Fluorescence Enhancement through Confined Oligomerization in Nanochannels: An Anthryl Oligomer in a Metal-Organic Framework

Abstract

Nanoconfinement offers opportunities to tune physical properties of molecular entities by altering their assembled structures. This also applies to acene-based molecules with potentially rich π–π interactions. Unlike most of the previous cases with acene-based guests directly incorporated into hosts, we take a further step by oligomerizing a fluorescent anthryl monomer, 9-vinylanthracene, inside nanochannels of a metal–organic framework, which is a pillared three-dimensional kagome net of [Zn2(bdc)2(dabco)] (bdc2– = 1,4-benzenedicarboxylate; dabco = 1,4-diazabicyclo[2.2.2]­octane). The fluorescence emission of the guest can be significantly enhanced after oligomerization, which is likely due to the suppressed nonemissive interaction between the oligomerized molecules in the nanospace and the MOF wall. The case we have demonstrated for fluorescence enhancement via confined oligomerization provides inspiration for the design of luminescent composites and is encouraging for further exploration of molecules in a nanoconfined space.

Hyper-Cross-Linked Resin Modified by a Micropore Polymer for Gas Adsorption and Separation

“…46 Wang used the 9-vinylanthracene as a monomer and polymerized it in a nanopore channel in an MOF adsorbent. 47 A new, smaller micropore of 0.8 nm was generated in the original 1.2 nm micropore. Similarly, Nipuni successfully loaded the polystrene into the micropore of the MOF-5 and finally increased the micropore volume at 1 nm.…”

“…In recent years, confined polymerization has been found to be a novel technique for changing the pore diameter and chemical property by a postmodification method. − Zhang has made macroporous silica a carrier while acrylic acid and allyl acetoacetate were used as monomers to prepare an ion-exchange resin (SiAcyl) which has a great palladium adsorption effect from electroplating wastewater . Wang used the 9-vinylanthracene as a monomer and polymerized it in a nanopore channel in an MOF adsorbent . A new, smaller micropore of 0.8 nm was generated in the original 1.2 nm micropore.…”

Tailoring Dye Emissions within Metal–Organic Frameworks for Tunable Luminescence and Ratiometric Temperature Sensing

“…Particularly, a small change in the polarity and shape of MOF nanochannels can result in a large shift in emission despite similar pore sizes. From a survey of the field, it is observed that excimers formation of various dyes, such as naphthalene, , anthracene (Ant), − pyrene, , and linkers, , within MOFs leads to progression in a number of fields, including modulation of emitting color and thermosensitive luminescence. Based on these findings, MOFs-confined dyes should be a good platform to explore the relationship between components and properties.…”