Solvent-Mediated Functionalization of Benzofuroxan on Electron-Rich Ruthenium Complex Platform

An unprecedented reactivity profile of biochemically relevant R-benzofuroxan (R=H, Me, Cl), with high structural diversity and molecular complexity on a selective {Ru(acac)₂ } (acac=acetylacetonate) platform, in conjugation with EtOH solvent mediation, is revealed. This led to the development of monomeric [Ru^III (acac)₂ (L^1R )] (1 a-1 c; L^1R =2-nitrosoanilido derivatives) and dimeric [{Ru^II (acac)₂ }₂ (L^2R )] (2 a-2 b; L^2R =(1E,2E)-N¹ ,N² -bis(2-nitrosophenyl)ethane-1,2-diimine derivatives) complexes in one pot with a change in the metal redox conditions. The functionalization of benzofuroxan in 1 and 2 implied in situ reduction of N=O to NH^- in the former and solvent-assisted multiple N-C coupling in the latter. The aforesaid transformation processes were authenticated through structural elucidation of representative complexes, and evaluated by their spectroscopic/electrochemical features, along with C₂ D₅ OD labeling and monitoring of the impact of substituents (R) in the benzofuroxan framework on the product distribution process. The noninnocent potential of newly developed L¹ and L² in 1 and 2, respectively, was also probed by spectroelectrochemistry in combination with DFT calculations.