Oxidorhenium(V) complexes with tridentate and tetradentate phenol-based ligands

Article abstract of DOI:10.1002/ejic.201000771

The synthesis of oxidorhenium(V) complexes with tridentate and potentially tetradentate ligands of the type [ReOX₂(L)] {X = Cl or Br; L = 2-[CH₂N(Me)CH₂CH₂OCH₃]-4,6-di-tBu- phenolate, 2-[CH₂N(Me)CH₂CH₂SCH ₂CH₃]-4,6-di-tBu-phenolate, 2-[CH₂N(Me)CH ₂CH₂N(CH₃)₂]-4,6-di-tBu-phenolate, 2-[CH₂N(Me)CH₂CH₂N(CH₂CH ₃)₂]-4,6-di-tBu-phenolate, 2-[CH₂N(CH ₂CH₂OCH₃)₂]-4,6-di-tBu-phenolate,2- [CH₂N(CH₂CH₂SCH₂CH₃) ₂]-4,6-di-tBu-phenolate, 2-[CH₂N{CH₂CH ₂N(CH₂CH₃)₂}₂]-4,6-di- tBu-phenolate} 1-14 is reported. All complexes were spectroscopically characterized and shown to be isomerically pure. Compounds 1, 2, 9, and 11 were crystallographically characterized and show similar octahedral geometries with trans O=Re-O and cis O=Re-Cl bonds. All synthesized complexes 1-14 are catalyst precursors for the epoxidation of cyclooctene with tert-butyl hydrogenperoxide (TBHP). Yields of the formed epoxide were up to 55a% with all precursors. Oxidorhenium(V) complexes of the type [ReOX₂L] (X = Cl, Br) that contain tridentate and tetradentate phenolate-based ligands were prepared and tested for their catalytic activity in epoxidation reactions.