236 Rare Molecules, Catalysts and Light-Emitting Materials Based On Coinage Metal Ions and Highly-Fluorinated Anions

Thursday, November 5, 2009: 8:10 AM
Ballroom C+D (Camino Real Hotel)
H. V. Rasika Dias , Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX
Coinage metal (Cu, Ag, Au) complexes of poly-fluorinated anions show remarkable thermal stability and interesting chemical and physical properties. For example, we have been able to isolate bottle-able silver(I) and gold(I) complexes of CO and ethylene using a highly fluorinated tris(pyrazolyl)borate ligand [HB(3,5-(CF3)2Pz)3]-. [HB(3,5-(CF3)2Pz)3]AgCO is an example of a non-classical metal carbonyl with a fairly high CO stretching frequency. The silver ethylene complex [HB(3,5-(CF3)2Pz)3]Ag(C2H4) is an air stable molecule with a tetrahedral metal site whereas the gold analog has a rare, three-coordinate, trigonal planar metal center. Fluorinated triazapentadienyl anions have afforded stable alkyne adducts of CuI, AgI, and AuI. Most of these molecules are excellent models for intermediates in coinage metal mediated processes involving CO, alkenes, and alkynes. Some of these molecules are also useful catalysts for a variety of transformations. For example, [HB(3,5-(CF3)2Pz)3]Ag(C2H4) is an excellent carbene transfer catalyst. It even catalyzes the addition of carbenes to C-Cl and C-H bonds as well as to aromatic rings. It is interesting to note that the pyrazoles used in these studies are also useful for preparing luminescent materials. {[3,5-(CF3)2Pz]Cu}3 is an orange emitter with tunable colors. They also show interesting p-acid/p-base chemistry with arenes leading to supra-molecular stacks. Recently, we managed to isolate CuI, AgI, and AuI complexes containing three ethylene molecules using simple poly-fluorinated counter ions like [SbF6]-. They have “wheel” structures.
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