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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. Barriers for the performance of graph neural networks (GNN) in discrete random structures

   https://doi.org/10.1073/pnas.2314092120  

   Gamarnik, David (November 2023, Proceedings of the National Academy of Sciences)

   Recently, graph neural network (GNN)-based algorithms were proposed to solve a variety of combinatorial optimization problems [M. J. Schuetz, J. K. Brubaker, H. G. Katzgraber,Nat. Mach. Intell.4, 367–377 (2022)]. GNN was tested in particular on randomly generated instances of these problems. The publication [M. J. Schuetz, J. K. Brubaker, H. G. Katzgraber,Nat. Mach. Intell.4, 367–377 (2022)] stirred a debate whether the GNN-based method was adequately benchmarked against best prior methods. In particular, critical commentaries [M. C. Angelini, F. Ricci-Tersenghi,Nat. Mach. Intell.5, 29–31 (2023)] and [S. Boettcher,Nat. Mach. Intell.5, 24–25 (2023)] point out that a simple greedy algorithm performs better than the GNN. We do not intend to discuss the merits of arguments and counterarguments in these papers. Rather, in this note, we establish a fundamental limitation for running GNN on random instances considered in these references, for a broad range of choices of GNN architecture. Specifically, these barriers hold when the depth of GNN does not scale with graph size (we note that depth 2 was used in experiments in [M. J. Schuetz, J. K. Brubaker, H. G. Katzgraber,Nat. Mach. Intell.4, 367–377 (2022)]), and importantly, these barriers hold regardless of any other parameters of GNN architecture. These limitations arise from the presence of the overlap gap property (OGP) phase transition, which is a barrier for many algorithms, including importantly local algorithms, of which GNN is an example. At the same time, some algorithms known prior to the introduction of GNN provide best results for these problems up to the OGP phase transition. This leaves very little space for GNN to outperform the known algorithms, and based on this, we side with the conclusions made in [M. C. Angelini, F. Ricci-Tersenghi,Nat. Mach. Intell.5, 29–31 (2023)] and [S. Boettcher,Nat. Mach. Intell.5, 24–25 (2023)]. 

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3. A Triply Negatively Charged Nanographene Bilayer with Spin Frustration

   https://doi.org/10.1002/anie.202217788  

   Wang, Wenqing; Ma, Xiao‐Hui; Liu, Min; Tang, Shuxuan; Ding, Xuguang; Zhao, Yue; Tan, Yuan‐Zhi; Kertesz, Miklos; Wang, Xinping (January 2023, Angewandte Chemie International Edition)

   Abstract We report on the largest open‐shell graphenic bilayer and also the first example of triply negatively charged radical π‐dimer. Upon three‐electron reduction, bilayer nanographene fragment molecule (C₉₆H₂₄Ar₆)₂(Ar=2,6‐dimethylphenyl) (1₂) was transformed to a triply negatively charged species1₂^3.−, which has been characterized by single‐crystal X‐ray diffraction, electron paramagnetic resonance (EPR) spectroscopy and magnetic properties on a superconducting quantum interference device (SQUID).1₂^3.−features a 96‐center‐3‐electron (96c/3e) pancake bond with a doublet ground state, which can be thermally excited to a quartet state. It consists of 34 π‐fused rings with 96 conjugatedsp²carbon atoms. Spin frustration is observed with the frustration parameterf>31.8 at low temperatures in1₂^3.−, which indicates graphene upon reduction doping may behave as a quantum spin liquid. 

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4. The parasite intraerythrocytic cycle and human circadian cycle are coupled during malaria infection

   https://doi.org/10.1073/pnas.2216522120  

   Motta, Francis C.; McGoff, Kevin; Moseley, Robert C.; Cho, Chun-Yi; Kelliher, Christina M.; Smith, Lauren M.; Ortiz, Michael S.; Leman, Adam R.; Campione, Sophia A.; Devos, Nicolas; et al (June 2023, Proceedings of the National Academy of Sciences)

   During infections with the malaria parasitesPlasmodium vivax, patients exhibit rhythmic fevers every 48 h. These fever cycles correspond with the time the parasites take to traverse the intraerythrocytic cycle (IEC). In otherPlasmodiumspecies that infect either humans or mice, the IEC is likely guided by a parasite-intrinsic clock [Rijo-Ferreiraet al.,Science368, 746–753 (2020); Smithet al.,Science368, 754–759 (2020)], suggesting that intrinsic clock mechanisms may be a fundamental feature of malaria parasites. Moreover, becausePlasmodiumcycle times are multiples of 24 h, the IECs may be coordinated with the host circadian clock(s). Such coordination could explain the synchronization of the parasite population in the host and enable alignment of IEC and circadian cycle phases. We utilized an ex vivo culture of whole blood from patients infected withP. vivaxto examine the dynamics of the host circadian transcriptome and the parasite IEC transcriptome. Transcriptome dynamics revealed that the phases of the host circadian cycle and the parasite IEC are correlated across multiple patients, showing that the cycles are phase coupled. In mouse model systems, host–parasite cycle coupling appears to provide a selective advantage for the parasite. Thus, understanding how host and parasite cycles are coupled in humans could enable antimalarial therapies that disrupt this coupling. 

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5. Brown Grease as a Precursor to Polyol Monomer for Polyurethane Synthesis

   https://doi.org/10.1002/slct.202503006  

   Ksor, Ykok_B; Tennyson, Andrew_G; Smith, Ashlyn_D; Smith, Rhett_C (August 2025, ChemistrySelect)

   Abstract The valorization of waste‐derived feedstocks for polymer synthesis represents a sustainable alternative to petroleum‐based materials. In this study, brown grease, a low‐value waste lipid source, is utilized as a precursor for polyol monomer synthesis via a two‐step functionalization process. Transesterification of brown grease with allyl alcohol generates allyl esters, which are subsequently modified via thiol‐ene click chemistry with 2‐mercaptoethanol to yield hydroxyl‐functionalized polyols (BG‐diol). The thiol‐ene reaction proceeds under mild UV‐initiated conditions, achieving high conversion efficiency (>90%) while preserving the structural integrity of the derived polyol.BG‐diolis further polymerized with 4,4′‐methylene diphenyl diisocyanate (MDI) through step‐growth polymerization to form brown grease‐derived polyurethane (BG‐PU). Comparative analysis ofBG‐PUwith polyurethane (PU) synthesized from purified oleic acid (OLA‐PU) demonstrates comparable molecular weight distributions (M_n = 14.4 kDa,M_w = 20.4 kDa forBG‐PU) and thermal properties (T_g = 24 °C,T_d,5%= 270 °C forBG‐PU). These results underscore the feasibility of brown grease as a cost‐effective and renewable alternative to plant oil‐based polyols, offering a pathway toward sustainable PU production while mitigating food security concerns. This approach exemplifies the potential of waste lipids in circular economy strategies for high‐performance polymer synthesis. 

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