Yuri Tulchinsky

Hebrew University of Jerusalem, Israel

Title: Reviving the Coordination Chemistry of Sulfonium Cations

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Biography

Yuri Tulchinsky has competed his PhD at the Technion – Israeli Institute of Technology in the field of organometallic chemistry with Prof. M. Gandelman in 2014. He then joined the group of Prof. M. Dinca at MIT where he worked on metal organic frameworks (MOF). Since 2018 Dr. Tulchinsky has been appointed as an Assisting Professor at the Hebrew University of Jerusalem. His research interests span different areas of organic, organometallic and supramolecular chemistry, in particular, development of unusual ligand frameworks for future applications in homogeneous catalysis.

Abstract

More than a century old, sulfonium ions are still intriguing species in the landscape of organic chemistry. On one hand they have found broad applications in organic synthesis and material science, but on the other hand, while isoelectronic to the ubiquitous tertiary phosphine ligands,  their own coordination chemistry has been neglected for the last  three decades. Only a handful of crystallographically characterized sulfonium complexes of Mo(0), W(0), and Mn(I) were reported,  where these ligands exhibited strongly ?-acidic character. Similar with phosphine ligands, sulfonium ligands also have low lying ?*-orbitals, which can accept electron density. However, because of the positive charge, there maybe repulsion between sulfonium and the metal center. This repulsion can be overcome by introducing supporting donor arms, so we designed the pincer ligands with two phosphine supporting donors and tripodal ligand with three supporting phosphine donors. Here we present the synthesis and full characterization of the first Rh(I) and Pt(II) complexes of pincer and tripodal sulfonium ligands. Moreover, for the first time, the coordinating ability of an aromatic sulfonium has been established. A thorough computational analysis of the exceptionally short S-Rh bonds obtained attests for the strongly ?-accepting nature of sulfonium cations and places them among the best ?-acceptor ligands available today.  Our calculations also show that when embedded within a pincer framework their ?-acidity is enhanced. Therefore, in addition to the stability and modularity that these frameworks offer, our pincer complexes might open the way for sulfonium cations to become powerful tools in ?-acid catalysis.