The work of a Lehigh chemistry professor, a graduate student, and a postdoctoral research associate was recently published in the prestigious international journal, Angewandte Chemie, and will form the foundation of continued work that will be conducted in Lehigh’s chemistry department.
The paper focuses on a six-month research project that successfully insulated lanthanides in the 2 oxidation state from solvents resulting in luminescent complexes, and paves the way for a variety of practical applications that could impact dual-mode imaging for diagnostic purposes, and use as an optical switch for small devices.
The published paper received the additional distinction of being identified as a VIP paper by the journal, one of fewer than 5 percent of the accepted papers to be so highly recommended and reviewed.
“It’s quite an honor,” says Bob Flowers, professor and chair of the chemistry department, who supervised the research project that also included graduate student Joseph A. Teprovich Jr. and postdoctoral research associate Edamana Prasad, who has since moved to the Indian Institute of Technology, Madras as an assistant professor of chemistry .
A rare opportunity for undergraduates
During the research that was supervised by Flowers, the students found that altering the coordination sphere of samarium(II) iodide induces remarkable property changes in the ground and excited state.
“Addition of 15-crown-5 to samarium(II) iodide in acetonitrile produces a complex that insulates the metal from interaction with solvent and substrates,” Flowers says. “The decreased reactivity of the ground state complex prevents reduction of substrates commonly reduced by samarium(II) and as a consequence, solvent induced luminescence quenching is minimized, leading to a significantly increased excited state lifetime.”
In practical terms, he adds, this approach shows that it is possible to generate highly stable and luminescent samarium(II) complexes in solution through the proper choice of ligand and solvent. As a result, this protocol provides the basis for the design of a new class of luminescent materials with a range of important applications.
Beyond earning the distinction of having a research paper both published and highly reviewed, this project provided a unique learning opportunity for the students – both graduate and undergraduate – who contributed to it, Flowers says.
“This type of project is relatively rare for an undergraduate, but a very important component of our program,” says Flowers, who has mentored more than 20 graduate students and 30 undergraduate students over the course of his academic career.
“In chemistry, we really get students into research as soon as possible,” he says. “I typically select students as early as their sophomore year, once they have basic organic training. And many students decide to stay on in my research group as long as they are at Lehigh.”
These experiences, he says, offer the students a unique advantage over their counterparts from other schools.
“Whether they go on to grad school, into industry, or onto medical school, this gives them a leg up on other applicants,” he says. “Lehigh provides a very unique environment for students to be engaged in important research, to work in teams, and to make real contributions, even as an undergrad. In my group especially, we make no distinction between the levels of student.”
Flowers cites a biology major in one of his labs whose work in organic synthesis is under review by an important journal—what he terms a rare opportunity for an undergrad, especially one who is not a chemistry major.
"The intellectual environment in the College of Arts & Sciences makes this possible” he says. “At the same time, the research environment that includes grads and post-docs, is of great educational and practical benefit.”
Flowers, who came to Lehigh three years ago from the department of chemistry and biochemistry at Texas Tech University, is overseeing a renaissance of sorts in the chemistry department.
“I’m very pleased with the growth and development of our department,” he says. “There’s been a significant amount of change over the past few years. We’ve hired five outstanding faculty to date, and we’re looking forward to continued growth in the coming years.”