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1. Platinum Elimination from Bis(triethylsilylpolyynyl) Complexes ( n ‐Bu ₂ C(CH ₂ PPh ₂ ) ₂ )Pt((C≡C) _n SiEt ₃ ) ₂ ( n =2, 3) and Macrocycles Comprised of Four L ₂ Pt Corners and Four C≡CC≡CC≡C Linkers; An Approach to Cyclo[24]carbon

   https://doi.org/10.1002/chem.202402833  

   Collins, Brenna_K; Gladysz, John_A (October 2024, Chemistry – A European Journal)

   Abstract The overarching goal of this study is to effect the elimination of platinum from adducts withcis–C≡C−Pt−C≡C‐ linkages, thereby generating novel conjugated polyynes. Thus, the bis(hexatriynyl) complextrans‐(p‐tol₃P)₂Pt((C≡C)₃H)₂is treated with 1,3‐diphosphines R₂C(CH₂PPh₂)₂to generate (R₂C(CH₂PPh₂)₂)₂Pt((C≡C)₃H)₂(14; R=c,n‐Bu;e,p‐tolCH₂). These condense with the diiodide complexes R₂C(CH₂PPh₂)₂PtI₂(9 a,c) in the presence of CuI (cat.) and excess HNEt₂to give the title macrocycles [(R₂C(CH₂PPh₂)₂)Pt(C≡C)₃]₄(16 c,e) as adducts of the byproduct [H₂NEt₂]⁺I⁻(30–66 %). DOSY NMR experiments establish that this association is maintained in solution, but NaOAc removes the ammonium salt. The bis(triethylsilylpolyynyl) complexes (n‐Bu₂C(CH₂PPh₂)₂)Pt((C≡C)_nSiEt₃)₂(n=2, 3) are synthesized analogously to14 c. They react with I₂at rt to give mainly the diiodide complex9 cand the coupling product Et₃Si(C≡CC≡C)_nSiEt₃. The possibility of competing reactions giving IC≡C species is investigated. Analogous reactions of the Pt₄C₂₄macrocycle16 calso give9 c, but no sp¹³C NMR signals or mass spectrometric C_x^z+ions (x=24–100) could be detected. It is proposed that some cyclo[24]carbon is generated, but then rapidly converts to other forms of elemental carbon. No cyclotetracosane (C₂₄H₄₈) is detected when this sequence is carried out in the presence of PtO₂and H₂. 

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2. The Nature of Lithium Bonding in C ₂ H ₂ Li ₂ , C ₆ Li ₆ , and Lithium Halide Dimers

   https://doi.org/10.1021/acs.organomet.9b00683  

   Liu, Yameng; Peng, Bin; Wang, Xiao; Xie, Yaoming; Schaefer, Henry F. (November 2019, Organometallics)
3. Switching CO ₂ Electroreduction Selectivity Between C ₁ and C ₂ Hydrocarbons on Cu Gas‐Diffusion Electrodes

   https://doi.org/10.1002/eem2.12307  

   Zhang, Jianfang; Li, Zhengyuan; Cai, Rui; Zhang, Tianyu; Yang, Shize; Ma, Lu; Wang, Yan; Wu, Yucheng; Wu, Jingjie (April 2022, ENERGY & ENVIRONMENTAL MATERIALS)

   Regulating the selectivity toward a target hydrocarbon product is still the focus of CO₂electroreduction. Here, we discover that the original surface Cu species in Cu gas‐diffusion electrodes plays a more important role than the surface roughness, local pH, and facet in governing the selectivity toward C₁or C₂hydrocarbons. The selectivity toward C₂H₄progressively increases, while CH₄decreases steadily upon lowering the Cu oxidation species fraction. At a relatively low electrodeposition voltage of 1.5 V, the Cu gas‐diffusion electrode with the highest Cu^δ+/Cu⁰ratio favors the pathways of hydrogenation to form CH₄with maximum Faradaic efficiency of 65.4% and partial current density of 228 mA cm⁻²at −0.83 V vs RHE. At 2.0 V, the Cu gas‐diffusion electrode with the lowest Cu^δ+/Cu⁰ratio prefers C–C coupling to form C₂₊products with Faradaic efficiency topping 80.1% at −0.75 V vs RHE, where the Faradaic efficiency of C₂H₄accounts for 46.4% and the partial current density of C₂H₄achieves 279 mA cm⁻². This work demonstrates that the selectivity from CH₄to C₂H₄is switchable by tuning surface Cu species composition of Cu gas‐diffusion electrodes. 

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4. Photocatalytic Ketyl Radical Initiated C _ketyl −C _sp2 /C _sp3 Coupling on ZnIn ₂ S ₄

   https://doi.org/10.1002/chem.202203785  

   Han, Chuang; Han, Guanqun; Habibur_Rahman, Md; Mannodi‐Kanakkithodi, Arun; Sun, Yujie (May 2023, Chemistry – A European Journal)

   Abstract Visible‐light‐driven C−C bond formation utilizing ketyl radical (C_ketyl) species has attracted increasing attention recently, as it provides a direct route for the synthesis of complex molecules. However, the most‐developed homogeneous photocatalytic systems for the generation and utilization of ketyl radicals usually entail noble metal‐based (e. g., Ru and Ir) photosensitizers, which suffer from not only high cost but also potential degradation and hence pose challenges in product separation and purification. In contrast, readily accessible, inexpensive, and recyclable semiconductors represent a class of attractive and alternative photocatalysts but remain much less explored for photocatalytic ketyl radical initiated C−C bond formation. This work demonstrates that a wide range of industrially important chemicals, including substituted chromanes and tertiary alcohols, can be produced on ZnIn₂S₄under visible light irradiation through intramolecular cyclization (C_ketyl−C_sp2) and intermolecular cross‐coupling (C_ketyl−C_sp3) reactions, respectively, using ketyl radicals. A suite of experimental studies aided by computational investigation were carried out to shed light on the mechanistic insights of these two types of ketyl radical initiated C−C coupling reactions on ZnIn₂S₄. 

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5. A Copper-Based Metal–Organic Framework for C ₂ H ₂ /CO ₂ Separation

   https://doi.org/10.1021/acs.inorgchem.1c02552  

   Wang, Xiaodan; Wang, Bin; Zhang, Xin; Xie, Yi; Arman, Hadi; Chen, Banglin (December 2021, Inorganic Chemistry)