Reactivity of Two-Electron-Reduced Boron Formazanate Compounds with Electrophiles: Facile N-H/N-C Bond Homolysis Due to the Formation of Stable Ligand Radicals.

ABSTRACT: The reactivity of a boron complex with a redox-active formazanate ligand, LBPh₂ [L = PhNNC( p-tol)NNPh], was studied. Two-electron reduction of this main-group complex generates the stable, nucleophilic dianion [LBPh₂]^2-, which reacts with the electrophiles BnBr and H₂O to form products that derive from ligand benzylation and protonation, respectively. The resulting complexes are anionic boron analogues of leucoverdazyls. N-C and N-H bond homolysis of these compounds was studied by exchange NMR spectroscopy and kinetic experiments. The weak N-C and N-H bonds in these systems derive from the stability of the resulting borataverdazyl radical, in which the unpaired electron is delocalized over the four N atoms in the ligand backbone. We thus demonstrate the ability of this system to take up two electrons and an electrophile (E⁺ = Bn⁺, H⁺) in a process that takes place on the organic ligand. In addition, we show that the [2e^-/E⁺] stored on the ligand can be converted to E^• radicals, reactivity that has implications in energy storage applications such as hydrogen evolution.

SUBMITTER: Mondol R 

PROVIDER: S-EPMC6106049 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature