Tris(imidazole)-containing phosphine: M2+ complexes as biomimetic catalysts. Importance of a L:M2+-OH- in the catalyzed bimolecular hydrolysis of p-nitrophenyl picolinate

A mononuclear cobalt(II) hydroxo complex: synthesis, molecular structure, and reactivity studies

“…The cell was prepared by taking ester (50.0 lL), catalyst (500.0 lL), and solvent acetonitrile (1,450 lL). The absorption data were recorded immediately after mixing the solution and followed until the formation of 4-nitrophenolate ion completed (means no change in the spectra was observed) [23]. Rate constants were calculated according to the published procedure [24,25].…”

Bifunctional Organometallic Catalysts Involving Proton Transfer or Hydrogen Bonding

“…Rather, each www.chemeurj.org complex was converted to a new species (23,24) incorporating all the atoms of hexyne and of the starting complexes. Though two-dimensional NMR spectroscopy results led to the formulation shown, ultimately X-ray diffraction [66] confirmed that indeed the heterocyclic nitrogen atom had added to C1 of hexyne, presumably at the stage of putative vinylidene complex 25.…”

“…Computational studies [66] of the alkyne-to-vinylidene transformation suggest bifunctional activation of the alkyne, as seen in Scheme 12. Following the important revelations from Tokunaga et al, [70] protonation of bound propyne by H a in 28 was considered.…”

Enhanced Hydrolysis of Carboxylic Acid Esters Catalyzed by Metallomicelles Made of Cu(II) and Zn(II) Complexes

“…These two pK a values are essentially the same as their counterparts obtained from the 1/k N vs [H + ] profiles. It is common that the pK a of the ligand hydroxyl group decreases by coordinating to metal ion (18)(19)(20), and this coordination can activate the ligand hydroxyl group to ionize at neutral pH, therefore, to act as a potent nuleophile retaining most of the reactivity of free hydroxide ion in the cleavage of carboxylic acid esters and phosphates.…”