167322-85-2Relevant academic research and scientific papers
Tetraaza macrocycles as ancillary ligands in early metal alkyl chemistry. Synthesis and characterization of out-of-plane (Me4taen)ZrX2 (X = alkyl, benzyl, NMe2, Cl) and (Me4taen)ZrX2(NHMe2) (X = Cl, CCPh) complexes
Black,Swenson,Jordan,Rogers
, p. 3539 - 3550 (1995)
The objectives of the present work were to develop efficient routes to (Me4taen)ZrR2 compounds and a general understanding of their structures and properties. The chemistry of cationic derivatives will be discussed in a subsequent paper. Alkane elimination reactions of the neutral macrocycle (Me4taen)H2 (1) and homoleptic ZrR4 compounds provide the most efficient approach to (Me4taen)ZrR2 complexes. Compound 1 reacts readily with ZrR4 (R = CH2Ph, CH2SiMe3) in pentane at 23°C affording (Me4taen)ZrCH2Ph)2 (2) and (Me4taen)Zr(CH2SiMe3)2 (3) in high yield. Complexes 2 and 3 are isolated as orange solids after recrystallization and have been characterized by 1H and 13C NMR and analysis. Complex 2 is sparingly soluble, 3 is quite soluble in benzene, and both are soluble and stable in THF and CH2Cl2. The 1H NMR spectra of 2 and 3 contain singlets for the Me4taen methyl and methine hydrogens, and two multiplets for the -CH2CH2- hydrogens. These data are consistent with cis C2v-symmetric structures, in which the `upper' and `lower' -CH2CH2- hydrogens are inequivalent. The ZrCH2 JCH values for 2 (106 Hz) and 3 (105 Hz) are at the low end of the normal range observed for alkyl complexes of electropositive metals, and indicate that the hydrocarbyl ligands are not significantly distorted by non-classical η2-benzyl or α-agostic interactions.
