Structural effects on the stability of [Fe-Fe]-hydrogenase mimic compounds under working

Abstract

Hydrogen gas has many important uses ranging from synthetic organic chemistry to energy conversion. In organic synthesis, hydrogen is frequently used in hydrogenations to reduce a double or triple bond into a single or double bond, respectively. For energy conversion, hydrogen can be produced in an electrolyzer by splitting water into hydrogen and oxygen, stored in a fuel tank, and later used in a fuel cell to convert the chemical energy from the H-H bond into electrical energy. This is how the Space Shuttle produced the power needed to conduct experiments in space where it isn’t feasible to carry and use heavy batteries for long-duration flights and it isn’t possible nor safe to use combustion-based generators. The need for this compound is high, but supply is often expensive and requires significant electrical input to make enough hydrogen to meet the demand. One possible hydrogen production source could come through biological and biomimetic processes using bacterial enzymes like hydrogenases. Currently there are a few catalysts that have been synthesized and their structures have been analyzed. The first major goal of this research was to examine structural effects on the reduction potentials in organic solvents. We have used computational chemistry to examine known catalysts and to design improved catalysts. Figure A.1 shows the main proposed structures which we have attempted, using cyclic voltammetry to determine each complex’s ability to act as hydrogen evolution reaction (HER) catalysts.