Strong Interaction with Carbon Filler of Polymers Obtained by Pyrene Functionalized Hoveyda-Grubbs 2nd Generation Catalyst

Abstract

Hoveyda-Grubbs 2nd generation catalyst that has the alkylidene functionalized with pyrene (HG2pyrene) was synthesized and characterized. This catalyst can be bound to carbonaceous filler (graphite, graphene or carbon nanotubes) by π-stacking interaction, but, since the catalytic site become poorly accessible to the incoming monomer, its activity in the ROMP (Ring Opening Metathesis Polymerization) is reduced. This is due to the fact that the above interaction also occurs with the aryl groups of NHC ligand of the ruthenium, as demonstrated by nuclear magnetic resonance and by fluorescence analysis of a solution of the catalyst with a molecule that simulated the structure of graphene. Very interesting results were obtained using HG2pyrene as a catalyst in the ROMP of 2-norbornene and 1,5-cyclooctadiene. The activity of this catalyst was the same as that obtained with the classical commercial HG2. Obviously, the polymers obtained with catalyst HG2pyrene have a pyrene as a chain end group. This group can give a strong π-stacking interaction with carbonaceous filler, producing a material that is able to promote the dispersion of other materials such as graphite in the polymer matrix.

Intramolecular Amino-thiolysis Cyclization of Graphene Oxide Modified with Sulfur Dioxide: XPS and Solid-State NMR Studies

“…Solid polymer electrolytes intercalate into graphite oxide due to the dipole–dipole and/or hydrogen bonding forces of attraction between the polymers and graphene oxide . A computational study on the interaction between pristine graphene and graphene oxide and several polymers found that the lowest energy conformer of the β-conformation of polyvinylidene fluoride with the hydrogen atoms facing the graphene had the strongest interaction. − …”