Isolatable paramagnetic and anionic transition metal complexes stabilized by main group heterocyclic carbenes for redox and photoredox active functional materials

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05099
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 34010:Inorganic/coordination chemistry-related
• Research Institution: Hiroshima University
• Principal Investigator: Shang Rong 広島大学, 先進理工系科学研究科(理), 助教 (70754216)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: photoredox / redox active ligand

Outline of Final Research Achievements

This project established synthetic route to a highly π-accepting anti-aromatic 4π B, N-heterocyclic Carbene (BNC), which allowed the isolation of an anionic gold(I) complex. This demonstrates that an interplay of electronegative elements such as boron and the numbers of π electrons in a planar conjugated ligand is crucial in tuning electronic properties of metal complexes. By using the same strategy, a CCC-type pincer based on a dipyridal-annulated N-heterocyclic carbene was developed, which allowed complexation to a Ir(I) precursor to form a homoleptic octahedral Ir(III) bispincer metallacycle. This dark purple complex underwent a step-wise 4e oxidation to yield a chiral Ir(III) complex with a triplet ground state. Together these findings present an effective design strategy for tuning electronic properties and/or accessing higher spin states of transition metal complexes.

Free Research Field

無機・錯体化学関連

Academic Significance and Societal Importance of the Research Achievements

The successful isolation of thermally stable, previously inaccessible complexes means we have developed an effective design strategy to access molecules with unusual photophysical properties, providing a powerful to further studies towards understanding of photoredox behaviors of metal complexes.