title: De novo structural prediction of transition metal complexes: application to technetium.
abstract: De novo structural prediction of transition metal complexes is investigated. Technetium complexes are chosen given their importance in medical imaging and nuclear waste remediation and for the chemical diversity they display. A new conformational searching algorithm (LIGB) for transition metals is described that allows one to search for different conformational and geometric isomers within a single simulation. In the preponderance of cases, both conformational searching techniques (LIGB and high-temperature molecular dynamics/simulated annealing) provide comparable results, while LIGB is superior for macrocyclic complexes. A genetic algorithm-optimized PM3(tm) parametrization for Tc is compared with the standard implementation and found to yield a significant improvement in predictive ability for the most prevalent Tc structural motifs. The utility of a coupled molecular mechanics-semiempirical quantum mechanics protocol is demonstrated for very rapid, efficient, and effective de novo prediction of transition metal complex geometries.
authors.affiliation: Department of Chemistry, The University of Memphis, Computational Research on Materials Institute (CROMIUM), Memphis, Tennessee 38152, USA.
authors.forename: Corneliu
authors.initials: C
authors.lastname: Buda
authors.forename: Stanley K
authors.initials: SK
authors.lastname: Burt
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Cundari
authors.forename: Peter S
authors.initials: PS
authors.lastname: Shenkin