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The application of soft materials, including gels, in different material and biological chemistry domains has gained momentum in the past few years. Environmental remediation, drug resistance, and delivery are significant concerns that are being investigated widely nowadays. In this work, we report the multifunctionality of a gelator molecule A2 (5,5′-((6-(phenylamino)-1,3,5-triazine-2,4-diyl)-bis-(azanediyl))-diisophthalic acid) in the gel state. The gelator molecule A2 was used to fabricate organogel and two metallogels using copper perchlorate and a Ru-based anticancer drug molecule, respectively. The organogel and Cu-metallogel show efficient adsorption capabilities of iodine in the vapor and solution phases. These iodine-loaded gel composites were utilized as efficient antibacterial agents against Escherichia coli and Helicobacter pylori (I10) bacterial strains. Additionally, owing to the pH-responsive nature of the gel material, the Ru-based anticancer drug-loaded metallogel, Ru-A2, was fabricated, and its activity in pH-responsive drug delivery to the cancerous cells was also investigated. [ABSTRACT FROM AUTHOR]

With the rapid development of the nuclear industry, the effective treatment of radioactive iodine has become an urgent and challenging task. In this article, we synthesized a nanoporous nitrogen-rich covalent organic framework (TTA-DMTP-COF) with a specific surface area of up to 2332 m2/g for the adsorption of iodine (I2) and methyl iodide (CH3I). Adsorption experiments showed that TTA-DMTP-COF exhibited effective I2 and CH3I adsorption properties; the maximum adsorption capacity of I2 is as high as 2.59 g·g–1, and the maximum adsorption capacity of CH3I is 1.60 g·g–1. In addition, TTA-DMTP-COF can effectively adsorb iodine from an iodine–cyclohexane solution, and the adsorption amount is as high as 516.46 mg/g. Mechanistic studies have shown that I2 and CH3I enter the nanopores of COF materials and form charge transfer complexes with various functional groups in TTA-DMTP-COF (including imines, triazine moieties, and residual amino groups). The N-methylation reaction specifically binds CH3I to the nucleophilic N site and generates polyiodides during the adsorption process. Our work demonstrates that TTA-DMTP-COF is an excellent candidate material capable of capturing radioactive iodine from air and solution in harsh environments. [ABSTRACT FROM AUTHOR]

The development of high-performance adsorbents for environmental remediation is a current need, and ionic porous organic polymers (iPOPs), due to their high physicochemical stability, high surface area, added electrostatic interaction, and easy reusability, have already established themselves as a better adsorbent. However, research on the structural design of high-performance iPOP-based adsorbents is still nascent. This study explored the building blocks' role in optimizing the polymers' charge density and surface area to develop better polymeric adsorbents. Among the three synthesized polymers, iPOP-ZN1, owing to its high surface area and high charge density in its active sites, proved to be the best adsorbent for adsorbing inorganic and organic pollutants in an aqueous medium. The polymers were efficient enough to capture and store iodine vapor in the solid state. Further, this study tried to address using iodine-loaded polymers in antibacterial action. Iodine-loaded iPOPs show impressive antibacterial behavior against E. coli , B. subtilis , and H. pylori.

Iodate reduction by dissimilatory iodate-reducing microorganisms (DIRMs) plays a crucial role in the biogeochemical cycling of iodine on Earth. However, the occurrence and distribution of DIRMs in iodine-rich groundwater remain unclear. In this study, we isolated the dissimilatory iodate-reducing bacterium Azonexus hydrophilus strain NCP973 from a geogenic high-iodine groundwater of China for the first time. The analysis of genome, transcriptome, and heterologous expression revealed that strain NCP973 uses the dissimilatory iodate-reducing enzyme IdrABP1P2 to reduce dissolved or in situ sediment-bound iodate to iodide. The location of IdrABP1P2 in the conjugative plasmid of strain NCP973 implies that IdrABP1P2 could be spread by horizontal gene transfer and allow the recipient microorganisms to participate in the enrichment of iodide in aquifers. Based on the global iodine-rich groundwater metagenomes and genomes, the identification of idrA showed that phylogenetically diverse DIRMs are widely distributed not only in geogenic high-iodine groundwater of China but also in radionuclide-contaminated groundwater of USA as well as in subsurface cavern waters in Germany and Italy. Moreover, the abundance of idrA was found to be higher in groundwater with a relatively high iodine content. Collectively, these results suggest that terrestrial iodine-affected groundwater systems are another important habitat for DIRMs in addition to marine environments, and their activity in aquifers triggers the mobilization and enrichment of iodine in groundwater worldwide.

The fight against pathogenic bacteria and viruses represents a challenging task requiring the development of innovative materials. The design of water-responsive disinfecting surfaces constitutes a pertinent endeavor to limit the spread of infectious pathogens that strive in wet environments and are often carried by the droplets or aerosols of biological fluids. In this context, we designed a polymeric nanostructured membrane which, when in contact with water, was able to release elemental iodine, a potent antimicrobial agent. The membrane was based on poly-(vinylidene fluoride-co-hexafluoropropylene) electrospun nanofibers containing nanoparticles of an archetypal metal–organic framework (MOF), UiO-66. The gas adsorption capacity of the MOF container was preserved upon incorporation into the polymeric nanofibers, which also exerted a protective effect against the fast structural collapse of UiO-66 in phosphate-buffered saline, a model for biological fluids. The membrane loaded high amounts of iodine via gas diffusion and its release was (mostly) triggered by contact with the aqueous medium. The antibacterial activity of the membrane was tested against the Escherichia coli strain DH5α and revealed prompt and robust disinfecting properties. The membrane also efficiently inhibited the infectivity of viral model vesicular stomatitis virus glycoprotein pseudotyped HIV-1 particles in HEK-293 cells in a short time. The observed synergistic effects between the MOF container and the polymeric support material constitute attractive features for the development of MOF-based materials for biological applications. [ABSTRACT FROM AUTHOR]

The biogeochemical processes of iodine are typically coupled with organic matter (OM) and the dynamic transformation of iron (Fe) minerals in aquifer systems, which are further regulated by the association of OM with Fe minerals. However, the roles of OM in the mobility of iodine on Fe-OM associations remain poorly understood. Based on batch adsorption experiments and subsequent solid-phase characterization, we delved into the immobilization and transformation of iodate and iodide on Fe-OM associations with different C/Fe ratios under anaerobic conditions. The results indicated that the Fe-OM associations with a higher C/Fe ratio (=1) exhibited greater capacity for immobilizing iodine (∼60-80% for iodate), which was attributed to the higher affinity of iodine to OM and the significantly decreased extent of Fe(II)-catalyzed transformation caused by associated OM. The organic compounds abundant in oxygen with high unsaturation were more preferentially associated with ferrihydrite than those with poor oxygen and low unsaturation; thus, the associated OM was capable of binding with 28.1-45.4% of reactive iodine. At comparable C/Fe ratios, the mobilization of iodine and aromatic organic compounds was more susceptible in the adsorption complexes compared to the coprecipitates. These new findings contribute to a deeper understanding of iodine cycling that is controlled by Fe-OM associations in anaerobic environments.

The spread of upper respiratory tract (URT) infections harms people's health and causes social burdens. Developing targeted treatment strategies for URT infections that exhibit good biocompatibility, stability, and strong antimicrobial effects remains challenging. The dual antimicrobial and antiviral effects of iodine (I 2 ) in combination with the cooling sensation of l-menthol in the respiratory tract can simultaneously alleviate URT inflammation symptoms. However, as both I 2 and l-menthol are volatile, addressing stability issues is crucial. In this study, a potassium iodide β-cyclodextrin metal-organic framework [β-CD-POF(I)] with appropriate particle size was used to coload and deliver I 2 and l-menthol. Primarily, β-CD-POF(I) was employed as the most efficient carrier to significantly enhance the stability of I 2 , surpassing any other known protection strategies in the pharmaceutical field (CD complexations, PVP conjugations, and cadexomer iodine). The mechanism underlying the improvement in stability of I 2 by β-CD-POF(I) was investigated through scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and molecular docking. The results revealed that the key processes involved in improving stability were the inclusion of I 2 by β-CD cavities in β-CD-POF(I) and the formation of polyiodide anion between iodine ions and I 2 . Furthermore, the potential of β-CD-POF(I) to load and deliver drugs was validated, and coloading of l-menthol and I 2 demonstrated reliable stability. β-CD-POF(I) achieved a rate of URT deposition ≥95% in vitro, and the combined antibacterial effects of coloaded I 2 and l-menthol was better than I 2 or PVP-I alone, with no irritation noted following URT administration in rabbits. Therefore, the stable coloading of drugs by β-CD-POF(I), leading to enhanced antimicrobial effects, provides a new strategy for treating URT infections.

Organoiodine compounds (OICs) are the dominant iodine species in groundwater systems. However, molecular mechanisms underlying the geochemical formation of geogenic OICs-contaminated groundwater remain unclear. Based upon multitarget field monitoring in combination with ultrahigh-resolution molecular characterization of organic components for alluvial-lacustrine aquifers, we identified a total of 939 OICs in groundwater under reducing and circumneutral pH conditions. In comparison to those in water-soluble organic matter (WSOM) in sediments, the OICs in dissolved organic matter (DOM) in groundwater typically contain fewer polycyclic aromatics and polyphenol compounds but more highly unsaturated compounds. Consequently, there were two major sources of geogenic OICs in groundwater: the migration of the OICs from aquifer sediments and abiotic reduction of iodate coupled with DOM iodination under reducing conditions. DOM iodination occurs primarily through the incorporation of reactive iodine that is generated by iodate reduction into highly unsaturated compounds, preferably containing hydrophilic functional groups as binding sites. It leads to elevation of the concentration of the OICs up to 183 μg/L in groundwater. This research provides new insights into the constraints of DOM molecular composition on the mobilization and enrichment of OICs in alluvial-lacustrine aquifers and thus improves our understanding of the genesis of geogenic iodine-contaminated groundwater systems.

Magnesium iodide (MgI 2 ) solid-electrolyte interface (SEI) layers have previously been shown to protect Mg metal anodes from passivation through products formed during Mg(TFSI) 2 electrolyte decomposition (TSFI = trifluorosulfonimide). MgI 2 formed in situ from small quantities of I 2 added to the electrolyte shows a drastic decrease in the overpotential for magnesium deposition and stripping. In this work, a MgI 2 SEI layer was created in an ex situ fashion and then the electrochemical characteristics of this MgI 2 SEI layer were probed both alone and with small quantities of I 2 or Bu 4 NI 3 additives to identify the electroactive species. Chronopotentiometry (CP) and cyclic voltammetry (CV) show that the MgI 2 SEI alone is insufficient for low overpotential magnesium cycling. I(3d) XPS data show that I 3 - is formed within the SEI layer, which can serve as the electroactive species when ligated with Mg 2+ for low overpotential (<50 mV at 0.1 mA cm -2 current density) cycling. Moreover, Raman shifts at 110 and 140 cm -1 are consistent with I 3 - formation, and these signatures are observed before and after CP experiments. The Mg 0 deposition curves in the CV with additives are consistent with diffusive species. Finally, electrochemical impedance spectroscopy (EIS) shows that there is a large decrease in the charge-transfer resistance within the SEI when either I 2 or Bu 4 NI 3 additives are used, which supports a solvating effect that facilitates magnesium deposition and stripping.

The combination of photodynamic therapy and radiotherapy has given rise to a modality called radiodynamic therapy (RDT), based on reactive oxygen species-producing radiosensitizers. The production of singlet oxygen, O 2 ( 1 Δ g ), by octahedral molybdenum (Mo 6 ) clusters upon X-ray irradiation allows for simplification of the architecture of radiosensitizing systems. In this context, we prepared a radiosensitizing system using copper-free click chemistry between a Mo 6 cluster bearing azido ligands and the homo-bifunctional linker bis-dPEG 11 -DBCO. The resulting compound formed nanoparticles, which featured production of O 2 ( 1 Δ g ) and efficient cellular uptake, leading to remarkable photo- and radiotoxic effects against the prostatic adenocarcinoma TRAMP-C2 cell line. Spheroids of TRAMP-C2 cells were also used for evaluation of toxicity and phototoxicity. In vivo experiments on a mouse model demonstrated that subcutaneous injection of the nanoparticles is a safe administration mode at a dose of up to 0.08 g kg -1 . The reported results confirm the relevancy of Mo 6 -based radiosensitizing nanosystems for RDT.

Ions containing iodine atoms at the vapor-aqueous solution interfaces critically affect aerosol growth and atmospheric chemistry due to their complex chemical nature and multivalency. While the surface propensity of iodide ions has been intensely discussed in the context of the Hofmeister series, the stability of various ions containing iodine atoms at the vapor-water interface has been debated. Here, we combine surface-specific sum-frequency generation (SFG) vibrational spectroscopy with ab initio molecular dynamics simulations to examine the extent to which iodide ions cover the aqueous surface. The SFG probe of the free O-D stretch mode of heavy water indicates that the free O-D group density decreases drastically at the interface when the bulk NaI concentration exceeds ∼2 M. The decrease in the free O-D group density is attributed to the spontaneous appearance of triiodide that covers the topmost interface rather than to the surface adsorption of iodide. This finding demonstrates that iodide is not surface-active, yet the highly surface-active triiodide is generated spontaneously at the water-air interface, even under dark and oxygen-free conditions. Our study provides an important first step toward clarifying iodine chemistry and pathways for aerosol formation.

Meeting the diverse requirements of effective wound repair while surpassing the single-function limitations of traditional wound dressings is a significant challenge. In this study, we successfully synthesized an inclusion complex of 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and iodine using the saturated aqueous solution method. Additionally, dialdehyde cellulose (DAC) was extracted from fat-free cotton through oxidation. To enhance wound healing, l-glutamine (l-glu) was utilized as a functional molecule, resulting in composite hydrogels with hemostatic, sterilizing, and wound-healing-promoting properties that were achieved by adsorbing the resulting inclusion complex. Through TG and SEM analysis, we confirmed that iodine was effectively accommodated by cyclodextrin and was uniformly attached to the hydrogel. The hydrogel exhibits exceptional long-term moisturizing and bactericidal properties, while also demonstrating excellent swelling, oxygen permeability, hemolytic, and mechanical properties, fully satisfying the requirements of wound treatment. External coagulation tests revealed that the hydrogel can rapidly coagulate 4.5 times its own weight of blood. Moreover, in a full-thickness scald mouse model, the hydrogel effectively promotes wound healing. The development of this multifunctional composite hydrogel presents a novel approach to advance wound dressing research, holding substantial potential for practical applications.

Iodine is a crucial nutrient for public health, and its presence in the terrestrial atmosphere is a key factor in determining the prevalence of iodine deficiency disorders. While oceanic iodine emissions decrease at lower sea surface temperatures, the primary contributors to atmospheric iodine can vary from oceanic sources in the summer to other sources in winter. However, the specific sources and their respective contributions have remained unexplored. Fortunately, the atomic ratio of 129 I to 127 I significantly differs between nuclear activity and fossil fuels like coal and petroleum, which formed millions to billions of years ago. This distinction makes 129 I a valuable tool for identifying iodine sources. In our study, we analyzed iodine isotopes and incorporated additional indicators such as element content in PM 2.5 samples. Our findings reveal, for the first time, that in winter inland areas, fuel oil, alongside coal combustion, is a significant source of atmospheric iodine. This research enhances our comprehension of the impact of human activities on iodine levels in the environment. This understanding is crucial not only for addressing iodine deficiency-related health concerns but also for comprehending stratospheric ozone depletion, a phenomenon closely associated with atmospheric iodine.

Iodate (IO 3 - ) can be abiotically reduced by Fe(II) or biotically reduced by the dissimilatory Fe(III)-reducing bacterium Shewanella oneidensis (MR-1) via its DmsEFAB and MtrCAB. However, the intermediates and stoichiometry between the Fe(II) and IO 3 - reaction and the relative contribution of abiotic and biotic IO 3 - reduction by biogenic Fe(II) and MR-1 in the presence of Fe(III) remain unclear. In this study, we found that abiotic reduction of IO 3 - by Fe(II) produced intermediates HIO and I - at a ratio of 1:2, followed by HIO disproportionation to I - and IO 3 - . Comparative analyses of IO 3 reduction by MR-1 under Fe-rich and Fe-limited conditions suggests that Fe(III)-reducing bacteria could contribute to the transformation of iodine species and I - enrichment in natural iodine-rich environments.Shewanella sp. ANA-3 in the presence of Fe(III)-citrate, Fe(III) oxides, or clay minerals showed that abiotic IO 3 - reduction by biogenic Fe(II) predominated under iron-rich conditions, while biotic IO 3 - reduction by DmsEFAB played a more dominant role under iron-poor conditions. Compared to that in the presence of Fe(III)-citrate, MR-1 WT reduced more IO 3 - in the presence of Fe(III) oxides and clay minerals. The observed abiotic and biotic IO 3 - reduction by MR-1 under Fe-rich and Fe-limited conditions suggests that Fe(III)-reducing bacteria could contribute to the transformation of iodine species and I - enrichment in natural iodine-rich environments.

Bromine and iodine species are precursors for forming disinfection byproducts in finished drinking waters. Our study incorporates spatial and temporal data to quantify concentrations of inorganic (bromide (Br - ), iodide (I - ), and iodate (IO 3 - ) and iodine (I T ) and iodine (I T ) species from 286 drinking water sources and 7 wastewater effluents across the United States. Br - ranged from <5-7800 μg/L (median of 62 μg/L in surface water (SW) and 95 μg/L in groundwater (GW)). I - was detected in 41% of SW (1-72 μg/L, median = <1 μg/L) and 62% of GW (<1-250 μg/L, median = 3 μg/L) samples. The median Br - /I - ratio in SW and GW was 22 μg/μg and 16 μg/μg, respectively, in paired samples with detect Br - and I - . Br T existed primarily as Br - , while I T was present as I - , and/or total organic iodine (TOI). Inorganic iodine species (I 3 - , and/or total organic iodine (TOI). Inorganic iodine species (I - and IO 3 - ) were predominant in GW samples, accounting for 60-100% of I T ; however, they contributed to only 20-50% of I T in SW samples. The unknown fraction of I T was attributed to TOI. In lakes, seasonal cycling of I-species was observed and was presumably due to algal productivity. Finally, Spearman Rank Correlation tests revealed a strong correlation between Br - and I T in SW ( R Br - ,IT = 0.83) following the log 10 (Br - , μg/L) = 0.65 × log 10 (I T , μg/L) - 0.17 relationship. Br - and I - in treated wastewater effluents (median Br - = 234 μg/L, median I - = 5 μg/L) were higher than drinking water sources.

The development of low-cost and high-efficiency iodine sorbents is of great significance for the control of nuclear pollution. In this work, we intercalate the tin sulfide cluster of [Sn 2 S 6 ] 4- to Mg/Al-type layered double hydroxides to obtain Sn 2 S 6 -LDH, which exhibits highly efficient capture performance of iodine vapor and iodine in solutions. The dispersion effect of the positively charged LDH layers contributes to the adequate exposure of [Sn 2 S 6 ] 4- anions, providing plentiful adsorption sites. For iodine vapor, Sn 2 S 6 -LDH showed an extremely large iodine capture capacity of 2954 mg/g with a large contribution from physisorption. For iodine in solutions, a significantly large sorption capacity of 1308 mg/g was achieved. During iodine capture, I 2 molecules were reduced to I - ions (by S 2- in [Sn 2 S 6 ] 4- ), which then reacted with Sn 4+ to form SnI 4 , where the molar amount of captured iodine is 4-fold that of Sn. Besides, the as-reduced I - combined with I 2 again to generate [I 3 ] - , which then entered the LDH interlayers to maintain electric neutrality. While reducing iodine, S 2- itself in [Sn 2 S 6 ] 4- was oxidized to S 8 , which further combined with SnI 4 to form a novel compound of SnI 4 (S 8 ) 2 . The excellent iodine capture capability endows Sn 2 S 6 -LDH with a promising application in trapping radioactive iodine.

Radiotherapy is inevitably accompanied by some degree of radiation resistance, which leads to local recurrence and even therapeutic failure. To overcome this limitation, herein, we report the room-temperature synthesis of an iodine- and ferrocene-loaded covalent organic framework (COF) nanozyme, termed TADI-COF-Fc , for the enhancement of radiotherapeutic efficacy in the treatment of radioresistant esophageal cancer. The iodine atoms on the COF framework not only exerted a direct effect on radiotherapy, increasing its efficacy by increasing X-ray absorption, but also promoted the radiolysis of water, which increased the production of reactive oxygen species (ROS). In addition, the ferrocene surface decoration disrupted redox homeostasis by increasing the levels of hydroxyl and lipid peroxide radicals and depleting intracellular antioxidants. Both in vitro and in vivo experiments substantiated the excellent radiotherapeutic response of TADI-COF-Fc . This study demonstrates the potential of COF-based multinanozymes as radiosensitizers and suggests a possible treatment integration strategy for combination oncotherapy.

We present experimental evidence that atomic and molecular iodine, I and I 2 , are produced spontaneously in the dark at the air-water interface of iodide-containing droplets without any added catalysts, oxidants, or irradiation. Specifically, we observe I 3 - emission into the gas phase from NaI-containing droplets over a range of droplet sizes. The formation of both products is enhanced in the presence of electron scavengers, either in the gas phase or in solution, and it clearly follows a Langmuir-Hinshelwood mechanism, suggesting an interfacial process. These observations are consistent with iodide oxidation at the interface, possibly initiated by the strong intrinsic electric field present there, followed by well-known solution-phase reactions of the iodine atom. This interfacial chemistry could be important in many contexts, including atmospheric aerosols.2 emission into the gas phase from NaI-containing droplets over a range of droplet sizes. The formation of both products is enhanced in the presence of electron scavengers, either in the gas phase or in solution, and it clearly follows a Langmuir-Hinshelwood mechanism, suggesting an interfacial process. These observations are consistent with iodide oxidation at the interface, possibly initiated by the strong intrinsic electric field present there, followed by well-known solution-phase reactions of the iodine atom. This interfacial chemistry could be important in many contexts, including atmospheric aerosols.

Iodine is an essential element that is used to make thyroid hormones. However, people usually ignore their iodine nutrition level, thus leading to a series of thyroid diseases, particularly in areas where medical resources are scarce. Thus, development of a portable, economical, and simple method for the detection of urinary iodine is of significant importance. Herein, a solid-phase fluorescence filter effect (SPFFE) induced by iodine was used to develop an SPFFE-based point-of-care testing (POCT) platform for the detection of urinary iodine by coupling with headspace sample introduction. This method can not only alleviate the matrix interference that occurred in the conventional inner filter effect (IFE) but also achieve high sensitivity. Furthermore, the urinary iodine (UI) POCT platform was developed through the integration of a sample pretreatment and fluorescence readout. This whole system costs less than US $20 and provides accurate temperature control and a portable fluorescence reading within 15-20 min. Compared to the traditional IFE-based assay, the SPFFE-based POCT platform allows the selective detection of iodine as low as 10 nM and has a linear range of 0.05-4 μM. In addition, it provides notable visualization from blue-violet to orange-red in the presence of iodine, which tends to indicate the iodine nutritional status of the human body. Eventually, the clinical applicability and feasibility of the UIPOCT platform as an early diagnostic test kit were confirmed by determining the iodine in urine samples from children and pregnant women.

Ultraviolet photodissociation or UVPD is an increasingly popular option for tandem-mass spectrometry experiments. UVPD can be carried out at many wavelengths, and it is important to understand how the results will be impacted by this choice. Here, we explore the utility of 213 nm photons for initiating bond-selective fragmentation. It is found that bonds previously determined to be labile at 266 nm, including carbon-iodine and sulfur-sulfur bonds, can also be cleaved with high selectivity at 213 nm. In addition, many carbon-sulfur bonds that are not subject to direct dissociation at 266 nm can be selectively fragmented at 213 nm. This capability can be used to site-specifically create alaninyl radicals that direct backbone dissociation at the radical site, creating diagnostic d-ions. Furthermore, the additional carbon-sulfur bond fragmentation capability leads to signature triplets for fragmentation of disulfide bonds. Absorption of amide bonds can enhance dissociation of nearby labile carbon-sulfur bonds and can be used for stochastic backbone fragmentation typical of UVPD experiments at shorter wavelengths. Several potential applications of the bond-selective fragmentation chemistry observed at 213 nm are discussed.ᅟ [ABSTRACT FROM AUTHOR]

The quest for the development of new protocols that provide general conditions for oxidative carbon-nitrogen bond formation has grown over recent years. Within this context, due to feasibility and benignity considerations in biochemical sciences, reactions that rely on main group oxidants as the only promoters have received particular interest. We have recently found that simple protonolysis events enable the incorporation of nitrogenated groups of the bissulfonimide family into the coordination sphere of common iodine(III) complexes such as diacetoxy iodobenzene. The products of the type ArI(OAc)(NTs2) represent rare examples of iodine(III) compounds displaying reactive iodine-nitrogen single bonds. Further protonolysis furnishes the corresponding iodine(III) compounds ArI(NTs2)2 containing two defined iodine-nitrogen single bonds for unprecedented dual transfer of both nitrogenated groups. It is of great synthetic importance that these new compounds contain iodine-nitrogen entities, which upon dissociation in solution lead to electrophilic iodine centers and nucleophilic nitrogen groups. This has enabled the development of a body of conceptually new amination reactions, which do not rely on conventional electrophilic nitrogen reagents but rather employ iodine(III) as an electrophilic activator and bissulfonimides as the source of subsequent nucleophilic amination. Additional diversification arises from the ambident nature of bissulfonimines enabling oxygenation pathways. The exciting chemistry covered in this Account comprises structural features of the reagents (including X-ray analysis), scope and limitation in synthetic amination of different hydrocarbons (including sp-, sp2-, and sp3-hybridized centers as in acetylenes, alkenes, enols, butadienes, allenes, arenes, and alkylketones), and physical-organic and theoretical analysis of the underlying reaction mechanisms. The oxidative transformations with all their rich diversifications originate from the versatile redox chemistry of the iodine(III) and iodine(I) pair, which shares several aspects of transition metal high oxidation state chemistry. For the present aryliodine(III) reagents, steric and electronic fine-tuning is possible through accurate engineering of the arene substituent. In addition to the general reactivity of the I-N bond, chiral aryliodine(III) reagents with defined stereochemical information in the aryl backbone are conceptually compatible with this approach. Thus, the development of enantioselective amination reactions with up to 99% ee was also successful. Several of the active enantioselective reagents have been isolated and structurally characterized. Following this approach for the important class of chiral vicinal diamines, an unprecedented direct diamination of alkenes could be conducted in an enantioselective catalytic manner under full intermolecular reaction control. This latter reaction is based on the precise engineering of a chiral aryliodine(III) catalyst in combination with bismesylimide as nitrogen source. It is the consequence of the precise understanding of the reaction behavior of structurally defined bisimidoiodine(III) reagents. [ABSTRACT FROM AUTHOR]

Here we present a study where what can be seen as a static modulation wave encompassing four successive arrays of interacting iodine atoms in crystalline 1,4-Bis((4′-(iodoethynyl)phenyl) ethynyl)bicyclo[2,2,2]octane rotors changes the structure from one-half molecule to three-and-a-half molecules in the asymmetric unit below a phase transition at 105 K. The remarkable finding is that the total 1H spin-lattice relaxation rate, T1-1, of unprecedented complexity to date in molecular rotors, is the weighted sum of the relaxation rates of the four contributing rotors relaxation rates, each with distinguishable exchange frequencies reflecting Arrhenius parameters with different activation barriers (Ea) and attempt frequencies (τo-1). This allows us to show in tandem with rotor-environment interaction energy calculations how the dynamics of molecular rotors are able to decode structural information from their surroundings with remarkable nanoscale precision. [ABSTRACT FROM AUTHOR]

The iodine–sulfur (IS) process is one of the most promising thermochemical water-splitting processes for nuclear hydrogen production. The Bunsen reaction, which produces sulfuric and hydriodic acids for two decomposition reactions, plays a crucial role in the IS process. Insufficient kinetics data and models of the Bunsen reaction have caused difficulties for designing a Bunsen reactor and optimizing and improving the efficiency of the process. The mass transfer and kinetics mechanism of the Bunsen reaction, which is a complicated gas–liquid slurry process, were first analyzed and proposed on the basis of double-film theory and thermodynamics calculation, and intrinsic reaction rate equation models were deduced with different hypothesized reaction mechanisms. Then, the models were further improved, and the experimental kinetics data were used to verify the models. Finally, a set of reaction rate equations was developed, thereby confirming its reliability for calculating the reaction kinetics data. The built models for mass transfer and reaction kinetics provide crucial information for the thorough understanding of the Bunsen reaction mechanism, selecting the reactor type, and designing the Bunsen reactor. [ABSTRACT FROM AUTHOR]

Multifunctional chemical analysis (MCA) systems provide a viable alternative for large scale instruction while supporting a hands-on approach to more advanced instrumentation. These systems are robust and typically use student stations connected to a remote central computer for data collection, minimizing the need for computers at every student workspace. MCA networks offer multiple measurement capabilities; however, constant-current coulometry is still an uncommon MCA option. The characterization of an assembled teaching coulometry instrument for online data acquisition using an MCA system is described. A constant-current source connected to nonisolated Pt electrodes in a 150 mL beaker serving as the reaction cell caused the iodine titrant to be electrochemically generated for subsequent reaction with the analyte reducing agent. A photoresistor mounted on the stir plate below the beaker monitored the darkening of the solution due to formation of the starch-iodine complex. The change in voltage from an operational amplifier circuit permitted this titration curve to be stored by the MCA system for subsequent graphical analysis by Excel. Characterization of the instrument for direct analyte determination is performed with ascorbic acid, thiols, thiosulfate, and bisulfite. The number of electrons per mole of thiol for iodine titration of glutathione and N-acetylcysteine varied differently as a function of pH, indicating different reaction pathways. Ascorbic acid and the thiols are determined in dietary supplements with a recovery of 90-100%, and % RSDs of triplicate measurements ranged from 0.7% to 5%. [ABSTRACT FROM AUTHOR]

Aryl thiols can be selectively converted to sulfonimidates or sulfonamides with three new S-X connections being made selectively in one pot. Using hypervalent iodine reagents in the presence of ammonium carbamate, NH- and O-groups are transferred under mild and practical conditions. Reducing the loading of ammonium carbamate changed the product distribution, converting the sulfonimidate to the sulfonamide. Studies into the possible intermediate species are presented, suggesting that multiple pathways may be possible via sulfinate esters, or related intermediates, with each species forming the same products. [ABSTRACT FROM AUTHOR]

A hypervalent iodine(III) reagent mediated oxidative skeletal rearrangement reaction of secondary amines is reported. The transformation, which uses PhI(OAc)2 in CF3CH2OH, was found to be highly efficient at inducing the direct 1,2-C-to-N migration of secondary amines. This method offers facile and divergent access to polycyclic and macrocyclic indole-fused compounds. The synthetic potential of the method is also demonstrated through its application to several substrates, including secondary as well as primary amines. [ABSTRACT FROM AUTHOR]

This letter describes an iron-catalyzed C(sp³)-H acyloxylation of aryl-2H azirines with hypervalent iodine(III) reagents (HIRs) serving as both an oxidant and a reagent. This methodology provides a rapid access to a wide range of monoacyloxylated 3-aryl-2H-azirines in moderate to good yields. [ABSTRACT FROM AUTHOR]

Highly correlated ab initio calculations have been performed to describe the potential energy curves (PECs) and the spectroscopic properties of the X2Π state and of the first excited state of the CI radical. Multi Reference configuration interaction calculations with Davidson correction (MRCI+Q) and relativistic effective core potential for the iodine atom have been performed. It is found that the two lowest electronic states, the X2Π and the a4Σ- states, are stable against dissociation and well separated from the other electronic states. Spectroscopic constants of these two states have been evaluated using their calculated PECs. Because of the presence of the iodine atom in this molecular system, spin-orbit (SO) interactions are playing an important role in the molecular and in the dissociation regions. The excitation energy of the a4Σ- state is calculated 1.67 eV (MRCI) above the X2Π ground state and 1.70/1.62 eV (MRCI with SO correction) for the Ω = 1/2 and 3/2 transitions, respectively. The dissociation energy D0 of the X2Π ground state is evaluated 2.66 eV (MRCI calculation) without SO correction and 2.46/2.36 eV with SO correction for the Ω = 1/2 and 3/2 components, respectively. The dissociation energy D0 of the a4Σ- state is evaluated 0.99 eV (MRCI calculation) without SO correction and 0.83/0.72 eV with SO correction for the Ω = 1/2 and 3/2 components, respectively. This work should help for the identification of this radical in laboratory and in atmospheric media. [ABSTRACT FROM AUTHOR]

We have re-evaluated the X40×10 benchmark for halogen bonding using conventional and explicitly correlated coupled cluster methods. For the aromatic dimers at small separation, improved CCSD(T)-MP2 “high-level corrections” (HLCs) cause substantial reductions in the dissociation energy. For the bromine and iodine species, (n–1)d subvalence correlation increases dissociation energies and turns out to be more important for noncovalent interactions than is generally realized; (n–1)sp subvalence correlation is much less important. The (n–1)d subvalence term is dominated by core–valence correlation; with the smaller cc-pVDZ-F12-PP and cc-pVTZ-F12-PP basis sets, basis set convergence for the core–core contribution becomes sufficiently erratic that it may compromise results overall. The two factors conspire to generate discrepancies of up to 0.9 kcal/mol (0.16 kcal/mol RMS) between the original X40×10 data and the present revision. [ABSTRACT FROM AUTHOR]

Treatment of cobaloximes(II), [Co(Hdmg)2(L)2] (Hdmg = dimethylglyoximate, L = neutral ligand), with perfluoroalkyl iodane reagents leads to the formation of perfluoroalkyl cobaloximes(III), [CoRF(Hdmg)2(L)] (RF = CF3, C2F5, n-C3F7, CF2CF2Ph; L = Py, NH3, MeNH2, PhNH2, MeOH). The synthetic protocol can be significantly simplified to a one-pot procedure starting from cobalt(II) acetate-tetrahydrate. The products have been fully characterized by NMR, IR, and UV/vis spectroscopy as well as single-crystal X-ray diffraction, and the thermal and photochemical reactivity has been studied. According to the Co-L distances in the crystal, the trans influence of the RF- ligands can be rated as C2F5- ≈ n-C3F7- < CF2CF2Ph- ≈ CF3- < CH3-. The thermal decomposition of the complexes is different from that of nonfluorinated analogues, probably including perfluoroalkylation of an Hdmg-ligand as the initial step. In the CF3 complexes, the Co-C bond is very resistant against photolysis, but the ligand L is readily exchanged by MeOH upon exposure to blue light. In the complexes with longer RF chains, the Co-C bond is more readily cleaved, and the product distribution depends strongly on the presence of O2. Thus, the alkane RFH is the main product under exclusion of O2, while a fluorinated methyl ester and HF are formed in a methanol solution exposed to air. [ABSTRACT FROM AUTHOR]

Cocrystallization of diiodine with a series of heteroaromatic N-oxides produced three types of halogen-bonded associates: (a) alternating chains comprising I2 molecules bridged by oxygen atoms of N-oxides of pyridine, quinoline, or 4-methylpyridine; (b) discrete 2:1 complexes, in which diiodine links a pair of acridine N-oxide molecules; and (c) amphoteric 1:1 adducts, in which one end of each diiodine molecule is halogen-bonded to N-oxide of 4-methoxypyridine or 4-chloroquinoline, and another diiodine’s end forms contacts with the other I2 molecules. In all cases, halogen bonds between diiodine and N-oxides are characterized by nearly linear I–I···O angles, close to perpendicular dihedral C–N–O···I angles and N–O···I angles of about 110°. The halogen bond length in the 1:1 adducts is about 0.3 Å shorter than those in the 2:1 associates and in the infinite chains. Computational analyses confirmed that the variations in I···O separations are related predominantly to the distinct effects of halogen bond competition in different supramolecular associates. Experimental and computational data also indicated that coordination of the second diiodine to the same oxygen atom of N-oxide has a smaller effect on the halogen bond length and energy than coordination of the second N-oxide to another iodine atom in the I2 molecule. [ABSTRACT FROM AUTHOR]

We have investigated the iodine retention behavior of silver zeolite sorbents under a variety of conditions. First, a preliminary study was achieved for the liquid phase in order to determine (i) the main kinetic and thermodynamic characteristics pertaining to the adsorption behavior and (ii) the influence of some zeolitic parameters (nature of the framework, silver content, preparation method, etc.) on the adsorption capacities. Thanks to the online monitoring of gas-phase I2 concentrations by UV-vis spectroscopy, the iodine dynamic adsorption/desorption behavior of some selected sorbents was then studied at 100 °C. It was found that faujasite sorbents with silver content higher than 20 wt % could maintain a high working capacity (up to 330 mg/g) and present a high ability for irreversible trapping. Finally, the stability of trapped iodine species was evidenced using additional tests performed at 120 °C in the presence of irradiation and humidity. [ABSTRACT FROM AUTHOR]

The Briggs-Rauscher reaction containing malonic acid may undergo a sudden transition from low (state I) to high iodide and iodine (state II) concentration states after a well-defined and strongly reproducible oscillatory period. This study clearly shows that even though the time-dependent behavior of the oscillatory state is reproducible, the time lag necessary for the appearance of the state I to state II transition after the system leaves the oscillatory state becomes irreproducible for an individual kinetic run. This crazy clock behavior of the state I to state II transition is identified by repeated experiments in which stirring rate is taken as a control parameter and all other parameters such as initial conditions, temperature, vessel surface, and the age of solution were kept constant. Surprisingly, a better stirring condition does not make the transition reproducible; it simply does not allow the transition to happen at all. The proposed mechanism, additional explanations, and proposals for this irreproducibility of state I to state II transition have been presented. Considering the fact that the number of crazy clock reactions is only a few, this study may contribute to a better understanding of fundaments of this phenomenon. [ABSTRACT FROM AUTHOR]

A nitrogen-iodine exchange protocol of diaryliodonium salts with sodium azide salt is developed for general construction of significant functional acridines and carbazoles, in which introduction of nitrogen at a late stage was successfully established avoiding heteroatom incompatibility. Inorganic sodium azide served as the sole nitrogen atom source in this transformation. The diversiform functional acridines and carbazoles were comprehensively achieved through annulated diaryliodonium salts, respectively. Notably, Acridine orange (a fluorescent indicator for cell lysosomal dye) and Carprofen (a nonsteroidal anti-inflammatory drug) were efficiently established through this protocol. [ABSTRACT FROM AUTHOR]

During nuclear waste disposal process, radioactive iodine as a fission product can be released. The widespread implementation of sustainable nuclear energy thus requires the development of efficient iodine stores that have simultaneously high capacity, stability and more importantly, storage density (and hence minimized system volume). Here, we report high I2 adsorption in a series of robust porous metal-organic materials, MFM-300(M) (M = Al, Sc, Fe, In). MFM-300(Sc) exhibits fully reversible I2 uptake of 1.54 g g-1, and its structure remains completely unperturbed upon inclusion/removal of I2. Direct observation and quantification of the adsorption, binding domains and dynamics of guest I2 molecules within these hosts have been achieved using XPS, TGA-MS, high resolution synchrotron X-ray diffraction, pair distribution function analysis, Raman, terahertz and neutron spectroscopy, coupled with density functional theory modeling. These complementary techniques reveal a comprehensive understanding of the host-I2 and I2-I2 binding interactions at a molecular level. The initial binding site of I2 in MFM-300(Sc), …, is located near the bridging hydroxyl group of the [ScO[sub 4](OH)[sub 2]] moiety […⋯H-O = 2.263(9) Å] with an occupancy of 0.268. … is located interstitially between two phenyl rings of neighboring ligand molecules […⋯phenyl ring = 3.378(9) and 4.228(5) Å]. … is 4.565(2) Å from the hydroxyl group with an occupancy of 0.208. Significantly, at high I2 loading an unprecedented self-aggregation of I2 molecules into triple-helical chains within the confined nanovoids has been observed at crystallographic resolution, leading to a highly efficient packing of I2 molecules with an exceptional I2 storage density of 3.08 g cm-3 in MFM-300(Sc). [ABSTRACT FROM AUTHOR]

Here we report that easily obtained per-ethylated pillar[6]arene (EtP6) is a new adsorbent for iodine capture with high chemical and thermal stability. Nonporous EtP6 solids are shown to capture not only volatile iodine in the air but also iodine dissolved in an organic solvent and aqueous solution. Uptake of iodine leads to a structural transformation of EtP6 in the solid state. In the single crystal structure of iodine-doped EtP6 (I2@EtP6), each adsorbed iodine molecule is located between two adjacent EtP6 molecules to form a linear supramolecular polymer. Iodine is released spontaneously from I2@EtP6 solids when they are immersed in cyclohexane. These EtP6 solids can be reused many times without losing iodine capture capacity. [ABSTRACT FROM AUTHOR]

A simple and efficient approach to endow the controllable multi-stimuli-responsive property for the supramolecular polymer was successfully developed by rationally introducing iodine into a novel naphthalimide-functionalized pillar[5]arene-based supramolecular polymer (PNA⊃GBP). Interestingly, by introducing iodine into the supramolecular polymer PNA⊃GBP, the iodine could not only control the optical properties and self-assembly states of PNA⊃GBP via electronic donor-acceptor effect but also control the molecular recognition properties by competitive redox reaction. Benefiting from these excellent iodine controlled multiresponse properties, the PNA⊃GBP showed selective fluorescent response for cyanide, cysteine, and mercury in supramolecular polymer gels, water solutions, and living cells with high sensitivities. The supramolecular polymer PNA⊃GBP could act as a novel smart material for selective detection CN-, Hg2+, and l-Cys. [ABSTRACT FROM AUTHOR]

Hydrocarbon-soluble and highly reactive [(L)xCa(CH2SiMe3)2] (L = tetrahydropyran, x = 4 (2a); L = tmeda, x = 2 (2b)) is synthesized by the metathesis reaction of Me3SiCH2CaI (1-I) with KCH2SiMe3. The durability of 2a in tetrahydropyran solution at 0 °C is sufficiently high for subsequent chemical transformations. The reaction of ICH2SiMe3 with calcium in diethyl ether yields unique cage compound [(Et2O)2Ca(I)2·(Et2O)2Ca(I)(OEt)·(Et2O)Ca(I)(CH2SiMe3)] (3). We demonstrate that alkylcalcium complexes are valuable reagents for calcium-iodine exchange reactions at Csp²-I functionalities. [ABSTRACT FROM AUTHOR]

The first ring-contraction monofluorination reaction mediated by a hypervalent iodine reagent is reported, and the use of the reaction for the synthesis of monofluorinated five-membered ring-fused oxazolines is described. By means of this reaction, a fluorine atom can be selectively introduced either on the five-membered ring or external to it, depending on whether or not the substrate has C-4 alkyl substituents. The reaction was used for the further conversion of probenecid and isoxepac. [ABSTRACT FROM AUTHOR]

Mild oxidation of bromides by iodine(III) reagents generated active electrophilic bromination species that were reacted with polyprenoids. By simple and minor variations of an I(III)/Br combination, the reactivity could be selectively steered toward dibromination, oxybromination, or bromocyclization, giving access to a wide array of brominated motifs. [ABSTRACT FROM AUTHOR]

The iodine-catalyzed catalytic formal [3 + 3 + 1] cycloaddition for the preparation of a seven-membered O-heterocyclic ring is presented, which is an achievement of methyl and carbonyl group reactivity of 3-methyl-5-pyrazolones to forge the Csp3-O bond. This novel protocol provides a straightforward and efficient access to structurally diverse fused O-heterocycles through an iodine-catalyzed iodination/Kornblum oxidation/oxidative coupling/C-O bond formation cascade reaction. This approach demonstrates the unprecedented concurrent realization of the unique reactivity among the methyl, methylene, and carbonyl groups in 3-methyl-5-pyrazolones for the construction of 2,3-dihydrooxepine rings. Moreover, a broad substrate scope displays a graceful diversity-oriented synthetic approach. [ABSTRACT FROM AUTHOR]

The chemistry of hypervalent iodine(III) compounds has gained great interest over the past 30 years. Hypervalent iodine(III) compounds show valuable ionic reactivity due to their high electrophilicity but also express radical reactivity as single electron oxidants for carbon and heteroatom radical generation. Looking at ionic chemistry, these iodine(III) reagents can act as electrophiles to efficiently construct C-CF3, X-CF3 (X = heteroatom), C-Rf (Rf = perfluoroalkyl), X-Rf, C-N3, C-CN, S-CN, and C-X bonds. In some cases, a Lewis or a Bronsted acid is necessary to increase their electrophilicity. In these transformations, the iodine(III) compounds react as formal "CF3+", "Rf+", "N3+", "Ar+", "CN+", and "X+" equivalents. On the other hand, one electron reduction of the I(III) reagents opens the door to the radical world, which is the topic of this Account that focuses on radical reactivity of hypervalent iodine(III) compounds such as the Togni reagent, Zhdankin reagent, diaryliodonium salts, aryliodonium ylides, aryl(cyano)iodonium triflates, and aryl(perfluoroalkyl)iodonium triflates. Radical generation starting with I(III) reagents can also occur via thermal or light mediated homolysis of the weak hypervalent bond in such reagents. This reactivity can be used for alkane C-H functionalization. We will address important pioneering work in the area but will mainly focus on studies that have been conducted by our group over the last 5 years. We entered the field by investigating transition metal free single electron reduction of Togni type reagents using the readily available sodium 2,2,6,6-tetramethylpiperidine-1-oxyl salt (TEMPONa) as an organic one electron reductant for clean generation of the trifluoromethyl radical and perfluoroalkyl radicals. That valuable approach was later successfully also applied to the generation of azidyl and aryl radicals starting with the corresponding benziodoxole (Zhdankin reagent) and iodonium salts. In the presence of alkenes as radical acceptors, vicinal trifluoromethyl-, azido-, and arylaminoxylation products result via a sequence comprising radical addition to the alkene and subsequent TEMPO trapping. Electron-rich arenes also react with I(III) reagents via single electron transfer (SET) to give arene radical cations, which can then engage in arylation reactions. We also recognized that the isonitrile functionality in aryl isonitriles is a highly efficient perfluoroalkyl radical acceptor, and reaction of Rf-benziodoxoles (Togni type reagents) in the presence of a radical initiator provides various perfluoroalkylated N-heterocycles (indoles, phenanthridines, quinolines, etc.). We further found that aryliodonium ylides, previously used as carbene precursors in metal-mediated cyclopropanation reactions, react via SET reduction with TEMPONa to the corresponding aryl radicals. As a drawback of all these transformations, we realized that only one ligand of the iodine(III) reagent gets transferred to the substrate. To further increase atom-economy of such conversions, we identified cyano or perfluoroalkyl iodonium triflate salts as valuable reagents for stereoselective vicinal alkyne difunctionalization, where two ligands from the I(III) reagent are sequentially transferred to an alkyne acceptor. Finally, we will discuss alkynyl-benziodoxoles as radical acceptors for alkynylation reactions. Similar reactivity was found for the Zhdankin reagent that has been successfully applied to azidation of C-radicals, and also cyanation is possible with a cyano I(III) reagent. To summarize, this Account focuses on the design, development, mechanistic understanding, and synthetic application of hypervalent iodine(III) reagents in radical chemistry. [ABSTRACT FROM AUTHOR]

A mild dearomatization enabled ortho-selective replacement of an aromatic C-H bond with a hexafluoroacetylacetone (hfacac) substituent has been developed. This reaction is dependent on a hypervalent iodine generated phenoxonium intermediate, a critical choice of solvent, and reagent addition order. The fluorinated dihydrobenzofuran product can be transformed into dihydrobenzofuran and benzofuran products decorated with a 2-trifluoromethyl group. The 3-trifluoromethylacyl substituted benzofurans rapidly form hydrates, which can be reduced to the corresponding alcohols. [ABSTRACT FROM AUTHOR]

Atomic chains are perfect systems for getting fundamental insights into the electron dynamics and coupling between the electronic and ionic degrees of freedom in one-dimensional metals. Depending on the band filling, they can exhibit Peierls instabilities (or charge density waves), where equally spaced chain of atoms with partially filled band is inherently unstable, exhibiting spontaneous distortion of the lattice that further leads to metal-insulator transition in the system. Here, using high-resolution scanning transmission electron microscopy, we directly image the atomic structures of a chain of iodine atoms confined inside carbon nanotubes. In addition to long equidistant chains, the ones consisting of iodine dimers and trimers were also observed, as well as transitions between them. First-principles calculations reproduce the experimentally observed bond lengths and lattice constants, showing that the ionic movement is largely unconstrained in the longitudinal direction, while naturally confined by the nanotube in the lateral directions. Moreover, the trimerized chain bears the hallmarks of a charge density wave. The transition is driven by changes in the charge transfer between the chain and the nanotube and is enabled by the charge compensation and additional screening provided by the nanotube. [ABSTRACT FROM AUTHOR]

Copper-catalyzed directed decarboxylative C-N cross-coupling, which is promoted by a hypervalent iodine oxidant, provides a new strategy for the site-selective formation of aliphatic C-N bonds. Despite the great synthetic potential, the mechanism of this reaction and especially the origin of the radical species still remain controversial. To resolve this problem, herein density functional theory (DFT) calculations have been employed to elucidate the mechanistic details of this reaction. As a result, a comprehensive reaction pathway involving IIII-O bond heterolysis, single electron transfer (SET), hydrogen atom transfer (HAT), decarboxylation, proton transfer, and reductive elimination is reported. Meanwhile, analyzing the necessity of the directing groups in realizing the site selectivity, we found that the chelation of the directing group to the Cu(III) center can remarkably facilitate the proton transfer process. [ABSTRACT FROM AUTHOR]