Asymmetric hydrogenation of alkenes with cationic iridium(I) complexes of 2-phosphino-1-aminoferrocene ligands

Iridium complexes with bidentate P,N ligands represent a class of catalysts that significantly expand the application range of asymmetric hydrogenation. New substrate classes, for which there have previously been no suitable catalysts, can now be efficiently hydrogenated in high conversion and enantioselectivity. These substrates are often of synthetic importance, thus iridium catalysis represents a significant advance in the field of asymmetric catalysis. Planar chiral ferrocenyl aminophosphine ligands in which both heteroatoms were directly bound to the cyclopentadienyl ring were prepared by BF3-activated lithiationsubstitution in the presence of a chiral diamine in 49-59% yield and 75-85% enantiomeric excess. Some of these ligands were recrystallized to enantiomeric purity via ammonium fluoroborate salt formation of the phosphine sulfide. A crystal structure of one of these compounds was obtained and features an intramolecular hydrogen bond between the nitrogen, hydrogen, and sulfur atoms. Neutralization, followed by desulfurization, provided the free ligands in enantiomeric purity. Iridium complexes with these ligands were formed via reaction with [Ir(COD)Clh followed by anion exchange with NaBArF. These complexes were successfully applied in homogeneous hydrogenation of several prochiral substrates, providing products in up to 92% enantiomeric excess. Variation of the dimethyl amino group to a pyrrolidine group had a negative effect on the selectivity of hydrogenation. Variation of the substituents on phosphorus to bulkier ortho-tolyl groups had a positive effect, while variation to the more electron rich dicyclohexyl phosphine had a negative effect on selectivity.

Multi-Objective Genetic Algorithms for the Single Allocation Hub Location Problem

Hub Location Problems play vital economic roles in transportation and telecommunication networks where goods or people must be efficiently transferred from an origin to a destination point whilst direct origin-destination links are impractical. This work investigates the single allocation hub location problem, and proposes a genetic algorithm (GA) approach for it. The effectiveness of using a single-objective criterion measure for the problem is first explored. Next, a multi-objective GA employing various fitness evaluation strategies such as Pareto ranking, sum of ranks, and weighted sum strategies is presented. The effectiveness of the multi-objective GA is shown by comparison with an Integer Programming strategy, the only other multi-objective approach found in the literature for this problem. Lastly, two new crossover operators are proposed and an empirical study is done using small to large problem instances of the Civil Aeronautics Board (CAB) and Australian Post (AP) data sets.

Demolishing the Competition: The Association between Competitive Video Game Play and Aggression among Adolescents and Young Adults

The link between video game play and aggression is an important issue as video games The link between video game play and aggression is an important issue as video games are the fastest growing form of entertainment in the world. Past research on this association has been focused primarily on the link between video game violence and aggression; however, this research has confounded the effect of video game violence versus competition on aggression. The main goal of the current dissertation, therefore, was to examine the short- and long-term associations between competitive video game play and aggression. In addition, the longitudinal work on this association to date has been limited to adolescent samples, but not young adults. Thus, the second goal of the dissertation research was to investigate whether video game play predicts aggression in the long-term among young adults in addition to adolescents. To address these goals, three studies were conducted. Study 1 consisted of a series of experiments examining the short-term effect of video game violence versus competition on aggression. Study 2 examined the long-term association between competitive video game play and aggression among adolescents, and Study 3 examined this long-term link among young adults, in addition to adolescents. Taken together, the results of the three dissertation studies converged to suggest that video game competition, rather than violence, may be a stronger predictor of aggression in both the short- and long-term. Overall, the current research represents an important advance in our understanding of the association between video game play and aggression, and leads to a new direction in the video game and aggression literature. are the fastest growing form of entertainment in the world. Past research on this association has been focused primarily on the link between video game violence and aggression; however, this research has confounded the effect of video game violence versus competition on aggression. The main goal of the current dissertation, therefore, was to examine the short- and long-term associations between competitive video game play and aggression. In addition, the longitudinal work on this association to date has been limited to adolescent samples, but not young adults. Thus, the second goal of the dissertation research was to investigate whether video game play predicts aggression in the long-term among young adults in addition to adolescents. To address these goals, three studies were conducted. Study 1 consisted of a series of experiments examining the short-term effect of video game violence versus competition on aggression. Study 2 examined the long-term association between competitive video game play and aggression among adolescents, and Study 3 examined this long-term link among young adults, in addition to adolescents. Taken together, the results of the three dissertation studies converged to suggest that video game competition, rather than violence, may be a stronger predictor of aggression in both the short- and long-term. Overall, the current research represents an important advance in our understanding of the association between video game play and aggression, and leads to a new direction in the video game and aggression literature.