with those of the corresponding acac complex (acac=2,4-pentanedionate) in order to investigate the substituent influence on the rates. The kD and kep values of the NO2acac complex are ca. 104 and ca. 106 times, respectively, larger than those of the CH3acac complex. The effect of substituents is electronic and the Hammett relationship was found to hold for both deuteration and epimerization rates. The
[Co(Xacac)2(Me-en)]+ (Xacac: NO2acac=3-nitro-2, 4-pentanedionate, Clacac=3-chloro-2,4-pentanedionate, CH3acac=3-methyl-2,4-pentanedionate; Me-en=
N-甲基乙二胺)在34.0°C下测定,结果将它们相互比较,并与相应的 acac 复合物(acac = 2,4-
戊二酸)进行比较,以研究取代基对速率的影响。NO2acac 复合物的 kD 和 kep 值约为。104 和约。分别比 CH3acac 复合物大 106 倍。取代基的影响是电子的,并且哈米特关系被发现对于
氘化率和差向异构化率都成立。还原 (Co3+/Co2+) 半波电位,通过旋转玻碳电极伏安法获得的 E1⁄2 从 CH3acac 络合物的 -0.59 V(vs. SCE)增加到 NO2acac 络合物的