An Acidity Scale of Tetrafluoroborate Salts of Phosphonium and Iron Hydride Compounds in [D2]Dichloromethane
作者:Tianshu Li、Alan J. Lough、Robert H. Morris
DOI:10.1002/chem.200601484
日期:2007.4.27
pK(CD(2)Cl(2)) values for 15 other hydride or dihydrogen complexes of the iron group elements and of diethyl ether were also placed on this scale. The crystal structures of [Fe(CO)3H(PCy(2)Ph)2][BF4] and [Fe(CO)3(PCy(2)Ph)2] revealed that the trans-oriented, bulky, unsymmetrical phosphane ligands distort the equatorial plane of the complexes. The acidity of iron carbonyl hydrides is an important feature of
酸与CD([Fe(CO)3H(PR3)2] [BF4]的氢化物[Fe(CO)3H(PR3)2] [BF4]的酸和许多phospho盐的共轭碱形式之间的反应平衡常数(K) 2)Cl(2)已通过20°C下的31P和1H NMR光谱测定。用于pK(CD(2)Cl(2))测定的锚定化合物为[HPCy3] [BF4]和pK( CD(2)Cl(2))值为9.7,由文献惯例指定(Cy:环己基)。创建了一个连续标度范围从9.7到-3的pK(CD(2)Cl(2))值,并将其与Angelici和同事报告的DeltaH值以及文献pK(a)值相关联。铁族元素和乙醚的其他15种氢化物或二氢配合物的pK(CD(2)Cl(2))值也按此比例放置。[Fe(CO)3H(PCy(2)Ph)2] [BF4]和[Fe(CO)3(PCy(2)Ph)2]的晶体结构表明,反方向取向的,庞大的,不对称的膦配体使复合体的赤道面变形。羰基铁氢化物的酸度是铁氢化酶反应的重要特征。