Pyridyl-Based Pentadentate Ligands: Base-Catalyzed Hydrolysis of <i>a</i><i>sym</i>-[Co(dmptacn)Cl]<sup>2+</sup>
作者:W. Gregory Jackson、Alistair J. Dickie、Rajumati Bhula、Josephine A. McKeon、Leone Spiccia、Suzanne J. Brudenell、David C. R. Hockless、Anthony C. Willis
DOI:10.1021/ic040041m
日期:2004.10.1
perchlorate salt. The kinetics of base-catalyzed hydrolysis establishes the usual [OH(-)] dependence (k(OH) = 0.040 M(-1) s(-1), 25 degrees C, I = 1.0 M, NaCl), but D-exchange experiments reveal that substantial if not complete reaction proceeds via the new pseudoaminate mechanism, i.e., via deprotonation at an alpha-CH(2) center rather than the NH. The significant kinetic isotope effect (k(H)/k(D) = 2.1)
通过1D和2D NMR研究表明,[Co(dmptacn)Cl](2+)(dmptacn = 1,4-双(吡啶基甲基)-1,4,7-三氮杂环壬烷)络合物是不对称异构体,其光学性质分辨率及其高氯酸盐的单晶X射线结构。碱催化水解的动力学建立了通常的[OH(-)]依赖性(k(OH)= 0.040 M(-1)s(-1),25摄氏度,I = 1.0 M,NaCl),但D-交换实验表明,如果不完全反应,将通过新的假胺化机理进行实质性反应,即通过在α-CH(2)中心而不是NH处的质子化。显着的动力学同位素效应(k(H)/ k(D)= 2.1)解释为限速去质子化,然后以与Cl(-)失去竞争的速率对共轭碱进行质子化。