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

Abstract

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 [RuIII (acac)2 (L1R )] (1 a-1 c; L1R =2-nitrosoanilido derivatives) and dimeric [{RuII (acac)2 }2 (L2R )] (2 a-2 b; L2R =(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.