Triphenyllead Hydroperoxide: A 1D Coordination Peroxo Polymer, Single-Crystal-to-Single-Crystal Disproportionation to a Superoxo/Hydroxo Complex, and Application in Catalysis

Abstract

The synthesis, transformation, and application in catalysis of triphenyllead hydroperoxide, the first dioxygen lead complex, are described. Triphenyllead hydroperoxide is characterized by 207Pb nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and single-crystal X-ray diffraction, revealing the first one-dimensional (1D) coordination peroxo polymer. Photolytic isomorphous transformation of Ph3PbOOH yields a mixed hydroxo/superoxo crystalline structure, the first nonalkali superoxo crystalline metal salt, which is stable up to 100 °C. Upon further photolysis, another isomorphous transformation of the superoxide to hydroxide is observed. These are the first single-crystal-to-single-crystal hydroperoxide-to-superoxide and then to hydroxide transformations reported to date. Photolysis of triphenyllead hydroperoxide yields two forms of superoxide-doped crystalline structures that are distinguished by widely different characteristic relaxation times. The use of Ph3PbOOH as an easy-to-handle solid two-electron oxidant for the highly enantioselective epoxidation of olefins is described.

Organoantimony Dihydroperoxides: Synthesis, Crystal Structures, and Hydrogen Bonding Networks

“…The TG data were consistent with the DTA results, and all reported thermal effects were accompanied by weight loss (Figures S16–S20). The thermal stability of the considered compounds was slightly lower than that of the previously characterized triphenyl Si and Ge hydroperoxides and similar to that of triphenyl Pb hydroperoxide …”

“…54−59 The O−O distances are close to that found in hydrogen peroxide 60 and correspond to those for OOH ligands coordinated with p-block elements in Cs 2 Sn-(OOH) 6 , 30 Ph 3 SiOOH, Ph 3 GeOOH, 29 and Ph 3 PbOOH [1.450(6) Å]. 24 Hydrogen-Bonded Networks. Previously, the similarities of hydrogen bonding between organic hydroperoxides and a large group of crystalline peroxosolvates were reported on the basis of the systematic analysis of the CSD.…”

“…The thermal stability of the considered compounds was slightly lower than that of the previously characterized triphenyl Si and Ge hydroperoxides 29 and similar to that of triphenyl Pb hydroperoxide. 24 FTIR and Raman Spectroscopies. The frequencies of FTIR band maxima and their assignments are listed in Table S12.…”

“…Selected geometrical parameters are listed in Table S2. The Sb–C and Sb–O bond lengths, as well as O–Sb–O and O–O–Sb angles, are typical for R 3 Sb(V) compounds and correspond to the previously reported crystal data. − The O–O distances are close to that found in hydrogen peroxide and correspond to those for OOH ligands coordinated with p-block elements in Cs 2 Sn(OOH) 6 , Ph 3 SiOOH, Ph 3 GeOOH, and Ph 3 PbOOH [1.450(6) Å] …”

“…Transition metal-based catalysts have been ubiquitous in state-of-the-art asymmetric epoxidation catalysis, focused on exploiting hydrogen peroxide as a stoichiometric oxidant, with manganese being the protagonist in this arena in the past decade. − A drawback of H 2 O 2 is its propensity to disproportionate in the presence of transition ions, which in some cases may essentially deteriorate the oxidant efficiency. Using inorganic adducts of H 2 O 2 or organoelement hydroperoxides has been considered as a potential solution for this limitation.…”