Tripodal trispyrazolylborates (Tp) are a well-known class of scorpionate ligands, widely used for the synthesis of complexes with interesting electronic and structural properties. Gratifyingly, 3,5-disubstitution of pyrazolyl arms on Tp ligand renders shielding for the bound metal, granting the formation of low-coordinate metals featuring metal-ligand multiple bonds, which are an interesting class of molecules both for their electronic properties and their reactivity. In the case of vanadium, vanadium nitrides are not only a likely intermediate in vanadium-based nitrogen fixation processes but also a potential catalyst for reduction/oxidation reactions. These promising materials also possess compelling electronic conductivity and high specific capacity. However, in contrast to the ubiquity of vanadyl ions (VO²⁺), there are very few examples of mononuclear neutral and anionic vanadium nitrides. The chemistry of vanadium phosphides becomes even more novel and unique as metal phosphides are more reactive and unstable, therefore, more challenging to isolate, characterize, and study. Hence, we have pursued the synthesis of such metal-ligand multiply bound species using Tp^t^Bu,Me. The VTp^t^Bu,MeCl and VTp^t^Bu,MeCl₂ precursors have been studied electronically using X- and Q-band EPR, and HF-EPR respectively. Additionally, these complexes were characterized by a variety of methods, including single-crystal x-ray crystallography. Herein, we present the synthesis, characterization, and reactivity of several multiply bound terminal and bridging pnictides and chalcogenides. CV, EPR, and SQUID data have been collected to provide a better electronic and magnetic understanding of such complexed molecules. Given the wide range of oxidation states amongst these synthesized vanadium complexes possessing similar coordination environments, intrigued us to also investigate these systems using K-edge XAS.

Cristina Prieto

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