Systematic Modulation of Lanthanide Physical Properties Using Functionalized Metallacrowns

In this project, funded by the Chemical Structure, Dynamics & Mechanism B Program of the Chemistry Division, Professor Vincent L. Pecoraro of the Department of Chemistry at the University of Michigan, Ann Arbor is developing a class of metallamacrocycles containing lanthanide ions. The goal of this research is to understand the electronic properties of lanthanide ions that are critical to a vast range of modern technologies such as magnetic materials, white light displays, and luminescent imaging in biological systems.

In addition, these studies seek to develop the foundation to make new molecular nanothermometers that can be used over a wide temperature range for applications in both the electronics industry as well as in basic biological research or eventually clinically to measure temperatures within cell organelles or animal tissue. The project lies at the interface of organic, inorganic, materials chemistry and biological chemistry.

The research is well suited for the education of scientists at all levels. Through general interest presentation, outreach to the lay public is also planned. An example is that Professor Pecoraro will give public lectures related to his research both in the United States and Europe.

Professor Pecoraro has a history of supporting the education and training for students underrepresented in science and these activities will continue.

Lanthanide containing metallacrowns can be exploited to understand the fundamental properties of lanthanides. Because these ions contain electrons in their f-orbitals, which are contracted within the d-orbitals, they have interesting properties related to molecular magnetism, magnetocoolants and luminescent emission. In this project, metallacrowns will be prepared to answer the following questions: (i) How does the molecular symmetry and coordination number influence the electronic structure of lanthanides that are highly emitting or display single ion slow magnetic relaxation? (ii) Can metallacrowns be used as emitting cores for the class of polymers known as dendrimers, which are being applied for a variety of advanced applications in chemistry and biology; and (iii) Can one use magnetic fields to interrogate the excited ground states of lanthanides to understand, and calculate, the extent of ground state mixing to these excited states?

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.