849416-89-3Relevant academic research and scientific papers
A new arene-bridged diamidophosphine ligand and its coordination chemistry with zirconium(IV)
MacLachlan, Erin A.,Fryzuk, Michael D.
, p. 1112 - 1118 (2008/10/09)
The arene-bridged dilithium diamidophosphine ligand, [(2,4,6-Me 3C6H2)NLi-2-(5-MeC6H 3)]2-PPh, [NPN]*Li2, was prepared from (2,4,6-Me3C6H2)(2-Br-4-MeC6H 3)NH, nBuLi, and PhPCl2 in Et2O and isolated as a dioxane adduct in ～85% yield. The solid-state structure of [NPN]-*Li2(THF)2 as determined by X-ray diffraction shows both lithiums bridged by the amido nitrogens with one Li ion coordinated to the phosphine donor. The reaction of [NPN]*H2 and Zr(NMe2)4 in toluene produced (NPN]*Zr(NMe 2)2 in 90% isolated yield. Addition of excess Me 3SiCl to [NPN]*Zr(NMe2)2 converts it to [NPN]*ZrCl2 in high yield. The solid-state structure of [NPN]*ZrCl2 as determined by X-ray diffraction shows the Zr center is a distorted trigonal bipyramid with the phosphine and the chloride apical. The ortho-Me's on the N-mesityl moiety are inequivalent in both the Li and Zr complexes of [NPN]* by NMR spectroscopy, while in [NPN]*H2 MesN ortho-Me's appear as broad singlets. VT-NMR of [NPN]*H2 indicated that ΔGrot ? of MesCipso-N is approximately 15.5 ± 0.3 kcal mol-1. The thermally labile and light-sensitive zirconium dimethyl complex [NPN]*ZrMe2 was prepared from [NPN]*ZrCl2 and MeMgCl in Et2O in 80% yield.
