Verkade base
In chemistry, a Verkade base is a superbase with the formula P3N. A colorless oil, it is an aminophosphine although its inventor John Verkade called it proazaphosphatrane. The trimethyl derivative or 2,5,8,9-tetraza-1-phosphabicycloundecane is the simplest. Diverse analogues of the Verkade base are known, e.g. with isopropyl groups in place of methyl.The Verkade base is generated by the reaction of N,N,N-trimethyltren with trisphosphine:
The principal reaction of the Verkade base is protonation. The proton attacks the Verkade base at phosphorus, inducing the formation of a transannular P-N bond. The product exemplifies the structure of an atrane.
The conjugate acid + has a pKa of 32.9 in acetonitrile. For comparison, the conjugate acid of triethylamine has a pKa's near 17 in acetonitrile. Owing to its ability to deprotonate weak carbon acids, the Verkade base catalyzes a variety of condensation reactions.Related compounds
are phosphorus derivatives with the formula RN=P3. They are about 1010 more basic than the Verkade base.
