Coordination chemistry of anticrowns: Synthesis and X-ray crystal structure determination of the polydecker sandwich complexes of cyclic trimeric perfluoro- o-phenylenemercury with azulene and 6-( N, N-dimethylamino)pentafulvene

Abstract

The interaction of cyclic trimeric perfluoro- o-phenylenemercury ( o-C 6F 4Hg) 3 ( 1) with azulene results in the formation of a complex, {[( o-C 6F 4Hg) 3](azulene)} ( 2), containing one molecule of azulene per one macrocycle molecule. The complex represents a polydecker sandwich wherein the azulene units alternate with the molecules of the mercury anticrown. The reaction of 1 with 6-( N, N-dimethylamino)pentafulvene (DMAPF) also gives a 1:1 complex, {[( o-C 6F 4Hg) 3](DMAPF)} ( 3), having a polydecker sandwich structure in the crystal. In complex 2, both the C 5 and C 7 rings of the azulene ligand are involved in the bonding to the Hg sites of 1. In complex 3, the C 5 ring of the fulvene ligand together with its exocyclic carbon atom take part in the coordination to the mercury centres. In both adducts, the negatively charged five-membered ring of the azulene and, correspondingly, the fulvene moieties is arranged in the space between the central Hg 3C 6 rings of the adjacent macrocycles while the remaining portion of these moieties is disposed outside this space. The molecules of azulene and DMAPF in 2 and 3 are bonded to 1 through donation of their π-electrons on vacant orbitals of the Hg atoms. The synthesized 2 and 3 are the first examples of structurally characterized complexes of azulene and DMAPF with a non-transition metal compound.