Complexes between n-alkylamines and nickel cyanide

Abstract

Complexes between primary n-alkylamines and nickel cyanide consist of alternating monolayers of amine and cyanide. The alkyl chains stand away from the plane of the cyanide layers and may show “solid-like” or “liquid-like” characteristics. The nitrogen of an amine molecule is keyed into the puckered cyanide surface and, in the “solid” complexes, keying into the opposing surface is exhibited by the terminal methyl group of the molecule. Methyl keying occurs readily if the alkyl chain contains an even number of carbon atoms. With odd-carbon chains, partial re-orientation of the molecule has to occur before the terminal methyl can adopt the keying position. The available space on the cyanide surface per alkylamine molecule is a critical factor in permitting this re-orientation of odd-carbon chains, and in preventing similar movement of even-carbon chains.