Qingheng Lai

Organic electrochemical transistors (OECTs) efficiently convert ionic signals into measurable electronic currents, enabling applications in bioelectronic sensors, neuromorphic devices, and low‐voltage integrated circuits. High device performance relies on conjugated polymer structures capable of balanced mixed ionic‐electronic conduction, motivating side‐chain engineering design strategies. Here we report a systematic study comparing the properties of DPP‐EDOT polymers in which branched alkyl side chains are progressively replaced by linear glycolated EG ₅ substituents (0%–100%) and evaluate their performance metrics in both conventional (cOECT) and vertical (vOECT) device architectures. Increasing EG ₅ content monotonically increases both steady‐state ( g _{m, max, norm} = 1.27 → 70.73 S·cm ⁻¹ ) and transient performance ( τ _ON/ τ _OFF = 903.91/473.9 → 2.4/0.4 ms) in cOECTs. In contrast, vOECTs exhibit a more pronounced composition‐dependent transition: the vertical architecture delivers outstanding performance only when EG ₅ content exceeds ∼50%, revealing a critical hydrophilicity requirement imposed by the reduced ion‐injection area and extended lateral ion‐transport pathways intrinsic to the vertical geometry. These findings establish architecture‐dependent molecular design principles for effectively pairing OMIECs with planar and vertical OECT configurations.

Efficient, selective, and environmentally benign catalytic nitrile synthesis is attractive for pharmaceuticals, specialty chemicals and materials, and large‐scale industrial applications. In this regard, metal‐catalyzed silylative conversion of primary amides to nitriles is emerging as a promising approach. This contribution reports the utilization of readily available lanthanide‐organic amido precatalysts, Ln[N(SiMe ₃ ) ₂ ] ₃ , Ln = lanthanide, to selectively convert primary alkyl and aryl/heterocyclic amides having diverse functional groups to nitriles, including pharma building blocks, in high yields using the silane reagents PhSiH ₃ and TMS‐O‐[Si(H)(Me)‐O‐] _n ‐TMS in a solvent‐free process. Kinetic and mechanistic data reveal the role of lanthanide amidates as the catalytically‐active species, while DFT analysis indicates a catalytic pathway unlike that found in transition metal complex‐catalyzed processes. Thus, the lanthanide amidate resting state actively participates in the catalysis, where rate‐determining bound amidate silylation is activated by the metal center and influenced by the bound amidate electronic and steric characteristics. DFT analysis of the catalytic cycle reveals that the relative energies of three intermediate endergonic steps, hence the rate‐determining step, depends on the silane concentration.

Current methods of processing accumulated polyolefin waste typically require harsh conditions, precious metals or high metal loadings to achieve appreciable activities. Here we examined supported, single-site organonickel catalysts for polyolefin upcycling. Chemisorption of Ni(COD)₂ (COD, 1,5-cyclooctadiene) onto Brønsted acidic sulfated alumina (AlS) yields a highly electrophilic Ni(I) precatalyst, AlS/Ni(COD)₂, which is converted under H₂ to the active AlS/Ni^IIH catalyst. This single-site system exhibits unique hydrogenolysis selectivity that favours cleaving branched polyolefin C–C linkages, enabling the hydrogenolytic separation of polyethylene and isotactic polypropylene (iPP) mixtures. Moreover, AlS/Ni^IIH remains highly selective and active for hydrogenolysis of iPP admixed with polyvinyl chloride, and the spent catalyst can be repeatedly regenerated by AlEt₃ treatment. Experimental mechanistic analysis and density functional theory modelling reveal a turnover-limiting C–C scission pathway featuring β-alkyl transfer and strong olefin binding. These results highlight the potential of nickel-based systems for the selective upcycling of complex plastic waste streams.

Methane dehydroaromatization (MDA) is one of the most promising technologies for directly transforming methane into aromatics. Unlike the extensively investigated Mo/ZSM‐5 catalysts, the structure and, consequently, the catalytic activity of Fe/ZSM‐5 are markedly influenced by the method of preparation, as shown here. In this study, we prepared 2 % and 4 % Fe/ZSM‐5 catalysts via wet impregnation (WI) and incipient wetness impregnation (IWI). Characterizations (XRD, STEM, UV‐Vis, NH₃‐TPD and H₂‐TPR) reveal that 2 %Fe‐WI mainly possesses isolated or low‐polymerized Fe species within zeolite channels, leading to a rapid activation and a higher benzene yield due to the faster reduction to iron suboxides under MDA conditions. In contrast, 2 %Fe‐IWI contains bulk iron oxide aggregates, resulting in a slower activation as these aggregates transform into iron carbide through successive reduction and carbonization. A deactivation kinetic study applied to the 2 % catalysts further demonstrates the quantitative relation between Fe site isolation and catalytic activity. Although both 4 % catalysts inevitably form sizable iron oxide clusters and particles due to the high Fe/Al ratio, similar trends are noted, with the WI catalysts exhibiting a shorter induction/activation period and a higher yield of benzene, paralleling observations made with 2 % catalysts.

Rh complexes of a tridentate PPP ligand bearing 1,2-pyrrolediyl linkers have been prepared, including examples with the central P donor being either a phosphine or a phosphide. Three bimetallic Rh complexes containing the diamandoid Rh2P2 core (P = phosphido) have been structurally and spectroscopically characterized. The Rh-Rh interaction in these three dimers was examined by way of structural comparisons and DFT investigations.

The novel electrophilic organo‐tantalum catalyst AlS/TaNp_x (1) (Np=neopentyl) is prepared by chemisorption of the alkylidene Np₃Ta=CH^tBu onto highly Brønsted acidic sulfated alumina (AlS). The proposed catalyst structure is supported by EXAFS, XANES, ICP, DRIFTS, elemental analysis, and SSNMR measurements and is in good agreement with DFT analysis. Catalyst 1 is highly effective for the hydrogenolysis of diverse linear and branched hydrocarbons, ranging from C2 to polyolefins. To the best of our knowledge, 1 exhibits one of the highest polyolefin hydrogenolysis activities (9,800 (CH₂ units) ⋅ mol(Ta)⁻¹ ⋅ h⁻¹ at 200 °C/17 atm H₂) reported to date in the peer‐reviewed literature. Unlike the AlS/ZrNp₂ analog, the Ta catalyst is more thermally stable and offers multiple potential C−C bond activation pathways. For hydrogenolysis, AlS/TaNp_x is effective for a wide variety of pre‐ and post‐consumer polyolefin plastics and is not significantly deactivated by standard polyolefin additives at typical industrial concentrations.

Protolysis of AlMe₃ or AlBuⁱ₃ with 2-diisopropylphosphinopyrrole (1) yields molecules containing two flanking phosphines and a central Al-Me (2-Me), Al-ⁱBu (2-ⁱBu), or Al-H (2-H) unit. The reactions of 2-Me with [L₂MCl]₂ (L = cyclooctene or 1/2 1,5-cyclooctadiene and M = Rh or Ir) in the presence of pyridine produces PAl^ClP pincer complexes (3-Rh and 3-Ir) with Al-Cl and M-Me bonds. The analogous reaction of a mixture of 2-ⁱBu and 2-H with [L₂MCl]₂ and pyridine resulted in the formation of analogous Rh-H (4-Rh) and Ir-H (4-Ir) complexes. Treatment of 3-Rh with NaBEt₃H produced compound 5-Rh with an Al-Me and a Rh-H bond; the analogous reaction of 3-Ir did not result in a clean product. 4-Ir accepted an equivalent of H₂ to produce 6-Ir with two terminal Ir-H bonds and one bridging Al-H-Ir moiety, whereas 4-Rh did not react with H₂. The density functional theoretical treatment is in accord with this finding, highlights the likely mechanism for the H₂ addition, and supports the bonding picture in 6-Ir arising from NMR and X-ray diffraction (XRD) observations. Spectroscopic data and XRD studies are consistent with distorted square-pyramidal structures (about Rh or Ir) for compounds 3-5, with an alane occupying the apical position. Complexes 3 and 4 possess some of the shortest known Rh-Al or Ir-Al distances.

: A homologous series of cationic electrophilic group IV metal hydrides (M = Ti, Zr, Hf) created by chemisorption of the corresponding MNp4 precursors on highly Brønsted acidic sulfated alumina (AlS) to yield loosely coordinated surface AlS/MNp2 (Np = neopentyl) species are systematically characterized by ICP, EXAFS/XANES, DRIFTS, and solid-state high-resolution multi-dimensional NMR spectroscopy (SSNMR), as well as by energy span DFT computation. With effective stirring, these complexes readily undergo reaction with H2 to yield AlS/M(alkyl)H species which are highly active for the hydrogenolysis of diverse commercial polyethylenes, α-olefin-ethylene copolymers, isotactic polypropylene, and post-consumer polyolefins including high-density polyethylenes, yielding medium and small linear and branched hydrocar-bons at turnover frequencies as high as 36,300 h-1 at 200 °C/17 atm H2 for M = Zr. For a given polyolefin and reaction conditions, turnover frequencies scale approximately as M = Zr > Hf > Ti, while catalyst thermal stability scales approxi-mately as M = Hf ≈ Zr > Ti, and these trends are qualitatively understandable from the DFT analysis. These catalytic re-sults reveal that the AlS/Hf(R)H- mediated hydrogenolysis favors wax-like and liquid products while the AlS/Zr(R)H-mediated hydrogenolysis can be tuned between gases and liquids. DFT analysis identifies β-alkyl elimination as the turn-over-limiting C-C scission process, which is particularly facile in these cationic d0 complexes, but not so in the neutrally charged analogues