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The first examples of a CNC pincer ligands with a central pyridinol derived ring were recently reported.  The differences in catalytic reactivity between CNC ligands with a central pyridine ring vs. a pyridinol derived ring are substantial and highly active and robust catalysts have been synthesized and studied.  In these pincer ligands, the 4-substituent can be OMe, OH, or O , and these latter two options allow for altered catalyst properties as a function of proton concn.  Catalytic studies have used ruthenium(II), nickel(II), and other transition metals.  We have made metal complexes that can be protonated or deprotonated reversibly in situ to switch on or off the photocatalytic performance towards CO redn.  Furthermore, the methoxy group on the pyridine ring offers unique catalysis advantages not seen with the unsubstituted analog.  Our best catalysts offer selective CO formation, >300 turnover cycles, and a 40 h lifetime.  Highly active self-sensitized catalysts have recently been developed.  Steric and electronic ligand effects are being studied with these catalysts by exptl. and computational methods.

With NSF MRI support, we have recently purchased a dual source single crystal diffractometer equipped with a high resoln. detector.  The purpose of this presentation is to publicize the new instrument and we seek users in the Southeast to maximize the pos. impact of this instrument on research efforts in the Southeastern US.  Users at primarily undergraduate institutions and historically black colleges and universities are particularly encouraged to use this new resource.  In general, an X-ray diffractometer allows accurate and precise measurements of the full three-dimensional structure of a mol., including bond distances and angles, and provides accurate information about the spatial arrangement of a mol. relative to neighboring mols.  The studies described here impact many areas, including org. and inorg. chem., materials chem. and biochem.  This instrument is an integral part of teaching as well as research and research training of graduate and undergraduate students in chem. and biochem. at this institution and at partner institutions.  This poster will describe some examples of how the new diffractometer will enhance research in inorg. chem., materials chem. (via diffuse scattering), and biochem.