Phospha Derivatives of Tris(2-aminoethyl)amine (<i>tren</i>) and Tris(3-aminopropyl)amine (<i>trpn</i>): Synthesis and Complexation Studies with Group 4 Metals
作者:Malte Sietzen、Sonja Batke、Lukas Merz、Hubert Wadepohl、Joachim Ballmann
DOI:10.1021/acs.organomet.5b00065
日期:2015.3.23
The N,N',N ''-triphenyl-substituted derivative of tris(2-aminoethyl)phosphine (Ph-3-phospha-tren, P(CH2CH2NHR)(3), R = Ph) and four derivatives of the related tris(3-aminopropyl)phosphine (phospha-trpn, P(CH2CH2CH2NHR)(3), R = Pr-i, Bu-t, (SiBuMe2)-Bu-t, Ph) have been synthesized in addition to the parent phospha-trpn. Out of these ligand systems, only the N,N',N ''-triphenyl-substituted phospha-trpn derivative P(CH2CH2CH2NHPh)(3) was found to be suitable for coordination to group 4 metals. For titanium, zirconium, and hafnium, the C-3-symmetric endo-P-configured dimethylamido complexes Ph[PN3]M(NMe2) of the former ligand have been prepared and converted into the corresponding triflates Ph[PN3]M(OTf). Starting from these triflates, the benzyl complexes Ph[PN3]M(Bn) (M = Ti, Zr, Hf) have been obtained via reaction with Bn2Mg(THF)(2). In case of titanium, the benzyl species Ph[PN3]Ti(Bn) is prone to thermal elimination of toluene, which results in the formation of a cyclometalated species. These findings are discussed in context with the very few group 4 trisamidophosphine complexes that have been reported earlier.