Complexation of cyclic trimeric perfluoro-o-phenylenemercury with nitriles. A remarkable sensitivity of the composition and structure of the resulting complexes to the nature of a nitrile

Cyclic trimeric perfluoro-o-phenylenemercury (o-C6F4Hg)(3) (I) is capable o f reacting with nitriles to form complexes whose composition and structure are dramatically dependent on the nature of the nitrile used. In the case o f acrylonitrile, the complex, [(o -C6F4Hg)(3)(CH2CHCN)], containing one nit rile molecule per one molecule of I is produced. According to an X-ray stru cture analysis, the acrylonitrile ligand in this complex is bonded to all H g atoms of the cycle through the nitrogen atom. The reaction of I with acet onitrile gives complex [(o-C6F4Hg)(3)(MeCN)(2)] which contains two nitrile ligand per one molecule of the macrocycle. This complex has a shape of a sp inning top the equatorial girdle of which is the mercury-containing metalla cycle, whilst the axis direction is fixed by the linear MeCN ligands locate d above and below the metallacycle plane. Finally, the isolated complex of I with benzonitrile, [(o-C6F4Hg)(3)(PhCN)(3)], contains three molecules of the coordinated nitrile per one macrocycle molecule. A remarkable structura l feature of this complex is that here all the nitrile ligands are located on one side of the metallacycle plane and, in addition, differ from each ot her in the geometry of coordination with the Hg atoms. (C) 2000 Elsevier Sc ience S.A. All rights reserved.