Water-Soluble Iron(IV)-Oxo Complexes Supported by Pentapyridine Ligands: Axial Ligand Effects on Hydrogen Atom and Oxygen Atom Transfer Reactivity.

Content Provider	Semantic Scholar
Author	Chantarojsiri, Teera Sun, Yan Guang Long, Jeffrey R. Chang, Christopher J.
Copyright Year	2015
Abstract	We report the photochemical generation and study of a family of water-soluble iron(IV)-oxo complexes supported by pentapyridine PY5Me2-X ligands (PY5Me2 = 2,6-bis(1,1-bis(2-pyridyl)ethyl)pyridine; X = CF3, H, Me, or NMe2), in which the oxidative reactivity of these ferryl species correlates with the electronic properties of the axial pyridine ligand. Synthesis of a systematic series of [Fe(II)(L)(PY5Me2-X)](2+) complexes, where L = CH3CN or H2O, and characterizations by several methods, including X-ray crystallography, cyclic voltammetry, and Mössbauer spectroscopy, show that increasing the electron-donating ability of the axial pyridine ligand tracks with less positive Fe(III)/Fe(II) reduction potentials and quadrupole splitting parameters. The Fe(II) precursors are readily oxidized to their Fe(IV)-oxo counterparts using either chemical outer-sphere oxidants such as CAN (ceric ammonium nitrate) or flash-quench photochemical oxidation with [Ru(bpy)3](2+) as a photosensitizer and K2S2O8 as a quencher. The Fe(IV)-oxo complexes are capable of oxidizing the C-H bonds of alkane (4-ethylbenzenesulfonate) and alcohol (benzyl alcohol) substrates via hydrogen atom transfer (HAT) and an olefin (4-styrenesulfonate) substrate by oxygen atom transfer (OAT). The [Fe(IV)(O)(PY5Me2-X)](2+) derivatives with electron-poor axial ligands show faster rates of HAT and OAT compared to their counterparts supported by electron-rich axial donors, but the magnitudes of these differences are relatively modest.
Starting Page	1073191118820135
Ending Page	1073191118820135
Page Count	1
File Format	PDF HTM / HTML
Alternate Webpage(s)	https://cloudfront.escholarship.org/dist/prd/content/qt9wm1m4nq/qt9wm1m4nq.pdf?t=o0hu7v
PubMed reference number	26039655v1
Alternate Webpage(s)	https://doi.org/10.1021/acs.inorgchem.5b00658
DOI	10.1021/acs.inorgchem.5b00658
Journal	Inorganic chemistry
Volume Number	54
Issue Number	12
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article