Oxidation of 4-(methylsulfanyl)-2,6-di(pyrazol-1-yl)pyridine(L^(SMe))with hydrogen peroxide or mCPBA yields 4-(methylsulfinyl)-2,6-di(pyrazol-1-yl)pyridine(L^(SOMe))and 4-(methylsulfonyl)-2,6-di(pyrazol-1-yl)-pyridine...Oxidation of 4-(methylsulfanyl)-2,6-di(pyrazol-1-yl)pyridine(L^(SMe))with hydrogen peroxide or mCPBA yields 4-(methylsulfinyl)-2,6-di(pyrazol-1-yl)pyridine(L^(SOMe))and 4-(methylsulfonyl)-2,6-di(pyrazol-1-yl)-pyridine(L^(SO_(2)Me)),respectively.Solid[Fe(L^(SMe))_(2)][ClO_(4)]_(2)(1[ClO_(4)]_(2))is high-spin at room temperature,and exhibits an abrupt spin-transition at T_(1/2)=256 K.A shoulder on the cooling side of theχMT vs.T curve is associated with a hysteretic crystallographic phase change,occurring around T↓=245 K and T↑=258 K.The phase change involves a 180°rotation of around half the methylsulfanyl substituents in the crystal.This contrasts with the previously reported BF_(4)−salt of the same compound,which is isostructural to 1[ClO_(4)]_(2)at room temperature but transforms to a different crystal phase in its low-spin state.Solid[Fe(LSOMe)_(2)][BF_(4)]_(2)(2[BF_(4)]_(2))and[Fe(LSO_(2)Me)_(2)][BF_(4)]_(2)(3[BF_(4)]_(2))both exhibit gradual spin-crossover equilibria centred significantly above room temperature.Solution measurements show that the oxidised sulfur centers in 2[BF_(4)]_(2)and 3[BF_(4)]_(2)stabilise the low spin states of those complexes.展开更多
基金funded by the EPSRC grants EP/I014039/1,EP/K012568/1 and EP/K00512X/1.
文摘Oxidation of 4-(methylsulfanyl)-2,6-di(pyrazol-1-yl)pyridine(L^(SMe))with hydrogen peroxide or mCPBA yields 4-(methylsulfinyl)-2,6-di(pyrazol-1-yl)pyridine(L^(SOMe))and 4-(methylsulfonyl)-2,6-di(pyrazol-1-yl)-pyridine(L^(SO_(2)Me)),respectively.Solid[Fe(L^(SMe))_(2)][ClO_(4)]_(2)(1[ClO_(4)]_(2))is high-spin at room temperature,and exhibits an abrupt spin-transition at T_(1/2)=256 K.A shoulder on the cooling side of theχMT vs.T curve is associated with a hysteretic crystallographic phase change,occurring around T↓=245 K and T↑=258 K.The phase change involves a 180°rotation of around half the methylsulfanyl substituents in the crystal.This contrasts with the previously reported BF_(4)−salt of the same compound,which is isostructural to 1[ClO_(4)]_(2)at room temperature but transforms to a different crystal phase in its low-spin state.Solid[Fe(LSOMe)_(2)][BF_(4)]_(2)(2[BF_(4)]_(2))and[Fe(LSO_(2)Me)_(2)][BF_(4)]_(2)(3[BF_(4)]_(2))both exhibit gradual spin-crossover equilibria centred significantly above room temperature.Solution measurements show that the oxidised sulfur centers in 2[BF_(4)]_(2)and 3[BF_(4)]_(2)stabilise the low spin states of those complexes.
