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1.
Tanja Soldatović Predrag Čanović Radivoje Nikolić Ratomir Jelić Živadin D. Bugarčić 《Journal of solution chemistry》2009,38(1):57-71
The formation equilibria of the [Pt(SMC)(H2O)2]+ complex with some biologically relevant ligands such as L-methionine (L-met) and glutathione (GSH) were studied. The stoichiometry
and stability constants of the formed complexes are reported, and the concentration distribution of the various complex species
has been evaluated as a function of pH. The reaction between [PtCl2(SMC)] and guanosine-5′-monophosphate (5′-GMP) was studied by 1H NMR spectroscopy. The NMR spectra indicated that first step is the hydrolysis of the [PtCl2(SMC)] complex and second step is the substitution of an aqua ligand, either in the cis or trans position with guanosine-5′-monophosphate in molar ratio 1:1. The values of rate constant showed faster substitution of coordinated
H2O in the trans position to the S donor atom of S-methyl-L-cysteine, whereas the slower reaction was assigned to the displacement of the
cis coordinated aqua molecule. This is due to the strong trans labilization effect of coordinated sulfur.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users. 相似文献
2.
D. Jurkin F. J. Gildehaus B. Wierczinski 《Journal of Radioanalytical and Nuclear Chemistry》2009,282(1):293-298
Due to physical decay properties commonly associated with therapeutic radionuclides, 188Re (t
1/2 = 16.98 h, E
max = 2.12 MeV) is of high interest for endovascular brachytherapy and endoradiotherapy in general. Rhenium precursors in the
low oxidation state +I, such as the organometallic fac-[Re(H2O)3(CO)3]+ are promising lead compounds compared to those with oxidation states +III and +V since they can be prepared under mild conditions
and do not tend to reoxidize to oxidation state +VII while multidentate ligands can be attached under substitution of coordinated
water molecules. This study comprises the application of the Free-Ion Selective Radiotracer Extraction (FISRE) technique in
order to determine dissociation rate constants of complexes bearing the [188Re(CO)3]+-core at tracer levels in vitro with regards to their time-dependent kinetic speciation. As ligands, the tridentate l-histidine as well as the dipeptides l-carnosine (β-alanyl-l-histidine) and glycyl-l-histidine were chosen in order to study the effects of different moieties attached to the primary amine of l-histidine. 相似文献
3.
Snežana Jovanović Jovana Bogojeski Marijana Petković 《Journal of Coordination Chemistry》2015,68(17-18):3148-3163
Substitution reactions of the dinuclear Pt(II) complexes, [{Pt(en)Cl}2(μ-pz)]2+ (1), [{Pt(dach)Cl}2(μ-pz)]2+ (2) and [{Pt(dach)Cl}2(μ-4,4?-bipy)]2+ (3), and corresponding aqua analogs with selected biologically important ligands, viz. 1,2,4-triazole, L-histidine (L-His) and guanosine-5?-monophosphate (5?-GMP) were studied under pseudo-first-order conditions as a function of concentration and temperature using UV–vis spectrophotometry. The reactions of the chloride complexes were followed in aqueous 25 mmol L?1 Hepes buffer in the presence of 40 mmol L?1 NaCl at pH 7.2, whereas the reactions of the aqua complexes were studied at pH 2.5. Two consecutive reaction steps, which both depend on the nucleophile concentration, were observed in all cases. The second-order rate constants for both reaction steps indicate a decrease in the order 1 > 2 > 3 for all complexes. Also, the pKa values of all three aqua complexes were determined. The order of the reactivity of the studied ligands is 1,2,4-triazole > L-His > 5?-GMP. 1H NMR spectroscopy and HPLC were used to follow the substitution of chloride in the dichloride 1, 2, and 3 complexes by guanosine-5?-monophosphate (5?-GMP). This study shows that the inert and bridging ligands have an important influence on the reactivity of the studied complexes. 相似文献
4.
The reactions of platinum(II) complexes, [PtCl2(dach)] (dach = (1R,2R)‐1,2‐diaminocyclohexane) and [PtCl2(en)] (en = ethylenediamine) with biologically relevant ligands such as 5′‐GMP (guanosine‐5′‐monophosphate) and l ‐His (l ‐histidine) were studied by UV–vis spectrophotometry, 1H NMR spectroscopy, and high‐performance liquid chromatography (HPLC). Spectrophotometrically, these reactions were investigated under pseudo‐first‐order conditions at 310 K in 25 mM Hepes buffer (pH 7.2) and 10 mM NaCl to prevent the hydrolysis of the complexes. The [PtCl2(en)] complex reacts faster than [PtCl2(dach)] in the reaction with studied nucleophiles. This confirms the fact that the reactivity of studied Pt(II) complexes depends on the structure of the inert bidentate ligand. Also, the substitution reactions with l ‐His are always faster than the reactions with nucleotide 5′‐GMP. The reactions of [PtCl2(dach)] and [PtCl2(en)] complexes with l ‐histidine are studied by 1H NMR spectroscopy. The obtained rate constants are in agreement with those obtained by UV–vis. The same reactions were studied by HPLC comparing the obtained chromatograms during the reaction. The changes in intensity of signals of the free and coordinated ligand show that after a few days there is only one dominant product in the system. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 43: 99–106, 2011 相似文献
5.
Ahmed Abdou El-Sherif 《Journal of solution chemistry》2006,35(9):1287-1301
cis-Dichloro(2-(aminomethyl)benzimidazole)palladium(II), [Pd(AMBI)Cl2], was synthesized and characterized. The stoichiometry and stability constants of the complexes formed between [Pd(AMBI)(H2O)2]2+ with various biologically relevant ligands containing different functional groups are investigated. The ligands used are dicarboxylic acids, amino acids, peptides and DNA constitutents. The results show the formation of 1:1 complexes with amino acids and dicarboxylic acids. The effect of the chelate ring size of the dicarboxylic acid complexes on their stability constants is examined. Peptides form both 1:1 complexes and the corresponding deprotonated amide species. Structural effects of the peptide on the amide deprotonation are investigated. DNA pyrimidinic constituents such as uracil, uridine, thymidine and thymine form 1:1 and 1:2 complexes, whereas purinic constituents such as inosine 5′-monophosphate (5′-IMP) and guanosine 5′-monophosphate (5′-GMP) form only 1:1 complexes. The concentration distribution of the complexes in solution was evaluated. The effect of increasing chloride ion concentration on the formation constant of CBDCA with Pd(AMBI)2+ was reported. 相似文献
6.
Xiu Lian Lu Lin Zhang Ji-Dong Lou Juan Yan Ping-Sheng Nong Xiao-Hong Chen Juan-Juan Yang Min Gao 《Transition Metal Chemistry》2010,35(5):513-519
Two new half-sandwich cyclopentadienyl ruthenium(II) complexes containing α-amino acids, [CpRu(PPh3)2(Ser)] (Ser = l-serine) and [CpRu(PPh3)(Met)] (Met = l-methionine), were synthesized and characterized by physicochemical methods. Interactions of these two complexes with calf
thymus DNA were investigated by UV–Vis absorption spectroscopy, emission spectroscopy and competitive binding studies. The
results indicate that both complexes can interact with DNA, leading to the damage of the double helix. [CpRu(PPh3)2(Ser)] binds to DNA by intercalation, while the binding mode for [CpRu(PPh3)(Met)] is more complicated due to the formation of an EB-DNA-complex (EB = ethidium bromide). The affinity of the Met complex
for DNA is stronger than that of the Ser complex, which could be due to groove–surface combination or electrostatic interaction
in addition to intercalative binding. 相似文献
7.
Dichlorocobalt(III) complexes of (2S,5S,9S)-trimethyltriethylenetetraamine (L1) and (2S,5R,9S)-trimethyltriethylenetetraamine (L2) have been prepared. Both L1 and L2 coordinate to the cobalt(III) ion to give three isomers: Λ-cis-α, Δ-cis-β, trans isomers for L1 and Δ-cis-α, Δ-cis-β, trans isomers for L2. Each of the trans-dichloro complexes of the two ligands have been isomerized stereospecifically to the cis-α-dichloro complex in methanol, and each of the cis-α-dichloro complexes stereospecifically to the trans-diaqua complex in water. Both the geometrical and optical inversions took place at the same time in the observed stereospecific isomerizations. 相似文献
8.
Evangelia Voureka John M. Tsangaris Aris Terzis Catherine P. Raptopoulou 《Transition Metal Chemistry》1996,21(3):244-249
Summary The complexes K[Pt(l-aze)Cl2, [Pt(l-aze)2] and [Pd(l-aze)2] (l-aze = l-azetidine-2-carboxylate) were prepared. X-ray structures show that [Pt(l-aze)2] and [Pd(l-aze)2] are isomorphous, having a planar tetragonal geometry with a trans configuration around the Pt and Pd atoms. Slight puckerings of the MN(1)N(11)O(11) chelate ring (M = Pt or Pd) and the azetidine ring were observed. The circular dichroism (c.d.) spectra of the complexes in aqueous solution agree with the structures found in the solid state as far as the hexadecant rule is concerned, giving, for the trans configuration of [M(l-ia)2] (where ia = imino acid), the profile of the c.d. signs for the three predominant d-d transitions as: +,-,-. I.r., conductivity and n.m.r. measurements are also reported and are in accord with the proposed structures. 相似文献
9.
Al-Allaf Talal A.K. Rashan Luay J. Steinborn Dirk Merzweiler Kurt Wagner Christoph 《Transition Metal Chemistry》2003,28(6):717-721
Several new PtII and PdII complexes bearing the enantiomerically pure (1R,2R)-(–)-l,2-cyclohexanediamine (dach) ligand, of general formula [MX2{(1R,2R)-dach}], where M = Pt or Pd, X2 = cis- or trans- or (1R,2R)-1,2-cyclohexyldicarboxylate anions, have been synthesized and characterized physicochemically and spectroscopically. These complexes have been screened in vitro against the three tumour cell lines K562, HeLa and L929, and the results obtained were compared with those of the reference standards, cisplatin, carboplatin and oxaliplatin; the known antitumour drugs. The single crystal X-ray structure determination of the [Pt(C2O4)(cis-dach)] complex has been discussed and compared with that of oxaliplatin, [Pt(C2O4){(1R,2R)-dach}]. 相似文献
10.
Maofeng Zhang Xiaoqing Wang Xianwen Zhang Pengfei Wang Shenglin Xiong Liang Shi Yitai Qian 《Journal of solid state chemistry》2009,182(11):3098-3104
Rare-earth hexaborides (RB6, R=Ce, Pr, Nd) nanocrystals were prepared by a facile solid state reaction in an autoclave. Single-crystalline RB6 nanocubes were fabricated at 500 °C starting from B2O3, RCl3·6H2O and Mg powder. RB6 nanoflakes and nanoparticles could be obtained around 400 °C using NaBH4 as boron resource. XRD patterns show that all of the hexaborides are cubic phase with high crystallinity and high purity and have lattice parameters that are consistent with nearly stoichiometric products. Raman spectra elucidate the active vibrational modes of the hexaborides. The TEM and FESEM images clearly show that the nanocubes have an average size of 200 nm and nanoparticles of 30 nm. Our experiment developed an efficient, simple and low-cost route to prepare RB6, which could be extended further to the preparation of other rare-earth metal hexaborides. 相似文献
11.
Bojidarka B. Koleva Tsonko Kolev Marc Lamshöft Michael Spiteller 《Transition Metal Chemistry》2008,33(7):911-919
The coordination behaviour of the tripeptide glycyl-l-phenylalanyl-glycine (H-Gly-Phe-Gly-OH) with Au(III), Pd(II), and Pt(II) in both solution and in the solid state has been
investigated experimentally. In addition, quantum chemical calculations have been carried out with a view to obtain the structures
and spectroscopic properties of the ligand and its complexes. Both in solution and in the solid state the tripeptide interacts
in a tetradentate manner with the Au(III) and Pd(II) ions through the NH2, two deprotonated amide N atoms and the COO−group, forming [Au(H-Gly-Phe-Gly-OH)H−2)] × H2O and [Pd(H-Gly-l-Phe-Gly-OH)H−2)]Na × H2O complexes. The MN3O chromophores are calculated to be near planar. Interaction with cisplatin leads to the formation of a mononuclear complex
with tridentate coordination of the ligand by NH2 and two N- atoms from the deprotonated amide groups ([Pt(H-Gly-l-Phe-Gly-OH)H−2)NH3] × 2H2O). The fourth coordination position of the Pt(II) is occupied by an NH3 ligand. The PtN4 chromophore is flat with a deviation from planarity of 0.3°.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
12.
Enisa Selimović Tatjana Vulović Biljana Petrović Živadin D. Bugarčić Jovana Bogojeski 《Transition Metal Chemistry》2013,38(6):635-640
The kinetics of the complex formation reactions of two [(TL tBu)PtCl]+ and [Pt(tpdm)Cl]+ complexes (TL tBu = 2,6-bis[(1,3-di-tert-butylimidazolin-2-imino)methyl]pyridine and tpdm = terpyridinedimethane) with N-donor ligands, l-histidine (L-His), inosine (Ino), inosine-5′-monophosphate (5′-IMP) and guanosine-5′-monophosphate (5′-GMP), were studied. All reactions were studied under pseudo-first-order conditions as a function of nucleophile concentration and temperature in aqueous 0.1 M NaClO4 solution in the presence of 10 mM NaCl using variable-temperature Uv–Vis spectrophotometry. The order of reactivity of the studied ligands is L-His > Ino > 5′-GMP > 5′-IMP. This order of reactivity is in relation to their electronic properties and structures. The mechanism of the substitution reactions is associative in nature as supported by the negative entropy of activation. 相似文献
13.
I. P. Romanova S. G. Fattakhov A. A. Nafikova I. I. Vandyukova R. R. Shagidullin N. M. Azancheev V. S. Reznik O. G. Sinyáshin 《Russian Chemical Bulletin》1998,47(9):1812-1819
The reactions of phosphine derivatives of diallyl isocyanurates with palladium(ii) dichloride lead to the formation of complexes, whose structure, composition, and stability depend on the length of the methylene
chain between the isocyanurate and diphenylphosphine fragments in the ligand. 1,3-Diallyl-5-[5′-(diphenylphosphino)pentyl
and 10′-(diphenyl-phosphino)decyl] isocyanurates with PdCl2 form monomeric L2PdCl2
trans-complexes in which P atoms of the ligands participate in coordination with the metal. 1,3-Diallyl-5-[2′-(diphenylphosphino)ethyl]
isocyanurate with PdCl2 forms a dimeric (LPdCl2)2 complex, which decomposes in a solution to the monomer including solvent molecule into the coordination sphere of the metal.
The reactions of 1,3-diallyl-5-[4′-(diphenylphosphino)butyl] isocyanurate and 1,3-diallyl-5-[6′-(diphenylphosphino)hexyl]
isocyanurate with PdCl2 give monomeric chelate LPdCl2 complexes in which one of the allyl groups of the isocyanurate cycle participates in coordination with the central ion along
with the phosphorus atom.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1859–1865, September, 1998. 相似文献
14.
Abeer T. Abd El-Karim Islam R. El-Sherif Wafaa M. Hosny Eyad K. Alkhadhairi Mutlaq S. Aljahdali Ahmed A. El-Sherif 《Journal of solution chemistry》2017,46(5):1024-1047
The stoichiometry and stability constants of the complexes formed between [Pd(MAMP)(H2O)2]2+ and various biologically relevant ligands containing different functional groups were investigated. The ligands used are amino acids, peptides and DNA constituents. The results show the formation of 1:1 complexes with amino acids and peptides and the corresponding deprotonated amide species. Structural effects of peptides on amide deprotonation were investigated. The purine and pyrimidine bases uracil, uridine, cytosine, inosine, inosine 5′-monophosphate (5′-IMP) and thymine form 1:1 and 1:2 complexes. The concentration distribution of the various complex species was calculated as a function of pH. The effect of chloride ion concentration on the formation constant of CBDCA with Pd(MAMP)2+ was also reported. The results show ring opening of CBDCA and monodentate complexation of the DNA constituent with the formation of [Pd(MAMP)(CBDCA-O)DNA], where (CBDCA-O) represents cyclobutane dicarboxylate coordinated by one carboxylate oxygen. The equilibrium constant of the displacement reaction of coordinated inosine, as a typical DNA constituent, by SMC and/or methionine was calculated. The results are expected to contribute to the chemistry of antitumor agents. The calculated parameters of the optimized complexes support the measured formation constants. 相似文献
15.
Yakup Baran Ismet Kaya Murat Turkyılmaz 《Journal of Thermal Analysis and Calorimetry》2012,107(3):869-875
The new tetradentate symmetrical (2R,2′S)-1,1′-piperazine-1,4-diyldipropane-2-thiol) (L1), (2S)-1-[bis(2-aminoethyl)amino]propan-2-ol) (L2), and 2-{(E)-[((1R,2S)-2-{[(1Z)-(2-hydroxy phenyl)methylene]amino}cyclohexyl)imino]methyl}phenol (L3) ligands were synthesized and characterized on the basis of FT-IR, 1H, 13C NMR, EI mass, and elemental analysis. Three commercially available ligands, (2,2′-[ethane-1,2-diylbis(thio)]diethanol (L4), 2,2′-dithiodiethanenamine (L5), and (2,2′-[ethane-1,2-diyldi(imino)] diethanol (L6), were also studied. Pt(II) complexes were characterized by FTIR, elemental analysis and thermal methods. Thermal behaviors
of these complexes were investigated in the range 10–1000 °C. Magnetic properties were also studied, and the all complexes
were found to be diamagnetic. The structures consist of the monomeric units in which the Pt(II) atoms exhibit square planar
geometry. N,N′-bis(salicylidene)-1,2-cyclohexane has been synthesized and characterized by X-ray single crystal diffraction measurement.
The ligand crystallizes in monoclinic crystal system and space group, Cc. 相似文献
16.
Murat Taş Seval Çamur Yalçın Kılıç 《Journal of Thermal Analysis and Calorimetry》2011,103(3):995-1000
The complexes were synthesized by the reaction between sodium salt of p-aminosalicylic acid (PAS) and Cu(II) for 1 and corresponding ethylenediamine (en) or its derivatives for 2–6. The complexes were characterized by using elemental analyses, FT-IR, UV–Vis, magnetic moment measurements, and thermal analyses
techniques. In complex 1[Cu2(PA)4(H2O)2], two Cu(II) ions were found as bridged by four μ-O:O′ p-aminosalicylato (PA) ligands, forming a cage structure, and two aqua ligands to form dinuclear square-pyramidal geometry
around Cu(II) ions. In the complexes 2–6, the PA (anionic form of p-aminosalicylic acid) coordinated to Cu(II) ions as monodentate manner by using its oxygen atom of deprotonated carboxylic
acid and ethylenediamine derivatives coordinated to the Cu(II) ions in bidentate manner to form mononuclear octahedral complexes
[Cu(PA)2(L)2] (L = ethylendiamine, N,N-dimethylethylendiamine, N,N′-dimethylethylendiamine, N,N,N′,N′-tetramethylethylendiamine, and 1,3-propanediamine, for complexes 2, 3, 4, 5, and 6, respectively). In all the complexes OH and NH2 groups of PA ligands were not coordinated to metals. 相似文献
17.
The hydrolytic reactions between various Pt(II) complexes of the type [Pt(L)Cl2] and [Pt(L)(CBDCA-O,O′] (L is ethylenediamine, en; (±)-trans-1,2-diaminocyclohexane, dach; (±)-1,2-propylenediamine, 1,2-pn and CBDCA is the 1,1-cyclobutanedicarboxylic anion) and the N-acetylated l-methionylglycine dipeptide (MeCOMet-Gly) were studied by 1H NMR spectroscopy. All reactions were realized at 37 °C with equimolar amounts of the Pt(II) complex and the dipeptide at pH 7.40 in 50 mM phosphate buffer in D2O. Under these experimental conditions, a very slow cleavage of the Met-Gly amide bond was observed and this hydrolytic reaction proceeds through the intermediate [Pt(L)(H2O)(MeCOMet-Gly-S)]+ complex. In general, it can be concluded that faster hydrolytic cleavage of the MeCOMet-Gly dipeptide was observed in the reaction with the chloride complex than with corresponding CBDCA Pt(II) complexes. The steric effects of the Pt(II) complex on the hydrolytic cleavage of the amide bond in the MeCOMet-Gly dipeptide were also investigated by 1H NMR spectroscopy. It was found that the rate of hydrolysis decreases as the steric bulk of the CBDCA and chlorido Pt(II) complexes increase (en > 1,2-pn > dach). These results contribute to a better understanding of the toxic side effects of Pt(II) antitumor drugs and should be taken into consideration when designing new potential Pt(II) antitumor drugs with preferably low toxic side effects. 相似文献
18.
Franco Cataldo Pietro Ragni Susana Iglesias-Groth Arturo Manchado 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(2):573-580
The sulphur-containing proteinaceous amino acids l-cysteine, l-cystine and l-methionine were irradiated in the solid state to a dose of 3.2 MGy. This dose corresponds to that delivered by radionuclide
decay in a timescale of 1.05 × 109 years to the organic matter buried at a depth >20 m in comets and asteroids. The purity of the sulphur-containing amino acids
was studied by differential scanning calorimetry (DSC) before and after the solid state radiolysis and the preservation of
the chirality after the radiolysis was studied by chirooptical methods (optical rotatory dispersion, ORD) and by FT-IR spectroscopy.
Although the high radiation dose of 3.2 MGy delivered, all the amino acids studied show a high radiation resistance. The best
radiation resistance was offered by l-cysteine. The radiolysis of l-cysteine leads to the formation of l-cystine. The radiation resistance of l-methionine is not at the level of l-cysteine but also l-methionine is able to survive the dose of 3.2 MGy. Furthermore in all cases examined the preservation of chirality after
radiolysis was clearly observed by the ORD spectroscopy although a certain level of radioracemization was measured in all
cases. The radioracemization is minimal in the case of l-cysteine and is more pronounced in the case of l-methionine. In conclusion, the study shows that the sulphur-containing amino acids can survive for 1.05 × 109 years and, after extrapolation of the data, even to the age of the Solar System i.e. to 4.6 × 109 years. 相似文献
19.
Abstract
Gallium complexes of l-glutamine have been studied polarographically in aqueous media. The reduction was found to be irreversible and diffusion controlled in the presence of 0.1 M KNO3 and 0.002% Triton-x-100. The values of kinetic parameters, transfer coefficient (α n), and formal rate constant ( k\textf,\texth0 k_{{{\text{f}},{\text{h}}}}^{0} ) of the electrode reactions were calculated by Koutecky's method. The stability constants and composition of the gallium(III)-l-glutamine complexes were evaluated with the help of the Deford-Hume method. The values of stability constants of 1:1, 1:2, and 1:3 gallium(III)-l-glutamine complexes are 1.35, 6.5, and 1,350 at 30 °C, respectively. The values of thermodynamic parameters, the free energy of activation, the enthalpy of activation, and the entropy of activation have been determined at 30 °C. The formation of the metal complexes has been found to be non-spontaneous, endothermic in nature, and entropically favorable at higher temperature. 相似文献20.
Lianzhi Li Jianfang Dong Jinghong Li Buqin Jing Daqi Wang 《Transition Metal Chemistry》2011,36(3):289-295
A ternary Cu(II) complex, [Cu(naph-ser)(bipy)]·0.125CH2Cl2 (naph-ser = a Schiff base derived from 2-hydroxy-1-naphthaldehyde and l-serine, bipy = 2, 2′-bipyridine), has been synthesized and structurally characterized. In the crystal structure, a supramolecular
assembly with left-handed double helices is formed by O–H···O hydrogen bonding interactions. The DNA-binding properties and
DNA-cleavage activity of the Cu(II) complex have been investigated by spectroscopic methods and agarose gel electrophoresis.
The results indicate that the Cu(II) complex can bind to CT-DNA via an intercalative mode and shows efficient cleavage activity
in the absence and presence of reducer. 相似文献