Perfluorophenyl Azides: New Applications in Surface Functionalization and Nanomaterial Synthesis

Abstract

ConspectusA major challenge in materials science is the ongoing search for coupling agents that are readily synthesized, capable of versatile chemistry, able to easily functionalize materials and surfaces, and efficient in covalently linking organic and inorganic entities. A decade ago, we began a research program investigating perfluorophenylazides (PFPAs) as the coupling agents in surface functionalization and nanomaterial synthesis. The p-substituted PFPAs are attractive heterobifunctional coupling agents because of their two distinct and synthetically distinguishable reactive centers: (i) the fluorinated phenylazide, which is capable of forming stable covalent adducts, and (ii) the functional group R, which can be tailored through synthesis.Two approaches have been undertaken for material synthesis and surface functionalization. The first method involves synthesizing PFPA bearing the first molecule or material with a functional linker R, and then attaching the resulting PFPA to the second material by activating the azido group. In the second approach, the material surface is first functionalized with PFPA via functional center R, and coupling of the second molecule or material is achieved with the surface azido groups. In this Account, we review the design and protocols of the two approaches, providing examples in which PFPA derivatives were successfully used in material surface functionalization, ligand conjugation, and the synthesis of hybrid nanomaterials.The methods developed have proved to be general and versatile, and they are applicable to a wide range of materials (especially those that lack reactive functional groups or are difficult to derivatize) and to various substrates of polymers, oxides, carbon materials, and metal films. The coupling chemistry can be initiated by light, heat, and electrons. Patterned structures can be generated by selectively activating the areas of interest. Furthermore, the process is easy to perform, and light activation occurs in minutes, greatly facilitating the efficiency of the reaction. PFPAs indeed demonstrate many benefits as versatile surface coupling agents and offer opportunities for further exploration.

Highly accelerated inverse electron-demand cycloaddition of electron-deficient azides with aliphatic cyclooctynes

“…We are confident that the latter insight will provide solid ground for the design of yet faster strain-promoted cycloadditions. A practical convenience of the IED reactions reported herein furthermore lies in the fact that BCN and several of the aromatic azides are readily synthesized or commercially available, such as, for example, photoaffinity labelling reagents based on azidotetrafluorobenzoic acid 38 . It is clear that the reaction rate constants of the here presented accelerated IED SPAAC still lag far behind those involved with IED cycloadditions of tetrazines.…”

Flexible and twistable non-volatile memory cell array with all-organic one diode–one resistor architecture

“…Typically, multi-layer organic frameworks experience poor performance or device failure because of erosion during layer-by-layer processing. To avoid this erosion, Bis-FB-N 3 was used to crosslink the alkyl chains in P3HT thin films via light-catalysed N-H insertion reactions 25 . The Bis-FB-N 3 acts as a negative photoresistor responding to 254 nm ultraviolet light and allows patterning of common alkylated organic materials 23,25 .…”

“…To avoid this erosion, Bis-FB-N 3 was used to crosslink the alkyl chains in P3HT thin films via light-catalysed N-H insertion reactions 25 . The Bis-FB-N 3 acts as a negative photoresistor responding to 254 nm ultraviolet light and allows patterning of common alkylated organic materials 23,25 . Crosslinking with Bis-FB-N 3 imbues the organic layer with a robust resistance against common organic solvents used for spin coating.…”

“…The memory and diode devices were patterned using a photoactive crosslinker (bis-perfluorobenzoazide: Bis-FB-N 3 ) to covalently link the PS and P3HT side chains via nitrene-based N-H insertion reactions, which confers solvent resistance to the active layers 25 . Each individual memory and diode device in the integrated memory cell work without malfunction.…”

C₆₀-Fullerene Bonded Silica Monolithic Capillary for Specific Separations of Aromatic Compounds

“…On the other hand, perfluorophenyl azide (PFPA) has a suitable reactivity coupling with carbon materials under moderate conditions and a variety of papers regarding the reaction for PFPA toward carbon materials have been reported by Yan et al [32][33][34][35][36]. In this case, the immobilized carbon materials have no introduction of polar groups because the reaction is carried out between a nitrene and a C=C bond.…”