Coordination Chemistry of Anticrowns. Interaction of the Perfluorinated Three-Mercury Anticrown (o-C₆F₄Hg)₃ with Azacrowns

The interaction of the three-mercury anticrown (o-C₆F₄Hg)₃ (1) with various azacrowns such as 2,9,16,23-tetra-tert-butylphthalocyanine (TBPC), octaazapentacyclooctacosane (OAOC), 1,4,8,11-tetraazacyclotetradecane (cyclam), and N,N,N-trimethyl-1,3,5-triazacyclohexane (TACH) has been studied. It has been shown that the reaction of 1 with TBPC in CH₂Cl₂ at 20 °C affords 1:1 complex {[(o-C₆F₄Hg)₃](TBPC)} (2) according to elemental analysis, and the interaction of 1 with OAOC·0.5H₂O in ether results in the formation of complex {[(o-C₆F₄Hg)₃]₂(OAOC)(H₂O)₂} (3). The molecules of azacrown and water in 3 are located between the parallel planes of two mercuramacrocycles strongly laterally shifted relative to one another and are bonded to them through Hg-N and Hg-O secondary interactions. An especially interesting complex, [(CH₂)₁₀(NH₂)₂(NH)₂]{[(o-C₆F₄Hg)₃]₂Cl₂} (4), has been obtained by the reaction of 1 with cyclam [(CH₂)₁₀(NH)₄] in CH₂Cl₂ at 20 °C. The complex has a structure of a double-decker sandwich wherein two chloride anions and the diprotonated molecule of cyclam as a counterdication are disposed between the parallel planes of two molecules of 1. Each chloride anion in 4 is η³-coordinated with the Hg centers of the neighboring anticrown, whereas the NH and NH₂⁺ groups of the diprotonated cyclam form three H-bonds with each of these chloride anions. The mechanism of the formation of this unusual sandwich is discussed. The synthesis and structure of an analogous complex, [(CH₂)₁₀(NH₂)₂(NH)₂]{[(o-C₆F₄Hg)₃]Cl₂}·2(CH₃)₂CO, which forms polydecker sandwiches in the crystal are also described. The interaction of 1 with cyclam in aqueous THF at 20 °C gives a complex, {[(o-C₆F₄Hg)₃][(CH₂)₁₀(NH)₄](THF)(H₂O)} (6), also forming infinite polymeric chains in the crystal. A characteristic structural feature of 6 is the presence in each its monomeric unit of a bipyramidal fragment formed by 1 and two different η³-coordinated Lewis bases (THF and water). From the reaction of 1 with TACH, a complex having a unique double-cage structure, {[(o-C₆F₄Hg)₃](TACH)₂} (7), has been isolated.