6 resultados para Peter I, Emperor of Russia, 1672-1725

em Brock University, Canada


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N-heterocyclic carbenes (NHCs) have undergone rapid development in recent years. Due to their strong a-electron donation and structural variability properties, NHCs are becoming a major class of ligands in organometallic chemistry. Compared with the other two types of NHCs (imidazolylidenes and imidazolinylidenes), benzimidazolylidenes have not been well represented. Limited synthetic approaches may impede the development ofbenzimidazolylidenes. This thesis is focused on the synthesis of phenanthroline-derived benzimidazolylidene ligands and their metal complexes. A series of benzimidazolylidene-iridium complexes were synthesized and characterized spectroscopically and crystallographic ally. All of the new complexes showed varying degrees of catalytic activity and enantioselectivity toward transfer hydrogenation and asymmetric hydrogenation. The best results were achieved in hydrogenation of methyl-2-acetamidoacrylate, which afforded (-)-(R)-methyl-2-acetamidopropanoate in 97% yield and 81 % ee.

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This study explores the mortuary remains of children from the MH-LH I periods of the Argolid, Greece. This examination concentrates on how the child in death acted as a tool for wealth and status display. Here, children are understood to have perpetuated, maintained, and reinforced status distinctions between families in their community. The analysis of one hundred child burials that date to these periods illustrates how the burials of children were important opportunities used by the families of children to display wealth and status. Thus, children can be viewed as important factors in the reorganization of social structure in the transition from the Middle to Late Helladic.

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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.

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Translation: Sir, It will probably be difficult for you to remember among the many strangers who annoy you with their admiration of a person to whom you kindly made civilities last year1 during a pleasant conversation about Corsica. I would be grateful if you could take a look at this sketch of his history.2 I present here the first of two letters. If you agree to them, I will send you the end. My brother, whom I recommend not to forget his deputies' commission to escort Paoli to his country,3 and to come and receive a lesson in virtue and humanity, will give them to you. I respectfully your most humble and obedient servant.4 Buonaparte, artillery officer Ajaccio, [Corsica] June 24 the first year of freedom [1790]5 1 Relations between Napoleon and Raynal have begun in 1789, which seems to confirm a confidence to Las Cases ( Memorial of St. Helena , La Pléiade , vol. I, p. 83) . 2 Latest version of history project of Corsica : Letters on Corsica to Abbe Raynal . 3 Joseph is part of a delegation sent by the city of Ajaccio to host Paoli 's return from exile in London . In doing so he has to go through Marseille where Raynal resides. 4 Shipping autograph, National Archives , 400 AP Biography 1. In the first years of Napoleon Bonaparte (1840) , Coston gives a rough version of this letter that it dates from 1786 , which is impossible because Raynal did not return to France that ' in 1787. Published for the first time in the Memories of Lord Holland (1851) , shipping is now kept in the national Archives Napoleons funds . 5 The letter is dated "June 24, the first year of freedom" (the word "freedom" is underlined twice). Given the dates of stay in Corsica Napoleon, it seems that is present in Ajaccio the month of June in 1790.

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A letter written by Napoleon Buonaparte (Bonaparte) to Guillaume Thomas Francois Raynal, dated at Ajaccio [Corsica] June 24 the first year of freedom [1790]. The letter is written in French. A transcription and a translation of the letter are also available.