Incarceration of Iodine in a Pyrene‐Based Metal–Organic Framework

Abstract

Ap yrene-based metal-organic framework (MOF) SION-8 captured iodine (I 2 )v apor with ac apacity of 460 and 250 mg g À1 MOF at room temperature and 75 8C, respectively.S ingle-crystal X-ray diffraction analysisa nd van-der-Waals-correctedd ensity functional theory calculations confirmed the presence of I 2 molecules within the pores of SION-8 and their interaction with the pyrene-based ligands.T he I 2 -pyrene interactions in the I 2 -loaded SION-8 led to a1 0 4 -fold increase of its electrical conductivity compared to the bare SION-8.U pon adsorption, ! 95 %o fI 2 molecules were incarcerated and could not be washed out, signifying the potentialofSION-8 towardst he permanent capture of radioactiveI 2 at room temperature.Radioactivei sotopes of iodine, mainly 129 Ia nd 131 I, are produced in nuclear-related processes and maya ccidentally be released into the atmosphere, as witnessed in Fukushima and Chernobyl,c onstituting am ajor hazard to humans and the environment. Isotope 131 Ih as ar adioactive decay half-life of about eight days, emits b À and g rays, and concentrates in the thyroid gland of the person exposed to the radioactive source causing thyroidc ancer.T he 129 Ii sotope has am uch longerl ife, with ah alf-lifeo f1 5.7 million years, and poses al ong-term disposalr isk. Capturing radioactive iodine is therefore necessary for safe nuclear wastes torage. [1] Wet scrubbing and the use of solid adsorbentsa re two general methodsf or iodine capture, with the latter being often preferred because it does not require the use of highly corrosive liquids. [1] The benchmark solid adsorbents for radioactive iodinec apture is thes ilver (Ag)-exchanged zeolitic mordenite, with an average I 2 -adsorption capacityo fa pproximately 100-130 mg g À1 mordernite at high temperatures (150-200 8C). [1, 2] In recenty ears, metal-organic frameworks (MOFs), which are crystalline materials formed by linkingm etal ions or metal clusters with multi-topic organic ligands, [3] have emergeda sp romising adsorbents for I 2 captured ue to their high porosity [4] and chemicaltunability. [5] For example, our group has previouslyreportedahigh I 2 vapor uptake by HKUST-1 and ZIF-8,a nd their composites with polymers, reaching 538 mg g À1HKUST-1 at 75 8C.[6] The Nenoff group and the Thallapally group have studied the adsorption of I 2 on HKUST-1a nd SBMOFs, respectively,i nt he presence of humidity. [7] However,t he degradation of these MOFs in water,a nd the leaching of I 2 from the I 2 -loaded MOFs when they are in contact with water and common organic solvents,g ive rise to considerable concerns regarding the potential of theseM OFs for I 2 capture. The I 2 leachingi st hought to be due to the weak interaction between the I 2 molecules with the pore surface of the MOF.Here, we report aM OF named SION-8,w hich is based on the employment of 1,3,6,8-tetrakis(p-benzoic acid)pyrene (H 4 TBAPy)a nd Ca II , [8] that can efficientlyc aptureI 2 vapor at both room temperature and at 75 8C. The strategy for I 2 capture is based on the well-know...

Pyrene-based metal organic frameworks: from synthesis to applications

“…MOFs can be designed for desired separation and capture processes by tuning the microporous channels and introducing functional groups. There are several pyrene-based MOFs in the literature that have been investigated for adsorption and separation owing to different reasons, such as (i) preferential binding sites on the carboxylates and aromatic rings on the linker, 90,195 (ii) permanent porosity and framework stability in the presence of water, 78 (iii) suitable pyrene-pyrene distance for the adsorption and separation of gas molecules, 57,77,85 (iv) the presence of rotatable units connected to pyrene ligand, resulting in enhanced loading of the guest molecules in the structure, 60 (v) donor-acceptor interaction between the adsorbate molecule and pyrene, 91 and (vi) the possibility of using functional groups within the MOF as structure-directing agents. 84 In this section, we will discuss pyrene-based MOFs that have been investigated for adsorption and separation of different molecules and Table 4 will be summarizing all the performances.…”

“…Pyrene-based MOFs have been studied for the capture of I 2 vapor based on the well-known donor-acceptor interaction between pyrene and I 2 . 223 Gładysiak et al 91 synthesized SION-8, which could adsorb I 2 vapor at room temperature by reaching 34 wt% (340 mg g MOF…”

Temperature-dependent interchromophoric interaction in a fluorescent pyrene-based metal–organic framework

“…In fact, efforts in investigating the interchromophoric interaction in pyrene-based organic and inorganic solid materials have been noticed 7. For the latter, recent focus is on pyrene-based metal–organic frameworks (MOFs) 8…”

Isomeric Scandium–Organic Frameworks with High Hydrolytic Stability and Selective Adsorption of Acetylene

“…The adsorption of iodine vapors by porous MOFs becomes an increasingly requisite topic of research. [55][56][57][58][59][60] The crystals of activated compounds 1 and 2 were exposed to iodine vapors at 100°C for 24 hours to ensure saturation of the samples with iodine. A change in their color from colorless to dark brown indicated the adsorption of iodine by samples (Fig.…”