Structures and spectra of bis-tripodal iron(II) chelates, [FeL2]2+, where L = tris(pyrazol-1-yl)methane, tris(pyridin-2-yl)methane, bis(pyrazol-1-yl)(pyridin-2-yl)methane and tris(pyridin-2-yl)phosphine oxide. Magnetism and spin crossover in the (pz)3CH case
Abstract
A range of six-co-ordinate bis-tripodal iron(II) chelates, [FeL2]2+, has been synthesized from iron-(II) or -(III) precursors where L = tris(pyrazol-1-yl)methane (pz)3CH, tris(pyridyl-2-yl)methane (py)3CH, bis(pyrazol-1-yl)(pyridin-2-yl)methane (pz)2(py)CH and O. Crystal structures have been determined for three compounds and in the (pz)3CH case for two polymorphs (α and β) which were obtained in two different laboratories from iron(III) salts using different