Hydrogen bonding for the terminal FeIV=O unit, so the distinction in reactivity may possibly be associated to the presence on the hydrogen bond. Certainly EXAFS analysis establishes the presence of a linear Fe e unit in 1F. DFT calculations happen to be carried out on both 1OH and 1F to shed additional light on this reactivity behavior. Experimental and Computational Facts Complexes 1 and 2 have been ready according to reported procedures.24,26 9,10dihydroanthracene (DHA, 97 ), Fluorene (99 ) and ferrocene (Fc, 98 ) purchased from Aldrich have been recrystallized (from EtOH for the former two and MeOH for the latter one particular) prior to use. Butyronitrile (PrCN, 99 ) purchased from Aldrich was purified and dried based on reported procedures.28 9,9,ten,10d4DHA was synthesized in line with reported procedures.25 Tetrabutylammonium fluoride hydrate (Bu4NF.xH2O) purchased from Aldrich (98 ) was dried below vacuum at 40 .29 Anhydrous dichloromethane (99.eight ) and acetonitrile (99.8 ) purchased from Aldrich had been used without having further treatment.(S)-2-Piperidinone-6-carboxylic acid web Bu4NOCD3 was ready according to reported procedures.30 UVvis spectra and kinetic time traces had been recorded on a HewlettPackard 8453A diode array spectrometer equipped with a cryostat from Unisoku Scientific Instruments, Osaka, Japan. This mixture permits kinetic research to become performed at temperatures down to 85 and to record a spectrum (inside the array of 190 to 1100 nm) just about every 0.1 second. For some rapid reactions with a reaction time of 10 seconds, time traces at one wavelength could be obtained with about 100 data points for dependable kinetic fits (See Figures 1). 31PNMR data were collected on a Varian VXR300 spectrometer. Reactivity studiesAll reactivity measurements were performed inside a three:1 mixture of CH2Cl2MeCN beneath Ar to enable measurements to become produced at 85 . A solution of 1F was ready by addition of 1.five equivalents Bu4NF to 1 (typically 0.two mM), while a answer of 1OH was prepared by reduction of 2 (generally 0.two mM) with 1 equivalent ferrocene. For any standard reactivity experiment, an acceptable quantity of substrate (from a stock remedy in CH2Cl2) was introduced towards the answer with the complex via a micro syringe, as well as the reaction remedy was monitored by UVvis spectroscopy. The pseudofirstorder price constants kobs were obtained by fitting the decay time traces and the secondorder price constants k2 were obtained by fitting the kobs versus substrateconcentration plots.Formula of 236406-56-7 The reaction options have been filtered by way of silica gel columns to remove iron complexes before solution analyses.PMID:23551549 The yield in the anthracene solution from DHA oxidation was quantified by the absorbance on the filtrates at 377 nm ( = 7700 M1 cm1). XAS studyFe Kedge Xray absorption spectra (XAS, fluorescence excitation, Ge detector) of a frozen resolution of 1F were recorded at 10 K in the Stanford SynchrotronNIHPA Author Manuscript NIHPA Author Manuscript NIHPA Author ManuscriptInorg Chem. Author manuscript; offered in PMC 2014 April 01.Xue et al.PageRadiation Laboratory (SSRL). The answer contained three mM of diiron species in three:1 PrCNMeCN, with 75 yield (2.2 mM) of 1F determined by M sbauer analysis. The energy variety was 6.9 to 8.0 keV. The monochromator was calibrated working with the Kedge power of iron foil at 7112.0 eV. The program EXAFSPAK31 was utilised for evaluation with the data and for EXAFS fitting, the latter in conjunction with FEFF 8.32 SSExafs33,34 was made use of for fitting in the preedge area of XAS spectra. Computational studiesAll calculations had been perf.
