tropylium造句

• Many metal complexes of tropylium ion are known.
• Though less stable than the tropylium cation, this carbenium ion can also from salts at room temperature.
• "' Tropylium tetrafluoroborate "'is an organic compound containing the tropylium cation and the non-coordinating tetrafluoroborate counteranion.
• "' Tropylium tetrafluoroborate "'is an organic compound containing the tropylium cation and the non-coordinating tetrafluoroborate counteranion.
• Carbenium ions are generally highly reactive due to having an incomplete tropylium ion, are relatively stable due to the positive charge being delocalised between the carbon atoms.
• Its tropylium cation : one electron from the seven-membered ring is transferred to the five-membered ring to give each ring aromatic stability by H點kel's rule.
• He began his formal studies at Queen Mary College, researching tropylium chemistry with Michael J . S . Dewar where he discovered how to isolate the tropylium cation from cyclooctatetraene.
• He began his formal studies at Queen Mary College, researching tropylium chemistry with Michael J . S . Dewar where he discovered how to isolate the tropylium cation from cyclooctatetraene.
• Some of his discoveries include the structure elucidation of the tropylium cation, the discovery of dichlorocarbene, bullvalene and fulvalene and the discovery of the mechanism of the Baeyer Villiger oxidation.
• The values for the relative cation reactivities are-0.4 for the malachite green cation, + 2.6 for the benzenediazonium cation, and + 4.5 for the tropylium cation.
• Similarly the tropylium cation ( ) has six pi electrons and is more stable than either the cycloheptatrienyl radical ( ) or its anion . and the triboracyclopropenyl dianion ( ) are considered examples of a 2?-electron system
• On the other hand, stable fulvalenes can be obtained by proper mesomeric form with for instance pentaheptafulvalene "'4 "', which can be thought of as a tropylium cation joined to a cyclopentadienyl anion ( both stable and aromatic ).
• For example, in proton NMR the electron-poor tropylium ion has its protons downfield at 9.17 ppm, those of the electron-rich cyclooctatetraenyl anion move upfield to 6.75 ppm and its dianion even more upfield to 5.56 ppm.