Les structures de cycles de taille moyenne II. La structure cristalline et moléculaire du bromure de cyclononylammonium

Abstract

Abstract The X‐ray analysis of cyclononylamine hydrobromide has revealed that the asymmetric unit of this crystal contains two structurally different molecules. The carbon skeletons of these two molecules are asymmetric and, although closely similar in general arrangement, differ from one another in terms of bond angles and torsion angles. The observed CC distances do not differ significantly from 1.54 Å; the CCC angles range from 111° to 124°, the mean value being 116° 43′. The torsion angles lie in the range 25° to 104°, syn‐planar and anti‐skew conformations being avoided in favour of nearly syn‐skew. The most striking point of difference between the two independent molecules is the position of attachment of the amino group. The local environment of this group in one ring is quite different from that in the other. The two molecules are, in fact, conformational isomers of one another.