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1.
Oleg V. Kulikov Gennady A. Krestov Wojciech Zielenkiewicz 《Journal of solution chemistry》1995,24(11):1155-1170
Enthalpies of dilution have been determined for binary aqueous solutions of 1-aza-18-crown-6 as well as for ternary aqueous solutions containing glycine, glycylglycine, glycyl-L--alanine, L--alanyl-glycine, L--alanyl-L--alanine, DL--alanyl-DL--alanine, trialanine and 18-crown-6 and/or 1-aza-18-crown-6 and or 1,10-diaza-18-crown-6 at 25°C. The results have been treated by the McMillan-Mayer approach in order to obtain enthalpic virial coefficients for homotactic and heterotactic interactions. A significant exo-effect is demonstrated by the enthalpically favorable interaction between peptides and the 18-crown-6. The additivity of the positive alanyl group contribution toh
xy has been confirmed on the basis of oligomeric data. The influence on the enthalpy of the 18-crown-6-peptide interaction of the methyl group position, in relation to the ammonium group in peptides, has been found to result in the exo-effect decreasing with a decrease of this distance. Some decrease in enthalpy of L--alanyl-L--alanine and DL--alanyl-DL--alanine by 18-crown-6 has been observed as well.Deceased. 相似文献
2.
Yasuyuki Takeda Takehiro Iwasaki Yoshihiro Kudo Hiroaki Matsuda 《Journal of inclusion phenomena and macrocyclic chemistry》1992,14(3-4):303-309
Thermodynamic parameters (H
ex
0
and S
ex
0
) for the overall extractions of monovalent metal (Na, K, Rb, and Tl) picrates with benzo-18-crown-6 (B18C6), and those (H
D,L
0
and S
D,L
0
) for the distribution of B18C6 were determined between chloroform and water. All the extracted B18C6 complexes were l:1:1 complexes (B18C6:metal ion: picrate anion). The H
ex
0
and S
ex
0
values for all the metals are negative. Every extraction of the metal picrate with B18C6 is completely enthalpy driven. The H
D,L
0
and S
D,L
0
values of B18C6 are both positive, and the partition of B18C6 is entirely entropy driven. Enthalpy (H
ex,ip
0
) and entropy changes (S
ex,ip
0
) for ion-pair extractions of B18C6-metal ion complexes with picrate anions were calculated. All the H
ex,ip
0
and S
ex,ip
0
values are negative, and the ion-pair extractions are completely enthalpy driven. 相似文献
3.
The interaction between Cd2+ and Pb2+ ions and 18-crown-6 (18C6), 1,10-diaza-18-crown-6 (C22) and 1,7-diaza-15-crown-5 (C21) were studied in water solvent at 25, 35, 45 and 55° using square wave voltammetric technique. The stoichiometry and stability of the complexes were determined by monitoring the shift in half-wave or peak potential of the polarographic waves of metal against the ligand concentration. Thermodynamic parameters such as G, H and S were obtained by using a polarographic double wall cell in which the temperature could be fixed to ±0.1°C. The results of all experiments show 1 : 1 complexes, but in addition to 1 : 1 ratio, a 2 : 1 ratio of ligand to cation is also obtained for C22–Pb2+ complex. The selectivity order for 18C6 and C22 is Pb2+ > Cd2+. The thermodynamic data G, H and S values show that the complexes are stabilized by both the enthalpy and entropy terms, but C22–Pb2+ complex is stabilized by only enthalpy term. 相似文献
4.
The energy of activation of CH
3
.
radical rupture from the radical (CH3)2juvyCCH(CH3)2 is 142.2 kJ mol–1; the selfcombination rate constant is kc {(CH3)2juvyCCH(CH3)2}=107.3 dm3 mol–1 s–1.
CH 3 . (CH3)2juvyCCH(CH3)2 142,2 /, kc {(CH3)2juvyCCH(CH3)2}=107,3 3–1 –1.相似文献
5.
The preferential exchange uptake of the cations Cs+, Ba2+ and Zn2+ from pure solutions by zeolite-13X follows the order Q [Cs+]>Q [Ba2+]>Q [Zn2+], while in case of binary mixtures the order is Q [Ba2+(Zn2+)]>Q [Ba2+(Cs+)]>Q [Cs+(Zn2+)]>Q [Cs+(Ba2+)]>Q [Zn2+(Cs+)]>Q [Zn2+(Ba2+)]. Ba2+ uptake from mixtures shows the least suppression effect.
Cs+, Ba+2 Zn+2 -13 Q[Cs+]>Q[Ba+2]>Q[Zn+2] Q[Ba+2(mix Zn+2)]>Q[Ba+2(mix Cs+)]>Q[Cs+(mix Zn+2)]>Q[Cs+(mix Ba+2)]>Q[Zn+2(mix Cs+)]>Q[Zn+2(mix Ba+2)]. Ba+2 .相似文献
6.
Yangjie Wu Haoyun An Jingchao Tao Jerald S. Bradshaw Reed M. Izatt 《Journal of inclusion phenomena and macrocyclic chemistry》1990,9(3):267-274
Complexes of nine 4'-substituted benzo-15-crown-5 ligands with sodium picrate were prepared. A good linear relationship of the . values from the UV spectra and Hammett [p - m] values was observed. Charge transfer complexes of ten 4'-substituted benzo-l5-crown-5 ligands with picric acid were isolated in crystalline form. The color of the complexes depended on the nature of the substituents. All of the complexes were identified by elemental analyses, UV and IR spectra. 相似文献
7.
E. V. Guseva T. E. Busygina R. A. Khasanshin V. K. Polovnyak E. G. Yarkova R. A. Yusupov 《Russian Journal of General Chemistry》2004,74(10):1478-1484
Compounds of the compositions [2(18-crown-6)6(H2O)2(C2H4Cl2){Pt2+(C2H4)}(Pt2Cl10)2–], [4(18-crown-6)2(OH3)+2(OH2)2(NH3)(Pt2Cl10)2–], [(dibenzo-18-crown-6)6(H2O){Pt2+(C2H4)}(Pt2Cl10)2–], and [4(dibenzo-18-crown-6)2(OH3)+2(OH2)2(NH3)Pt2Cl10)2–] were prepared by reactions of H2PtCl6 with 18-crown-6 and dibenzo-18-crown-6.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 10, 2004, pp. 1593–1599.Original Russian Text Copyright © 2004 by Guseva, Busygina, Khasanshin, Polovnyak, Yarkova, Yusupov.This revised version was published online in April 2005 with a corrected cover date. 相似文献
8.
A. M. Volodin A. E. Cherkashin K. N. Prokopiev 《Reaction Kinetics and Catalysis Letters》1992,46(2):373-378
Anion-radicals of oxygen O
2
–
and complexes of molecular oxygen with hole centers [X·O2] (g1=2.002, g2=2.009, g
3
1
=2–015, g
3
2
=2.016) and [Y·O2] (g=2.004, g=2.012) have been found to form under CaO irradiation in the range of surface absorption (h4 eV). ESR spectra of X and Y centers have not been observed. They are suggested to be anion-radicals O
st
–
in various coordinations: (O
3C
–
)st and (O
4C
–
)st, respectively.
- O 2 – [XO2] (g1=2.002, g2=2.009, g 3 1 =2.015, g 3 2 =2.016) (g=2.004, g=2.012) CaO (h4 ). X Y . , - O st – , : (O 3C – )st (O 4C – )st, .相似文献
9.
Three types of sorption interactions with the corresponding Pd aquachlorocomplexes [Pd(H2O)2Cl2]0, [Pd(H2O)Cl3]– and [PdCl4]2– have been discovered on -Al2O3 at surface concentrations for the active component and the competing HCl ranging within 0.05–1.25 and 1.2–4.8 mol m–2, respectively.
0,05–1,25 /2 1,2 4,8 /2 -Al2O3 , : [Pd(H2O)2Cl2]0, [Pd(H2O)Cl3]– [PdCl4]2–.相似文献
10.
V. M. Mastikhin O. B. Lapina V. F. Lyakhova 《Reaction Kinetics and Catalysis Letters》1980,14(3):323-327
Systems V2O5–KHSO4 and V2O5–K2SO4 have been studied by the51V NMR method. The first system demonstrates the same states of vanadium as the previously studied V2O5–K2S2O7, in this system a compound with an equimolar ratio of components has been found. In V2O5–K2SO4 the state of vanadium differs from the above systems and the formation of a compound with V/K=4 is observed.
51V KHSO4–V2O5 K2SO4–V2O5. , K2S2O7–V2O5, . K2SO4–V2O5 V/K4.相似文献
11.
N-(4-Benzo[15-crown-5])biphenylaminoglyoxime (H2L) and sodium chloride salt of N-(4-benzo[15-crown-5])biphenylaminoglyoxime (H2L · NaCl) have been prepared from 4-biphenylchloroglyoxime, 4-aminobenzo[15-crown-5], and sodium bicarbonate and sodium chloride. Nickel(II), cobalt(II), and copper(II) complexes with H2L and H2L · NaCl have a metal–ligand ratio of 1 : 2 and the ligand coordinates through the two N atoms, as do most of the vic-dioximes. Their IR spectra and elemental analyses are given, together with 1H NMR spectra of the ligands. 相似文献
12.
N. M. Ostrovskii E. M. Chalganov Yu. K. Demanov Yu. N. Kolomytsev O. B. Bogomolova 《Reaction Kinetics and Catalysis Letters》1990,41(2):277-282
To check coke formation on metallic (Pto) and acidic (Al3+) centers of Pt/Al2O3 and Pt–Sn/Al2O3 catalysts, the application of IR spectroscopy of adsorbed CO for detecting Pto–CO (2070 cm–1) and Al3+–CO (2190 cm–1) bonds has been substantiated. Decrease in the number of active Pto and Al3+ centers is shown to correlate with that in the dehydrogenation rate of cyclohexane and in the isomerization rate of heptane, respectively.
(Pto) (Al3+) Pt/Al2O3 Pt–Sn/Al2O3 - CO Pto–CO (2070 –1) Al3+–CO (2190 –1). , Pto , Al3+- .相似文献
13.
V. S. Tkach F. K. Schmidt G. V. Ratovskii N. D. Malakhova N. A. Murasheva M. L. Chernyshev O. V. Burlakova 《Reaction Kinetics and Catalysis Letters》1988,36(2):257-262
The interaction between the components of catalytic Pd(acac)2–PR3–BF3OEt2 systems dimerizing propylene to linear hexenes with 59 % selectivity, has been studied by UV and1H NMR spectroscopy methods. Formation mechanism of catalytically active [R3P–Pd–H]+BF
4
–
compounds is suggested.
, 1 Pd(acac)2–PR3–BF3OEt2, 59%, [R3P–Pd–H]+BF 4 – .相似文献
14.
Thiodiglycolates of heavy lanthanides, prepared in the reactions of the hydroxides of the rare earths with thiodiglycolic acid, have the general formula Ln2(C4
H
4O4S)3·nH2O, wheren=5 for Ln=Tb and Dy,n=6 for Ln=Ho, Er and Tm, andn=7 for Ln=Yb and Lu. On heating, the hydrated complexes lose the crystallization water in two steps, and the resulting anhydrous complexes decompose to the oxides Ln2O3 and Tb4O7 via the intermediate formation of Ln2O3–x(SO4)x.The temperatures of oxide formation decrease with increasing atomic number of the lanthanides. The solubilities of the heavy lanthanide thiodiglycolates are of the order of 10–2 mol · dm–3.
Zusammenfassung In der Reaktion von Seltenerdenhydroxiden und Thiodiglykolsäure wurden die Thiodiglykolate von Lanthaniden mit der allgemeinen Formel Ln2(C4H4O4S)3 ·nH2O hergestellt (mitn=5 für Ln=Tb und Dy, mitn=6 für Ln=Ho, Er und Tm und mitn=7 für Ln=Yb und Lu). Die Hydratkomplexe verlieren ihr Kristallwasser beim Erhitzen in zwei Stufen, die entstehenden wasserfreien Komplexe zerfallen über die intermediäre Form Ln2O3–x (SO4)x in die Oxide Ln2O3 und Tb4O7. Die Temperatur der Oxidbildung nimmt mit steigender Ordnungszahl der Lanthaniden ab. Die Löslichkeit der untersuchten Lanthanidenthiodiglykolate liegt in der Größenordnung 10–2 mol/dm–3.
Ln2(C4H4O4S)3-n2, =5 Ln=Tb Dy,=6 Ln=, m, =7 Ln=Yb Lu. , Ln2O3 b47 Ln2O3–x(SO4) x . . 10–2 · –3.相似文献
15.
Yu. V. Chernyshova L. I. Kuznetsova R. I. Maksimovskaya K. I. Matveev 《Reaction Kinetics and Catalysis Letters》1989,38(1):57-62
The rate constants of interactions of PW12-nVnO40
(3+n)– (n=1–4) heteropoly anions (HPAs) and various PW10V2O40
–5 isomers with VO2+ were measured. The reactions occurred via formation of intermediate active complexes with V(IV) ions incorporated into the coordination sphere of HPA.
VO2+ PW12-nVnO40 –(3+n) (n=1–4) PW10V2O40 –5. , V(IV) .相似文献
16.
S. Sarge H. K. Cammenga B. Becker R. Rohr-Aehle R. Tacke 《Journal of Thermal Analysis and Calorimetry》1988,33(4):1185-1192
Silanes of the type R1R2Si(H)CH2OEl(O)xR
y
3
[R=organyl; El=C (x=y=1), S (x=2,y=1), P (x=1y=2)] undergo a thermally induced rearrangement to give silanes of the type R1R2Si (CH3)OEl(O)xR
y
3
. The energetic (reaction enthalpy) and kinetic data (reaction order, enthalpy and entropy of activation) of this reaction were determined by means of differential scanning calorimetry. The results obtained are discussed in terms of mechanistic aspects.
相似文献
Zusammenfassung Silane des Typs R1R2Si(H)CH2OE10xR y 3 mit R=organyl; E1=C (x=y=1), S(x=2, y=1) oder P (x=1,y=2) zeigen eine thermisch induzierte Umlagerung zu Silanen des Typs R1R2Si(CH3)OE10xR y 3 . Energetische (Reaktionsenthalpie) und kinetische Daten (Reaktionsordnung, Aktivierungsenthalpie und -entropie) dieser Umlagerungsreaktion wurden mittels DSC ermittelt. Die mechanistischen Aspekte der Ergebnisse werden diskutiert.
R1R2Si(H)OE1(O)xR y 3 , R= , E1=C (x=y=1), S (x=2,y=1), P (x=1,y=2), R1R2Si(CH3)OE1(O)xR y 3 . ( ) ( , ) . .
相似文献
17.
Summary Vanadium(III) chloride reacts with 1,10-phenanthroline and 2,2-bipyridyl, and with substituted derivatives of each ligand (B), in ethanol or in acetonitrile as solvent (L), to yield two different series of complexes. These are (a) the neutral species VCl3BL, where B = 1,10-phenanthroline, 5-chloro-1,10-phenanthroline, 5-methyl-1,10-phenanthroline, 4,7-dimethyl-1,10-phenanthroline, 2,2-bipyridyl, 4,4-dimethyl-2,2-bipyridyl, L = ethanol. The complexes in which B = 1,10-phenanthroline or 2,2-bipyridyl were also obtained with L = acetonitrile, (b) [VCl2B2]+[VCl4B]– where B is the same series of ligands listed above. Vanadium(III) chloride yields VCl3 (terpy) with 2,2,2 -terpyridyl. All the complexes have been characterised by elemental analyses, conductance measurements, electronic- and i.r. spectral measurements, and by their temperature-range (297–77 K) magnetic moments; ring substituents have little influence on any chemical or physical properties of these complexes. 相似文献
18.
Kinetic parameters of thermal decomposition of compounds of general formulaM
2
I
M
II[Ni(NO2)6], whereM
I= K+, Rb+ or Cs+ andM
II= Ca2+, Sr2+ or Ba2+, were investigated on the basis of the respective thermal curves. Calculations of the reaction order and activation energy carried out by the Coats-Redfern method and by Doyle's method (modified by Zsakó) gave similar results, The reaction order is 2 for all the compounds investigated. In the group of potassium salts the activation energy increases fromM
II=Ca2+ toM
II=Ba2+. In the groups of rubidium and caesium salts, the lowest activation energy is observed whenM
II=Sr2+. Such behaviour of the nitritonickelates is explained in terms of structures and the principle of maximum density.
Zusammenfassung Die kinetischen Parameter der thermischen Zersetzung von Verbindungen der allgemeinen FormelM 2 I M II [Ni(NO2)6] (M I= K+, Rb+ oder Cs+ und MII = =Ca2+, Sr2+ oder Ba2+) wurden auf Grund der entsprechenden thermischen Kurven untersucht. Die an Hand der Coats-Redfern Methode und der durch Zsakó modifizierten Doyleschen Methode durchgeführten Berechnungen der Reaktionsordnung und der Aktivierungsenergie ergaben ähnliche Resultate. Die Reaktionsordnung ist 2 für sämtliche untersuchten Verbindungen. In der Gruppe der Kaliumsalze steigt die Aktivierungsenergie vonM II=Ca2+ in RichtungM II=Ba2+ an. In der Gruppe der Rubidium- und Caesiumsalze wird die niedrigste Aktivierungsenergie beiM II=Sr2+ beobachtet. Dieses Verhalten der Nitritonickelate wird durch die Strukturen und das Prinzip der maximalen Dichte erklärt.
1 2 II[Ni(NO2)6], I= +, Rb+Cs+,a II= 2+,8r2+2+. , - ( ), . 2. + 2+. II=S2+. .相似文献
19.
A. Lycourghiotis 《Reaction Kinetics and Catalysis Letters》1981,17(1-2):165-168
The influence of Na+ cations, introduced into the support from different compounds, on the formation of cobalt species on -alumina surface has been studied. The monitoring of the Co3O4/CoAl2O4 critical ratio has been obtained using diffuse reflectance spectroscopy (DRS). Sodium cations were deposited on the carrier surface by dry impregnation with aqueous solutions of NaNO3, NaOH and CH3COONa as well as with a solution of CH3COONa in CH3COOH. The active phase was mounted on the doped supports by pore volume impregnation with aqueous Co(NO3)2·6H2O solutions. Sodium cations catalyze the solid transformation of Co3O4 into CoAl2O4. The extent of this transformation is nearly independent of the particular sodium compound used.
Na+, , , - . Co3O4/CoAl2O4 - . NaNO3 NaOH CH3COONa, CH3COONa CH3COOH. Co(NO3)2·6H2O. , Co3O4 CoAl2O4. .相似文献
20.
Kinetic parameters of thermal decomposition of compounds of the general formula M
2
I
MII[Cu(NO2)6] (where MI=K+, Rb+ or Cs+; and MII=Ca2+, Sr2+, Ba2+ or Pb2+) and K2Pb[X(NO2)6] (where X=Co2+, Ni2+, Zn2+) are determined from the corresponding thermal curves. The order of reaction (n) and the activation energy (E
a) are derived. The kinetic data is discussed in terms of the effects of outer sphere cations and the central ion on the activation energy.
Zusammenfassung Die kinetischen Parameter der thermischen Zersetzung von Verbindungen des allgemeinen Typs M 2 I MII[Cu(NO2)6] (M1=K+, Rb+ oder Cs+; MII=Ca2+, Sr2+, Ba2+ oder Pb2+) bzw. K2Pb[X(NO2)6] (X=Co2+, Ni2+, Zn2+) werden aus den entsprechenden thermischen Kurven bestimmt. Die Reaktionsordnung (n) und die Aktivierungsenergie (E a) werden abgeleitet. Die kinetischen Parameter werden hinsichtlich der Effekte der Kationen in der Äu\eren SphÄre und des zentralen Ions auf die Aktivierungsenergie diskutiert.
Résumé Les paramètres cinétiques de la décomposition thermique des composés de formule générale M 2 I MII[Cu(NO2)6] où MI=K+, Rb+ ou Cs+ et MII=Ca2+, Sr2+, Ba2+ ou Pb2 + et K2Pb[X(NO2)6] où X=Co2+, Ni2+, Zn2+ ont été déterminés à partir des courbes thermoanalytiques correspondantes. L'ordre de réaction (n) et l'énergie d'activation (E a) ont été calculés. Les effets des cations de la sphère externe et ceux de l'ion central sur l'énergie d'activation sont discutés.
M 2 I MII[Cu(NO2)6, I=+, Rb+ Cs+; II=C2+, Sr2+, 2+ 2+, K2Pb[X(NO2)6], X=2+ Ni2+; Zn2+. (n) (E a ). .相似文献