Group 14 metallocenes and structure--function relationships in metalloenzymes
A general synthetic method has been developed for the synthesis of posttransition metal, triple-decker cations. The addition of positively charged halfsandwich cations to neutral metallocenes affords triple-decker cations of the formula, [η5 -(C5Me5)3E2] + . Examples of both group 13 and group 14 complexes have been prepared and structurally characterized. These triple-decker cations provide a platform, which shows promise for the development of nanomaterials, such as molecular wires. Group 14 metallocene complexes containing the 1,3- bis(trimethylsilyl)indenide ligand have also been synthesized and structurally characterized. Rational syntheses for complexes of the formulas [1,3- (Me3Si)2(η5 -C9H5)]2E and [1,3-(Me3Si)2(η5 -C9H5)](η5 -C5Me5)E have been developed. The lability of the indenide ligand renders these complexes promising potential precursors for group 14 nanoparticle formation. The merger of organometallic chemistry with molecular biology to provide creative solutions to difficult problems opened an opportunity to apply the background I have acquired in structure chemistry to the study of three metalloenzymes, 3-dehydroquinate synthase, 5-enolpyruvylshikimate 3-phosphate synthase, and Mycobacterium tuberculosis catalase-peroxidase (M. tuberculosis CP). Computational analsysis of the crystal structure of each system provided valuable insight into residues that play a key role in the activity of the enzymes. This knowledge can in turn be applied to the development of the small-molecule inhibitors of the enzymes. In addition to computational analysis of M. tuberculosis CP, an X-ray crystal structure of this enzyme was determined to a resolution of 2.4 Å.