Coupled copper centers for molecular motion in [3]rotaxanes

INOR 576

Kristy A. McNitt, Kumar Parimal, Albert C. Fahrenbach, fahrenbachus@yahoo.com, and Amar H Flood, aflood@indiana.edu. Department of Chemistry, Indiana University, Bloomington, IN 47405
Molecular devices are the nanoscale equivalent of macroscopic machines. Devices of this class rely on the coupling of redox-activity with co-conformational mechanical motions. Potential examples include the Cu-based polypyridines on account of their bistable stereoelectronic preferences that switch from 4- to 5-coordinate, for Cu(+1) and Cu(+2), respectively. However, what happens when the copper center is oxidized but only upto the +1.5 state? To address this question, we are employing a ligand that bridges two copper centers to generate the Cu(+1.5) centers simultaneously. Towards this goal, [3]pseudorotaxanes of the bridging ligand 3,6-bis(2-pyridyl-5-methyl)-1,2,4,5-tetrazine (diMe-BPTZ) threaded by two phenanthroline-based macrocycles have been developed. Dynamic complex formation was confirmed using mass spectrometry, NMR and UV-Vis-NIR spectroscopy. The mixed-valent signature observed in the electrochemistry suggests the +1.5 state is feasible. Consequently, these preliminary studies and progress towards the corresponding redox-switchable [3]rotaxanes will be described
 

Characterization and Applications of Coordination Compounds
7:00 PM-10:00 PM, Tuesday, August 21, 2007 BCEC -- Exhibit Hall - B2, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, August 20, 2007 BCEC -- Exhibit Hall - B2, Sci-Mix

Division of Inorganic Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007