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T.-J. Lee T.-Y. Lee W.-B. Juang C.-S. Chung 《Acta Crystallographica. Section C, Structural Chemistry》1985,41(11):1596-1598
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In order to investigate the effect of structure variation upon complex dissociation rate constants, the kinetics of the dissociation of (C·rac·5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane)copper(II) (red) cation has been examined spectrophotometrically at 25.0°C in 0.1–5.0 M HNO3. The cleavage of the second copper-nitrogen bond is proposed as the rate-determining step for this reaction. The possible pathways for the cleavages of the copper-nitrogen bonds, the factors influencing the dissociation rates, and the factors affecting the relative importance of each of these possible pathways are considered. 相似文献
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A. Grzejdziak 《Monatshefte für Chemie / Chemical Monthly》1994,125(2):107-117
Summary Protonation constants of 1,4,8,11-tetraazacyclotetradecane (T ACT) and 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (TMT ACT) (=0.1) were determined bypH-metry. The values are logK
1=10.922, logK
2=10.511, logK
3=2.646, logK
4=1.620 forT ACT, and logK
1=9.387, logK
2=9.050, logK
3=2.491, logK
4=1.380 forTMTACT. Absorption maxima of the complexes AgTA CT(NO3)2 and AgTMTACT(NO3)2 were found to be 1=280 nm, 2=350 nm, and 1=290 nm, 2=400 nm, respectively. The disproportionation constants of Ag(I) ions in the presence of the amines were determined by potentiometry: forTA CT logK
d
=12.778, and forTMT ACT logK
d
=11.778. The mechanisms of the electrode processes taking place in solutions of the complexes under investigation were examined by means of chronovoltamperometric and coulometric measurements. The formal potential,E
f
0
, of the system: AgTMT ACT
2++e AgTMT ACT
+ is +0.450 V vs. NHE.
Untersuchungen zu den Gleichgewichten Ag(I) -1,4,8,11-Tetraazacyclotetradekan und Ag(I) -1,4,8,11-Tetramethyl-1,4,8,11-tetraazacyclotetradekan in Wasser
Zusammenfassung Die Protonierungskonstanten von 1,4,8,11-Tetraazacyclotetradekan (TACT) und 1,4,8,11-Tetramethyl-1,4,8,11-tetraazacyclotetradekan (TMT ACT) wurdenpH-metrisch bei =0.1 bestimmt. Folgende Werte wurden ermittelt: logK 1=10.922, logK 2=10.511, logK 3=2.646, logK 4=1.620 fürTACT und logK 1=9.387, logK 2=9.050, logK 3=2.491, logK 4=1.380 fürTMT ACT. Die Absorptionsmaxima der Komplexe AgTACT(NO3)2 und AgTMTACT(NO3)2 waren 1=280 nm, 2=350 nm, bzw. 1=290 nm, 2=400 nm. Die Disproportionierungskonstanten der Ag(I)-Ionen in Gegenwart der Amine wurden potentiometrisch bestimmt: logK d =12.778 fürTACT und logK d =11.778 fürTMTACT. Der Mechanismus des Elektrodenprozesses in den Komplexlösungen wurde mittels Chronovoltamperometrie und Coulometrie überprüft. Das formale PotentialE f 0 des Systems AgTMT ACT 2++eAgTMT ACT + ist +0.450 V gegenüber NHE.相似文献
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