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Abstract In this work we report the synthesis, structure, and electronic properties of carbon‐rich compounds dehydrobiphenyleno[12]annulenes (DBP[12]As) comprising antiaromatic four‐membered rings (4MR) and 12‐membered ring (12MR). Ultraviolet–visible absorption spectra and electrochemical behaviors of DBP[12]As confirmed their relatively narrow highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gap values and high HOMO energy levels, which were supported by density functional theory simulations. Parent DBP[12]A adopts a slipped herringbone structure in a crystalline state, with the molecules forming 1D stacks via π–π interactions. The experimentally derived bond lengths, bonding analyses using the Wiberg bond indices, and localized orbital locator calculation support a stronger double bond character for the 12MR bonds than the 4MR bonds in the inner six‐membered ring. The chemical shifts of hydrogens in¹H NMR spectra, as well as magnetically induced ring current analyses using quantum chemical calculations, indicate that the 4MRs have stronger antiaromatic character than the 12MR. The present information is useful for a fundamental understanding of carbon‐rich compounds with different antiaromatic units as well as designing novel molecules with unique electronic properties. 

This article highlights recent computational research on heme-based carbene transfer reactions. Mechanistic insights reveal how cofactor components, coordination modes, substrates, and protein environments influence reactivity and selectivity. 

Building large-scale quantum communication networks has its unique challenges. Here, we demonstrate that a network-wide synergistic usage of quantum memories distributed in a quantum communication network offers a fundamental advantage. We first map the problem of quantum communication with local usage of memories into a classical continuum percolation model. Then, we show that this mapping can be improved through a cooperation of quantum distillation and relay protocols via remote access to distributed memories. This improved mapping, which we term $\alpha$-percolation, can be formulated in terms of graph-merging rules, analogous to the decimation rules of the renormalization group treatment of disordered quantum magnets. These rules can be performed in any order, yielding the same optimal result that is characterized by the emergence of a “positive feedback'' mechanism and the formation of spatially disconnected “hopping'' communication components – both marking significant improvements beyond the traditional point-to-point consideration of quantum communication in networked structures. 

Abstract Optically active point defects in wide‐bandgap semiconductors have been demonstrated to be attractive for a variety of quantum and nanoscale applications. In particular, color centers in hexagonal boron nitride (hBN) have recently gained substantial attention owing to their spectral tunability, brightness, stability, and room‐temperature operation. Despite all of the recent studies, precise detection of the defect‐induced mid‐gap electronic states (MESs) and their simultaneous correlations with the observed emission in hBN remain elusive. Directly probing these MESs provides a powerful approach toward atomic identification and optical control of the defect centers underlying the sub‐bandgap emission in hBN. Combining optical and electron spectroscopy, the existence of mid‐gap absorptive features is revealed at the emissive sites in hBN, along with an atom‐by‐atom identification of the underlying defect configuration. The atomically resolved defect structure, primarily constituted by vacancies and carbon/oxygen substitutions, is further studied via first‐principles calculations, which support the correlation with the observed MESs through the electronic density of states. This work provides a direct relationship between the observed visible emission in hBN, the underlying defect structure, and its absorptive MESs, opening venues for atomic‐scale and optical control in hBN for quantum technology. 

Abstract Variational quantum eigensolvers (VQEs) represent a promising approach to computing molecular ground states and energies on modern quantum computers. These approaches use a classical computer to optimize the parameters of a trial wave function, while the quantum computer simulates the energy by preparing and measuring a set of bitstring observations, referred to as shots, over which an expected value is computed. Although more shots improve the accuracy of the expected ground state, it also increases the simulation cost. Hence, we propose modifications to the standard Bayesian optimization algorithm to leverage few‐shot circuit observations to solve VQEs with fewer quantum resources. We demonstrate the effectiveness of our proposed approach, Bayesian optimization with priors on surface topology (BOPT), by comparing optimizers for molecular systems and demonstrate how current quantum hardware can aid in finding ground‐state energies. 

Lignin‐derived deep eutectic solvents (DESs) have been investigated as sustainable green media for biomass processing. However, the properties and processability of DESs have not been fully understood with the chemical structures of their constituents for biomass fractionation. In this article, the properties of the phenolic DESs are discussed with different numbers of functional groups, such as –OCH₃and –CHO in their hydrogen bond donor (HBD) structures. The formation of DES is significantly related to the hydrogen bond between its constituents, identified by nuclear magnetic resonance (NMR) analysis and density functional theory calculation (DFT). Lower viscosity and net basicity of DES are achieved with fewer –OCH₃on HBD structures, resulting in enhanced processability and fractionation efficiency. The thermal stability of the DES is also influenced by the –OCH₃and –CHO of HBD, as indicated by its onset temperature. The recyclability of the phenolic DES is confirmed by the fractionation performance of the recycled DES. Understanding the structural impacts of DES constituents on the properties and performance is crucial for designing solvents in biorefinery applications. 

Abstract Photoinduced proton transfer powers a myriad of functional processes from bioimaging to photocatalysis. However, the elusive structure‐photoacidity and thermodynamics‐kinetics relationships remain the hurdle for developing such useful tools. Herein, these problems are tackled by systematically investigating photoacids with varied strengths via substitutions on the archetypal green fluorescent protein chromophore. This study quantitatively demonstrates that the thermodynamic driving force of excited‐state proton transfer (ESPT) in water is governed by electronic and steric effects exerted by the substituent. Importantly, two different treatments are proposed in calculating ESPT driving force for the fluorescent and nonfluorescent photoacids. In the latter case, the unusually fast ESPT kinetics result from the extra driving force due to the Franck‐Condon excess vibrational energy besides the free energy difference, thus providing the missing link in current ESPT theory. Furthermore, the thermodynamics‐kinetics relationship for ESPT is unveiled to follow the Bell‐Evans‐Polanyi principle. The work offers the highly desirable predictive power to engineer photoacids with strategic substituents for targeted properties. 

Abstract Fluorinated materials are promising sorbents for the selective removal of per‐ and polyfluoroalkyl substances (PFAS) due to their unique fluorophilic interactions. However, there are gaps in the understanding of design principles toward fluorinated materials for optimized PFAS remediation. In this work, we vary the length of fluorinated side‐chains in copolymer‐functionalized electrodes to study their effect on electrochemically‐mediated PFAS capture and release. Molecular dynamics simulations and adsorption experiments reveal that binding is governed by the total amount of fluorophilic interactions rather than the length of the fluorinated side‐chain. Moreover, the length of the fluorinated side‐chain alters the polymer packing and porosity, which in turn affects PFAS capture and release. Simulations reveal that short‐chain PFAS percolate into the pores of the polymer matrix, while long‐chain PFAS aggregate on the surface, facilitating a faster desorption. Experiments show that desorption is enhanced upon applying potential, regenerating over 80% of the electrode and providing a reversible mechanism for the adsorption and release of PFAS. Additionally, the copolymer sorbents demosntrate selectivity between PFAS, achieving separation factors >190 for perfluorooctanoic acid (PFOA, 7 C–F) over perfluorobutanoic acid (PFBA, 3 C–F). This study provides insights into the design of functional fluorinated materials for electrochemical PFAS separations.