Co-crystallization with acetylene. Part III. Molecular complexes with aromatic azacycles?

CrystEngComm Pub Date: 2004-09-24 DOI: 10.1039/B410636A

Abstract

Using C–H?N interactions, acetylene can be introduced at increased pressure to form molecular complexes with azacyclic N-acceptors which can be crystallized and investigated by X-ray methods. With pyridine, we expected dumbbell-like 2∶1 complexes with acetylene in the middle, instead a 1∶1 zigzag chain is formed where each of the N-atoms accepts two hydrogen atoms from two acetylene molecules. The same happens with 2,5-dimethylpyridine which, together with water, results in a complex having the water chains networked by acetylene molecules. With 2,5-dimethylpyrazine, linear chains are found which are additionally stabilized by sp3 and sp2 C–H?N interactions. 2,6-Di-tert-butylpyridine forms a clathrate with acetylene.

Graphical abstract: Co-crystallization with acetylene. Part III. Molecular complexes with aromatic azacycles
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