208772-18-3Relevant articles and documents
Triptycene-based, carboxylate-bridged biomimetic diiron(II) complexes
Li, Yang,Soe, Chan Myae Myae,Wilson, Justin J.,Tuang, Suan Lian,Apfel, Ulf-Peter,Lippard, Stephen J.
, p. 2011 - 2019 (2013)
A triptycene-based bis(benzimidazole) ester ligand, L3, was designed to enhance the electron-donating ability of the heterocyclic nitrogen atoms relative to those of the first-generation bis(benzoxazole) analogs, L1 and L2. A convergent synthesis of L3 was designed and executed. Three-component titration experiments using UV/Vis spectroscopy revealed that the desired diiron(II) complex could be obtained with a 1:2:1 ratio of L3/Fe(OTf)2(MeCN) 2/external carboxylate reactants. X-ray crystallographic studies of two diiron complexes derived in this manner from L3 revealed their formulas to be [Fe2L3(μ-OH)(μ-O2CR)(OTf)2], where R = 2,6-bis(p-tolyl)phenyl (7) or triphenylmethyl (8). The structures are similar to that of a diiron complex derived from L1, [Fe2L1(μ-OH)(μ- O2CArTol)(OTf)2] (9), a notable difference being that, in 7 and 8, the geometry at iron more closely resembles square-pyramidal than trigonal-bipyramidal. Moessbauer spectroscopic analyses of 7 and 8 indicate the presence of high-spin diiron(II) cores. These results demonstrate the importance of substituting benzimidazole for benzoxazole for assembling biomimetic diiron complexes with syn disposition of two N-donor ligands, as found in O2-activating carboxylate-bridged diiron centers in biological systems. Copyright
