Martin Conda-Sheridan and Dr. John D. Lamb, Chemistry and Biochemistry Department

The aim of the project was to prepare monomers, dimmers and trimmers of pyridine substituted resorcinarenes. This work was the continuation of a previous project in which we studied the interactions of a dipicolilamine cavitand with anions. We decided to go a step further by investigating the reactions of our compound with metals. In addition to that we intend to see how the mentioned metal will bind or coordinate with organic and inorganic anions. Furthermore we tried to achieve host guest interactions between the mentioned anions and our compounds. The knowledge of such interactions has potential applications in medicine, the pharmaceutical industry as catalysts or enzyme mimics, and environmental control.

In order to do this we used various zinc salts; perchlorate, chloride, sulfate, perrhenate among them. We used one and two equivalents of the above mentioned salts dissolved in methanol and added to a solution of our compound. We heated, in all cases, at 45 ºC for 3 days. Them, we analyzed the obtained compounds by Nuclear Magnetic Resonance spectroscopy (NMR). The preliminary results were motivating. In fact, they were presented at the American Chemical Society that was carried out in San Diego last winter. However, we were not able to corroborate our results and publish a peer review paper. We attended conferences and consulted with colleagues and found out that they also got problems when studying the relations between zinc and resorcinarene derivatives. It is not clear if this is due to the filled “d” orbital of the zinc and its inability to fully coordinated these compounds or due to a fast interchange within conformations that overcomes the time scale of our instruments.

However, even when the results were not confirmed many positive things were achieved. Not only we gave a step further in the initial exploration of these new compounds but the implementation of cutting edge techniques at the BYU Chemistry department. One of the the sonic spray mass spectroscopy had been developed at BYU, resulted in a chapter in a PhD dissertation and is being explored. Additionally, for the first time we used Pulsed Gradient Spin Echo (PGSE, also known as gradient difussion) at the BYU NMR facilities. This technique is widely used for scientists like Peter Stang (member of the national Academy of Sciences) or Enrico Delcanale, a well known Italian scientists. Basically, we apply a magnetic field to a solution which produces a tumbling in the molecules according to their size. This tumbling gives a coefficient that can be used to calculate the volume and radii f the compound of interest. We were able to calculate some volumes and match them with theoretical values. We were able to achieve an accuracy of + 95% in most of the cases. As I mentioned, we were not able to corroborate some results because we believe our compounds interchange between their possible conformations faster than the time needed for NMR detection. However, as formerly mentioned, the implementation of two new spectroscopic techniques at the BYU Chemistry department (Sonic Spray-MS and PGSE) is a positive outcome for the project. My professor plans t keep studying and expand this project until the publishing of the paper is achieved.