Mixed‐Valence Vanadium (IV/V) Glycolates and Lactates with N‐Heterocycle Ligands: Localized Structures and Catalytic Oxidation of Thioanisole

Abstract

Dimeric mixed-valence vanadium (IV/V) glycolates and lactates with N-heterocycle ligands, (4) and (NH 4 ) 2 [V 2 O 3 (bpy) 2 (R,S-lact) 2 ]Cl·H 2 O (5), have been isolated in a wide pH range from weak acidic to alkaline solutions (H 2 glyc = glycolic acid, H 2 lact = lactic acid, phen = 1,10-phenanthroline, bpy = 2,2′-bipyridine). The glycolates and lactates in 1 and 2 [a]

Regioselectivity of concerted proton–electron transfer at the surface of a polyoxovanadate cluster

“…Additional evidence for localization of electron density across the [V 2 O 3 ] 3+ regime in this framework can be obtained by comparing the UV-vis/NIR spectrum of 2-V 6 O 8 2− to other [V 2 O 3 ] 3+ -containing complexes in the literature. 40,41 Mixed-valent dimeric species feature a broad absorption band beginning at 750 nm and stretching beyond 1000 nm in analogy the observed spectrum for 2-V 6 O 8 2− .…”

“…Such asymmetry in the solid state is consistent with previously reported V IV/V mixed-valent vanadium-oxo dimers which feature similarly differentiated V–O b bond lengths on either side of the μ 2 -O 2− ligand. 40,41 Indeed, these works describe V 2 O 3 subunits supported by multidentate ligands, and have been shown to feature Δ V–Ob values as high as 0.2 Å resulting from localization of V IV and V V in the solid phase at low temperature. 40 In these examples, the high-valent, d 0 vanadium ion is bound more tightly to the oxide ligand, as indicated by a truncated V–O b bond distance.…”

“…40,41 Indeed, these works describe V 2 O 3 subunits supported by multidentate ligands, and have been shown to feature Δ V–Ob values as high as 0.2 Å resulting from localization of V IV and V V in the solid phase at low temperature. 40 In these examples, the high-valent, d 0 vanadium ion is bound more tightly to the oxide ligand, as indicated by a truncated V–O b bond distance.…”

“…The lack of additional equivalent vanadate units in 2-V 6 O 8 2− further limits electron shuttling beyond the two μ 2 -oxide-bound V centres, rendering its electronic structure more similar to the ligand-supported oxide-bridged V dimers described above. 40,41…”

Heterogeneous catalysis for thioanisole oxidation using hydrogen peroxide and Copper, Nickel and Zinc tungstates prepared by the polymeric precursor method

“…The selective detoxification of organosulfide-containing chemical nerve agents to less toxic sulfoxide compounds also has important applications [3]. Efforts have been made towards the development of catalytic methods using homogeneous catalysts for the oxidation of sulfides to sulfoxides and/or sulfones [4][5][6][7][8][9][10].…”