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1. Critical Role of Li ⁺ ··· Li ⁺ Distance and Anion Restriction in Conductivity and Lithium‐Ion Transference Number of Molecular Crystals for Solid State Electrolytes

   https://doi.org/10.1002/aenm.202503433  

   Paul, Shujit Chandra; Zdilla, Michael J; Wunder, Stephanie L (November 2025, Advanced Energy Materials)

   Abstract Insights into structure‐conductivity mechanisms are investigated for a series of six (dinitrile)₂LiPF₆ molecular crystals with varied alkyl chain lengths, N≡C─(CH₂)_n─C≡N, n  = 2, 3, 4, 5, 6, and 2Me‐glutaronitrile. The molecular crystals have separate Li⁺ and channels, with the Li⁺ions weakly coordinated by four ─C≡N groups. The following correlations are observed: i) shorter Li⁺⋯ Li⁺ hopping distances (5.72–8.08 Å) increase ionic conductivity (3.1 × 10⁻⁴–0.15 × 10⁻⁴ S cm⁻¹ at 25 °C) for all (dinitrile)₂LiPF₆; ii) when there are unrestricted anion channels, the lithium ion transference number increases ( = 0.39–0.62) as the void volume (565–250 ų) and Li⁺⋯ Li⁺ hopping distance (7.15–5.72 Å) decrease, since a greater fraction of the charge is contributed by the Li⁺ions; this correlates with n= 2, 4, 5, 6; iii) the exceptions are Gln (n  = 3) and 2Me‐Gln, where there are restricted channels for anion migration, and in this case: iv) conductivity decreases (0.57–0.15 × 10⁻⁴ S cm⁻¹ at 25 °C), since contributions to the conductivity from anion migration decrease, but v) increases (0.64–0.7) since a greater fraction of the charge is carried by the Li⁺ ions. 

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2. Photochemistry of N ‐aryl and N ‐alkyl dibenzothiophene sulfoximines

   https://doi.org/10.1111/php.13978  

   Throgmorton, John C; Iverson, Alexis J; McCulla, Ryan D (June 2024, Photochemistry and Photobiology)

   Abstract N‐phenyl dibenzothiophene sulfoximine has been demonstrated to produce phenyl nitrene and dibenzothiopheneS‐oxide upon irradiation with UV‐A light, and dibenzothiopheneS‐oxide upon further irradiation releases triplet atomic oxygen. Thus,N‐phenyl dibenzothiophene sulfoximine exhibits a rare dual‐release capability in its photochemistry. In this work,N‐substituted dibenzothiophene sulfoximine derivatives are irradiated with UV‐A light to compare their photochemistry and quantum yield of dibenzothiopheneS‐oxide production with that ofN‐phenyl dibenzothiophene sulfoximine. BothN‐aryl andN‐alkyl derivatives of dibenzothiophene sulfoximine are examined to observe their effects on the quantum yield of the photolysis reaction. Adding electron withdrawingN‐aryl substituents is shown to increase the quantum yield of dibenzothiopheneS‐oxide production, while adding electron donatingN‐aryl substituents is shown to decrease the quantum yield. The quantum yield was slightly lowered or not increased by mostN‐alkyl substituents. Furthermore, the quantum yield was not augmented by branching and steric hindrance effects associated with theN‐alkyl substituents. These results suggest that electronic modulation of the sulfoximine bonds affects the observed photolysis reaction. 

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3. Effects of temperature on chaotropic anion-induced shape transitions of star molecular bottlebrushes with heterografted poly(ethylene oxide) and poly( N , N -dialkylaminoethyl methacrylate) side chains in acidic water

   https://doi.org/10.1039/D1SM00728A  

   Lewoczko, Evan M.; Kelly, Michael T.; Kent, Ethan W.; Zhao, Bin (July 2021, Soft Matter)

   null (Ed.)

   This article reports a study of the effects of temperature on chaotropic anion (CA)-induced star-globule shape transitions in acidic water of three-arm star bottlebrushes composed of heterografted poly(ethylene oxide) (PEO) and either poly(2-( N , N -dimethylamino)ethyl methacrylate) (PDMAEMA) or poly(2-( N , N -diethylamino)ethyl methacrylate) (PDEAEMA) (the brushes denoted as SMB-11 and -22, respectively). The brush polymers were synthesized by grafting alkyne-end-functionalized PEO and PDMAEMA or PDEAEMA onto an azide-bearing three-arm star backbone polymer using the copper( i )-catalyzed alkyne-azide cycloaddition reaction. Six anions were studied for their effects on the conformations of SMB-11 and -22 in acidic water: super CAs [Fe(CN) 6 ] 3− and [Fe(CN)6] 4− , moderate CAs PF 6 − and ClO 4 − , weak CA I − , and for comparison, kosmotropic anion SO 4 2− . At 25 °C, the addition of super and moderate CAs induced shape transitions of SMB-11 and -22 in pH 4.50 water from a starlike to a collapsed globular state stabilized by PEO side chains, which was driven by the ion pairing of protonated tertiary amine groups with CAs and the chaotropic effect. The shape changes occurred at much lower salt concentrations for super CAs than moderate CAs. Upon heating from near room temperature to 70 °C, the super CA-collapsed brushes remained in the globular state, whereas the moderate CA-collapsed brushes underwent reversible globule-to-star shape transitions. The transition temperature increased with increasing salt concentration and was found to be higher for SMB-22 at the same salt concentration, presumably caused by the chaotropic effect. In contrast, I − and SO 4 2− had small effects on the conformations of SMB-11 and -22 at 25 °C in the studied salt concentration range, and only small and gradual size variations were observed upon heating to 70 °C. The results reported here may have potential uses in the design of stimuli-responsive systems for substance encapsulation and release. 

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4. Unnatural Lysines with Reduced Sidechain N ‐Basicity: Synthesis of N ‐trifluoroethyl Substituted Lysine and Homologs

   https://doi.org/10.1002/slct.202203132  

   Jameson, Brian; Glaser, Rainer (December 2022, ChemistrySelect)

   Abstract The syntheses are reported of N^ϵ‐(2,2,2‐trifluoroethyl)‐D,L‐lysine (^tFK) and N^ζ‐(2,2,2‐trifluoroethyl)‐D,L‐homolysine (^tFK₊₁) from amino alcohols HO−(CH₂)_n−NH₂. The syntheses involve reductive amination, Appel bromination, and the stereoselective bond formation between C_α of the amino acid and the fluorinated alkyl chain in the Schöllkopf bislactim amino acid synthesis. The methyl esters of the fluorinated amino acids are the relevant substrates for oligopeptide synthesis. With theR‐Schöllkopf reagent, we stereoselectively generated methyl N^ϵ‐boc‐N^ϵ‐(2,2,2‐trifluoroethyl)‐L‐lysinate and methyl N^ζ‐boc‐N^ζ‐(2,2,2‐trifluoroethyl)‐L‐homolysinate. Products and intermediates were characterized by ¹H NMR, ¹³C NMR, COSY, HSQC, and LCMS. A variety of N‐functionality may be introduced by reacting hemiacetals with different appendages. This fluorine modification reduces the sidechain N‐basicity by combined ‐I effect of the three fluorines. This effect increases the [amine]/[ammonium ion] ratio of the sidechain amine in lysine to facilitate carbamylation at lower pH conditions. 

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5. Exceptional TcO ₄ ⁻ sorption capacity and highly efficient ReO ₄ ⁻ luminescence sensing by Zr ⁴⁺ MOFs

   https://doi.org/10.1039/c8ta07901c  

   Rapti, Sofia; Diamantis, Stavros A.; Dafnomili, Argyro; Pournara, Anastasia; Skliri, Euaggelia; Armatas, Gerasimos S.; Tsipis, Athanassios C.; Spanopoulos, Ioannis; Malliakas, Christos D.; Kanatzidis, Mercouri G.; et al (October 2018, Journal of Materials Chemistry A)

   The sorption properties of [Zr 6 O 4 (OH) 4 (NH 3 + -BDC) 6 ]Cl 6 · x H 2 O ( MOR-1 ) and H 16 [Zr 6 O 16 (H 2 PATP) 4 ]Cl 8 · x H 2 O ( MOR-2 ) towards ReO 4 − and TcO 4 − were studied in detail. Both MOR-1 and MOR-2 are very effective sorbents for ReO 4 − and TcO 4 − anions, with MOR-2 showing the highest sorption capacity (up to 4.1 ± 0.4 mmol g −1 ) among the known metal organic materials. Importantly, the exceptional sorption capacity of MOR-2 is retained even under conditions simulating acidic nuclear waste. In addition, MOR-1 and MOR-2 exhibit selective luminescence ReO 4 − sensing properties, demonstrated for the first time for MOF materials. 

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