Computational Exploration of Metal Complexes for Stress-Strain Modulation

Thursday, November 12, 2009: 10:00 AM
Jackson A (Gaylord Opryland Hotel)

Berend Christopher Rinderspacher, Army Research Laboratory, Aberdeen, MD
Jan W. Andzelm, Army Research Laboratory, Aberdeen, MD
Robert H. Lambeth, Army Research Laboratory, Aberdeen, MD
Adam M. Rawlett, Army Research Laboratory, Aberdeen, MD

There is a significant interest in designing metallo-supramolecular polymers that have superior elastic properties and can efficiently dissipate energy. Such polymers have organometallic modules with metals coordinated to organic molecules. Optimal polymers with required stress-strain profiles depend, among other factors, on the strength of the organometallic modules. Systematic search for optimal modules remains difficult because of the astronomical number of possible structures. We have formulated an Inverse Molecular Design (IMD) that efficiently predicts optimal architectures of organometallic modules. This IMD method is related to branch-and-bound/tree-search approach for constrained searching of chemical spaces based on an interpolation of property values on a hypercube.

We present calculations on polymer-linked metal complexes for the evaluation of energy dissipation. To this end, we investigate the energy profiles of stretching, bending and shearing of complexes according to external forces exerted on each complex via the attached polymer strands. Zn, Fe and Cr in conjunction with pyridine derivatives were considered in a poly-ethyleneglycol environment with various counterions. We have used a multiscale simulation approach consisting of quantum-mechanical(Semi-empirical and density-functional) methods and molecular dynamics simulations to predict various deformation modes in a realistic polymer environment.

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