Chapter 3 Chemistry and Stereochemistry of Polymerization and Copolymerization Reactions with Transition Metal Catalysts

Ligand Decomposition during Nanoparticle Synthesis: Influence of Ligand Structure and Precursor Selection

“…The unsaturated (olefin) organic monomers used in these studies overlap with a wide library of ligands used in NP synthesis, including α-olefins, , amines, − , and carboxylic acids. ,− ,,− In addition to the use of ligands in these reactions, variables such as temperature and metal catalysts overlap with the temperatures and metal precursors ( e.g. , acetylacetonates) used to synthesize NPs …”

“…39,49−52,54,56−60 In addition to the use of ligands in these reactions, variables such as temperature and metal catalysts overlap with the temperatures and metal precursors (e.g., acetylacetonates) used to synthesize NPs. 42 Considering the aforementioned instances of ligand polymerization and graphitization both during and outside of NP synthesis, there is interest in decoupling variables (i.e., ligand functional group, ligand bond saturation, and nonmetal and metal precursor selection), which results in changes to the ligands' structure. As such, this work investigates how these variables lead to unintended ligand decomposition during NP synthesis.…”

“…, polymerization and graphitization) during NP synthesis is an emerging observation. Traditional polymerization of olefins is most commonly achieved through the use of Ziegler–Natta and metallocene catalysts and co-catalysts, − cationic reactions with acidic reagents, anionic reactions with nucleophilic reagents, − or radical reactions. , The decomposition of olefin monomers into cyclic moieties such as polycyclic aromatic hydrocarbons and nanographite can occur via Diel–Alder reactions, − intermolecular cyclization, and thermal cracking. − Additionally, pyrolysis ( i.e ., thermal decomposition) ,, and solvothermal treatments , of organic monomers have been used to synthesize carbon-based NPs or carbon dots. The unsaturated (olefin) organic monomers used in these studies overlap with a wide library of ligands used in NP synthesis, including α-olefins, , amines, − , and carboxylic acids. ,− ,,− In addition to the use of ligands in these reactions, variables such as temperature and metal catalysts overlap with the temperatures and metal precursors ( e.g.…”

Tailor-Made Thermoplastic Elastomeric Stereoblock Polypropylenes by Modulation of Monomer Pressure

“…24 The melting temperatures of the polymers increase with PD i in the order (A, P1) ≪ E3 < E1 < B (logarithmically for the solid polymers) corroborating the increase of the isotactic block size. 25 Interestingly, logarithmic dependence of T m on PD also can be derived from the data of Natta 26 for isotactic PP's 19 (see Supporting Information).…”

“…Polymerization at constant propylene pressure of 1 atm produces a blend of the oily, stereoirregular polymers A and D (P1), whereas polymerization at 10 atm yields after separation by fractional extraction a mixture of a stereoirregular and a largely isotactic fractions (polymers A and B), in accordance with the literature data. 12,13,16,17 Interestingly, the frequencies of the isotactic (mmmm) and syndiotactic (rrrr) pentads in the 13 C NMR spectrum of P1 are higher than the 6.25% expected for a nonstereoselective monomer insertion (Bernoullian distribution), and a noticeable shoulder at 20.97−20.99 ppm, assigned to the mmmrmr heptad, 18 hints the presence of considerable amounts of boundaries between isotactic and stereoirregular blocks 19 (Scheme 2).…”