Electrostatic potential as a measure of gas phase carbocation stability

• Assessment of the relative stabilities of carbocations is important for interpreting reaction mechanisms as well as in organic synthesis. A common approach is in terms of hydride affinities; however these depend on a second system, a neutral molecule, as well as the ion. In the present work, we propose a measure of gas phase carbocation stability that is dependent solely on the properties of the ion: the magnitude of the most positive surface electrostatic potential associated with the carbon framework. This quantity, labeled V-S,V-max, reflects a key factor, the extent to which the positive charge has been delocalized. We have computed V-S,V-max for 28 carbocations, and we show that the overall trends predicted are physically meaningful in terms of experimental observations. Mulliken atomic charges are not satisfactory for this purpose.

Ämnesord

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

Nyckelord

carbocations

carbenium ions

relative stabilities

electrostatic potentials

atoms

ion

trinitromethanide

stabilization

heterolysis

molecules

cations

salts

c3h3

bond

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)