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PhF behaves rather differently from other halobenzene derivatives owing to the pi-donor properties of fluoride. For example, the para position is more activated than benzene toward electrophiles. For this reason, it can be converted to 1-bromo-4-fluorobenzene with relatively high efficiency. [3]
The +M effect, also known as the positive mesomeric effect, occurs when the substituent is an electron donating group. The group must have one of two things: a lone pair of electrons, or a negative charge. In the +M effect, the pi electrons are transferred from the group towards the conjugate system, increasing the density of the system.
In theoretical physics, the hierarchy problem is the problem concerning the large discrepancy between aspects of the weak force and gravity. [1] There is no scientific consensus on why, for example, the weak force is 10 24 times stronger than gravity .
Cuban authorities struggled to return power to the island on Thursday morning after Hurricane Rafael knocked out the country`s electrical grid, leaving 10 million people in the dark. The grid ...
Canadian Prime Minister Justin Trudeau promised President-elect Donald Trump that Canada would toughen controls over the long undefended joint border, a senior Canadian official said on Sunday.
The alpha effect refers to the increased nucleophilicity of an atom due to the presence of an adjacent (alpha) atom with lone pair electrons. [2] This first atom does not necessarily exhibit increased basicity compared with a similar atom without an adjacent electron-donating atom, resulting in a deviation from the classical Brønsted-type ...
This article is part of The D.C. Brief, TIME’s politics newsletter. Sign up here to get stories like this sent to your inbox.. Publicly, Joe Biden never wavered. Privately, those close to him ...
The many-body problem is a general name for a vast category of physical problems pertaining to the properties of microscopic systems made of many interacting particles. Microscopic here implies that quantum mechanics has to be used to provide an accurate description of the system.