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Wyniki wyszukiwania dla: ZASADY LEWISA
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Zdolni z Pomorza 2017/18 - Teorie kwasów i zasad
Kursy OnlineCel kursu: Celem kursu jest zapoznanie uczniów z teoriami mającymi na celu opis substancji o właściwościach kwasowych i zasadowych. Uczniowie poznają również praktyczne aspekty wykorzystania tej grupy związków. Opis kursu: W czasach starożytnych sprawa wydawała się prosta: albo coś charakteryzowało się kwaśnym smakiem, albo nie. Potrzeba było jednak stuleci prac alchemików, filozofów przyrody i chemików, aby wyjaśnić ich naturę...
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Zdolni z Pomorza 2019/20 - Nieco więcej o kwasach i zasadach
Kursy OnlineCel kursu: Celem kursu jest zaznajomienie uczestników z teoriami kwasów i zasad, podstawami równowagi chemicznej oraz skalą pH. Opis kursu: Pojęcie kwasów i zasad jest wprowadzane już na wczesnych etapach edukacji, jednak okazuje się, że teorii wyjaśniających, co jest kwasem, a co zasadą jest wiele. Jak np. wyjaśnić, że chlorek glinu AlCl₃ można uznać za kwas, skoro nie posiada on atomów wodoru? W trakcie kursu poznamy teorię...
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Monomeric Triphosphinoboranes: Intramolecular Lewis Acid–Base Interactions between Boron and Phosphorus Atoms
PublikacjaHerein, we present the synthesis of the first fully characterized monomeric triphosphinoboranes. The simple reaction of boron tribromide with three equivalents of bulky lithium phosphide tBu2PLi yielded triphosphinoborane (tBu2P)3B. Triphosphinoboranes with diversified phosphanyl substituents were obtained via a two-step reaction, in which isolable bromodiphosphinoborane (tBu2P)2BBr is first formed and then reacts with one equivalent...
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Phosphinophosphoranes: Mixed-Valent Phosphorus Compounds with Ambiphilic Properties
PublikacjaHerein, we present a simple synthesis of mixed-valent phosphinophosphoranes bearing three- and five-coordinate phosphorus centers. Compounds with phosphorus–phosphorus bonds were synthesized via a reaction of lithium phosphides RR′PLi with cat2PCl (cat = catecholate), whereas derivatives with methylene-linked phosphorus centers were obtained via a reaction of phosphanylmethanides RR′CH2Li with cat2PCl. The presence of accessible...
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Reactivity of triphosphinoboranes towards H3B·SMe2: access to derivatives of boraphosphacycloalkanes with diverse substituents
PublikacjaTriphosphinoboranes activated the B–H bond in the BH3 molecule without any catalysts at room temperature. Hydroboration reactions led to boraphosphacyloalkanes with diverse structures. The outcomes of reactions depend on the size of the phosphanyl substituent on the boron atom of the parent triphosphinoborane, where derivatives of boraphosphacyclobutane and boraphosphacyclohexane were obtained. Furthermore, the precursor of triphosphinoboranes,...
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Phosphinoborenium cations stabilized by N-heterocyclic carbenes: synthesis, structure, and reactivity
PublikacjaPhosphinoborenium cations stabilized by N-heterocyclic carbenes (NHCs) were synthesized via the reaction of bromo(phosphino)boranes with NHCs. Their structures were investigated by heteronuclear magnetic resonance spectroscopy, X-ray diffraction, and density functional theory calculations. They possess a planar trigonal boron center directly bonded with the pyramidal phosphanyl group (PR2) and can be treated as cationic phosphinoboranes....
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Application of nonmetallic frustrated cations in the activation of small molecules
PublikacjaThe concept of nonmetallic frustrated cations has been used in small molecule activation. The in situ generated ambiphilic phosphinoborinium cation activated phenyl isocyanate, diisopropylcarbodiimide, and acetonitrile under very mild conditions without any catalyst, yielding single-, double-, or mixed-activation products. Furthermore, the mechanisms of the reactions of the phosphinoborinium cation with small molecules were elucidated...