名称:
Synthesis, crystal structure, and reactivity of a four-coordinate iron(II) chloride complex bearing the sterically demanding tert-butyl-tris(3-isopropylpyrazolyl)borato ligand
摘要:
The salt elimination reaction between FeCl2(THF)(1.5) and the sterically hindered thallium tert-butyl-tris(3-isopropylpyrazolyl) borate, Tl[t-BuTp(i-Pr)], affords the new air and moisture-sensitive, high-spin, four-coordinate complex Fe[t-BuTp(i-Pr)]Cl (1) in 52% yield. Compound 1 has been characterized by elemental analysis, paramagnetic H-1 NMR, and X-ray crystal structure determination. Fe[t-BuTp(i-Pr)]Cl is monomeric, and the homoscorpionate ligand is kappa(3)-coordinated. The Fe(II) ion lies in a trigonally distorted tetrahedral environment with average N-Fe-N and N-Fe-Cl angles of 89.4(2)degrees and 125.7(2)degrees, respectively. Upon reactions with methyllithium followed by carbonylation, the six-coordinate acetyl-dicarbonyl derivative Fe[t-BuTp(i-Pr)](CO)(2){C(=O)Me) was identified by IR spectroscopy. The reaction of 1 with ethylmagnesiumbromide furnished a mixture of mononuclear Grignard complexes Mg[t-BuTp(i-Pr)]X (X = Et, Cl, Br), resulting formally from a facile and quantitative replacement of the [Fe-Cl](+) fragment by [Mg-X](+). (c) 2007 Elsevier B.V. All rights reserved.