Nonheme iron(II) complexes of macrocyclic ligands in the generation of oxoiron(IV) complexes and the catalytic epoxidation of olefins.
Mononuclear nonheme oxoiron(IV) complexes bearing 15-membered macrocyclic ligands were generated from the reactions of their corresponding iron(II) complexes and iodosylbenzene (PhIO) in CH(3)CN. The oxoiron(IV) species were characterized with various spectroscopic techniques such as UV-vis spectrophotometer, electron paramagnetic resonance, electrospray ionization mass spectrometer, and resonance Raman spectroscopy. The oxoiron(IV) complexes were inactive in olefin epoxidation. In contrast, when iron(II) or oxoiron(IV) complexes were combined with PhIO in the presence of olefins, high yields of epoxide products were obtained. These results indicate that in addition to the oxoiron(IV) species, there must be at least one more active oxidant (e.g., Fe(IV)-OIPh adduct or oxoiron(V) species) that effects the olefin epoxidation. We have also demonstrated that the ligand environment of iron catalysts is an important factor in controlling the catalytic activity as well as the product selectivity in the epoxidation of olefins by PhIO.
Suh
Yumi
Y
Department of Chemistry, Division of Nano Sciences, and Center for Biomimetic Systems, Ewha Womans University, Seoul 120-750, Republic of Korea.
Seo
Mi Sook
MS
Kim
Kwan Mook
KM
Kim
Youn Sang
YS
Jang
Ho G
HG
Tosha
Takehiko
T
Kitagawa
Teizo
T
Kim
Jinheung
J
Nam
Wonwoo
W
D000475:Alkenes / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D005296:Ferrous Compounds / Q000737:chemistry*; D007462:Iodobenzenes / Q000737:chemistry / Q000378:metabolism; D007501:Iron / Q000737:chemistry* / Q000378:metabolism; D008024:Ligands; D047028:Macrocyclic Compounds / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*
D000475:Alkenes; D005296:Ferrous Compounds; D007462:Iodobenzenes; D008024:Ligands; D047028:Macrocyclic Compounds; C066317:ferryl iron; D007501:Iron; D010100:Oxygen; C037276:iodosobenzene