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1.
Summary Aquocomplexes of copper(II) and nickel(II) involving (H2NCH2)2, H2NCH2CH2NHCH2CH2NH2 and H2NCH2CH2NHCH2CH2NHCH2CH2NH2 as ligands were prepared and characterised. Using a pH-stat method, the kinetics of the base hydrolysis of amino acid esters such as H2NCH2CO2CH3·HCl (GE), (HO)C6H4CH2-(NH2)CO2CH3·HCl (TE), CH3S(CH2)2CH(NH2)CO2CH3· HCl (ME), HSCH2CH(NH2)CO2C2H5·HCl (CE),
(HE) and [—SCH2CH(NH2)CO2CH3]2·2HCl (CysE) was studied. These complexes substantially enhance the rate of hydrolysis, the values of the second-order rate constants being some 10–30 times greater than those obtained in the presence of simple metal ions. 相似文献
2.
Rhodium(III), palladium(II) and platinum(II) complexes of Bis(o-aminobenzenesulfonyl)ethylenediamine
New complexes of the formulae K3[RhL
3]·2 H2O, [PdL]·H2O and [M(LH2)Cl2] [whereM = Pd, Pt andLH2 = bis(o-aminobenzenesulfonyl)ethylenediamine] have been prepared and characterized by conductivity measurements, thermogravimetric analysis, X-ray powder patterns and IR, Ligand Field and1H-NMR spectroscopy.
Rhodium(III), Palladium(II)- und Platin(II)-Komplexe mit Bis(o-aminobenzolosulfonyl)ethylendiamin (Kurze Mitteilung)
Zusammenfassung Neue Komplexe der allgemeinen Formeln K3[RhL 3]·2H2O, [PdL]·H2O und [M(LH2)Cl2] mitM = Pd, Pt undLH2 = Bis(o-aminobenzolosulfonyl)ethylendiamin wurden dargestellt und mit Konduktionsmessungen, thermogravimetrischen Analysen, Röntgenstrukturanalysen, IR, Ligandfeld- und1H-NMR-Spektroskopie charakterisiert.相似文献
3.
Summary Solid aquo CuII complexes of Schiff bases derived from amino acids have been prepared and characterized. Using a pH-stat method, the kinetics of base hydrolysis of the amino acid esters H2NCH2CO2Me·HCl (GE), (HO)-C6H4CH2(NH2)CO2Me·HCl (TE), MeS(CH2)2CH(NH2)-CO2Me·HCl (ME), HSCH2CH(NH2)CO2Et·HCl (CE), C3H3N2CH2CH(NH2)CO2Me·2HCl (HE) and [—SCH2-CH(NH2)CO2Me]2·2HCl (CysE) have been studied. The complexes enhanced the rate of hydrolysis substantially, the values of the second-order rate constants being some 10–50 times greater than those obtained in the presence of the simple CuII ion. 相似文献
4.
B. Seshagiri Rao Rabindranath Nanda Kumuda Kanta Tripathy 《Transition Metal Chemistry》1981,6(2):97-100
Summary The kinetics of acid hydrolysis ofcis-[CoCl(btzH)(en)2]2+ andcis-[CoCl(btzMe)(en)2]2+ complexes (where btzH = benzotriazole, btzMe =N-methylbenzotriazole and en = ethylenediamine) have been investigated in HClO4 at ionic strength 1 = 0.25 mol dm–3 in the 30–40° range. In the 1.0 x 10–1 to 1.0 X 10–3 mol dm–3 acid strength range, the rate of aquation of the [CoCl(btzH)(en)2]2+ cation follows the relationship:-d ln[complex]/dt = k1 + k2KNH[H+]–1, where k1 and k2 are aquation rate constants of the acid independent and acid dependent steps respectively, and KNH is the acid dissociation constant of the coordinated benzotriazole.cis-[CoCl(btzMe)-(en)2]2+ undergoes acid independent hydrolysis presumably due to the absence of a labile N-H proton. The base hydrolysis could be followed for thecis-[CoCl(btzMe)(en)2]2+ complex only by measuring hydrolysis rates at 0°. 相似文献
5.
Summary Base hydrolysis of the bis(ethylenediamine)thiosulphatocobalt(III) was investigated spectrophotometrically between 35 and 65 °C and with base concentrations (NaOH) up to 2.0 mol dm–3. The hydrolysis consists of a one-stage reaction, followed by a slow dechelation step, and then by a fast ligand loss. The reaction is base-dependent. The products of the reaction are an equilibrium mixture ofcis- andtrans-Coen2 (OH)
2
+
. Activation parameters for the reaction as determined by the Eyring equation, are H=77.8±4.6 kJ mol–1 and S=–75±20 JK–1 mol–1. 相似文献
6.
Summary The kinetics of aquation and base hydrolysis reactions ofcis-[(en)2Co(imH)O2CC6H4OH-o-o]2+ (imH = imidazole) have been investigated in a medium of 1.0 M ionic strength, In the 0,1–1,0 M [H+] range (60–70°) aquation proceedsvia spontaneous and acid catalysed paths
. In the 0,05–1.0 M [OH–] range (30–40°), the complex exists predominantly as the bis-deprotonated species,cis-[(en)2Co(im)O2CC6H4O-o], and the pseudo-first-order rate constant fits the relationship kobs = kb + kb° [OH–] satisfactorily. The labilizing action of coordinated imidazolate anion(im–) on the cobalt(III)-bound salicylate is 103 times stronger than that of imidazole. The mechanism is essentially Id in the aquation paths and SN1cb (Co-O bond fission) in the alkali independent and dependent paths respectively. 相似文献
7.
Summary The kinetics of the first step of base hydrolysis oftrans-bis(Hmalonato)bis(ethylenediamine)cobalt(III) [malH–=HO2CCH2CO
2
–
] has been investigated in the 15–35° C range, I=0.3 mol dm–3 (NaClO4) and [OH–]=0.015–0.29 mol dm–3. The rate law is given by –d In[complex]T/dt=k1[OH–] and at 30° C, k1=8.5×10–3 dm3 mol–1s–1, H=117.0±7.0 kJ mol–1 and S=99.0±24.0 JK–1mol–1. The activation parameters data are consistent with the SN1 cb mechanism. 相似文献
8.
Summary Cobalt(II), nickel(II), palladium(II) and platinum(II) complexes witho-(OCD),m-(MCD) andp-chlorophenyldithiocarbamate (PCD) ligands have been synthesised and characterised by chemical analyses, molecular weight determinations, conductance measurements, electronic and i.r. spectral studies. The thermal behaviour of the complexes has been studied by t.g. and d.t.a. techniques in a static air atmosphere and heats of reaction of different decomposition steps have been calculated from the d.t.a. curves. The thermal decomposition products of the complexes were identified by elemental analyses and i.r. spectra. 相似文献
9.
Summary The kinetics of iodination of malonate and pyruvate in the title complexes are reported at 35.0 °C and I=0.3 M. The reaction is first order in substrate and zeroth order in [I2]. This result is commensurate with rate determining enolisation of the active methylene and methyl groups of the malonate and pyruvate respectively. The reaction is catalysed by H2O, OH– and by the buffer anions used. The rate data suggest that the malonate methylene group in the [Co(en)2-O2CCH2CO2]2+ chelate is considerably more active towards electrophilic substitution than is the case in [Co(NH3)5O2CCH2CO2]2+. 相似文献
10.
Binary and ternary complex formation equilibria of copper(II) with glycyl-dl-leucine and amino acids or their esters were investigated potentiometrically at 25°C and a constant ionic strength. The kinetics of base hydrolysis of amino acid esters in their ternary complexes were monitored using the pH-stat method. The ester groups, with the exception of the histidine methyl ester, undergo rapid promoted hydrolysis. The rate and catalysis constants were evaluated from the experimental data. 相似文献
11.
Summary The synthesis and characterization of new NiII, PdII, PtII and CoIII complexes, with the BF
inf2
sup+
-bridged,bis(-di-oximato) ligands are described. The initially formed six-coordinate hydrogen-bonded macrocycles, were used as metal templates to prepare the corresponding BF
inf2
sup+
- capped macrocycles. The complexes were characterized by1H-n.m.r. and i.r. spectroscopy, and by elemental analysis. 相似文献
12.
Santosh K. Mondal Parimal Paul Rita Roy Kamalaksha Nag 《Transition Metal Chemistry》1984,9(7):247-250
Summary Complexes of nickel(II), palladium(II), copper(II), cobalt(II), and cobalt(III) with methyl-2-(-salicylaldiminoethyl)-cyclopent-1-en-dithiocarboxylate (H2L1) and methyl-2-(-salicylaldiminoisopropyl)cyclopent-1-en-dithiocarboxylate (H2L2) have been prepared. They contain the donor sites ONNS. The metal(II) ions from neutral, monomeric square planar chelate complexes. The cobalt(III) complexes [CoL1-(H2O)2]X (X=Cl or ClO4) appear to betrans-diaqua-species. All compounds have been characterized by a number of physico-chemical methods. 相似文献
13.
Summary Ternary complexes of copper(II) with diethylenetriamine (dien), together with monodentate ligands, including -amino acid esters, were studied using potentiometric and conductometric techniques. The formation constants of the resulting binary and ternary complexes were determined. The kinetics of the base hydrolysis of the above esters in the presence of copper(II)-dien complex were studied at 30°C. The rate and catalysis constants were estimated. 相似文献
14.
Summary Cobalt(III) complexes of the typetrans-[Co(AA)2(ox)] (where AA = aminoacidato, gly = glycinato, sar = sarcosinato, DL-ala = DL-alaninato, L-ala = L-alaninato; ox = oxalate); [Co(L-val)2CO3] and DL-[Co(en)2sar]I2 where L-val = L-valinato, en = ethylenediamine) have been investigated for their bacterial activity againstEscherichia coli B using well-cultured techniques on EMB agar and in minimal glucose media. The activities decrease in the order:trans-(N)(+)K[Co(sar)2(ox)] >trans-(N)(+)K[Co(L-ala)2(ox)] >trans-(N)(–)K[Co (gly)2(ox)] >trans-(N)(+)K[Co(DL-ala)2(ox)] >trans-(N)(+)K[Co(gly)2(ox)] >trans(+)K[Co(DL-ala)2(ox)] >trans-K[Co(L-val)2CO3]. 相似文献
15.
Summary TheN-aminorhodanine (L) complexes: PdLX, (X = Br or I), ML1.5Cl2 (M = Pd or Pt), PtL2X2 (X = Br, I or ClO4), PdL3(ClO4)2, PdL1.5Cl4 and PdL3(ClO4)4 have been prepared and investigated. The ligand is bonded to the metal ion through the aminic nitrogen atom as monodentate or through this atom and the thiocarbonylic sulphur atom when it acts as chelating or bridging ligand. The carbonylic oxygen atom is never coordinated. 相似文献
16.
Summary The aquation ofcis-[Co(en)2(NH2Et)O2CR]2+ [R=H or Me] is strongly acid-catalysed and the rate and activation parameters for this process are reported. No significant rate difference is observed in the spontaneous aquation path for the complexes. The acetato complex undergoes acid catalysed aquation at a rate comparable to the of the corresponding formato complex, in contrast with the relative basicities of the coordinated formate and acetate. This result is interpreted in terms of relative solvation effects of the initial and transition states of both complexes.The base hydrolysis of both complexes obeys overall second order kinetics in the 0.05[OH–]T 0.35 mol dm–3 range (I=0.5 mol dm–3). The formato complex reacts five times faster than its acetato analogue under comparable conditions, which is fully consistent with the dissociative mode of activation of the amido conjugate base involving Co–O bond heterolysis. A substantially large positive value for the activation entropy supports SN1CB mechanism for base hydrolysis. 相似文献
17.
Annibale Giuliano Marangoni Giampaolo Pitteri Bruno Visentin Fabiano Bobbo Tatiana 《Transition Metal Chemistry》2000,25(4):485-489
The reactions of AuIII, PtII and PdII complexes with 2-pyridinecarboxaldehyde (2CHO-py) have been examined in protic (H2O, MeOH, EtOH) and aprotic (DMF, CH2Cl2) solvents. Compounds in which the pyridine ligand is N-coordinated, either in the original aldehydic form or in a new form
derived from addition of one or two protic molecules, have been isolated, namely: [Au(2CHO-py · H2O)Cl3], [Au(2CHO-py · MeOH)Cl3], [Au(2CHO-py · 2EtOH)Cl3], cis-[Pt(2CHO-py)2Cl2], trans-[Pd(2CHO-py)2Cl2], trans-[Pt(dmso)(2CHO-py)Cl2], [Pt{C5H4N-(CH2SMe)}Cl(2CHO-py)](ClO4), [Pt(terpy)(2CHOpy)](ClO4)2, [Pt(terpy)(2CHO-py · H2O)](ClO4)2 (terpy = 2,2′:6′,2′′-terpyridine). 1H-n.m.r. experiments show that the addition of the protic molecule(s) to the PtII and PdII complexes is reversible. The effects of the nature of the metal ion and the ancillary ligands as well as of the total charge
of the complexes on the relative stability of the addition products are discussed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
18.
Summary Complexes of 2-mercapto-1-methylimidazole (TMZ) with PtII, PdII, RhIII and RuIII of the general formulae Pt(TMZ)2Cl2, Pd(TMZ)4Cl2. Rh(TMZ)Cl3 and Ru(TMZ)Cl3 have been obtained. The thermal stabilities of the compounds were estimated by derivatographic measurements and the electron-donating atom of the measurements and the electron-donating atom of the ligand was identified from the i.r. absorbtion spectra. Lattice constants for the PtII and PdII complexes were estimated from their x-ray powder diffraction patterns. 相似文献
19.
Mohamed M. Aly 《Transition Metal Chemistry》1990,15(2):99-105
Summary Two types of the CoII complexes L1Co (H2L1=N,N-ethylenebis(isonitrosoacetylacetoneimine) were prepared. In type (a) the chelate rings are five-membered whereas in type (b) they are six-membered. The type (b) complexes were converted to type (a) in refluxing solutions. Half-ionization of the ligand is observed in the complexes HL1 Co(O2CMe) and HL1MnCl, where the chelate rings are five- and six-membered respectively. The octahedral complex L1FeCl·H2O has chelate rings of type (a) as does the complex L2Co (H2L2=unsymmetric Schiff baseN,N-ethylene(isonitrosoacetylacetoneimineacetylacetoneimine). Twocis complexes (La
2Lb
3)Pd and (La
3)2Pd are characterized (HL3=isonitrosoacetylacetoneimine, (a) and (b) denote the type of chelate ring). Structures for the metal complexes and the sizes of the chelate rings are suggested on the basis of analytical and spectral evidence. 相似文献
20.
Summary Investigations were carried out on the isomerization and base hydrolysis ofcis andtrans forms of dithiosulphatobis-(ethylenediamine)cobalt(III) ions. Thecis form isomerizes to thetrans form in neutral aqueous medium, rates being 1.15, 2.30 and 4.0×10–5s–1, respectively at 42, 50 and 58 °C. Thetrans complex isomerizes to thecis form in basic solution only, the rate varying with pH in a sigmoid pattern. In presence of OH–, an acid-base equilibrium of the complex ion sets in, but only the basic form takes part in the isomerization reaction. Hydrolysis of thecis isomer proceeds through a base-dependent path only, but that of thetrans isomer proceeds both through base-dependent and base-independent paths. The mechanisms are associative in nature. Thetrans form reacts faster thancis in all cases. 相似文献