1383684-60-3Relevant academic research and scientific papers
Synthesis, electronic structure, and alkene hydrosilylation activity of terpyridine and bis(imino)pyridine iron dialkyl complexes
Tondreau, Aaron M.,Atienza, Crisita Carmen Hojilla,Darmon, Jonathan M.,Milsmann, Carsten,Hoyt, Helen M.,Weller, Keith J.,Nye, Susan A.,Lewis, Kenrick M.,Boyer, Julie,Delis, Johannes G. P.,Lobkovsky, Emil,Chirik, Paul J.
, p. 4886 - 4893 (2012)
Iron dialkyl complexes, [N3]Fe(CH2SiMe 3)2, with three different classes of tridentate, nitrogen-based [N3] ligands, aryl-substituted bis(imino)pyridines, terpyridine, and pyridine bis(oxazoline), have been synthesized and evaluated in the catalytic hydrosilylation of olefins with tertiary silanes. The 2,2′:6′,2″-terpyridine (terpy) complex, (terpy)Fe(CH2SiMe3)2, was prepared either via alkylation of (terpy)FeCl2 with LiCH2SiMe3 or by pyridine displacement from (pyridine)2Fe(CH2SiMe 3)2 by free terpyridine. The aryl-substituted bis(imino)pyridine compounds, (RPDI)Fe(CH2SiMe 3)2 (RPDI = 2,6-(2,6-R2-C 6H3N=CMe)2C5H3N), with smaller 2,6-dialkyl substituents (R = Et, Me) or a 2-iPr substituent (2-iPrPDI)Fe(CH2SiMe3)2 ( 2-iPrPDI = 2,6-(2-iPr-C6H4N=CMe) 2C5H3N, are effective precursors (0.5 mol %) for the anti-Markovnikov hydrosilylation of 1-octene with (Me 3SiO)2MeSiH and (EtO)3SiH over the course of 1 h at 60 °C. No hydrosilylation activity was observed with Et3SiH. The most hindered member of the series, (iPrPDI)Fe(CH 2SiMe3)2, and the pyridine bis(oxazoline) iron compound, (R,R)-(iPrPybox)Fe(CH2SiMe3) 2 (iPrPybox = 2,6-bis[isopropyl-2-oxazolin-2-yl]pyridine), were inactive for the hydrosilylation of 1-octene with all tertiary silanes studied. By contrast, the terpyridine precursor, (terpy)Fe(CH 2SiMe3)2, reached >95% conversion at 60 °C with Et3SiH and (Me3SiO)2MeSiH. In addition, the hydrosilylation of vinylcyclohexene oxide was accomplished in the presence of 1.0 mol % (terpy)Fe(CH2SiMe3)2, demonstrating functional group compatibility unique to this compound that is absent from bis(imino)pyridine iron compounds. The electronic structures of all three classes of iron dialkyl compounds have been evaluated by a combination of X-ray diffraction, magnetochemistry, Moessbauer spectroscopy, and density functional theory calculations. All of the compounds are best described as high-spin iron(III) compounds with antiferromagnetic coupling to chelate radical anions.
