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1.
E. Makrlík P. Vaňura P. Selucky 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(3):547-551
Extraction of microamounts of cesium by a nitrobenzene solution of ammonium dicarbollylcobaltate
( \textNH 4 + \textB - ) ( {{\text{NH}}_{ 4}^{ + } {\text{B}}^{ - } }) and thallium dicarbollylcobaltate
( \textTl + \textB - ) ( {{\text{Tl}}^{ + } {\text{B}}^{ - } }) in the presence of 2,3-naphtho-15-crown-5 (N15C5, L) has been investigated. The equilibrium data have been explained assuming
that the complexes
\textML + {\text{ML}}^{ + } and
\textML 2 + {\text{ML}}_{ 2}^{ + }
( \textM + = \textNH4 + ,\textTl + ,\textCs + ) ( {{\text{M}}^{ + } = {\text{NH}}_{4}^{ + } ,{\text{Tl}}^{ + } ,{\text{Cs}}^{ + } } ) are present in the organic phase. The stability constants of the
\textML + {\text{ML}}^{ + } and
\textML2 + {\text{ML}}_{2}^{ + } species
( \textM + = \textNH4 + ,\textTl + ) ( {{\text{M}}^{ + } = {\text{NH}}_{4}^{ + } ,{\text{Tl}}^{ + } }) in nitrobenzene saturated with water have been determined. It was found that the stability of the complex cations
\textML + {\text{ML}}^{ + } and
\textML2 + {\text{ML}}_{2}^{ + }
(\textM + = \textNH4 + ,\textTl + ,\textCs + ; \textL = \textN15\textC5) ({{\text{M}}^{ + } = {\text{NH}}_{4}^{ + } ,{\text{Tl}}^{ + } ,{\text{Cs}}^{ + } ;\;{\text{L}} = {\text{N}}15{\text{C}}5}) in the mentioned medium increases in the
\textCs + < \textNH4 + < \textTl + {\text{Cs}}^{ + }\,<\, {\text{NH}}_{4}^{ + }\,<\,{\text{Tl}}^{ + } order. 相似文献
2.
In this article, a thermodynamic study on the interaction of Jack bean urease, JBU, with
\textHg 2+ {\text{Hg}}^{ 2+ } and
\textAg + {\text{Ag}}^{ + } ions were studied by isothermal titration calorimetry (ITC) at 300 and 310 K in 30 mM Tris buffer solution, pH 7.0. The heats
of
\textJBU + \textHg 2+ {\text{JBU}} + {\text{Hg}}^{ 2+ } and
\textJBU + \textAg + {\text{JBU}} + {\text{Ag}}^{ + } interactions are reported and analyzed in terms of the extended solvation model. It was indicated that there are a set of
12 identical and non-cooperative sites for
\textHg 2+ {\text{Hg}}^{ 2+ } and
\textAg + {\text{Ag}}^{ + } ions. The binding of
\textHg 2+ {\text{Hg}}^{ 2+ } and
\textAg + {\text{Ag}}^{ + } ions with JBU are exothermic with association equilibrium constants of 5415.65 and 4368.15 for
\textAg + {\text{Ag}}^{ + } and 2389 and 2087 M - 1 M^{ - 1} for
\textHg 2+ {\text{Hg}}^{ 2+ } at 300 and 310 K, respectively. 相似文献
3.
Extraction of microamounts of strontium and barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of polyethylene glycol PEG 1000 (L) has been investigated. The equilibrium data have been explained assuming
that the complexes
\textH 2 \textL2 + {\text{H}}_{ 2} {\text{L}}^{2 + } ,
\textML 2+ {\text{ML}}^{ 2+ } and
\textMHL 3+ {\text{MHL}}^{ 3+ }
( \textM 2+ = \textSr 2+ , \textBa 2+ ) \left( {{\text{M}}^{ 2+ } = {\text{Sr}}^{ 2+ } ,\,\,{\text{Ba}}^{ 2+ } } \right) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated
with water have been determined. It was found that in water-saturated nitrobenzene the stability constant of the
\textBaL 2+ {\text{BaL}}^{ 2+ } cationic complex species is somewhat higher than that of the complex
\textSrL 2+ {\text{SrL}}^{ 2+ } . 相似文献
4.
E. Makrlík P. Selucky P. Vaňura 《Journal of Radioanalytical and Nuclear Chemistry》2011,290(2):397-401
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium
\textM 2+ ( \textaq ) + \textSr 2+ ( \textorg ) ? \textM 2+ ( \textorg ) + \text Sr 2+ ( \textaq ) {\text{M}}^{ 2+ } \left( {\text{aq}} \right) + {\text{Sr}}^{ 2+ } \left( {\text{org}} \right) \Leftrightarrow {\text{M}}^{ 2+ } \left( {\text{org}} \right) + {\text{ Sr}}^{ 2+ } \left( {\text{aq}} \right) taking place in the two-phase water–phenyltrifluoromethyl sulfone (abbrev. FS 13) system (M2+ = Mg2+, Ca2+, Ba2+, Cu2+, Zn2+, Cd2+, Pb2+,
\textUO22 + {\text{UO}}_{2}^{2 + } , Mn2+, Fe2+, Co2+, Ni2+; aq = aqueous phase, org = FS 13 phase) were evaluated. Furthermore, the individual extraction constants of the M2+ cations in this two-phase system were calculated; they were found to increase in the series of Mg2+,
\textUO22 + {\text{UO}}_{2}^{2 + } < Ca2+, Co2+ < Cd2+, Ni2+ < Zn2+ < Cu2+, Mn2+, Fe2+ < Pb2+ < Ba2+. 相似文献
5.
The standard molar Gibbs free energy of formation of YRhO3(s) has been determined using a solid-state electrochemical cell wherein calcia-stabilized zirconia was used as an electrolyte.
The cell can be represented by:
( - )\textPt - Rh/{ \textY2\textO\text3( \texts ) + \textYRh\textO3( \texts ) + \textRh( \texts ) }//\textCSZ//\textO2( p( \textO2 ) = 21.21 \textkPa )/\textPt - Rh( + ) \left( - \right){\text{Pt - Rh/}}\left\{ {{{\text{Y}}_2}{{\text{O}}_{\text{3}}}\left( {\text{s}} \right) + {\text{YRh}}{{\text{O}}_3}\left( {\text{s}} \right) + {\text{Rh}}\left( {\text{s}} \right)} \right\}//{\text{CSZ//}}{{\text{O}}_2}\left( {p\left( {{{\text{O}}_2}} \right) = 21.21\;{\text{kPa}}} \right)/{\text{Pt - Rh}}\left( + \right) . The electromotive force was measured in the temperature range from 920.0 to 1,197.3 K. The standard molar Gibbs energy of
the formation of YRhO3(s) from elements in their standard state using this electrochemical cell has been calculated and can be represented by:
D\textfG\texto{ \textYRh\textO3( \texts ) }/\textkJ \textmo\textl - 1( ±1.61 ) = - 1,147.4 + 0.2815 T ( \textK ) {\Delta_{\text{f}}}{G^{\text{o}}}\left\{ {{\text{YRh}}{{\text{O}}_3}\left( {\text{s}} \right)} \right\}/{\text{kJ}}\;{\text{mo}}{{\text{l}}^{ - 1}}\left( {\pm 1.61} \right) = - 1,147.4 + 0.2815\;T\;\left( {\text{K}} \right) . Standard molar heat capacity Cop,m C^{o}_{{p,m}} (T) of YRhO3(s) was measured using a heat flux-type differential scanning calorimeter in two different temperature ranges from 127 to
299 K and 305 to 646 K. The heat capacity in the higher temperature range was fitted into a polynomial expression and can
be represented by: $ {*{20}{c}} {\mathop C\nolimits_{p,m}^{\text{o}} \left( {{\text{YRh}}{{\text{O}}_3},{\text{s,}}T} \right)\left( {{\text{J}}\;{{\text{K}}^{ - 1}}{\text{mo}}{{\text{l}}^{ - 1}}} \right)} & { = 109.838 + 23.318 \times {{10}^{ - 3}}T\left( {\text{K}} \right)} & { - 12.5964 \times {{10}^5}/{T^2}\left( {\text{K}} \right).} \\ {} & {\left( {305 \leqslant T\left( {\text{K}} \right) \leqslant 646} \right)} & {} \\ $ \begin{array}{*{20}{c}} {\mathop C\nolimits_{p,m}^{\text{o}} \left( {{\text{YRh}}{{\text{O}}_3},{\text{s,}}T} \right)\left( {{\text{J}}\;{{\text{K}}^{ - 1}}{\text{mo}}{{\text{l}}^{ - 1}}} \right)} & { = 109.838 + 23.318 \times {{10}^{ - 3}}T\left( {\text{K}} \right)} & { - 12.5964 \times {{10}^5}/{T^2}\left( {\text{K}} \right).} \\ {} & {\left( {305 \leqslant T\left( {\text{K}} \right) \leqslant 646} \right)} & {} \\ \end{array} The heat capacity of YRhO3(s) was used along with the data obtained from the electrochemical cell to calculate the standard enthalpy and entropy of
formation of the compound at 298.15 K. 相似文献
6.
The oxidation of aquaethylenediaminetetraacetatocobaltate(II) [Co(EDTA)(H2O)]−2 by N-bromosuccinimide (NBS) in aqueous solution has been studied spectrophotometrically over the pH 6.10–7.02 range at 25 °C.
The reaction is first-order with respect to complex and the oxidant, and it obeys the following rate law:
\textRate = k\textet K 2 K 3 [ \textCo\textII ( \textEDTA )( \textH 2 \textO ) - 2 ]\textT [\textNBS] \mathord | / |
\vphantom [\textNBS] ( [ \textH + ] + K 2 ) ( [ \textH + ] + K 2 ) {\text{Rate}} = k^{\text{et} } K_{ 2} K_{ 3} \left[ {{\text{Co}}^{\text{II}} \left( {\text{EDTA}} \right)\left( {{\text{H}}_{ 2} {\text{O}}} \right)^{ - 2} } \right]_{\text{T}} {{[{\text{NBS}}]} \mathord{\left/ {\vphantom {{[{\text{NBS}}]} {\left( {\left[ {{\text{H}}^{ + } } \right]{ + }K_{ 2} } \right)}}} \right. \kern-\nulldelimiterspace} {\left( {\left[ {{\text{H}}^{ + } } \right]{ + }K_{ 2} } \right)}} 相似文献
7.
Ponnusamy Sami Kandasamy Venkateshwari Natarajan Mariselvi Arunachalam Sarathi Kasi Rajasekaran 《Transition Metal Chemistry》2010,35(2):137-142
l-cysteine undergoes facile electron transfer with heteropoly 10-tungstodivanadophosphate,
[ \textPV\textV \textV\textV \textW 1 0 \textO 4 0 ]5 - , \left[ {{\text{PV}}^{\text{V}} {\text{V}}^{\text{V}} {\text{W}}_{ 1 0} {\text{O}}_{ 4 0} } \right]^{5 - } , at ambient temperature in aqueous acid medium. The stoichiometric ratio of [cysteine]/[oxidant] is 2.0. The products of the
reaction are cystine and two electron-reduced heteropoly blue, [PVIVVIVW10O40]7−. The rates of the electron transfer reaction were measured spectrophotometrically in acetate–acetic acid buffers at 25 °C.
The orders of the reaction with respect to both [cysteine] and [oxidant] are unity, and the reaction exhibits simple second-order
kinetics at constant pH. The pH-rate profile indicates the participation of deprotonated cysteine in the reaction. The reaction
proceeds through an outer-sphere mechanism. For the dianion −SCH2CH(NH3
+)COO−, the rate constant for the cross electron transfer reaction is 96 M−1s−1 at 25 °C. The self-exchange rate constant for the
- \textSCH2 \textCH( \textNH3 + )\textCOO - \mathord | / |
\vphantom - \textSCH2 \textCH( \textNH3 + )\textCOO - ·\textSCH2 \textCH( \textNH3 + )\textCOO - ·\textSCH2 \textCH( \textNH3 + )\textCOO - {{{}^{ - }{\text{SCH}}_{2} {\text{CH}}\left( {{{\text{NH}}_{3}}^{ + } } \right){\text{COO}}^{ - } } \mathord{\left/ {\vphantom {{{}^{ - }{\text{SCH}}_{2} {\text{CH}}\left( {{{\text{NH}}_{3}}^{ + } } \right){\text{COO}}^{ - } } {{}^{ \bullet }{\text{SCH}}_{2} {\text{CH}}\left( {{{\text{NH}}_{3}}^{ + } } \right){\text{COO}}^{ - } }}} \right. \kern-\nulldelimiterspace} {{}^{ \bullet }{\text{SCH}}_{2} {\text{CH}}\left( {{{\text{NH}}_{3}}^{ + } } \right){\text{COO}}^{ - } }} couple was evaluated using the Rehm–Weller relationship. 相似文献
8.
Ricardo Picciochi Hermínio P. Diogo Manuel E. Minas da Piedade 《Journal of Thermal Analysis and Calorimetry》2010,100(2):391-401
Combustion calorimetry, Calvet-drop sublimation calorimetry, and the Knudsen effusion method were used to determine the standard
(p
o = 0.1 MPa) molar enthalpies of formation of monoclinic (form I) and gaseous paracetamol, at T = 298.15 K:
\Updelta\textf H\textm\texto ( \textC 8 \textH 9 \textO 2 \textN,\text cr I ) = - ( 4 10.4 ±1. 3)\text kJ \textmol - 1 \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} \left( {{\text{C}}_{ 8} {\text{H}}_{ 9} {\text{O}}_{ 2} {\text{N}},{\text{ cr I}}} \right) = - ( 4 10.4 \pm 1. 3){\text{ kJ}}\;{\text{mol}}^{ - 1} and
\Updelta\textf H\textm\texto ( \textC 8 \textH 9 \textO 2 \textN,\text g ) = - ( 2 80.5 ±1. 9)\text kJ \textmol - 1 . \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} \left( {{\text{C}}_{ 8} {\text{H}}_{ 9} {\text{O}}_{ 2} {\text{N}},{\text{ g}}} \right) = - ( 2 80.5 \pm 1. 9){\text{ kJ}}\;{\text{mol}}^{ - 1} . From the obtained
\Updelta\textf H\textm\texto ( \textC 8 \textH 9 \textO 2 \textN,\text cr I ) \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} \left( {{\text{C}}_{ 8} {\text{H}}_{ 9} {\text{O}}_{ 2} {\text{N}},{\text{ cr I}}} \right) value and published data, it was also possible to derive the standard molar enthalpies of formation of the two other known
polymorphs of paracetamol (forms II and III), at 298.15 K:
\Updelta\textf H\textm\texto ( \textC 8 \textH 9 \textO 2 \textN,\text crII ) = - ( 40 8.4 ±1. 3)\text kJ \textmol - 1 \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} \left( {{\text{C}}_{ 8} {\text{H}}_{ 9} {\text{O}}_{ 2} {\text{N}},{\text{ crII}}} \right) = - ( 40 8.4 \pm 1. 3){\text{ kJ}}\;{\text{mol}}^{ - 1} and
\Updelta\textf H\textm\texto ( \textC 8 \textH 9 \textO 2 \textN,\text crIII ) = - ( 40 7.4 ±1. 3)\text kJ \textmol - 1 . \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} \left( {{\text{C}}_{ 8} {\text{H}}_{ 9} {\text{O}}_{ 2} {\text{N}},{\text{ crIII}}} \right) = - ( 40 7.4 \pm 1. 3){\text{ kJ}}\;{\text{mol}}^{ - 1} . The proposed
\Updelta\textf H\textm\texto ( \textC 8 \textH 9 \textO 2 \textN,\text g ) \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} \left( {{\text{C}}_{ 8} {\text{H}}_{ 9} {\text{O}}_{ 2} {\text{N}},{\text{ g}}} \right) value, together with the experimental enthalpies of formation of acetophenone and 4′-hydroxyacetophenone, taken from the
literature, and a re-evaluated enthalpy of formation of acetanilide,
\Updelta\textf H\textm\texto ( \textC 8 \textH 9 \textON,\text g ) = - ( 10 9. 2 ± 2. 2)\text kJ \textmol - 1 , \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} \left( {{\text{C}}_{ 8} {\text{H}}_{ 9} {\text{ON}},{\text{ g}}} \right) = - ( 10 9. 2\,\pm\,2. 2){\text{ kJ}}\;{\text{mol}}^{ - 1} , were used to assess the predictions of the B3LYP/cc-pVTZ and CBS-QB3 methods for the enthalpy of a isodesmic and isogyric
reaction involving those species. This test supported the reliability of the theoretical methods, and indicated a good thermodynamic
consistency between the
\Updelta\textf H\textm\texto \Updelta_{\text{f}} H_{\text{m}}^{\text{o}} (C8H9O2N, g) value obtained in this study and the remaining experimental data used in the
\Updelta\textr H\textm\texto \Updelta_{\text{r}} H_{\text{m}}^{\text{o}} calculation. It also led to the conclusion that the presently recommended enthalpy of formation of gaseous acetanilide in
Cox and Pilcher and Pedley’s compilations should be corrected by ~20 kJ mol−1. 相似文献
9.
Emanuel Makrlík J. Budka P. Vaňura P. Selucky 《Monatshefte für Chemie / Chemical Monthly》2009,287(3):157-160
AbstractFrom extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium \textM2 + ( \textaq ) + 1 ·\textSr2 + ( \textnb ) \rightleftarrows 1 ·\textM2 + ( \textnb ) + \textSr2 + ( \textaq ) {\text{M}}^{2 + } \left( {\text{aq}} \right) + {\mathbf{1}} \cdot {\text{Sr}}^{2 + } \left( {\text{nb}} \right) \rightleftarrows {\mathbf{1}} \cdot {\text{M}}^{2 + } \left( {\text{nb}} \right) + {\text{Sr}}^{2 + } \left( {\text{aq}} \right) taking place in the two-phase water–nitrobenzene system (M2+ = Ca2+, Ba2+, Cu2+, Zn2+, Cd2+, Pb2+, UO2 2+, Mn2+, Co2+, Ni2+; 1 = tetraphenyl p-tert-butylcalix[4]arene tetraketone; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Further, the stability constants of the 1 · M2+ complexes in water-saturated nitrobenzene were calculated; they were found to increase in the cation order Ba2+, Mn2+ < Co2+ < Cu2+, Ni2+ < Zn2+, Cd2+, UO2 2+ < Ca2+ < Pb2+. 相似文献10.
From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium
\textCs + ( \textaq ) + \textA - ( \textaq ) + 1( \textnb )\underset \rightleftharpoons 1·\textCs + ( \textnb ) + \textA - ( \textnb ) {\text{Cs}}^{ + } \left( {\text{aq}} \right) + {\text{A}}^{ - } \left( {\text{aq}} \right) + {\mathbf{1}}\left( {\text{nb}} \right)\underset {} \rightleftharpoons {\mathbf{1}}\cdot{\text{Cs}}^{ + } \left( {\text{nb}} \right) + {\text{A}}^{ - } \left( {\text{nb}} \right) taking place in the two-phase water-nitrobenzene system (A− = picrate, 1 = dibenzo-21-crown-7; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K
ex (1·Cs+, A−) = 4.4 ± 0.1. Further, the stability constant of the 1·Cs+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb (1·Cs+) = 6.3 ± 0.1. Finally, by using quantum mechanical DFT calculations, the most probable structure of the resulting cationic
complex species 1·Cs+ was solved. 相似文献
11.
E. Makrlík P. Vaňura P. Selucký 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(1):217-222
Extraction of microamounts of calcium and strontium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of tetraisopropyl methylene diphosphonate [T(iPr)MDP, L] has been investigated. The equilibrium data have
been explained assuming that the species HL+,
\textHL2 + {\text{HL}}_{2}^{ + } ,
\textML22 + {\text{ML}}_{2}^{2 + } and
\textML32 + {\text{ML}}_{3}^{2 + } (M2+ = Ca2+, Sr2+) are extracted into the organic phase. The values of extraction and stability constants of the cationic complexes in nitrobenzene
saturated with water have been determined. In the considered nitrobenzene medium, it was found that the stability constants
of the
\textCaLn2 + {\text{CaL}}_{n}^{2 + } complexes, where n = 2, 3 and L is T(iPr)MDP, are somewhat higher than those of the corresponding complex species
\textSrLn2 + {\text{SrL}}_{n}^{2 + } . 相似文献
12.
E. Makrlík P. Vaňura P. Selucký I. V. Smirnov V. A. Babain 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(1):335-340
Extraction of microamounts of calcium and strontium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B−) in the presence of diphenyl-N,N-dibutylcarbamoylmethyl phosphine oxide (DPDBCMPO, L) has been investigated. The equilibrium data have been explained assuming
that the species HL+,
\textHL2 + {\text{HL}}_{2}^{ + } , CaL2+,
\textCaL 2 2 + {\text{CaL}}_{ 2}^{{ 2 { + }}} ,
\textCaL 3 2 + {\text{CaL}}_{ 3}^{{ 2 { + }}} , SrL2+,
\textSrL 2 2 + {\text{SrL}}_{ 2}^{{ 2 { + }}} ,
\textSrL 3 2 + {\text{SrL}}_{ 3}^{{ 2 { + }}} and
\textSrL 4 2 + {\text{SrL}}_{ 4}^{{ 2 { + }}} are extracted into the organic phase. The values of extraction and stability constants of the cationic complexes in nitrobenzene
saturated with water have been determined. In the considered nitrobenzene medium, it was found that the stability constants
of the complexes CaL2+,
\textCaL 2 2 + {\text{CaL}}_{ 2}^{{ 2 { + }}} and
\textCaL 3 2 + {\text{CaL}}_{ 3}^{{ 2 { + }}} , where L is DPDBCMPO, are somewhat higher than those of the corresponding complex species SrL2+,
\textSrL 2 2 + {\text{SrL}}_{ 2}^{{ 2 { + }}} and
\textSrL 3 2 + {\text{SrL}}_{ 3}^{{ 2 { + }}} . 相似文献
13.
[
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ]M (M = K, Tl) reacts with “GaI” to give a series of compounds that feature Ga–Ga bonds, namely [
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→GaI3, [
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ]GaGaI2GaI2(
\textHpz\textMe2 {\text{Hpz}}^{{{\text{Me}}_{2} }} ) and [
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga(GaI2)2Ga[
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ], in addition to the cationic, mononuclear Ga(III) complex {[
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ]2Ga}+. Likewise, [
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ]M (M = K, Tl) reacts with (HGaCl2)
2
and Ga[GaCl4] to give [
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→GaCl3, {[
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ]2Ga}[GaCl4], and {[
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ]GaGa[
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ]}[GaCl4]2. The adduct [
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→B(C6F5)3 may be obtained via treatment of [
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ]K with “GaI” followed by addition of B(C6F5)3. Comparison of the deviation from planarity of the GaY3 ligands in [
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→GaY3 (Y = Cl, I) and [
\textTm\textBu\textt {\text{Tm}}^{{{\text{Bu}}^{\text{t}} }} ]Ga→GaY3, as evaluated by the sum of the Y–Ga–Y bond angles, Σ(Y–Ga–Y), indicates that the [
\textTm\textBu\textt {\text{Tm}}^{{{\text{Bu}}^{\text{t}} }} ]Ga moiety is a marginally better donor than [
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga. In contrast, the displacement from planarity for the B(C6F5)3 ligand of [
\textTp\textMe2 {\text{Tp}}^{{{\text{Me}}_{2} }} ]Ga→B(C6F5)3 is greater than that of [
\textTm\textBu\textt {\text{Tm}}^{{{\text{Bu}}^{\text{t}} }} ]Ga→B(C6F5)3, an observation that is interpreted in terms of interligand steric interactions in the former complex compressing the C–B–C
bond angles. 相似文献
14.
E. Makrlík P. Vaňura P. Selucky V. A. Babain I. V. Smirnov 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(3):839-844
Extraction of microamounts of europium and americium by a phenyltrifluoromethyl sulfone (FS 13) solution of hydrogen dicarbollylcobaltate
(H+B−) in the presence of N,N,N′,N′-tetraethyl-2,6-dipicolinamide (TEtDPA, L) has been investigated. The equilibrium data have been explained assuming that the
species HL+,
\textHL 2 + , {\text{HL}}_{ 2}^{ + } ,
\textML23 + {\text{ML}_{2}^{3 +}} and
\textML 3 3+ {\text{ML}_{ 3}^{ 3+}} (M3+ = Eu3+, Am3+) are extracted into the organic phase. The values of extraction and stability constants of the cationic complex species in
FS 13 saturated with water have been determined. It was found that the stability constants of the corresponding complexes
\textEuLn 3+ {\text{EuL}}_{n}^{ 3+ } and
\textAmLn 3+ {\text{AmL}}_{n}^{ 3+ }, where n = 2, 3 and L is TEtDPA, in the mentioned FS 13 medium are comparable. 相似文献
15.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+ (aq) + NaL+ (nb) ⇔ ML+ (nb) + Na+ (aq) taking place in the two-phase water–nitrobenzene system (M+ = H3O+,
\textNH4+ {\text{NH}}_{4}{}^{+} , Ag+, Tl+; L = hexaethyl p-tert-butylcalix[6]arene hexaacetate; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants
of the ML+ complexes in nitrobenzene saturated with water were calculated; they were found to increase in the following order:
\textAg + < NH4 + < \textH 3 \textO + < \textNa + < \textTl + . {\text{Ag}}^{ + } \, < \,\hbox{NH}_{4}{}^{ + } \, < \,{\text{H}}_{ 3} {\text{O}}^{ + } \, < \,{\text{Na}}^{ + } \, < \,{\text{Tl}}^{ + }. 相似文献
16.
Ponnusamy Sami Thangarajan Durai Anand Mariappan Premanathan Kasi Rajasekaran 《Transition Metal Chemistry》2010,35(8):1019-1025
Glutathione (GSH) undergoes facile electron transfer with vanadium(V)-substituted Keggin-type heteropolyoxometalates,
[ \textPV\textV \textW 1 1 \textO 4 0 ] 4 - [ {\text{PV}}^{\text{V}} {\text{W}}_{ 1 1} {\text{O}}_{ 4 0} ]^{{ 4 { - }}} (HPA1) and
[ \textPV\textV \textV\textV \textW 1 0 \textO 4 0 ] 5 - [ {\text{PV}}^{\text{V}} {\text{V}}^{\text{V}} {\text{W}}_{ 1 0} {\text{O}}_{ 4 0} ]^{{ 5 { - }}} (HPA2). The kinetics of these reactions have been investigated in phthalate buffers spectrophotometrically at 25 °C in aqueous
medium. One mole of HPA1 consumes one mole of GSH and the product is the one-electron reduced heteropoly blue,
[ \textPV\textIV \textW 1 1 \textO 40 ] 5- [ {\text{PV}}^{\text{IV}} {\text{W}}_{ 1 1} {\text{O}}_{ 40} ]^{ 5- } . But in the GSH-HPA2 reaction, one mole of HPA2 consumes two moles of GSH and gives the two-electron reduced heteropoly blue
[ \textPV\textIV \textV\textIV \textW 10 \textO 40 ] 7- [ {\text{PV}}^{\text{IV}} {\text{V}}^{\text{IV}} {\text{W}}_{ 10} {\text{O}}_{ 40} ]^{ 7- } . Both reactions show overall third-order kinetics. At constant pH, the order with respect to both [HPA] species is one and
order with respect to [GSH] is two. At constant [GSH], the rate shows inverse dependence on [H+], suggesting participation of the deprotonated thiol group of GSH in the reaction. A suitable mechanism has been proposed
and a rate law for the title reaction is derived. The antimicrobial activities of HPA1, HPA2 and
[ \textPV\textV \textV\textV \textV\textV \textW 9 \textO 4 0 ] 6 - [ {\text{PV}}^{\text{V}} {\text{V}}^{\text{V}} {\text{V}}^{\text{V}} {\text{W}}_{ 9} {\text{O}}_{ 4 0} ]^{{ 6 { - }}} (HPA3) against MRSA were tested in vitro in combination with vancomycin and penicillin G. The HPAs sensitize MRSA towards
penicillin G. 相似文献
17.
A novel method for the determination of membrane hydration numbers of cations in conducting polymers
M. J. M. Jafeen M. A. Careem S. Skaarup 《Journal of Solid State Electrochemistry》2012,16(5):1753-1759
Polypyrrole polymer films doped with the large, immobile dodecylbenzene sulfonate anions operating in alkali halide aqueous
electrolytes has been used as a novel physico-chemical environment to develop a more direct way of obtaining reliable values
for the hydration numbers of cations. Simultaneous cyclic voltammetry and electrochemical quartz crystal microbalance technique
was used to determine the amount of charge inserted and the total mass change during the reduction process in a polypyrrole
film. From these values, the number of water molecules accompanying each cation was evaluated. The number of water molecules
entering the polymer during the initial part of the first reduction was found to be constant and independent of the concentration
of the electrolyte below ∼1 M. This well-defined value can be considered as the primary membrane hydration number of the cation
involved in the reduction process. The goal was to investigate both the effects of cation size and of cation charge. The membrane
hydration number values obtained by this simple and direct method for a number of cations are:
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