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The PI spent one year at the University of Canterbury (UC) in Christchurch, New Zealand, with Assoc. Prof. Richard Hartshorn in the Department of Chemistry acting as host.  Two research articles detailing this collaboration have already been published.   The PI also was able to attend IC08, an international conference of inorganic chemists from Australia and New Zealand, and ChemEd09, a New Zealand chemistry education conference, both held in Christchurch where the PI gave presentations.  Upon return to South Dakota, a plenary talk about this international collaboration was given by the PI at the Northern Plains Undergraduate Research Center summer symposium hosted by the University of South Dakota in late July.  Three projects were conducted over the past year and relied upon collaboration with several people within the Chemistry Department at UC.  A seminar highlighting research accomplishments during the past year was also given in the UC Chemistry Department in June. 

A)  Characterization of Large-Amplitude Molecular Switches.  We have demonstrated a new switching mechanism for the opening and closing of cyclic macrocycles via the protonation of an amide carbonyl oxygen (formation of an oxonium ion) that then hydrogen bonds to an ether oxygen on the opposite side of the macrocycle.  Numerous crystal structures have been solved showing both the closed (protonated) and open (deprotonated) forms of the switch, however NMR evidence was necessary to show the switch position when deprotonated in solution.  Dr. Marie Squire at UC provided the necessary expertise regarding implementing gradiated NOE experiments which determined the macrocycles adopt open conformations when deprotonated in solution.  This work has since been published in Inorganic Chemistry. Dr. Squire is a coauthor.

B)  ROMP Polymerization of Norbonene-Substituted Macrocycles.  One potential application of these protonated macrocycles is in fuel cell membranes where the acidic proton can be potentially transported between the macrocycle and counteroxoanions throughout the membrane.  Towards developing new membrane materials, norbonene functionalized macrocycles were successfully synthesized and subjected to ROMP polymerization.   Both Grubb's 1^st generation and 2^nd generation catalysts were used to try and open the norbornene ring; however neither catalyst led to polymeric materials of any sufficient quantity.   Both elemental analysis and thermogravimetric analysis experiments showed that the norbornene monomer was essentially unchanged.   One reason may be the extremely large size of the macrocycle, connected to the norbornene at the 2-position, blocks association with the Grubb's catalyst.  The PI was able to personally discuss this with Professor Grubb's who attended IC08 in Christchurch as a  plenary speaker.

C)  Coordination Chemistry of Bridging Anthraquinone/(Iso)nicotinic Acid Derivatives.  The macrocycles used above are based on an anthraquinone scaffold to which, in a separate project, two nicotinic or isonicotinic acids were condensed as esters.  The nicotinic/isonicotinic groups can either act as chelating or bridging ligands with metal ions.  Reaction of these ligands with [M(NCCH₃)₄]+ (M = Ag+ and Cu+) yields three types of complexes:  Nicotinic – both chelating monomers and bridging dimers.  Isonicotinic – only bridging dimers.  The nicotinic bridging dimers showed no M-M association, while the isonicotinic analog has a short M-M bond.  A wide range of coordination modes and coordination numbers was observed with silver.  This chemistry was also expanded to bis(pyrimidine)anthraquinone derivatives in an initial attempt to synthesize supramolecular complexes.  This expands previous work where dimeric complexes that have specific applications in catalysis reactions could not be synthesized. The project, including numerous crystal structures conducted at UC Chemistry and including Prof. Hartshorn as coauthor, has been published in Polyhedron.