Synthesis and Reactivity of Phosphatetrahedranes and Related Species: New Phosphaorganic Building Blocks

• Applicant: Professor Dr. Robert Wolf
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 451444676

Tetrahedranes are a class of reactive organic molecules consisting of four carbon atoms in a tetrahedral arrangement. They are highly reactive due to their comparatively high bond strain. Neutral tetrahedranes with heteroatoms in the backbone were hardly known until recently. In 2019, our research group published the synthesis of di-tert-butyldiphosphatetrahedrane, (tBuCP)₂, the first tetrahedrane with phosphorus and carbon in the tetrahedral backbone. Cummins and coworkers described the synthesis of tri-tert-butylphosphatetrahedrane, (tBuC)₃P, almost simultaneously in 2020. The discovery of these first phosphatetrahedranes marked the beginning of a previously unknown field of research in the field of organophosphorus chemistry. In this project, we conduct fundamental and comprehensive research into the synthesis, chemical properties, and reactivity of phosphatetrahedranes. The investigations aim at the isolation of new phosphatetrahedranes as well as fundamental studies on reactivity with electrophiles, nucleophiles and reducing agents and on coordination chemistry with transition metals. In the first funding period, we elucidated the molecular and electronic structure of our di-tert-butyldiphosphatetrahedrane, (tBuCP)₂. In addition, we gained deep insight in the reaction patterns of this compound, which has become a useful synthetic building block. The second funding period will complement these investigations, focusing on the reactivity of (tBuCP)₂ toward main group radicals and on photochemical reactions. The major objective of the second funding period will be the synthesis of new phosphatetrahedranes. To this end, we will optimize the Ni-catalyzed synthesis of diphosphatetrahedranes and design new catalysts for the dimerization of phosphaalknyes. In addition, we will develop the synthesis of related mono- and triphosphatetrahedranes using cross-dimerization and transmetalation strategies. The reactivity studies of the new phosphatetrahedranes will be studied and compared to that of (tBuCP)₂ and P₄. The investigations proposed in this project will provide a deeper understanding of the chemistry of phosphatetetrahedranes. They will also form the basis for the discovery of other unusual organophosphorus compounds.

• DFG Programme: Research Grants