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1. Study of Υ(10753) decays to π+π−Υ(nS) final states at Belle II

   https://doi.org/10.1007/JHEP07(2024)116  

   Adachi, I; Aggarwal, L; Ahmed, H; Aihara, H; Akopov, N; Aloisio, A; Anh_Ky, N; Asner, D M; Atmacan, H; Aushev, T; et al (July 2024, Journal of High Energy Physics)

   A<sc>bstract</sc> We present an analysis of the processe⁺e⁻→π⁺π⁻Υ(nS) (wheren= 1, 2, or 3) reconstructed in 19.6 fb⁻¹of Belle II data during a special run of the SuperKEKB collider at four energy points near the peak of the Υ(10753) resonance. By analyzing the mass distribution of theπ⁺π⁻Υ(nS) system and the Born cross sections of thee⁺e⁻→π⁺π⁻Υ(nS) process, we report the first observation of Υ(10753) decays to theπ⁺π⁻Υ(1S) andπ⁺π⁻Υ(2S) final states, and find no evidence for decays toπ⁺π⁻Υ(3S). Possible intermediate states in theπ⁺π⁻Υ(1S,2S) transitions are also investigated, and no evidence for decays proceeding via the$$ {\pi}^{\mp }{Z}_b^{\pm } $$ ${\pi }^{\mp }{Z}_b^{\pm }$orf₀(980)Υ(nS) intermediate states is found. We measure Born cross sections for thee⁺e⁻→π⁺π⁻Υ(nS) process that, combined with results from Belle, obtain the mass and width of Υ(10753) to be (10756.6 ± 2.7 ± 0.9) MeV/c²and (29.0 ± 8.8 ± 1.2) MeV, respectively. The relative ratios of the Born cross sections at the Υ(10753) resonance peak are also reported for the first time. 

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2. Search for the $$ {B}_c^{+} $$ → χc1(3872)π+ decay

   https://doi.org/10.1007/JHEP06(2025)013  

   Aaij, R; Abdelmotteleb, A_S W; Abellan_Beteta, C; Abudinén, F; Ackernley, T; Adefisoye, A A; Adeva, B; Adinolfi, M; Adlarson, P; Agapopoulou, C; et al (June 2025, Journal of High Energy Physics)

   A<sc>bstract</sc> A search for the decay$$ {B}_c^{+} $$ $B_c^{+}$→ χ_c1(3872)π⁺is reported using proton-proton collision data collected with the LHCb detector between 2011 and 2018 at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb⁻¹. No significant signal is observed. Using the decay$$ {B}_c^{+} $$ $B_c^{+}$→ψ(2S)π⁺as a normalisation channel, an upper limit for the ratio of branching fractions$$ {\mathcal{R}}_{\psi (2S)}^{\chi_{c1}(3872)}=\frac{{\mathcal{B}}_{B_c^{+}\to {\chi}_{c1}(3872){\pi}^{+}}}{{\mathcal{B}}_{B_c^{+}\to \psi (2S){\pi}^{+}}}\times \frac{{\mathcal{B}}_{\chi_{c1}(3872)\to J/\psi {\pi}^{+}{\pi}^{-}}}{{\mathcal{B}}_{\psi (2S)\to J/\psi {\pi}^{+}{\pi}^{-}}}<0.05(0.06), $$ $R_{\psi \left(2S\right)}^{{\chi }_{c1}\left(3872\right)}=\frac{B_{B_c^{+}\to {\chi }_{c1}\left(3872\right){\pi }^{+}}}{B_{B_c^{+}\to \psi \left(2S\right){\pi }^{+}}}\times \frac{B_{{\chi }_{c1}\left(3872\right)\to J/\psi {\pi }^{+}{\pi }^{-}}}{B_{\psi \left(2S\right)\to J/\psi {\pi }^{+}{\pi }^{-}}}<0.05\left(0.06\right),$ is set at the 90 (95)% confidence level. 

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3. A multi‐descriptor analysis of substituent effects on the structure and aromaticity of benzene derivatives: π‐Conjugation versus charge effects

   https://doi.org/10.1002/jcc.27296  

   Chagas, Julio C. V.; Milanez, Bruno D.; Oliveira, Vytor P.; Pinheiro Jr, Max; Ferrão, Luiz F. A.; Aquino, Adelia J. A.; Lischka, Hans; Machado, Franciso B. C. (December 2023, Journal of Computational Chemistry)

   Abstract This work provides a detailed multi‐component analysis of aromaticity in monosubstituted (X = CH₃, C, C, NH₂, NH⁻, NH⁺, OH, O⁻, and O⁺) andpara‐homodisubstituted (X = CH₃, CH₂, NH₂, NH, OH, and O) benzene derivatives. We investigate the effects of substituents using single‐reference (B3LYP/DFT) and multireference (CASSCF/MRCI) methods, focusing on structural (HOMA), vibrational (AI(vib)), topological (ELF_π), electronic (MCI), magnetic (NICS), and stability (S₀–T₁splitting) properties. The findings reveal that appropriateπ‐electron‐donating andπ‐electron‐accepting substituents with suitable size and symmetry can interact with theπ‐system of the ring, significantly influencingπ‐electron delocalization. While the charge factor has a minimal impact onπ‐electron delocalization, the presence of ap_zorbital capable of interacting with theπ‐electron delocalization is the primary factor leading to a deviation from the typical aromaticity characteristics observed in benzene. 

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4. Strong π-stacking causes unusually large anisotropic thermal expansion and thermochromism

   https://doi.org/10.1073/pnas.2106572118  

   Dharmarwardana, Madushani; Otten, Brooke M.; Ghimire, Mukunda M.; Arimilli, Bhargav S.; Williams, Christopher M.; Boateng, Stephen; Lu, Zhou; McCandless, Gregory T.; Gassensmith, Jeremiah J.; Omary, Mohammad A. (October 2021, Proceedings of the National Academy of Sciences)

   π-stacking in ground-state dimers/trimers/tetramers ofN-butoxyphenyl(naphthalene)diimide (BNDI) exceeds 50 kcal ⋅ mol⁻¹in strength, drastically surpassing that for the^*3[pyrene]₂excimer (∼30 kcal ⋅ mol⁻¹; formal bond order = 1) and similar to other weak-to-moderate classical covalent bonds. Cooperative π-stacking in triclinic (BNDI-T) and monoclinic (BNDI-M) polymorphs effects unusually large linear thermal expansion coefficients (α_a, α_b, α_c, β) of (452, −16.8, −154, 273) × 10⁻⁶⋅ K⁻¹and (70.1, −44.7, 163, 177) × 10⁻⁶⋅ K⁻¹, respectively. BNDI-T exhibits highly reversible thermochromism over a 300-K range, manifest by color changes from orange (ambient temperature) toward red (cryogenic temperatures) or yellow (375 K), with repeated thermal cycling sustained for over at least 2 y. 

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5. Syntheses and crystal structures of three triphenylsulfonium salts of manganese(II), iron(III) and cobalt(II)

   https://doi.org/10.1107/S2056989025006668  

   Callaway, Waylan; Elterman, Matthew; Krasilnikov, Nikita; Roberts, Gavin; Rutan, Davis; Spencer, Ty; Padgett, Clifford W; Lynch, Will E (August 2025, Acta Crystallographica Section E Crystallographic Communications)

   Bis(triphenylsulfonium) tetrachloridomanganate(II), (C₁₈H₁₅S)₂[MnCl₄] (I), triphenylsulfonium tetrachloridoferrate(III), (C₁₈H₁₅S)[FeCl₄] (II), and bis(triphenylsulfonium) tetrachloridocobaltate(II), (C₁₈H₁₅S)₂[CoCl₄] (III), crystallize in the monoclinic space groupsP2₁/n[(I) and (III)] andP2₁/c[(II)]. Compounds (I) and (III) each contain two crystallographically independent triphenylsulfonium (TPS⁺) cations in the asymmetric unit, whereas (II) has one. In all three compounds, the sulfonium centers adopt distorted trigonal–pyramidal geometries, with S—C bond lengths falling roughly in the 1.78–1.79 Å range and C—S—C angles observed at about 101 to 106°. The [MCl₄]ⁿ⁻anions (M= Mn²⁺, Fe³⁺, Co²⁺;n= 2,1,2) adopt slightly distorted tetrahedral geometries, withM—Cl bond lengths in the 2.19–2.38 Å range and Cl—M—Cl angles of approximately 104–113°. Hirshfeld surface analyses shows that H...H and H...C contacts dominate the TPS⁺cation environments, whereas H...Cl and shortM—S interactions link each [MCl₄]ⁿ⁻anion to the surrounding cations. In (I) and (III), inversion-centered π–π stacking further consolidates the crystal packing, while in (II) no π–π interactions are observed. 

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