Browsing by Subject "Mechanism"
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(2021)An overview on utilization of dual nickel/photocatalyst protocols to conduct aryl-heteroatom cross-coupling reactions is presented. Basic concepts of photocatalysis, including different relaxation pathways, the difference of singlet and triplet states, and parameters used to predict reactivity are first disclosed. The general components used in dual nickel/photocatalyst protocols are presented followed by the discussion on reactivity trends. The reactivity trends are compared with other common aryl-heteroatom cross-coupling protocols (Buchwald-Hartwig-, Ullmann- and Chan-Lam couplings) illustrating the general advantages and disadvantages of each cross-coupling method. The scope of different dual nickel/photocatalyst protocols are then explored, concentrating on cross-coupling of amines, alcohols/thiols and carboxylic acids. The developments in mechanistic understanding on the dual nickel/photocatalyst aryl-heteroatom cross-couplings in recent years are reviewed. It is concluded that photocatalytic single electron transfer-based cycles, proposed for a number of coupling protocols, are very unlikely to take place. It is made clear that, based on the current knowledge, two principle mechanism are reasonable: energy transfer or thermal Ni(I)/Ni(III) cycles. Problems concerning energy transfer mechanisms are also discussed. Finally, applicability of dual nickel/photocatalyst aryl-heteroatom cross-coupling for industrially significant transformations is briefly discussed.
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(2022)Corruption, which affects the development of human society nowadays, has been called the “cancer” of international politics. Currently, countries worldwide are faced with corruption to varying degrees, which diverts funds for development to private individuals or power groups, makes the poor poorer, affects the rule of law in the entire country and traps the country in an “inequality trap”. This dissertation attempts to interpret, through a comparative study, why corruption rates remain high in China. The starting point is examined in this dissertation is why the corruption rate in Finland is much lower than in China. This study compares and analyses the anti-corruption ecology and mechanisms of the two countries, including the definition of corruption, the current state of corruption, the causes of corruption, the legal framework, the institutional set-up of anti-corruption, and the set-up of prevention mechanisms and the differences in social supervision. The comparative approach allows for quick identification of institutional and legal differences between the two countries. The results show that there is rarely a motive for Finnish officials to be involved in corruption, that the Ministry of Justice has collaborated to build an anti-corruption network that allows all departments to participate, and that the existence of an Ombudsman and Chancellor of Justice system allows for oversight of government operations. The transparent and open government allows the public to participate in social supervision. China is more diverse in terms of the causes of corruption, with incomplete legal constructs and over-powered anti-corruption agencies, leading to the involvement of anti-corruption officials in corruption. Mechanisms to prevent corruption lack national-level guidance, and the government is not transparent enough, resulting in the public’s right to know not being guaranteed and making it difficult for social oversight to function. This is why the corruption rate in China is higher than that in Finland.
Now showing items 1-2 of 2