Fluorescently Tagged Poly(methyl methacrylate)s.

Plastic pollution is a global problem affecting the environment and, consequently, people's well-being. Careful and timely end-of-life plastic recycling is certainly a way, albeit a partial one, to remedy the problem. The immediate identification and selection of the different types of plastic materials in the recycling process certainly facilitate its recovery and reuse, allowing the damage caused by plastic emission into the environment to be limited.

CO-Based Polycarbonates through Ring-Opening Polymerization of Cyclic Carbonates Promoted by a NHC-Based Zinc Complex.

A backbone-substituted N-heterocyclic carbene (NHC) zinc complex, in combination with alcohol initiators, has been shown to be an effective catalyst for the ring-opening polymerization (ROP) of trimethylene carbonate (TMC) to poly(trimethylene carbonate) (PTMC) devoid of oxetane linkages. The ROP of TMC proceeded in solution to give PTMC, possessing controlled molecular mass (2500 < < 10000) and low dispersity ( ∼ 1.2).

Compendium of Safety Regulatory for Safe Applications of Aerogels.

An increasing number of aerogels as nanostructured highly porous materials are entering the market in every day products, with an attractive portfolio of properties for emerging applications ranging from health care and leisure to electronics, cosmetics, energy, agriculture, food and environmental. However, the novelty in properties and forms of aerogels makes the development of a legislative framework particularly challenging for ensuring the safe development and use of nano-enabled products. The presented safety regulatory Compendium intends to share knowledge with the international aerogels community, as well as end-users and stakeholders, on the regulatory and safe handling procedures, as best safety practices, to be followed during the production process, handling, transport and end-use of aerogel-based formulations to mitigate human and environmental risks considering lack of data availability for this purpose in general.

Spectroscopic data of norbornene and oxanorbornene dicarboximides functionalized with carbazole and coumarin groups.

This article describes data related to the research paper entitled "ROMP of norbornene and oxanorbornene derivatives with pendant fluorophore carbazole and coumarin groups" [1]. Six novel norbornene and oxanorbornene dicarboximides derivatives functionalized with carbazole or coumarin moieties, are synthesized and investigated in the preparation of fluorescent polymers by Ring-Opening Metathesis Polymerization (ROMP). Herein, we report on the characterization of all these compounds by 1D and 2D Nuclear Magnetic Resonance (NMR), UV-Visible and fluorescence spectroscopy.

Ruthenium-based olefin metathesis catalysts with monodentate unsymmetrical NHC ligands.

An overview on the catalytic properties of ruthenium complexes for olefin metathesis bearing monodentate unsymmetrical N-heterocyclic diaminocarbene ligands is provided. The non-symmetric nature of these NHC architectures strongly influences activity and selectivity of the resulting catalysts. The main achievements that have been accomplished in significant areas of olefin metathesis up to the current state of research are discussed.

Stable ruthenium olefin metathesis catalysts bearing symmetrical NHC ligands with primary and secondary N-alkyl groups.

Four novel stable Hoveyda-Grubbs-type catalysts containing N,N'-dineopentyl- and N,N'-dicyclohexyl-substituted N-heterocyclic carbene (NHC) ligands with syn and anti phenyl groups on the ring backbone were synthesized and fully characterized. The catalytic potential of these complexes was investigated in metathesis reactions of both standard and renewable substrates. Compared to the Hoveyda-Grubbs second generation catalyst (HGII), all of the new catalysts showed high performances in most of the examined metathesis transformations.

NHC Backbone Configuration in Ruthenium-Catalyzed Olefin Metathesis.

The catalytic properties of olefin metathesis ruthenium complexes bearing N-heterocyclic carbene ligands with stereogenic centers on the backbone are described. Differences in catalytic behavior depending on the backbone configurations of symmetrical and unsymmetrical NHCs are discussed. In addition, an overview on asymmetric olefin metathesis promoted by chiral catalysts bearing C₂-symmetric and C₁-symmetric NHCs is provided.

Ruthenium olefin metathesis catalysts featuring unsymmetrical N-heterocyclic carbenes.

New ruthenium Grubbs' and Hoveyda-Grubbs' second generation catalysts bearing N-alkyl/N-isopropylphenyl N-heterocyclic carbene (NHC) ligands with syn or anti backbone configuration were obtained and compared in model olefin metathesis reactions. Different catalytic efficiencies were observed depending on the size of the N-alkyl group (methyl or cyclohexyl) and on the backbone configuration. The presence of an N-cyclohexyl substituent determined the most significant reactivity differences between catalysts with syn or anti phenyl groups on the backbone.

Stereolability of chiral ruthenium catalysts with frozen NHC ligand conformations investigated by dynamic-HPLC.

The stereolability of chiral Hoveyda-Grubbs II type ruthenium complexes bearing N-heterocyclic carbene (NHC) ligands with Syn-phenyl groups on the backbone and Syn- or Anti-oriented o-tolyl N-substituents was studied by resorting to dynamic high-performance liquid chromatography (D-HPLC). A complete chromatographic picture of the involved stereoisomers (four for Anti- and two for Syn-complexes) was achieved at very low temperatures (-53°C and -40°C respectively), at which the NHC-Ru bond rotations were frozen out. Inspection of the chromatographic profiles recorded at higher temperatures revealed the presence of plateau zones between the couples of either Syn or Anti stereoisomers, attesting to the active interconversion between the eluted species.

Study of the activity of Grubbs catalyst-functionalized multiwalled carbon nanotubes in the ring opening metathesis polymerization.

The synthesis of polynorbornene by ring opening metathesis polymerization (ROMP), in the presence of 1st and 2nd generation Grubbs catalyst-functionalized multiwalled carbon nanotubes (MWCNT), has been studied. MWCNTs were obtained by catalytic chemical vapour deposition (CCVD) of ethylene. A full characterization of the 1st and 2nd generation Grubbs catalyst-functionalized nanotubes was performed by FTIR and TG-DTG-MS.

The pivotal role of symmetry in the ruthenium-catalyzed ring-closing metathesis of olefins.

The synthesis of Ru-based precatalysts with N-heterocyclic carbene (NHC) ligands bearing syn- and anti-methyl groups on the NHC backbone and aryl N-substituents with differing steric bulk was carried out. The catalytic behavior of the monophospine Ru precatalysts (7a, 7b, 8a, and 8b) was compared to the corresponding family of phosphine-free catalysts (9a, 9b, 10a and 10b) in the ring-closing metathesis (RCM) of olefins. These catalysts showed high efficiency in RCM reactions and the syn-isomers 7a and 9a, in particular, proved to be among the most active catalysts in the formation of tetrasubstituted olefins through RCM.