Coordination Chemistry of Mercury-Containing Anticrowns. Complexation of Perfluoro-o,o′-biphenylenemercury with o-Xylene and Acetonitrile and the First X-ray Diffraction Evidence for Its Trimeric Structure

The paper reports the first X-ray diffraction data evidencing the cyclic trimeric structure of the earlier synthesized octafluoro-o,o′-biphenylenemercury (8), being of considerable interest as a potential anticrown. The conclusion on the trimeric (o,o′-C6F4C6F4Hg)3 structure of this mercuracycle is based on an X-ray structural analysis of its o-xylene and acetonitrile complexes {[(o,o′-C6F4C6F4Hg)3](o-Me2C6H4)2} (9) and {[(o,o′-C6F4C6F4Hg)3](MeCN)3} (10), which were obtained from 8 in an analytically pure state and fully characterized. Complex 9 contains two o-xylene species per one molecule of 8 and forms in the crystal infinite chains consisting of alternating mercuramacrocycle units and bridging o-xylene ligands. One more o-xylene molecule in each macrocyclic fragment of the chain serves as a terminal ligand. Both bridging and terminal molecules of o-xylene are coordinated in all cases with only one Hg site of the corresponding mercuracycle. The back transformation of complex 9 into 8 and o-xylene occu...