Soft Lewis Base Research Articles

Sulfur-containing soft Lewis base polymers for improved lithium-ion conductivity under polymer-in-salt conditions

Abstract Solid polymer electrolytes have been intensively studied to improve the safety and energy density of lithium-ion batteries (LiBs). Although high-rate performance of LiBs has been reported in electrolytes under polymer-in-salt conditions with an excess of lithium salts and polymers, effective conditions for achieving high ionic conductivity remain unresolved. In this study, we elucidate the mechanism and high Li-ion transportability of poly(sulfone-thioether) under polymer-in-salt conditions. In particular, the composition of the polymer with an asymmetric Li salt, lithium(fluorosulfonyl)(trifluoromethane sulfonyl)imide (LiFTFSI), induced a high ionic conductivity above 10−5 S/cm, which is higher than that of the poly(ethylene oxide) (PEO)-Li salt system. Under polymer-in-salt conditions, the enhanced conductivity of poly(sulfone-thioether) contrasts with the conductivity drop observed in the conventional PEO system. These results show the superiority of polymers with soft Lewis bases, such as sulfur donor atoms, for Li-ion transport under polymer-in-salt conditions.

Sulfur in Waste-Free Sustainable Synthesis: Advancing Carbon-Carbon Coupling Techniques.

This review explores the pivotal role of sulfur in advancing sustainable carbon-carbon (C-C) coupling reactions. The unique electronic properties of sulfur, as a soft Lewis base with significant mesomeric effect make it an excellent candidate for initiating radical transformations, directing C-H-activation, and facilitating cycloaddition and C-S bond dissociation reactions. These attributes are crucial for developing waste-free methodologies in green chemistry. Our mini-review is focused on existing sulfur-directed C-C coupling techniques, emphasizing their sustainability and comparing state-of-the-art methods with traditional approaches. The review highlights the importance of this research in addressing current challenges in organic synthesis and catalysis. The innovative use of sulfur in photocatalytic, electrochemical and metal-catalyzed processes not only exemplifies significant advancements in the field but also opens new avenues for environmentally friendly chemical processes. By focusing on atom economy and waste minimization, the analysis provides broad appeal and potential for future developments in sustainable organic chemistry.

Sulfur in Waste‐Free Sustainable Synthesis: Advancing Carbon–Carbon Coupling Techniques

AbstractThis review explores the pivotal role of sulfur in advancing sustainable carbon‐carbon (C−C) coupling reactions. The unique electronic properties of sulfur, as a soft Lewis base with significant mesomeric effect make it an excellent candidate for initiating radical transformations, directing C−H‐activation, and facilitating cycloaddition and C−S bond dissociation reactions. These attributes are crucial for developing waste‐free methodologies in green chemistry. Our mini‐review is focused on existing sulfur‐directed C−C coupling techniques, emphasizing their sustainability and comparing state‐of‐the‐art methods with traditional approaches. The review highlights the importance of this research in addressing current challenges in organic synthesis and catalysis. The innovative use of sulfur in photocatalytic, electrochemical and metal‐catalyzed processes not only exemplifies significant advancements in the field but also opens new avenues for environmentally friendly chemical processes. By focusing on atom economy and waste minimization, the analysis provides broad appeal and potential for future developments in sustainable organic chemistry.

Highly efficient capture of iodine vapor by [Mo3S13]2− intercalated layered double hydroxides

From the swollen LDH, bulky [Mo3S13]2− anions are facilely introduced into the LDH interlayers to assemble the Mo3S13-LDH composite, which exhibits excellent iodine capture performance and good irradiation resistance. The positive-charged LDH layers may disperse the [Mo3S13]2− uniformly within the interlayers, providing abundant adsorption sites for effectively trapping iodine. The Mo-S bond serving as a soft Lewis base has strong affinity to I2 with soft Lewis acidic characteristic, which is conducive to improvement of iodine capture via physical sorption. Besides, chemisorption has a significant contribution to the iodine adsorption. The S22−/S2− in [Mo3S13]2− can reduce the I2 to [I3]− ions, which are facilely fixed within the LDH gallery in virtue of electrostatic attraction. Meanwhile, the S22−/S2− themselves are oxidized to S8 and SO42−, while Mo4+ is oxidized (by O2 in air) to Mo6+, which combines with SO42− forming amorphous Mo(SO4)3. With the collective interactions of chemical and physical adsorption, the Mo3S13-LDH demonstrates an extremely large iodine adsorption capacity of 1580 mg/g. Under γ radiation, the structure of Mo3S13-LDH well maintains and iodine adsorption capability does not deteriorate, indicating the good irradiation resistance. This work provides an important reference to tailor cost-effective sorbents for trapping iodine from radioactive nuclear wastes.

Molar excess of coordinating N-heterocyclic carbene ligands triggers kinetic digestion of gold nanocrystals.

There has been much interest in evaluating the strength of the coordination interactions between N-heterocyclic carbene (NHC) molecules and transition metal ions, nanocolloids and surfaces. We implement a top-down core digestion test of Au nanoparticles (AuNPs) triggered by incubation with a large molar excess of poly(ethylene glycol)-appended NHC molecules, where kinetic dislodging of surface atoms and formation of NHC-Au complexes progressively take place. We characterize the structure and chemical nature of the generated PEG-NHC-Au complexes using 1D and 2D 1H-13C NMR spectroscopy, supplemented with matrix assisted laser desorption/ionization mass spectrometry, and transmission electron microscopy. We further apply the same test using thiol-modified molecules and find that though etching can be measured the kinetics are substantially slower. We discuss our findings within the classic digestion of transition metal ores and colloids induced by interactions with sodium cyanide, which provides an insight into the strength of coordination between the strong σ-donating (soft Lewis base) NHC and Au surfaces (having a soft Lewis acid character), as compared to gold-to-gold covalent binding.

Elucidating the Role of Chalcogenide‐Based Interface Passivators in Enhancing the Stability of Perovskite Solar Cells

AbstractChalcogenide‐based Lewis bases are widely used in perovskite solar cells (PSCs) due to their effectiveness in passivating Pb2+ and Pb0‐related defects. However, the underlying principles governing their defect passivation and the relative efficacy of different chalcogen elements remain poorly understood. This study evaluates the effectiveness of oxygen, sulfur, and selenium‐based interface passivator molecules in enhancing the stability and power conversion efficiency (PCE) of perovskite solar cell devices. The hard and soft acid and base (HSAB) principle has been utilized here to gain insights into the defect passivation behavior of chalcogenide‐based molecules. The photoluminescence, ideality factor, and trap density measurements reveal that the sulfide and selenide‐passivated devices exhibit superior defect passivation compared to the oxide‐passivated control device. In terms of stability, the average T75 lifetime (time at which 75% of the initial PCE is retained) of the oxide, sulfide, and selenide passivated samples is 6%, 30%, and 50% higher compared to their un‐passivated counterparts. This enhanced stability with the sulfide and selenide‐based passivators can be attributed to their soft Lewis base nature, which resulted in stronger interaction with the Pb‐related defects, as evidenced by the density‐functional theory calculations and X‐Ray photoelectron spectroscopy study.

Catalytic Main‐Group Metal Complexes of Phosphine‐Based Pincer Ligands

AbstractPincer ligand complexes, which appeared nearly five decades ago, have provided a valuable platform for the study of fundamental chemical processes and the development of efficient catalysts for many chemical transformations. These complexes have usually contained transition metal atoms or ions, and their respective pincer ligands have often featured phosphine donor groups, which strongly coordinate to the metal center and allow its steric and electronic properties to be fine‐tuned. The increasing need to develop cost‐effective and sustainable catalytic processes has driven the search for main‐group metals as alternatives to commonly‐used transition metals. In this review, we show that despite the inherent mismatch between phosphines, which are soft Lewis bases, and main‐group metal ions, which are hard Lewis acids, a series of well‐defined phosphine‐based pincer complexes containing Li(I), Na(I), K(I), Mg(II), Ca(II), Zn(II) and Al(III) have been reported, which have proven to be active catalysts for industrially‐relevant transformations.

Tuning Intermolecular Interactions to Enhance the Cyclability of Non-Aqueous, Organic Redox Flow Batteries.

Enhancing the electrochemical stability and reversibility of redox-active organic molecules is crucial to improve the performance of non-aqueous redox flow batteries (RFBs). Compared with the widely adopted strategy of molecular engineering, we show in this study that tuning the intermolecular interaction between the active material with the supporting electrolyte is another feasible way to address the performance of non-aqueous organic RFBs. Combined with theoretical and experimental investigations, the influence of Lewis acidity of the supporting electrolyte cations and anions on the electrochemical stability and reversibility of bipyridine-based anode material is revealed. As a demonstration, a redox flow cell based on 4,4'-bipyridine anolyte and ferrocene catholyte shows greatly enhanced performance by using supporting electrolyte composed of soft Lewis acid and soft Lewis base. This study provides an alternative, yet highly effective way to addressing the cyclability of an organic compound for non-aqueous RFBs.

(Keynote) N-Heterocyclic Carbene-coated Gold Nanoparticles and Luminescent Quantum Dots

N-heterocyclic carbenes (NHCs) have generated much interest for use as versatile metal-coordinating groups, since they were first synthesized by Arduengo and coworkers in 1991. NHC molecules can be considered as L-type ligands, because they share their non-bonding electron pairs with the σ-accepting orbital of transition metals, and this endows them with strong coordination interactions. NHC-appended molecules have recently been actively exploited as potentially effective ligands for the surface passivation of various colloidal nanomaterials.We investigate the coordination interactions between a few representative colloidal nanocrystals, including gold nanoparticles (AuNPs) and luminescent quantum dots (QDs), and a NHC-based polymer ligand. The latter presents multiple NHC groups and several short poly (ethylene glycol) (PEG) chains as solubilizing blocks. We find that our NHC-decorated ligands rapidly coordinate onto both sets of nanocrystals, which we attribute to their soft Lewis base nature. These ideally match the soft Lewis acid character of transition metal colloid surfaces, promoting strong coordination bonding through soft‐soft interaction. We combine NMR spectroscopy, fluorescence spectroscopy, high-resolution transmission electron microscopy supplemented with dynamic light scattering to characterize the nature of the binding interactions. Furthermore, the long-term stability of the NHC-stabilized nanocolloids have been tested after phase transfer to water, a highly challenging chemical venue for such groups, due to the moisture sensitive nature of NHC molecules. Data show that our NHC-polymer-stabilized AuNPs and QDs exhibit long-term colloidal stability in buffer media while preserving their optical and fluorescing properties, with no sign of degradation or aggregation build up for at least one year of storage. We will discuss the ligand design and synthesis, characterization of the polymer-stabilized nanocrystals under various conditions, with a particular focus on the beneficial effects of ligand multi-coordination interactions onto the nanocolloid surfaces.

Gallium Methylene in the Pocket

Adduct complexes Ga6(μ-CH2)9(DMAP)3(THF) and Ga8(μ-CH2)12(PEt3)x (x = 4 and 6) could be obtained upon crystallization of Ga8(CH2)12 from THF/DMAP (hard Lewis bases) and PEt3 (soft Lewis base), respectively. Mixed methyl/methylene {Ga4} species with either bridging aryloxy, thiophenolato, or arylamido ligands were accessible via the treatment of Ga8(CH2)12 with phenols (HOC6H2Me3-2,4,6 and HOC6H3Me2-2,6), thiophenol HSC6H2Me3-2,4,6, and anilines (H2NC6H2Me3-2,4,6 and H2NC6H3Me2-2,6). Such tetrametallic complexes Ga4(μ2-CH2)2(CH3)4(μ2-XAr)4 (X = O, S, NH) are isostructural, displaying an adamantane-like core structure. The sterically more demanding phenol HOC6H3tBu2-2,6 afforded the {Ga5} cluster Ga5(μ2-CH2)6(OC6H3tBu2-2,6)3(THF)2 with the gallium centers exclusively bridged by methylene groups. Treatment of Ga8(CH2)12 with other protic substrates HOR/H2NR′, including HOCH2tBu, HOSi(OtBu)3, H2NC6H3iPr2-2,6, and H2NSiPh3 point to a pronounced stereoelectronic dependency and intricacy of such transformations but provided helpful information about potential side products such as [(CH3)2Ga(μ-X)]2 (X = OR, HNR′) and reaction intermediates. Efficient methylene → imido transformations using Ga8(CH2)12/aniline mixtures could not be implemented.

Passivation of positively charged cationic defects in perovskite with nitrogen-donor crown ether enabling efficient perovskite solar cells

Positively charged cationic defects are the main source of defects in metal-halide perovskite solar cells. They determine the quasi-Fermi level of electrons under illumination and contribute to non-radiative recombination loss, causing an open-circuit voltage deficit. In addition, they act as ion migration pathways for halide hopping, thus deteriorating long-term stability. Herein, a nitrogen-donor crown ether as a positive defect passivator is developed, which demonstrates a soft Lewis base nature, a large donor number and a higher formation constant with positively charged cationic defects. Density functional theory calculation indicates that the electron-donating nitrogen atom dramatically increases the electron density of oxygen atoms, leading to a strong affinity with positively charged cationic defects (Pb2+ and Cs+). The electron trap density in perovskite is significantly reduced by 27 %, resulting in an increased build-in potential. By adding a small amount of nitrogen-donor crown ether to the precursor solution, the perovskite solar cells achieve an efficiency of 24.07 % with an open-circuit voltage of 1.174 V and a fill factor of 82.15 %. Moreover, the unencapsulated perovskite solar cells show a T80 lifetime of 510 h under continuous operation (1 sun equivalent illumination, maximum power point tracking condition, dry N2 atmosphere), and enhanced moisture and heat stability.

Superior Iodine Uptake Capacity Enabled by an Open Metal-Sulfide Framework Composed of Three Types of Active Sites

Superior Iodine Uptake Capacity Enabled by an Open Metal-Sulfide Framework Composed of Three Types of Active Sites

Impact of anion polarizability on ion pairing in microhydrated salt clusters.

Despite longstanding interest in the mechanism of salt dissolution in aqueous media, a molecular level understanding remains incomplete. Here, cryogenic ion trap vibrational action spectroscopy is combined with electronic structure calculations to track salt hydration in a gas phase model system one water molecule at a time. The infrared photodissociation spectra of microhydrated lithium dihalide anions [LiXX'(H2O) n ]- (XX' = I2, ClI and Cl2; n = 1-3) in the OH stretching region (3800-2800 cm-1) provide a detailed picture of how anion polarizability influences the competition among ion-ion, ion-water and water-water interactions. While exclusively contact ion pairs are observed for n = 1, the formation of solvent-shared ion pairs, identified by markedly red-shifted OH stretching bands (<3200 cm-1), originating from the bridging water molecules, is favored already for n = 2. For n = 3, Li+ reaches its maximum coordination number of four only in [LiI2(H2O)3]-, in accordance with the hard and soft Lewis acid and base principle. Water-water hydrogen bond formation leads to a different solvent-shared ion pair motif in [LiI2(H2O)3]- and network formation even restabilizes the contact ion pair motif in [LiCl2(H2O)3]-. Structural assignments are exclusively possible after the consideration of anharmonic effects. Molecular dynamics simulations confirm that the significance of large amplitude motion (of the water molecules) increases with increasing anion polarizability and that needs to be considered already at cryogenic temperatures.

Reusable Polyacrylonitrile‐Sulfur Extractor of Heavy Metal Ions from Wastewater

AbstractMercury, lead, and cadmium are among the most toxic and carcinogenic heavy metal ions (HMIs), posing serious threats to the sustainability of aquatic ecosystems and public health. There is an urgent need to remove these ions from water by a cheap but green process. Traditional methods have insufficient removal efficiency and reusability. Structurally robust, large surface‐area adsorbents functionalized with high‐selectivity affinity to HMIs are attractive filter materials. Here, an adsorbent prepared by vulcanization of polyacrylonitrile (PAN), a nitrogen‐rich polymer, is reported, giving rise to PAN‐S nanoparticles with cyclic π‐conjugated backbone and electronic conductivity. PAN‐S can be coated on ultra‐robust melamine (ML) foam by simple dipping and drying. In agreement with hard/soft acid/base theory, N‐ and S‐containing soft Lewis bases have strong binding to Hg2+, Pb2+, Cu2+, and Cd2+, with extraordinary capture efficiency and performance stability. Furthermore, the used filters, when collected and electrochemically biased in a recycling bath, can release the HMIs into the bath and electrodeposit on the counter‐electrode as metallic Hg0, Pb0, Cu0, and Cd0, and the PAN‐S@ML filter can then be reused at least 6 times as new. The electronically conductive PAN‐S@ML filter can be fabricated cheaply and holds promise for scale‐up applications.

Interpret the elimination behaviors of lead and vanadium from the water by employing functionalized biochars in diverse environmental conditions

Wide-ranging researches have been executed to treat groundwater from different mining areas, although complex behaviors of diverse metal ion species in the groundwater have not been illustrated clearly. This research study explored the mechanisms through which Pb(II) and V(V) are eliminated in single and binary-metal removal processes by oxygen, nitrogen, and sulfur-doped biochars also considering the kinetic and characterization techniques. The adsorption efficiency of V (V) was enhanced by oxygen-doped biochar at pH 4 with an adsorption capacity of ~70 mg/g. However, Pb (II) was rapidly removed at pH 6 with a higher adsorption capacity of ~180 mg/g by the nitrogen and sulfur-doped biochar forming PbCO3 and V(CO)6 crystals along the single-metal removal process. These results could be explained by the Hard Soft Acid Base theory. The hard Lewis acid vanadium was attracted by the hard Lewis base oxygen, and the intermediate Lewis acid lead was attracted by the intermediate and soft Lewis base nitrogen and sulfur. Besides, the removal ability of Pb(II) and V(V) in the binary-metal removal process showed a similar phenomenon for all types of biochars at pH 4 with the adsorption capacity of ~400 mg/g for Pb(II) and 175 mg/g for V(V), but the composition of vanadium species remains unclear on the surface of the biochars. Initially, H3V2O7−, H2VO4−, and HVO42− species were electrostatically attracted by the oxygen-based functionalities, then V(V) species was partially reduced to VO2+ by the oxygen, nitrogen, and sulfur functionalities in different ratios. Finally, H3V2O7−, H2VO4−, and HVO42− species produced Pb5(VO4)3Cl and Pb2V2O7 which co-precipitate with Pb(II), but VO2+ does not generate any form of precipitates. The above-explained technique supports the treatment of vanadium mining groundwater with valuable vanadinite (Pb5(VO4)3Cl) mineral.

Probing the Catalytic Mechanism and Inhibition of SAMHD1 Using the Differential Properties of Rp- and Sp-dNTPαS Diastereomers.

SAMHD1 is a fundamental regulator of cellular dNTPs that catalyzes their hydrolysis into 2′-deoxynucleoside and triphosphate, restricting the replication of viruses, including HIV-1, in CD4+ myeloid lineage and resting T-cells. SAMHD1 mutations are associated with the autoimmune disease Aicardi-Goutières syndrome (AGS) and certain cancers. More recently, SAMHD1 has been linked to anticancer drug resistance and the suppression of the interferon response to cytosolic nucleic acids after DNA damage. Here, we probe dNTP hydrolysis and inhibition of SAMHD1 using the Rp and Sp diastereomers of dNTPαS nucleotides. Our biochemical and enzymological data show that the α-phosphorothioate substitution in Sp-dNTPαS but not Rp-dNTPαS diastereomers prevents Mg2+ ion coordination at both the allosteric and catalytic sites, rendering SAMHD1 unable to form stable, catalytically active homotetramers or hydrolyze substrate dNTPs at the catalytic site. Furthermore, we find that Sp-dNTPαS diastereomers competitively inhibit dNTP hydrolysis, while Rp-dNTPαS nucleotides stabilize tetramerization and are hydrolyzed with similar kinetic parameters to cognate dNTPs. For the first time, we present a cocrystal structure of SAMHD1 with a substrate, Rp-dGTPαS, in which an Fe–Mg-bridging water species is poised for nucleophilic attack on the Pα. We conclude that it is the incompatibility of Mg2+, a hard Lewis acid, and the α-phosphorothioate thiol, a soft Lewis base, that prevents the Sp-dNTPαS nucleotides coordinating in a catalytically productive conformation. On the basis of these data, we present a model for SAMHD1 stereospecific hydrolysis of Rp-dNTPαS nucleotides and for a mode of competitive inhibition by Sp-dNTPαS nucleotides that competes with formation of the enzyme–substrate complex.

Hard and soft Lewis-base behavior for efficient and stable CsPbBr3 perovskite light-emitting diodes

Abstract All-inorganic CsPbBr3 perovskite is an attractive emission material for high-stability perovskite light-emitting diodes (PeLEDs), due to the high thermal and chemical stability. However, the external quantum efficiencies (EQEs) of CsPbBr3 based PeLEDs are still far behind their organic–inorganic congeners. Massive defect states on the surface of CsPbBr3 perovskite grains should be the main reason. Lewis base additives have been widely used to passivate surface defects. However, systematic investigations which relate to improving the passivation effect via rational molecule design are still lacking. Here, we demonstrate that the CsPbBr3 film’s optical and electrical properties can be significantly boosted by tailoring the hardness–softness of the Lewis base additives. Three carboxylate Lewis bases with different tail groups are selected to in-situ passivate CsPbBr3 perovskite films. Our research indicates that 4-(trifluoromethyl) benzoate acid anion (TBA−) with the powerful electron-withdrawing group trifluoromethyl and benzene ring possesses the softest COO− bonding head. TBA− thus acts as a soft Lewis base and possesses a robust combination with unsaturated lead atoms caused by halogen vacancies. Based on this, the all-inorganic CsPbBr3 PeLEDs with a maximum EQE up to 16.75% and a half-lifetime over 129 h at an initial brightness of 100 cd m−2 is thus delivered.

Silicon Tetrakis(trifluoromethanesulfonate): A Simple Neutral Silane Acting as a Soft and Hard Lewis Superacid.

A facile synthesis and isolation of pristine silicon tetrakis(trifluoromethanesulfonate), Si(OTf)4, is reported, acting as the first neutral silicon‐based Lewis superacid suitable towards soft and hard Lewis bases. Its OTf groups have a dual function: they are excellent leaving groups and modulate the degree of reactivity towards soft and hard Lewis bases. Exposed to soft Lewis donors, Si(OTf)4 leads to [L2Si(OTf)4] complexes (L=isocyanide, thioether and carbonyl compounds) with retention of all Si−OTf bonds. In contrast, it can cleave C−X bonds (X=F, Cl) of hard organic Lewis bases with a high tendency to form SiX4 (X=F, Cl) after halide/triflate exchange. Most notable, Si(OTf)4 allows a gentle oxydefluorination of mono‐ and bis(trifluoromethyl)benzenes, resulting in the formation of the corresponding benzoylium species, which are stabilized by the weakly coordinating [Si(OTf)6] dianion.

Novel montmorillonite-sulfur composite for enhancement of selective adsorption toward cesium

The selective elimination of radioactive cesium from complicated wastewater is imperative in view of environment and human health. Montmorillonite has been accepted as one of the most promising adsorbents for cesium purification. However, its poor selectivity still remains a major challenge. Herein, a novel montmorillonite-sulfur composite was developed via a facile one-step solvent-free method and used for Cs+ removal. Owing to the fact that soft Lewis base S2− ligand interacted more strongly with softer Lewis acid Cs+ than other cations, the capacity and selectivity towards Cs+ was significantly enhanced. In this case, a large capacity of 160.9 mg g−1 was achieved. The distribution coefficient value (∼4000 mL g−1) was 3-times larger than that of pristine montmorillonite (∼1500 mL g−1). Moreover, this composite could be easily recycled and reused within five times recycling experiments. Therefore, this low-cost and facilely prepared composite are expected to be used for the selective removal of Cs+ from complicated wastewater containing various competing ions.

Gas-Induced Ion-Free Stable Radical Anion Formation of Organic Semiconducting Solids as Highly Gas-Selective Probes.

The formation of stabilized radical anions on organic materials in the solid state is an important issue in radical-based fundamental research and various applications. Herein, for the first time, we report on gas-induced ion-free stable radical anion formation (SRAF) of organic semiconducting solids with high gas selectivities through the use of organic field-effect transistor (OFET) gas sensors and electron spin resonance spectroscopy. In contrast to the previously reported SRAF, which requires either anionic analytes in solution and/or cationic substituents on π-electron-deficient aromatic cores, NDI-EWGs consist of an n-type semiconducting naphthalene diimide (NDI) and various electron-withdrawing groups (EWGs) that exhibit non-ion-involved, gas-selective SRAF in the solid state. In the presence of hard Lewis base gases, NDI-EWG-based OFETs exhibit enhanced conductivity (Current-ON mode) through the formation of an SRAF NDI/gas complex, while in the presence of borderline and soft Lewis base gases, NDI-EWG-based OFETs show decreased conductivity (Current-OFF mode) by the formation of a resistive NDI/gas complex. Organic semiconducting solids with EWGs exhibiting highly gas-selective solid-SRAF constitute a very promising platform for radical-based chemistry and can be used in various applications, such as highly gas-selective probes.