Two cis-Dioxomolybdenum(VI) Complexes with Tridentate ONO Aroylhydrazone Schiff Bases: Syntheses, Characterization, Crystal Structures, and Catalytic Epoxidation Property

Abstract

Two new cis-dioxomolybdenum(VI) complexes, [MoO₂(L¹)MeOH] (I) and [MoO₂(L²)MeOH] (II) with potentially tridentate ONO aroylhydrazone Schiff bases derived from 3-methoxysalicylaldehyde with 4-bromobenzohydrazide and 4-trifluoromethylbenzohydrazide, respectively, have been synthesized and fully characterized on the basis of elemental analysis, FT-IR, molar conductivity, and electronic spectra. Structures of the complexes have been accomplished by single crystal X-ray diffraction (СIF files CCDC nos. 1433352 (I) and 1433318 (II)). The complexes have distorted octahedral structures in which the aroylhydrazones behave as binegative ligands. It is also revealed from the crystal structures that the Mo(VI) center adopts NO₅ donor environment, and the octahedral coordination is furnished by two oxido groups and oxygen atoms of methanol or deprotonated methanol molecules. The catalytic properties were investigated for epoxidation of cyclooctene using aqueous tert-butyl hydroperoxide as the oxidant.