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1. Facile Synthesis of (C ₆ F ₅ ) ₂ BBr and (C ₆ F ₅ ) ₂ BX(OEt ₂ ) (X=Cl, Br) using Hydrogen Halides and Piers’ Borane

   https://doi.org/10.1002/zaac.202300007  

   Wong, Anthony; Alcántara, Gustavo; Avalos, Matthew; Wu, Guang; Ménard, Gabriel (March 2023, Zeitschrift für anorganische und allgemeine Chemie)

   Abstract We report the facile and efficient synthesis of common electrophilic haloboranes via a protonolysis reaction between Piers’ borane, HB(C₆F₅)₂, and H−X (X=Cl, Br). This route benefits from fast reaction times, easy setup, and minimal workup to yield the analytically pure etherates, (C₆F₅)₂BCl(OEt₂) (1) and (C₆F₅)₂BBr(OEt₂) (2), as well as the ether‐free tri‐coordinate species, (C₆F₅)₂BBr (3). 

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2. Crystal structures of three copper(II)–2,2′-bipyridine (bpy) compounds, [Cu(bpy) ₂ (H ₂ O)][SiF ₆ ]·4H ₂ O, [Cu(bpy) ₂ (TaF ₆ ) ₂ ] and [Cu(bpy) ₃ ][TaF ₆ ] ₂ and a related coordination polymer, [Cu(bpy)(H ₂ O) ₂ SnF ₆ ] _n

   https://doi.org/10.1107/S2056989021000633  

   Nisbet, Matthew L.; Hiralal, Emily; Poeppelmeier, Kenneth R. (February 2021, Acta Crystallographica Section E Crystallographic Communications)

   null (Ed.)

   We report the hydrothermal syntheses and crystal structures of aquabis(2,2′-bipyridine-κ 2 N , N ′)copper(II) hexafluoridosilicate tetrahydrate, [Cu(bpy) 2 (H 2 O)][SiF 6 ]·4H 2 O (bpy is 2,2′-bipyridine, C 10 H 8 N 2 ), (I), bis(2,2′-bipyridine-3κ 2 N , N ′)-di-μ-fluorido-1:3κ 2 F : F ;2:3κ 2 F : F -decafluorido-1κ 5 F ,2κ 5 F -ditantalum(V)copper(II), [Cu(bpy) 2 (TaF 6 ) 2 ], (II), tris(2,2′-bipyridine-κ 2 N , N ′)copper(II) bis[hexafluoridotantalate(V)], [Cu(bpy) 3 ][TaF 6 ] 2 , (III), and catena -poly[[diaqua(2,2′-bipyridine-κ 2 N , N ′)copper(II)]-μ-fluorido-tetrafluoridotin-μ-fluorido], [Cu(bpy)(H 2 O) 2 SnF 6 ] n , (IV). Compounds (I), (II) and (III) contain locally chiral copper coordination complexes with C 2 , D 2 , and D 3 symmetry, respectively. The extended structures of (I) and (IV) are consolidated by O—H...F and O—H...O hydrogen bonds. The structure of (III) was found to be a merohedral (racemic) twin. 

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3. Electronic relaxation dynamics in [Au ₂₅ (SR) ₁₈ ] ⁻¹ (R = CH ₃ , C ₂ H ₅ , C ₃ H ₇ , MPA, PET) thiolate-protected nanoclusters

   https://doi.org/10.1039/C9CP04039K  

   Senanayake, Ravithree D.; Aikens, Christine M. (March 2020, Physical Chemistry Chemical Physics)

   null (Ed.)

   We investigate the excited electron dynamics in [Au 25 (SR) 18 ] −1 (R = CH 3 , C 2 H 5 , C 3 H 7 , MPA, PET) [MPA = mercaptopropanoic acid, PET = phenylethylthiol] nanoparticles to understand how different ligands affect the excited state dynamics in this system. The population dynamics of the core and higher excited states lying in the energy range 0.00–2.20 eV are studied using a surface hopping method with decoherence correction in a real-time DFT approach. All of the ligated clusters follow a similar trend in decay for the core states (S 1 –S 6 ). The observed time constants are on the picosecond time scale (2–19 ps), which agrees with the experimental time scale, and this study confirms that the time constants observed experimentally could originate from core-to-core transitions and not from core-to-semiring transitions. In the presence of higher excited states, R = H, CH 3 , C 2 H 5 , C 3 H 7 , and PET demonstrate similar relaxations trends whereas R = MPA shows slightly different relaxation of the core states due to a smaller gap between the LUMO+1 and LUMO+2 gap in its electronic structure. The S 1 (HOMO → LUMO) state gives the slowest decay in all ligated clusters, while S 7 has a relatively long decay. Furthermore, separate electron and hole relaxations were performed on the [Au 25 (SCH 3 ) 18 ] −1 nanocluster to understand how independent electron and hole relaxations contribute to the overall relaxation dynamics. 

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4. Thermoelectric Properties of p‐ and n‐ type Eu ₅ Sn ₂ As ₆

   https://doi.org/10.1002/zaac.202100386  

   Devlin, Kasey P.; Gomez, Braulio; Kauzlarich, Susan M. (February 2022, Zeitschrift für anorganische und allgemeine Chemie)

   Abstract Eu₅Sn₂As₆is a Zintl phase crystalizing in the orthorhombic space groupPbamwith one‐dimensional chains of corner‐shared SnAs₄tetrahedra running in thec‐direction. Eu₅Sn₂As₆has an impressive room temperature Seebeck of >100 μV/K and < – 100 μV/K at 600 K crossing fromp‐ ton‐type at 650 K. The maximum thermoelectric figure of merit,zT, for Eu₅Sn₂As₆is small (0.075), comparable to that of the Zintl phase Ca₅Al₂Sb₆whose thermoelectric performance was improved by doping Na onto the Ca sites. In this study, we show that the thermoelectric properties of Eu₅Sn₂As₆can be improved by substituting with K or La. The series Eu_5‐xK_xSn₂As₆provides an increase in maximumzTof 0.22 forx=0.15 due to a decrease resistivity while the onset of bipolar conduction systematically increases in temperature. Upon La substitution, Eu_5‐xLa_xSn₂As₆results in a newn‐type Zintl phase across the temperature range of 300–800 K. 

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5. On the formation and the isomer specific detection of methylacetylene (CH ₃ CCH), propene (CH ₃ CHCH ₂ ), cyclopropane (c-C ₃ H ₆ ), vinylacetylene (CH ₂ CHCCH), and 1,3-butadiene (CH ₂ CHCHCH ₂ ) from interstellar methane ice analogues

   https://doi.org/10.1039/C8CP03921F  

   Abplanalp, Matthew J.; Góbi, Sándor; Kaiser, Ralf I. (March 2019, Physical Chemistry Chemical Physics)

   Pure methane (CH 4 ) ices processed by energetic electrons under ultra-high vacuum conditions to simulate secondary electrons formed via galactic cosmic rays (GCRs) penetrating interstellar ice mantles have been shown to produce an array of complex hydrocarbons with the general formulae: C n H 2n+2 ( n = 4–8), C n H 2n ( n = 3–9), C n H 2n−2 ( n = 3–9), C n H 2n−4 ( n = 4–9), and C n H 2n−6 ( n = 6–7). By monitoring the in situ chemical evolution of the ice combined with temperature programmed desorption (TPD) studies and tunable single photon ionization coupled to a reflectron time-of-flight mass spectrometer, specific isomers of C 3 H 4 , C 3 H 6 , C 4 H 4 , and C 4 H 6 were probed. These experiments confirmed the synthesis of methylacetylene (CH 3 CCH), propene (CH 3 CHCH 2 ), cyclopropane (c-C 3 H 6 ), vinylacetylene (CH 2 CHCCH), 1-butyne (HCCC 2 H 5 ), 2-butyne (CH 3 CCCH 3 ), 1,2-butadiene (H 2 CCCH(CH 3 )), and 1,3-butadiene (CH 2 CHCHCH 2 ) with yields of 2.17 ± 0.95 × 10 −4 , 3.7 ± 1.5 × 10 −3 , 1.23 ± 0.77 × 10 −4 , 1.28 ± 0.65 × 10 −4 , 4.01 ± 1.98 × 10 −5 , 1.97 ± 0.98 × 10 −4 , 1.90 ± 0.84 × 10 −5 , and 1.41 ± 0.72 × 10 −4 molecules eV −1 , respectively. Mechanistic studies exploring the formation routes of methylacetylene, propene, and vinylacetylene were also conducted, and revealed the additional formation of the 1,2,3-butatriene isomer. Several of the above isomers, methylacetylene, propene, vinylacetylene, and 1,3-butadiene, have repeatedly been shown to be important precursors in the formation of polycyclic aromatic hydrocarbons (PAHs), but until now their interstellar synthesis has remained elusive. 

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