Pentafluorosulfanyl Substituents in Polymerization Catalysis

Abstract

Highly electron-withdrawing pentafluorosulfanyl groups were probed as substituents in an organometallic catalyst. In Ni(II) salicylaldiminato complexes as an example case, these highly electron-withdrawing substituents allow for polymerization of ethylene to higher molecular weights with reduced branching due to significant reductions in β-hydrogen elimination. Combined with the excellent functional group tolerance of neutral Ni(II) complexes, this suppression of β-hydrogen elimination allows for the direct polymerization of ethylene in water to nanocrystal dispersions of disentangled, ultrahigh-molecular-weight linear polyethylene.

Remote Perfluoroalkyl Substituents are Key to Living Aqueous Ethylene Polymerization

“…To understand their role in catalysis, we investigated the influence of long perfluoroalkyl substituents (linear C 6 F 13 groups) in different established salicylaldiminato Ni II motifs under a set of polymerization reaction conditions. We targeted the N ‐(quar)terphenyl‐based 1‐R F /L and 2‐R F /L (Figure ), known to be active in aqueous and nonaqueous ethylene polymerization to linear high‐molecular‐weight polyethylene . We also modified the N‐naphthyl‐type catalyst 3‐R F /L (Figure ), capable of a controlled/living ethylene polymerization in a variety of solvents, and introduced C 6 F 13 ‐substituents to selected positions .…”

A simple and versatile nickel platform for the generation of branched high molecular weight polyolefins

“…The ability of complexes Ni4 and Ni-OH to generate UHMWPE is quite surprising considering their sterically open characteristics. The synthesis of UHMWPE using nickel catalysts remains challenging, and very few nickel systems have these capabilities [64][65][66][67][68][69][70] . Furthermore, it is even more challenging to develop heterogeneous nickel catalyst with such capabilities, and to the best of our knowledge, this type of system has not been reported previously.…”

Photoredox Catalytic Activation of Sulfur Hexafluoride for Pentafluorosulfanylation of α‐Methyl‐ and α‐Phenyl Styrene

“…In contrastt ot he extensively appliedC F 3 group, the pentafluorosulfanyl (SF 5 )g roup is ar elatively new fluorinated substituent and one of the most underexplored ones;t herefore often designated as "forgottenf unctional group". [8] In contrast to the weakness of the CF 3 group, namely its sensitivity towards hydrolytic activation,t he SF 5 group is both thermally and chemically stable and not prone to hydrolysis under physiological conditions, is highlye lectronegative, and is lipophilic. [8] In contrast to the weakness of the CF 3 group, namely its sensitivity towards hydrolytic activation,t he SF 5 group is both thermally and chemically stable and not prone to hydrolysis under physiological conditions, is highlye lectronegative, and is lipophilic.…”

“…[6] This is surprising with respect to the proposed, highly beneficial properties of the SF 5 group, especially as bioisostericr eplacement in pharmaceutically active compounds, [7] but also for the design of polymerization catalysts. [8] In contrast to the weakness of the CF 3 group, namely its sensitivity towards hydrolytic activation,t he SF 5 group is both thermally and chemically stable and not prone to hydrolysis under physiological conditions, is highlye lectronegative, and is lipophilic. [9] This renders the SF 5 -compounds as prospective alternatives to common CF 3 -compoundsi nd rugs, and does not simply represent am ore expensive perfluorinated functional group.…”