PHOSPHATO COMPLEXES OF COBALT(3) .V. ANATION OF DIAQUOBIS(ETHYLENEDIAMINE)COBALT(3) BY ORTHOPHOSPHATES

被引:31
作者
LINCOLN, SF
STRANKS, DR
机构
[1] Department of Physical and Inorganic Chemistry, University of Adelaide, SA
关键词
D O I
10.1071/CH9681745
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The anation reaction of [Co en2(OH2)2]3+ by PO43-, and their protonic analogues, is shown to proceed in two kinetic steps. The first is the rapid equilibrium formation of ion-pairs, followed by a slow substitution step. Ion-pair formation causes a significant shift in the cis-trans equilibrium position at pH 7. The anation rate exhibits a sharp maximum around pH 7, and kinetic studies demonstrate that the anation proceeds predominantly via the trans-[Co en2OH. OH2]2+. HPO2−4ion-pair. The rate of inner-sphere substitution from this ion-pair (k = 0.255 min−1 at 47.9º, ΔH‡ = 30.0 ± 0.6 kcal mole−1 =, ΔS‡ = +(19 ± 3) e. u.) is 10-20 times slower than the estimated rate of water exchange with trans-[Co en2OH. OH2I2+. Specific structures are assigned to the ion-pairs and these structures influence rates of substitution. At high phosphate concentrations, there is spectral evidence for the slower formation of diphosphate complexes. The relevance of these kinetic observations to the generation and preparation of phosphato complexes is discussed. © 1968 CSIRO. All rights reserved.
引用
收藏
页码:1745 / &
相关论文
共 12 条
[1]  
EIGEN M, 1965, ADV CHEM SER, P55
[2]   EXCHANGE AND ISOMERIZATION RATES OF COMPLEX IONS OF AQUO-BIS-(ETHYLENEDIAMINE)-COBALT(III)SERIES [J].
KRUSE, W ;
TAUBE, H .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1961, 83 (06) :1280-&
[3]   OPTICAL ROTATORY POWER OF CO-ORDINATION COMPOUNDS .V. OUTER-SPHERE COMPLEXES OF TRIS-DIAMINE-COBALT(3) COMPLEX IONS [J].
LARSSON, R ;
MASON, SF ;
NORMAN, BJ .
JOURNAL OF THE CHEMICAL SOCIETY A -INORGANIC PHYSICAL THEORETICAL, 1966, (03) :301-&
[4]   PHOSPHATO COMPLEXES OF COBALT(3) .3. HYDROLYSIS REACTIONS IN PERCHLORIC ACID MEDIA [J].
LINCOLN, SF ;
STRANKS, DR .
AUSTRALIAN JOURNAL OF CHEMISTRY, 1968, 21 (01) :67-&
[5]   PHOSPHATO COMPLEXES OF COBALT(3) .2. REVERSIBLE CHELATION AND RING-OPENING REACTIONS [J].
LINCOLN, SF ;
STRANKS, DR .
AUSTRALIAN JOURNAL OF CHEMISTRY, 1968, 21 (01) :57-&
[6]  
MASON SF, 1964, P CHEM SOC LONDON, P339
[7]   SPECTROSCOPIC AND CONFIGURATIONAL ASSIGNMENTS FROM ION-PAIRING EFFECTS [J].
MASON, SF ;
NORMAN, BJ .
CHEMICAL COMMUNICATIONS, 1965, (05) :73-&
[8]  
RASMUSSEN SE, 1952, ACTA CHEM SCAND, V6, P1265
[9]   STUDIES ON PHOSPHATO AND METHYL PHOSPHATO COMPLEXES OF PENTAAMMINECOBALT(111) CLASS [J].
SCHMIDT, W ;
TAUBE, H .
INORGANIC CHEMISTRY, 1963, 2 (04) :698-&
[10]   EFFECTS OF ELECTROLYTES ON CIRCULAR DICHROISM CURVES OF CATIONIC COMPLEX IONS [J].
SMITH, HL ;
DOUGLAS, BE .
INORGANIC CHEMISTRY, 1966, 5 (05) :784-&