Phloroglucinol and resorcinol based mononuclear dioxidomolybdenum (VI) complexes: Synthesis, structural characterization and catalytic epoxidation

Five mononuclear dioxidomolybdenum(VI) complexes of phloroglucinol and resorcinol derived ligands are reported. Two types of ligands are accessible through condensation of 2,4,6-trisacetyl-1,3,5-trihydroxybenzene (2,4,6-triacetylphloroglucinol) and benzoylhydrazide (H(2)ptk-bhz, I) or 2-furoylhydrazide (H(2)ptk-fah, II) and condensation of 4,6-diactylresorcinol and benzoylhydrazide (H(2)dar-bhz, III), 2-furoylhydrazide (H(2)dar-fah, IV) or nicotinoylhydrazide (H(2)dar-nah, V). Isolated complexes, [(MoO2)-O-VI(ptk-bhz) (MeOH)] (1), [(MoO2)-O-VI(ptk-fah)(MeOH)] (2), [(MoO2)-O-VI(dar-bhz)(MeOH)1 (3), [(MoO2)-O-VI(dar-fah)(MeOH)] (4) and [(MoO2)-O-VI(dar-nah)(MeOH)1 (5) have been characterized by spectroscopic techniques like FT-IR, UV-Vis, H-1 NMR and single crystal X-ray diffraction (for complexes 1, 3 and 5) analysis. These complexes have been tested for the epoxidation of alkenes in the presence of 30% H2O2 and NaHCO3 where latter one acts as an additive. Under optimized reaction conditions, a good conversion of alkenes along with their selective epoxidation and high turnover number was achieved. (C) 2017 Elsevier Ltd. All rights reserved.