Oxidative N-dealkylation in cobalt–bispidine–H₂O₂systems

Abstract

The reaction of the Co(II) complex with the rigid bispidine ligand L1 with two tertiary amine and two pyridine donors, [Co(II)(L1)(OH2)2]2+, with H2O2 and O2 produces [Co(II)(L2)(OH2)2]3+, where L2 is demethylated at one of the amine donors, and CH2O.

Stable Five‐ and Six‐Coordinate Cobalt(III) Complexes with a Pentadentate Bispidine Ligand

“…[18] , were analyzed by Xray crystallography ( Figure 1, Table 1). [19,20] In contrast to these observations, the structures of the Co II and Zn II complexes of L 1 and L 2 are six-coordinate, and the metal-donor bond lengths are as expected from other bispidine complexes (Table 1). [17,21] There are no unusual coordination geometries with the parent ligands L 1a and L 2a with a smaller chelate ring involving N py3 .…”

“…[17,21] There are no unusual coordination geometries with the parent ligands L 1a and L 2a with a smaller chelate ring involving N py3 . [17,18,20,21] [17,20,22] MM and DFT calculations were used to confirm these hypotheses. The quality of the DFT approach used (see the Experimental Section) is confirmed by the excellent agreement between computed and experimental structures and energetics (see Table 1 (comput: .…”

Optimization of the Efficiency of Oxidation Catalysts Based on Iron Bispidine Complexes

“…Due to the availability of a wide variety of easy to prepare tetra-and pentadentate bispidine ligands (2,4-and 3-or 7-substituted 3,7-diazabicyclo[3.3.1]nonane; see Scheme 1 for the pentadentate 2,4,7-substituted bispidines L 1 -L 3 discussed in this communication) and based on their rich coordination chemistry, [8] their oxygen activation performance with copper, [9][10][11][12] cobalt, [13] vanadium, [14] ruthenium, [15,16] and iron [17][18][19][20][21] systems have been studied in detail. The iron systems in particular have been shown to be efficient oxygenation catalysts, and the iron chemistry of the L 1 -based pentadentate as well as the corresponding 2,4-substituted tetradentate bispidine ligands have indeed been shown to have, among the corresponding families of iron complexes, the highest Fe IV/III reduction potentials and the highest efficiencies in a range of C-H activation and oxygen-transfer reactions.…”

Divalent Nickel, Cobalt and Iron Complexes of an Amide‐Appended N2S2 Ligand: Synthesis, Characterization and Reactivity with Hydroxide Anion

“…Cobalt(II) complexes have been previously shown to undergo reaction with O 2 to generate reactive Co III peroxide or hydroperoxide complexes that mediate the N-dealkylation of supporting chelate ligands. [23] The production of only ca. 50 % of the chelate ligand amide methanolysis product after 5 d at 50°C contrasts with the reactivity of the zinc analog [(bmppa -)Zn]-ClO 4 , wherein a 96 % yield of bmapa is obtained after heating of the complex in methanol at 40(1)°C for 48 h and removal of the Zn II ion.…”