Understanding the Role of Hyponitrite in Nitric Oxide Reduction

Herein, we review the preparation and coordination chemistry of cis and trans isomers of hyponitrite, [N2O2](2-). Hyponitrite is known to bind to metals via a variety of bonding modes. In fact, at least eight different bonding modes have been observed, which is remarkable for such a simple ligand. More importantly, it is apparent that the cis isomer of hyponitrite is more reactive than the trans isomer because the barrier of N2O elimination from cis-hyponitrite is lower than that of trans-hyponitrite. This observation may have important mechanistic implications for both heterogeneous NOx reduction catalysts and NO reductase. However, our understanding of the hyponitrite ligand has been limited by the lack of a general route to this fragment, and most instances of its formation have been serendipitous

Synthesis, characterization, and properties of some cyclopentadienyl molybdenum nitrosyl benzyl complexes

Reaction of CpMo(NO)(CH2Ph)Cl with Me2 Mg, Ph2Mg, or PhCCLi reagents in THF affords the corresponding alkyl, aryl, or alkynyl CpMo(NO)(CH2Ph)R (R = hydrocarbyl) complexes as orange powders in good yields. Unlike related 16-electron CpMo(NO)R2complexes, these 18-electron species exhibit good thermal stability due to their η2-benzyl-Mo interactions. Treatment of CpMo(NO)(CH2Ph)Cl with Na(DME)Cp provides dark green Cp2Mo(NO)(CH2Ph), whose solid-state molecular structure has been established by a single-crystal X-ray crystallographic analysis. The two Cp rings display different binding modes to the Mo atom, while the benzyl ligand is coordinated to the metal Center in an η1fashion. The triflate complex, CpMo(NO)(CH2Ph)(OTf), is obtained by addition of AgOTf to the benzyl chloride precursor. The covalent Mo - OTf bond in this compound can be disrupted by the addition of Lewis bases (L) such as PPh3 or pyridine, leading to the corresponding [CpMo(NO)(CH2Ph)(L)][OTf] salts. Attempts to generate neutral benzylidene complexes by deprotonation of [CpMo(NO)(CH2Ph)(PPh3)][OTf] have not yet been successful