Recent Studies in Synthetic and Structural Coordination Chemistry
Russell P. Watson,1 Daniel L. Reger,2 and Allan J. Canty3
1Analytical Chemistry Division, NIST, Gaithersburg, MD
2University of South Carolina, Columbia, SC
3University of Tasmania, Hobart, Tasmania, Australia
The rational design of solid materials with useful physical and chemical properties is one of the primary goals of crystal engineering. Because crystals can be considered the ultimate supermolecules, many of the concepts relevant to the field of supramolecular chemistry are of direct importance to crystal design. Just as “molecular synthons” may be employed in organic chemistry for the construction of complex, discrete molecules, “supramolecular synthons” may be used as building blocks for supermolecules. A greater understanding of the intermolecular interactions that give rise to supramolecular synthons, therefore, is critical for the ability to employ these synthons in crystal design. The first part of this presentation focuses on the molecular and supramolecular coordination chemistry of polytopic, bis(pyrazolyl)methane ligands. The propensity of these ligands to enter into weak hydrogen bonding and π–π stacking interactions, creating in some instances a supramolecular synthon, the “quadruple pyrazolyl embrace,” makes this family of ligands a reliable tool for constructing network solids of varying dimensions.
The second part of this presentation focuses on recent efforts to prepare η1-alkynylplatinum(IV) complexes, which have been proposed as intermediates in carbon–carbon bond-forming reactions. These platinum complexes are also useful in mechanistic studies as models for their palladium counterparts, which are often more active catalysts but are too reactive to isolate in the tetravalent state. The characterization of the η1-alkynylplatinum complexes and their decomposition products provides information on both the nature of the palladium(IV) and platinum(IV) reactive intermediates and a rationalization of the observed coupling products. This presentation will cover the use of the hypervalent iodine(III) reagents I(C6H5)(C≡CR)(O3SCF3) in preparing η1-alkynylplatinum(IV) species. The study of these complexes by variable-temperature nuclear magnetic resonance spectroscopy, and the investigation of their decomposition products by gas chromatography−mass spectroscopy is also presented.
Mentor: R. Gregory Downing
Author: Russell P. Watson
Analytical Chemistry Division, CSTL
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