Carbonyl exchange between [MX3(13CO)]–(MX = PdCl, PtCl or PtBr) and 12CO has been studied by IR and 13C NMR spectroscopies as a function of temperature. The exchange is first-order in both CO and complex concentration, and the activation entropies are negative, suggesting an associative reaction mechanism. There is a small solvent effect, but no chloride dependence. Activation parameters and rate constants
通过IR和13 C NMR光谱研究了[MX 3(13 CO)] –(MX = PdCl,PtCl或PtBr)与12 CO之间的羰基交换随温度的变化。CO和复杂浓度的交换都是一阶的,活化熵为负,表明缔合反应机理。溶剂作用很小,但不依赖
氯离子。激活参数和速率常数,依次为ΔH ‡/ kJ mol –1,ΔS ‡/ JK –1 mol –1 k es 298 / dm 3 mol –1 s –1表示[PdCl 3(CO)] – 60±8,–47±30,0.57±0.07;对于[PtCl 3(CO)] – 60±7,–91±22,(3.3±0.3)×10 –3,对于[PtBr 3(CO)] – 49±6,–104±19,(6.0 + 0.2 )×10 –2(95%置信区间)。这比类似的
乙烯卤化物络合物中的
乙烯交换慢三到六个数量级。