Biphasic Aqueous Organometallic Catalysis Promoted by Cyclodextrins: How to Design the Water-Soluble Phenylphosphane to Avoid Interaction with Cyclodextrin
generated by the methyl groups on the CD secondary face. The absence or presence of an interaction between phosphanes and methylated β-CD was also confirmed by catalytic experiments. Thus, the phosphanes that do not interact with the methylated CD were the most efficient mass-transfer promoters in an aqueousbiphasic palladium-catalyzed Tsuji–Trost reaction.
Carbon, on active duty: The addition of activatedcarbon into the reaction medium appears to be a simple and efficient method to solve mass‐transfer limitations in aqueousorganometalliccatalysis (see figure).
活性碳:将活性炭添加到反应介质中似乎是解决水性有机金属催化中传质限制的一种简单有效的方法(见图)。
Molecular Recognition Between a Water-Soluble Organometallic Complex and a ?-Cyclodextrin: First Example of Second-Sphere Coordination Adducts Possessing a Catalytic Activity
Formation of stable second-sphere adductsbetween a water-soluble organometallic complex and a cyclodextrin (CD) is possible by finely designing the structure of the water-soluble phosphane. The key point to obtain such adducts was the synthesis of a water-soluble phosphane which possesses a tert-butylphenyl group recognized by the CD and separated from the phosphorus atom by a phenyl ring to avoid
The effect of activatedcarbons has been studied in the palladium-catalyzed cleavage reaction of allylalkylcarbonate under aqueous biphasic conditions. A number of parameters were investigated, such as the type of carbon, the structure of the water-soluble ligand, the water conditions, and the metal complex loading. It was found that the intrinsic properties of carbons had a strong influence on the
在水性两相条件下,钯的碳酸烯丙烷基酯的裂解反应中,已经研究了活性炭的作用。研究了许多参数,例如碳的类型,水溶性配体的结构,水的条件和金属配合物的负载量。发现碳的内在性质对反应速率有很大的影响。AC-WV碳具有最大的中孔部分和最低的氧表面基团含量,可获得最佳性能。考虑到AC-WV充当了传质促进剂,从而增加了界面面积以及孔体积中反应性物种之间的碰撞,从而使结果合理化。孔内催化剂和反应物的约束作用的假设等温研究和31 P 1 H} NMR研究支持了通过吸附-解吸过程。
Impact of cyclodextrins on the behavior of amphiphilic ligands in aqueous organometallic catalysis
modified beta-cyclodextrin (RAME-beta-CD) in aqueous medium could have a beneficial impact on the catalytic performances of phosphane-based aggregates in the Pd-catalyzed cleavage of allyl carbonates (Tsuji-Trost reaction). The RAME-beta-CD/phosphane supramolecular interactions helped explain the catalytic results. The presence of RAME-beta-CD in the aqueous compartment improved the phosphane-based aggregate