Heterobimetallic molecules that exhibit metal-to-metal charge transfer (MMCT)

To meet the energy demands for a sustainable future, abundant carbon-neutral sources of liquid fuel are needed. While existing technologies such as biomass conversion, wind electricity or photovoltaic cells can provide stopgap measures as carbon-neutral energy sources, large-scale liquid fuel production requires the development of new and direct solar-to-fuel technologies. Currently, there is no single device that efficiently incorporates the necessary elements for artificial photosynthesis into an integrated system.

Metal-to-metal charge transfer A d1V(IV)-O-Ti(IV) complex

This project focuses on elucidating one of the fundamental requirements for solar fuel devices: the fundamental chemistry of excited state electron transfer from a chromophore to a fuel-producing reduction catalyst. In this area, the primary scientific gap is control of excited state electron transfer out of the light absorbing chromophore. In order for excited state electron transfer to occur, the excited state must be sufficiently long-lived. The discovery of new molecules is vital for fundamental studies of the properties important for efficient charge collection and utilization in solar-to-fuel systems. We are discovering new d1 (shown above) and d3 mono-oxo bridged heterobimetallic molecules with visible-light induced metal-to-metal charge transfer (MMCT) transitions. These have advantages over existing systems for tuning properties such as excited state lifetimes and electron transfer rates, as well as being composed of abundant metals that are theoretically scalable for terawatt deployment.

Functional materials through self-assembly of functionalized cycloparaphenylene building blocks

The synthesis of novel carbon-based electronic structures remains an important area of study for the next generation of nano-electronic applications. Historically, research on such structures has focused on conducting polymers, C60 derivatives, or carbon nanotubes. The research in our group explores the possibility for synthetically decorating cycloparaphenylene (cpp) “nanohoops” with metal-arene coordination compounds. These coordination complexes will then be used to link the cpp hoops together, and will serve as the building blocks for self-assembly of these molecular components into extended structures such as chains and nets. By taking a bottom-up approach to the synthesis of such structures, we gain the ability to finely tune the properties of the resulting materials. Of particular interest is controlling the rate and the mechanism of electron transfer through the resulting extended pi network by altering the oxidation state or coordination mode of the arene-metal complex.

We also are working on ways to use the resulting network as a template for the chemical growth of nanotube structures. The resulting material would reflect the structure of the initial self-assembly, and allow for single types of carbon nanotubes to be placed in pre-determined patterns.

Collaborative Projects

Our group is also involved in a number of collaborative projects with other groups at NCSU, including the Shultz group, the Ghiladi group, and the Franzen group.

Outside Collaborators include the Pushkar Groupat Purdue University, the Tamblyn Group at the University of Ontario Institute of Technology, the Cuk Groupat UC-Berkeley, and the Yachandra/Yano Group at LBNL.

Funding ($$$)

2012 Ralph E. Powe Junior Faculty Enhancement Award

#Scifund Challenge- Round 1 through Rockethub

- Round 2 through

NCSU Startup Funds

Walter Weare 2014