Synthesis and crystal structure of 2-[(2,3,5,6-tetra-fluoro-pyridin-4-yl)amino]-ethyl methacrylate.

In the title compound, C11H10F4N2O2, the conformation about the N-C-C-O bond is gauche [torsion angle = 61.84 (13)°]. In the crystal, N-H⋯O hydrogen bonds link the mol-ecules into [010] chains, which are cross-linked by C-H⋯F and C-H⋯π contacts. Hirshfeld surface analysis was conducted to aid in the visualization of these various influences on the packing. This analysis showed that the largest contribution to the surface contacts arises from F⋯H/H⋯F inter-actions (35.6%), followed by O⋯H/H⋯O (17.8%) and H⋯H (12.7%).

Perfluoropyridine: Discovery, Chemistry, and Applications in Polymers and Material Science.

Perfluoropyridine (PFPy) is an organofluorine compound that has been employed for a variety of applications, from straightforward chemical synthesis to more advanced functions, such as fluorinated networks and polymers. This can be directly attributed to the highly reactive nature of PFPy, especially towards nucleophilic aromatic substitution (SNAr). The aim of this review is to highlight the discovery and synthesis of PFPy, discuss its reactive nature towards SNAr, and to summarize known reports of the utilization and thermal analysis of PFPy containing fluoropolymers and fluorinated network materials.

Recent Studies on Fluorinated Silica Nanometer-Sized Particles.

Since initially being reported, fluorinated silica nanometer-sized particles (F-SiNPs) have gained much interest in the scientific community, due to their unique properties. These properties, include, low surface energies, increased mechanical strength, thermal robustness, and chemical resistance, and are a direct result of the incorporation of fluorine with a nanometer-sized silica network. This review aims to summarize the synthetic methods that have, and are still, being utilized to prepare these specialized materials. Following this, applications for F-SiNPs, with an emphasis on recent examples, will be presented in further detail.

Synthesis of fluorinated silica nanoparticles containing latent reactive groups for post-synthetic modification and for tunable surface energy.

A new PFCP-based chlorosilane monomer containing a latent reactive fluorine atom was synthesized utilizing a hydrosilylation reaction. This monomer was used to functionalize Stöber silica nanoparticles, or network silicas, and the ability to tailor the properties of the functionalized nanoparticles was investigated by reacting the latent reactive fluorinated alkene with various nucleophiles. In order to model the chemical transformations occuring with the PFCP-functionalized particles, a new PFCP-containing molecular silica was prepared using a hydrosilylation reaction. The molecular silica was designed such that it contained a latent reactive fluorine atom and could also undergo post-synthetic modifications with various nucleophiles. The ability to modify the latent reactive group and tune the properties of the molecular and network silicas was verified by multi-nuclear NMR ((1)H, (13)C, (19)F, and (29)Si), thermal characterizations, and by investigating the hydrophobicity and surface morphology of spin-cast films prepared from the molecular and network silicas.

Enhanced Surface Properties of Branched Poly(ether sulfone) from Semifluorinated Polyhedral Oligomeric Silsequioxanes.

Hybrid systems in which poly(ether sulfone) (PESU) chains are grafted to semifluorinated polyhedral oligomeric silsesquioxane (POSS) cores are expected to integrate the advantages of both fluoropolymers and POSS into the polymer system to yield excellent surface properties. For that purpose, we synthesized a novel octa-functional perfluorocyclopentenyl-POSS (PFCP-POSS), which was used as a "core" grafting point. Commercial PESU was successfully grafted to PFCP-POSS via the nucleophilic addition-elimination reaction between the phenolic chain ends and reactive PFCP moieties to yield a hybrid branched polymer possessing a semifluorinated POSS core. X-ray photoelectron spectroscopy, neutron reflectivity, and atomic force microscopy indicated that the preparation of nanostructured polymer surfaces occurs by migration of the low surface energy components (PFCP-POSS molecules), while POSS aggregation is suppressed by covalent attachment to the long PESU chains. The resulting PFCP-POSS modified PESU films were highly transparent and yielded hydrophobic surfaces with low surface energy and high modulus for potential applications in high performance coatings and composites.

Multifunctional thiols from the highly selective reaction of mercaptoalcohols with chlorosilanes.

Multifunctional thiols were synthesized by the selective reaction of chlorosilanes with mercaptoalcohols. Reaction of the mercaptoalcohols through the thiol group was not observed. Utilizing this method, thiols of varying structural diversity were prepared.