INOR 315 |
| A supramolecular design strategy for forming self-assembled main group complexes is presented. We report a series of assemblies made up of a variety of dithiol ligands as examples of this new class of compounds: [M2L3], “syn”-[As2L2Cl2] and “anti”-[M2L2Cl2] (M = As, Sb, Pb). The design strategy incorporates the unusual, yet predictable trigonal pyramidal coordination geometry of As(III), Sb(III) and Pb(II) featuring a stereochemically-active lone pair when coordinated by sulfur-based ligands. The strategy inherently incorporates specificity for As(III) into the ligand design by targeting the unusual coordination geometry of As(III). By relying on high-yielding self-assembly reactions, very stable multinuclear complexes form. Preliminary studies reveal the organic ligands are selective for arsenic and form robust complexes with As(III) and Sb(III) in solution. Furthermore, strong arsenic-pi interactions exist in all of these assemblies and help direct the arsenic lone pairs into the small cavities of the molecules. This As-pi interaction can be used as a directing force for the self-assembly of dinuclear As2L2Cl2 macrocycles that exist as an equilibrium mixture of both “syn” and “anti” diastereomers. The diastereomeric excess of these self-assembly reactions is controlled in a predictable manner through the use of achiral, isomeric ligands. A general strategy for the preparation of As2L2Cl2 macrocycles is established, and control over the diastereoselective self-assembly of regioisomeric macrocycles in solution and the crystalline state is described. |
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Synthetic Coordination Chemistry
7:00 PM-10:00 PM, Sunday, August 19, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Inorganic Chemistry |