Nabavizadeh S Masoud, Rashidi Mehdi
Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454, Iran.
J Am Chem Soc. 2006 Jan 11;128(1):351-7. doi: 10.1021/ja056505c.
This article presents a sigma acceptor strength scale for methyltrioxorhenium(VII) (MTO), one of the most versatile and useful high oxidation state organometallics ever described. The spectrophotometric titration of MTO with a series of N-donor bases in CCl(4) gives formation constants (K(f)) and enthalpies for the adduct formation reactions. An excellent linearity of log K(f) with respect to the Hammett sigma constants of the substituents on the ligands was observed. The resulting rho constant is proposed to be a good indication of the Lewis acidity of MTO. The enthalpies of adduct formation of N-donors with MTO also fit the ECW model to predict the values of E(A) and C(A) parameters for MTO. The parameters can be used to predict an acidity scale for MTO. These parameters also allow the chemists to predict and correlate quantitatively the enthalpies of MTO. Lewis base interactions. Significant chemical insights result from the fit of the data to the ECW model.
本文提出了一种用于甲基三氧化铼（VII）（MTO）的σ受体强度标度，MTO是有史以来描述的用途最广泛、最有用的高氧化态有机金属化合物之一。在四氯化碳中用一系列含氮供体碱对MTO进行分光光度滴定，得出加合物形成反应的形成常数（K(f)）和焓。观察到log K(f)与配体上取代基的哈米特σ常数之间具有良好的线性关系。所得到的ρ常数被认为是MTO路易斯酸度的良好指标。含氮供体与MTO形成加合物的焓也符合ECW模型，以预测MTO的E(A)和C(A)参数值。这些参数可用于预测MTO的酸度标度。这些参数还使化学家能够定量预测和关联MTO的焓。路易斯碱相互作用。数据与ECW模型的拟合产生了重要的化学见解。
