The surprisingly beneficial effect of soft donors on the performance of early transition metal olefin polymerisation catalysts
作者:Daniel C. H. Oakes、Brian S. Kimberley、Vernon C. Gibson、David J. Jones、Andrew J. P. White、David J. Williams
DOI:10.1039/b409870f
日期:——
Group 4 metal complexes containing phenoxy-amide ligands bearing soft pendant donors are shown to give more highly active ethylene polymerisation catalysts than counterparts containing hard donors or systems without a pendant donor.
Synthesis and Characterization of Titanium(IV) Complexes Bearing Monoanionic [O<sup>-</sup>NX] (X = O, S, Se) Tridentate Ligands and Their Behaviors in Ethylene Homo- and Copolymerizaton with 1-Hexene
作者:Cong Wang、Zhi Ma、Xiu-Li Sun、Yuan Gao、Yang-Hui Guo、Yong Tang、Li-Ping Shi
DOI:10.1021/om060062j
日期:2006.6.1
A series of novel titanium(IV) complexes bearing monoanionic [O-NX] (X = O, S, Se) ligands is designed by sidearm approach. These complexes were synthesized, characterized, and employed as catalysts in ethylene homo- and copolymerization. X-ray diffraction studies on these new compounds reveal a distorted octahedral coordination of the central metal with the three chlorine ligands in a mer disposition
Unprecedented Reversible Migration of Amide to Schiff Base Ligands Attached to Tin: Latent Single-Site Initiators for Lactide Polymerization
作者:Nonsee Nimitsiriwat、Edward L. Marshall、Vernon C. Gibson、Mark R. J. Elsegood、Sophie H. Dale
DOI:10.1021/ja0470315
日期:2004.10.1
In an unprecedented transformation, amide ligands are found to attack the imine carbon centers of tridentate Schiff base ligands attached to tin. The process is reversible, and the resultant (masked) amide species can be exploited as latent single-site initiators for the controlled polymerization of rac-lactide.
The Reversible Amination of Tin(II)-Ligated Imines: Latent Initiators for the Polymerization of <i>rac</i>-Lactide
作者:Nonsee Nimitsiriwat、Vernon C. Gibson、Edward L. Marshall、Mark R. J. Elsegood
DOI:10.1021/ic701671s
日期:2008.6.1
The 1:1 reactions of nine potentially tridentate salicylaldimines with tin(II) diamides, Sn(NR2)(2) (R = Me, Et, Pr-i, SiMe3) have been investigated. With Sn((NPr2)-Pr-i)(2) and Sn(NTMS2)(2), the anticipated products of amine elimination, iminophenoxy tin(II) mono(amide)s, are formed. However, for R = Me and R = Et, nucleophilic attack of the amide at the imino carbon occurs to generate tin(II) complexes of tetradentate, dianionic aminoamidophenoxide ligands. The transfer of the amide is shown to be reversible, with both alcoholysis and the initiation of rac-lactide polymerization apparently mediated by the terminal amide tautomer.