Coordination Chemistry and Reactivity of a Cupric Hydroperoxide Species Featuring a Proximal H-Bonding Substituent
摘要:
At -90 degrees C in acetone, a stable hydroperoxo complex [(BA)(CuOOH)-O-II](+) (2) (BA, a tetradentate N-4 ligand possessing a pendant -N(H)CH2C6H5 group) is generated by reacting [(BA)Cu-II(CH3COCH3)](2+) with only 1 equiv of H2O2/Et3N. The exceptional stability of 2 is ascribed to internal H-bonding. Species 2 is also generated in a manner not previously known in copper chemistry, by adding 1.5 equiv of H2O2 (no base) to the cuprous complex [(BA)Cu-I](+). The broad implications for this finding are discussed. Species 2 slowly converts to a mu-1,2-peroxodicopper(II) analogue (3) characterized by UV-vis and resonance Raman spectroscopies. Unlike a close analogue not possessing internal H-bonding, 2 affords no oxidative reactivity with internal or external substrates. However, 2 can be protonated to release H2O2, but only with HClO4, while 1 equiv Et3N restores 2.
Intramolecular Hydrogen Bonding Enhances Stability and Reactivity of Mononuclear Cupric Superoxide Complexes
作者:Mayukh Bhadra、Jung Yoon C. Lee、Ryan E. Cowley、Sunghee Kim、Maxime A. Siegler、Edward I. Solomon、Kenneth D. Karlin
DOI:10.1021/jacs.8b04671
日期:2018.7.25
, cupric-superoxo) complexes, as the first and/or key reactive intermediates in (bio)chemical Cu-oxidative processes, including in the monooxygenases PHM and DβM, have been systematically stabilized by intramolecular hydrogen bonding within a TMPA ligand-based framework. Also, gradual strengthening of ligand-derived H-bonding dramatically enhances the [(L)CuII(O2•-)]+ reactivity toward hydrogen-atom
Peroxynitrite chemistry derived from nitric oxide reaction with a Cu(<scp>ii</scp>)–OOH species and a copper mediated NO reductive coupling reaction
作者:Sunghee Kim、Maxime A. Siegler、Kenneth D. Karlin
DOI:10.1039/c3cc47942k
日期:——
New peroxynitrite-copper chemistry ensues via addition of nitricoxide ( NO(g)) to a Cu(II)-hydroperoxo species. In characterizing the system, the ligand-Cu(i) complex was shown to effect a seldom observed NO(g) reductive coupling reaction. Biological implications are discussed.