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However, the cyclopropenyl anion has 4 π electrons in a cyclic system and in fact has a substantially higher pK a than 1-propene because it is antiaromatic and thus destabilized. [3] Because antiaromatic compounds are often short-lived and difficult to work with experimentally, antiaromatic destabilization energy is often modeled by simulation ...
In 2011, Jordi Poater and Miquel Solà expanded the rule to open-shell spherical compounds, finding they were aromatic when they had 2n 2 + 2n + 1 π-electrons, with spin S = (n + 1/2) - corresponding to a half-filled last energy level with the same spin. For instance C 60 1– is also observed to be aromatic with a spin of 11/2. [16]
Cyclopropanone has been prepared by reaction of ketene with diazomethane [1] [2] in an unreactive solvent such as dichloromethane. [3] These solutions are stable at −78 °C. In the presence of protic reagents such as carboxylic acids, primary and secondary amines, and alcohols, cyclopropanone converts to adducts, which are often isolatable at ...
Homoaromaticity, in organic chemistry, refers to a special case of aromaticity in which conjugation is interrupted by a single sp 3 hybridized carbon atom. Although this sp 3 center disrupts the continuous overlap of p-orbitals, traditionally thought to be a requirement for aromaticity, considerable thermodynamic stability and many of the spectroscopic, magnetic, and chemical properties ...
Cyclopropenone is an organic compound with molecular formula C 3 H 2 O consisting of a cyclopropene carbon framework with a ketone functional group. It is a colorless, volatile liquid that boils near room temperature. [1] Neat cyclopropenone polymerizes upon standing at room temperature, [2] and chemical vendors typically supply it as an acetal ...
3 Cyclopropenyl anion. 2 comments. 4 Peer review and responses during the educational assignment in Fall 2013. 5 Peer Review 1. 1 comment Toggle Peer Review 1 subsection.
The cyclopentadienyl anion is a planar, cyclic, regular-pentagonal ion; it has 6 π-electrons (4n + 2, where n = 1), which fulfills Hückel's rule of aromaticity. Each double bond and lone pair provides 2 π-electrons, which are delocalized into the ring. [4] Cyclopentadiene has a pKa of about 16. It is acidic relative to many carbon acids.
A related process is the cyclisation of 1,3-dibromopropane via a Wurtz coupling. This was used for the first synthesis of cyclopropane by August Freund in 1881. Originally this reaction was performed using sodium, [20] however the yield can be improved by exchanging this for zinc. [21] BrCH 2 CH 2 CH 2 Br + 2 Na → (CH 2) 3 + 2 NaBr