Alkyne

Alkynes are hydrocarbons that have at least one triple bond between two carbon atoms. The alkynes are traditionally known as acetylenes, though the name acetylene is also used to refer specifically to the simplest member of the series, known officially as ethyne.

Metal acetylides

A terminal alkyne with a strong base such as sodium, sodium amide, n-butyllithium or a grignard reagent gives the anion of the terminal alkyne and a metal acetylide. Acetylenes are fairly acidic and have pKa values (25) between that of ammonia (35) or ethanol with 16. The explanation for this acidity is that the negative charge in acetylide is stabilized as a result of the high s character of the sp orbital in which the electron pair resides. Electrons in a s orbital benefit from closer proximity to the positively charged atom nucleus and therefore lower in energy.

Related Topics:
Strong base - Sodium - Sodium amide - N-butyllithium - Grignard reagent - Anion - PKa - Ammonia - Ethanol

~ ~ ~ ~ ~ ~ ~ ~ ~ ~