Highly Luminescent Multinuclear Coinage Metal Arrays with a Twist: A New Approach to Design Light-Emitting Molecular Strings and Coils

Kennesaw State University Research And Service Foundation, Kennesaw GA

Investigators

Abstract

With support of the Chemical Synthesis Program in the Division of Chemistry, Michael Stollenz of the Department of Chemistry and Biochemistry at Kennesaw State University will explore novel molecules containing individual metal atoms of the elements copper, silver, and gold that are arranged in a linear fashion and are in close proximity to each other. These complexes are highly luminescent and the luminescence properties can be controlled by the structures of these complexes. Such molecular strings also have the potential to serve as conducting molecular wires and coils for applications in miniaturized electronic devices on the submicroscopic scale. Luminescent complexes with multiple copper, silver, and gold ions are of particular interest in this regard, since they can be applied in molecular/organic light-emitting diodes (OLEDs). For the construction of molecular strings of this nature, tailored synthetic methodologies are required to target and control linear arrangements of the individual metal ions. Stollenz and his group will work to develop a new methodology for producing not only strictly linear arrays of copper, silver, and gold ions, but also arrangements that are substantially bent and therefore represent molecular coils. The major goal is to investigate how the structural changes affect the emission properties of these compounds. A long-term prospect for such molecular coils, if embedded in electronic circuits, is to utilize them as tiny electromagnets that can be integrated in nanomachines and other nanoscaled electronic devices. Such devices can in turn be applied in nanorobots that deliver drugs inside a human body. If these devices are luminescent, their path can be followed by fluorescence imaging. The broader impacts of this work will include the mentoring and training of undergraduate and masters students from the significant population of underserved groups at Kennesaw State University. This research program focuses on the development and implementation of new strategies to multinuclear coinage metal arrays as molecular strings and coils that serve as key components in molecular/organic light-emitting diodes (OLEDs). The underlying synthetic methods aim to provide a fundamental approach to control aggregation of linear cluster assemblies and to provide a insight into the coordination chemistry of multinuclear complex arrays in general. Specifically, a library of new bis(amidine) ligands that are capable of accommodating at least four copper centers, arranged in a linear fashion, are being targeted. The incorporation of Cu(I) ions will be accomplished by employing a clean organometallic Cu(I) source, mesitylcopper. Bis(amidine) ligands with additional terminal N-donor groups will be selectively protected by MR (M = Cu, Ag, Au; R = Cl, Mes) complex fragments. These hitherto unknown dinuclear metalloligands will be utilized as building blocks for new linear or bundled homonuclear Cu(I) or heterobimetallic Cu(I)/Ag(I) or Cu(I)/Au(I) cluster assemblies with promise as luminescent materials. Finally, this program will provide in-depth training of undergraduate/graduate research students and postdocs in synthesis, characterization techniques (crystallography and spectroscopy), oral presentation skills, scientific writing, laboratory safety, and data management. These activities will prepare research students and postdoctoral researchers to achieve their ambitious career goals in science or industry. 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.