New methods for the targeted and selective development of polyphosphorus frameworks

• Applicants: Professor Dr. Jan J. Weigand; Professor Dr. Robert Wolf
• Subject Area: Inorganic Molecular Chemistry - Synthesis and Characterisation
• Term: since 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 288774733

In the course of the first funding period (36 month), we were able to show that many of the reaction pathways originally postulated by us for the construction, fragmentation or rearrangement of polyphosphorus compounds can be realized. The project is planned for a total time of 72 months and we are very optimistic that our further investigations will also be very successful based on the results of the first project phase. In continuation of the exploratory investigations of the first period, we will pursue our goals: A) coordination of polyphosphorus cations on metal complex fragments and structural transformation of the polyphosphorus framework, B) reduction of the polyphosphorus cations to neutral polyphosphans and C) synthesis of new polyphosphorus frameworks by condensation of transition metal phosphides and polyphosphorus cations and, if necessary, modifying them based on our previous results. Furthermore, the successful synthesis of interesting polyphosphido complexes opens up new possibilities for further implementations, so that in the following project phase we want to add another subproject D) Targeted rearrangement and fragmentation reactions of polyphosphido complexes. As already postulated in the first project phase, we received a number of coordination complexes with different coordination modes for some of the polyphosphorus cations with various metal carbonyls that we have examined so far. These complexes are extremely interesting from a photochemical point of view, which makes them particularly attractive in terms of photochemical behavior. For this reason, we want to investigate targeted transformations of our complexes by excitation, especially with visible light. In addition, a certain systematics of the reaction behavior of the compounds can be derived from the Toolbox Wolf and the Toolbox Weigand from the first project phase, which opens up new possibilities for targeted use of their reactivity. We often observe a chloride (halogen) -induced fragmentation of the polyphosphorus cations to extremely interesting new compounds when they are reacted with a metal anions. In addition, it was also shown that in some reactions of the phosphorus cations with metallates, sometimes with oxidation of the metallate anion to a metal complex in oxidation state 0, scrambling reactions occur, which we now understand well and now deploy specifically for the synthesis of new, highly reactive synthesis building blocks. A large number of reactions found so far shows that our concept of combining phosphorus cations and metallates leads to new synthetic building blocks, which we are planning to use in further condensation reactions.

• DFG Programme: Research Grants