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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. 

Abstract G‐quadruplexes (G4s) are non‐canonical DNA structures implicated in a number of biological processes. Small‐molecule ligands can alter stability and folding of G4s, which can potentially be exploited for therapeutic purposes. In this work, we investigate the interaction of telomeric DNA fragment fromTetrahymena thermophila(TET25, 5′‐G(TTGGGG)_4‐3′) with a G4 ligand PyDH2 belonging to the bisquinolinium family. When alone, TET25 adopts a mixture of three conformations, with the most abundant being a four‐tetrad hybrid G4. In the presence of PyDH2, surprisingly, TET25 folds into an antiparallel chair G4, with PyDH2 intercalated between G‐tetrads 2 and 3, according to our crystal structure. The structure represents the second example, and the first crystallographic evidence, of ligand intercalation into a G4. In solution, the interaction of PyDH2 and TET25 leads to a number of complexes differing by G4 topology and binding stoichiometry, strong stabilization of G4 (∆T_m = 12.4 °C in the presence of one equiv. of PyDH2) and large hysteresis of ∼10 °C, suggesting that ligand binding and G4 folding processes are complex. 

Abstract Cationic biocides play a crucial role in the disinfection of domestic and healthcare surfaces. Due to the rise of bacterial resistance towards common cationic disinfectants like quaternary ammonium compounds (QACs), the development of novel actives is necessary for effective infection prevention and control. Toward this end, a series of 15 chimeric biscationic amphiphilic compounds, bearing both ammonium and phosphonium residues, were prepared to probe the structure and efficacy of mixed cationic ammonium‐phosphonium structures. Compounds were obtained in two steps and good yields, with straightforward and chromatography‐free purifications. Antibacterial activity evaluation of these compounds against a panel of seven bacterial strains, including two MRSA strains as well as opportunistic pathogenA. baumannii, were encouraging, as low micromolar inhibitory activity was observed for multiple structures. Alkyl chain length on the ammonium group was, as expected, a major determinant of bioactivity. In addition, high therapeutic indexes (up to 125‐fold) for triphenyl phosphonium‐bearing amphiphiles were observed when comparing antimicrobial activity to mammalian cell lysis activity.