A broad series of fully characterized, well-defined silica-supported W metathesis catalysts with the general formula [(≡SiO)W(═NAr)(═CHCMe2R)(X)] (Ar = 2,6-iPr2C6H3 (AriPr), 2,6-Cl2C6H3 (ArCl), 2-CF3C6H4 (ArCF3), and C6F5 (ArF5); X = OC(CF3)3 (OtBuF9), OCMe(CF3)2 (OtBuF6), OtBu, OSi(OtBu)3, 2,5-dimethylpyrrolyl (Me2Pyr) and R = Me or Ph) was prepared by grafting bis-X substituted complexes [W(NAr)(═CHCMe2R)(X)2] on silica partially dehydroxylated at 700 °C (SiO2-(700)), and their activity was evaluated with the goal to obtain detailed structure-activity relationships. Quantitative influence of the ligand set on the activity (turnover frequency, TOF) in self-metathesis of cis-4-nonene was investigated using multivariate linear regression analysis tools. The TOF of these catalysts (activity) can be well predicted from simple steric and electronic parameters of the parent protonated ligands; it is described by the mutual contribution of the NBO charge of the nitrogen or the IR intensity of the symmetric N-H stretch of the ArNH2, corresponding to the imido ligand, together with the Sterimol B5 and pKa of HX, representing the X ligand. This quantitative and predictive structure-activity relationship analysis of well-defined heterogeneous catalysts shows that high activity is associated with the combination of X and NAr ligands of opposite electronic character and paves the way toward rational development of metathesis catalysts.
Predicting "realistic" compounds of given chemical reactions with virtual synthesis tools usually requires the manual intervention of experienced chemists in the enumeration phase for the selection of appropriate reactants, assignment of the corresponding reaction sites, and removal of the unlikely products. To automate the virtual synthesis process, we have moved the expertise intensive parts from the compound library design phase to the reaction library design phase. ChemAxon is building an in silico reaction library containing important preparative transformations, where each reaction definition contains a generic transformation scheme and additional rules to handle the various starting compounds according to the corresponding chemo-, regio-, and stereoselectivity issues. Having well designed reaction definitions in hand, our software tool is able to generate synthetically feasible compound libraries with minimal effort in the enumeration phase.
The research objective of this study is to examine the changes in technological unemployment and to evaluate Keynes’ theory based on a literature analysis concerning the fourth industrial revolution. The methodology used in this study is a literature analysis of 86 papers published between 2011 and 2020 on topics related to Industry 4.0, the labor market, and technological unemployment. The change caused by the labor market raises employment sustainability issues. Among the goals adopted at the 2012 UN Rio+20 Conference on Sustainable Development, this study is directly related to goals 8 and 9, and indirectly to goal 10. Research evidence suggests that the impact of Industry 4.0 processes will reduce the amount of labor needed, bringing us closer to Keynes’ vision of three hours a day. The analysis suggests that reduced working hours will increase economic efficiency through more intensive work. The literature is used to determine whether the trend of reduced working hours can be interpreted as a positive or negative phenomenon. The extent of technological unemployment is determined by the digitalization strategy of each country and the speed of its introduction, as well as the readiness of the education system in a given country to retrain vulnerable groups in the labor market. However, the overall picture is positive: on the one hand, digital transformation opens up a wide range of opportunities for a more human life, and on the other hand, from an economic point of view, digitalization will become an inescapable element of competition by reducing marginal costs. The study’s novelty is that the effects of Industry 4.0 and technological unemployment on the labor market are analyzed in the context of Keynes’ theory.
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