Computer-aided design of transition metal ligands for atmospheric pressure ammonia syntesis – running

The industrially produced organic nitrogen compounds (mainly fertilizers, polymers, pharmaceutical ingredients) are synthesized from elementary nitrogen (N2). The N2 molecule is one of the most abundant chemical particles in nature (the air we breathe contains 78% N2), which makes it a cheap raw material for the industry, however, its synthetic application is highly expensive. Currently, 2% of the global energy consumption can be traced back to the century-old Haber-Bosch ammonia synthesis, which is the only economically feasible way of industrial nitrogen fixation. Since the enormous energy demand of the process derives from the high temperature and pressure (400-500 °C, 150-250 bar) applied in the reaction, the key for designing cheap and environmental-friendly alternative synthesis methods is to work under ambient conditions (room temperature, atmospheric pressure). In the recent years, numerous researches were conducted on the structure of the nitrogenase enzyme found in several organisms as it is capable of transforming N2 molecules to biologically usable compounds at ambient temperature and pressure. Based on the structure of the active site of the protein, special transition metal complexes ("artificial nitrogenases") can be designed that can catalyze atmospheric pressure ammonia synthesis. Nevertheless, these promising trials are far from industrial applicability as the stability of these complexes and the measured reaction rate is very low - the reason for the poor catalytic performance is, however, unknown. The aim of this theoretical chemistry research is to explore the structure-reactivity relationships that determine the critical properties (turnover number, turnover frequency) of artificial nitrogenases and to design more efficient nitrogenase-like transition metal complexes.

Project owner:
Benedek Zsolt (Szervetlen és Analitikai Kémia Tanszék)
Web address:
Szervetlen és Analitikai Kémia Tanszék (VBK-IAACHEM)