Donor–Acceptor Metallocene Catalysts for the Production of UHMW‐PE: Pushing the Selectivity for Chain Growth to Its Limits

Abstract

Superkunststoff! Donor‐Acceptor‐Zirconocene mit einem Donor(P)‐substituierten Fluorenylliganden und einem Acceptor(B)‐substituierten Cyclopentadienylliganden (siehe Struktur) katalysieren die Ethylenpolymerisation mit hoher Aktivität und enormer Selektivität für das Kettenwachstum selbst bei hohen Temperaturen und machen so ultrahochmolekulare Polyethylene zugänglich (viskositätsgemittelte Molekulargewichte Mη>1×106 g mol−1).

Synthesis of Various Branched Ultra-High-Molecular-Weight Polyethylenes Using Sterically Hindered Acenaphthene-Based α-Diimine Ni(II) Catalysts

“…26−38 Ultra-high-molecular-weight polyethylenes (UHMWPEs), molecular weight values of which are in the range of 10 6 − 10 7 g mol −1 , have attracted much attention because these unique polymers have outstanding physical and mechanical properties. 39 Most notable are their chemical, photochemical, and biological stability, lubricity, abrasion resistance, and high impact toughness. 40 For example, they can be used in total joint replacement and medical devices.…”

Remarkable Promotion Effect of Sulfation over the SiO2‐Supported Vanadium‐Oxide‐Based Catalysts for UHMWPE

“…Similar results are disclosed in a Cp‐chromium(IV)‐based catalyst supported on carbon materials as well . Ostoja Starzewski et al designed a number of acceptor/donor zirconocenes to regulate the rotation of the Cp rings so that the MW of the produced PEs was efficiently promoted even to 11 × 10 6 g mol −1 . The FI (Fujita Invented) catalysts, due to their living polymerization nature, are also extensively used for UHWMPE synthesis, and the homogeneous bisphenoxyimine titanium (IV) are often used to produce in situ disentangled UHMWPE with super high activity .…”

Atypical “Masked” Frustrated Lewis Pair Character in a Geminal‐Linked Phosphine‐Borane

“…To further confirm that NÀ H bond activation of ammonia borane was occurring in the presence of 1, we repeated a similar reaction using the isotopologue D 3 N • BH 3 . [20] As ex-pected, 1 H, 2 H, 13 C{ 1 H} and 11 B{ 1 H} NMR spectroscopic analysis of the reaction mixture confirmed the formation of D 2 NBCy 2 and the mono-deuteride H 3 B • i Pr 2 P(C 13 H 8 D) (4-d). [14] with thermal ellipsoids plotted at 50 % probability.…”

“…[12] Subsequent salt metathesis between Li(C 13 H 9 ) and i Pr 2 PCl in hexanes yields i Pr 2 P(C 13 H 9 ) as a white powder in 91 % yield. [13] Treatment of this fluorenyl-phosphine i Pr 2 P(C 13 H 9 ) with t BuLi followed by addition of ClBCy 2 in a one-pot procedure affords the FLP, i Pr 2 P(C 13 H 8 )BCy 2 (Cy = cyclohexyl) (1), in 37 % yield.…”

“…All hydrogen atoms are omitted for clarity. Selected bond lengths [Å] and angles [°]: P1À C1 1.9015 (13), C1À B1 1.6294 (18); P1À C1À B1 117.56 (9). b) Computed HOMO (left, À 7.08 eV) and LUMO (right, À 0.42 eV) of 1, plotted with an isovalue of 0.03.…”