminooxy}propane), have been synthesized and characterized by X-ray crystallography. The unit cell
of complex 1 contains two crystallographically independent but chemically identical [CuL1] molecules and one crystalline water molecule, showing a slightly distorted square-planar coordination geometry and forming
a wave-like pattern running along the a-axis via hydrogen bonding and π···π stacking interactions. Complex 2 has a dinuclear structure, comprising two Cu(II) atoms, two completely deprotonated phenolate bisoxime (L2)2− moieties (in the form of enol), and both coordinated and hemi-crystalline DMF molecules. Complex 2 has square-planar and square-pyramidal geometries around the two copper centers, whose basic coordination planes are almost
perpendicular and form an infinite three-dimensional supramolecular network structure involving intermolecular C–H···N, C–H···O,
and C–H···π(Ph) hydrogen bonding and π···π stacking interactions of neighboring pyrazole rings. 相似文献