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Polycyclic hydrocarbons consisting of two or more directly fused antiaromatic subunits are rare due to their high reactivity. However, it is important to understand how the interactions between the antiaromatic subunits influence the electronic properties of the fused structure. Herein, we present the synthesis of two fused indacene dimer isomers: s‐indaceno[2,1‐a]‐s‐indacene (s‐ID) and as‐indaceno[3,2‐b]‐as‐indacene (as‐ID), containing two fused antiaromatic s‐indacene or as‐indacene units, respectively. Their structures were confirmed by X‐ray crystallographic analysis. 1H NMR/ESR measurements and DFT calculations revealed that both s‐ID and as‐ID have an open‐shell singlet ground state. However, while localized antiaromaticity was observed in s‐ID, as‐ID showed weak global aromaticity. Moreover, as‐ID exhibited a larger diradical character and a smaller singlet‐triplet gap than s‐ID. All the differences can be attributed to their distinct quinoidal substructures. [ABSTRACT FROM AUTHOR]

Polycyclic hydrocarbons consisting of two or more directly fused antiaromatic subunits are rare due to their high reactivity. However, it is important to understand how the interactions between the antiaromatic subunits influence the electronic properties of the fused structure. Herein, we present the synthesis of two fused indacene dimer isomers: s‐indaceno[2,1‐a]‐s‐indacene (s‐ID) and as‐indaceno[3,2‐b]‐as‐indacene (as‐ID), containing two fused antiaromatic s‐indacene or as‐indacene units, respectively. Their structures were confirmed by X‐ray crystallographic analysis. 1H NMR/ESR measurements and DFT calculations revealed that both s‐ID and as‐ID have an open‐shell singlet ground state. However, while localized antiaromaticity was observed in s‐ID, as‐ID showed weak global aromaticity. Moreover, as‐ID exhibited a larger diradical character and a smaller singlet‐triplet gap than s‐ID. All the differences can be attributed to their distinct quinoidal substructures. [ABSTRACT FROM AUTHOR]

Chiral shape‐persistent molecular nanocarbons are promising chiroptical materials; their synthesis, however, remains a big challenge. Herein, we report the facile synthesis and chiral resolution of a double‐stranded figure‐eight carbon nanobelt 1 in which two [5]helicene units are fused together. Two synthetic routes were developed, and, in particular, a strategy involving Suzuki coupling‐mediated macrocyclization followed by Bi(OTf)3‐catalyzed cyclization of vinyl ether turned out to be the most efficient. The structure of 1 was confirmed by X‐ray crystallographic analysis. The isolated (P,P)‐ and (M,M)‐ enantiomers show persistent chiroptical properties with relatively large dissymmetric factors (|gabs|=5.4×10−3 and |glum|=1.0×10−2), which can be explained by the effective electron delocalization along the fully conjugated belt and the unique D2 symmetry. 1 exhibits local aromatic character with a dominant structure containing eight Clar's aromatic sextet rings. [ABSTRACT FROM AUTHOR]

Chiral shape‐persistent molecular nanocarbons are promising chiroptical materials; their synthesis, however, remains a big challenge. Herein, we report the facile synthesis and chiral resolution of a double‐stranded figure‐eight carbon nanobelt 1 in which two [5]helicene units are fused together. Two synthetic routes were developed, and, in particular, a strategy involving Suzuki coupling‐mediated macrocyclization followed by Bi(OTf)3‐catalyzed cyclization of vinyl ether turned out to be the most efficient. The structure of 1 was confirmed by X‐ray crystallographic analysis. The isolated (P,P)‐ and (M,M)‐ enantiomers show persistent chiroptical properties with relatively large dissymmetric factors (|gabs|=5.4×10−3 and |glum|=1.0×10−2), which can be explained by the effective electron delocalization along the fully conjugated belt and the unique D2 symmetry. 1 exhibits local aromatic character with a dominant structure containing eight Clar's aromatic sextet rings. [ABSTRACT FROM AUTHOR]

Circumcoronene, a hexagonal graphene fragment with six zigzag edges, has been the focus of theoretical studies for many years, but its synthesis in solution has remained a challenge. In this study, we present a facile method for synthesizing three derivatives of circumcoronene using Brønsted/Lewis acid‐mediated cyclization of vinyl ether or alkyne. Their structures were confirmed through X‐ray crystallographic analysis. Bond length analysis, NMR measurement, and theoretical calculations showed that circumcoronene mostly follows Clar's bonding model and exhibits dominant local aromaticity. Its absorption and emission spectra are similar to those of the smaller hexagonal coronene due to its six‐fold symmetry. [ABSTRACT FROM AUTHOR]

Circumcoronene, a hexagonal graphene fragment with six zigzag edges, has been the focus of theoretical studies for many years, but its synthesis in solution has remained a challenge. In this study, we present a facile method for synthesizing three derivatives of circumcoronene using Brønsted/Lewis acid‐mediated cyclization of vinyl ether or alkyne. Their structures were confirmed through X‐ray crystallographic analysis. Bond length analysis, NMR measurement, and theoretical calculations showed that circumcoronene mostly follows Clar's bonding model and exhibits dominant local aromaticity. Its absorption and emission spectra are similar to those of the smaller hexagonal coronene due to its six‐fold symmetry. [ABSTRACT FROM AUTHOR]

An [8]cyclo‐para‐phenylmethine derivative ([8]CPPM‐Mes) was synthesized. X‐ray analysis revealed a tub‐shaped geometry similar to the cyclooctatetraene, with alternating benzenoid/quinoid structure. Variable‐temperature NMR measurements disclosed a slow valence tautomerization process with an interconversion energy barrier of about 11.7 kcal mol−1 at coalescence temperature (273 K), and two more lower‐barrier dynamic processes involving flipping of the 1,4‐phenyl rings on the backbone and rotation of the mesityl substituents. Its dication ([8]CPPM‐Mes2+) adopts a bowl‐like geometry with a smaller depth of the cavity, and a slow bowl inversion process was observed by dynamic NMR. The bond lengths of the benzenoid/quinoid rings are more averaged via electron delocalization and the molecule shows global aromaticity, which was further validated by NMR and theoretical analysis. [8]CPPM‐Mes2+ exhibits open‐shell diradical character with a small singlet‐triplet energy gap (−1.8 kcal mol−1). [ABSTRACT FROM AUTHOR]

An [8]cyclo‐para‐phenylmethine derivative ([8]CPPM‐Mes) was synthesized. X‐ray analysis revealed a tub‐shaped geometry similar to the cyclooctatetraene, with alternating benzenoid/quinoid structure. Variable‐temperature NMR measurements disclosed a slow valence tautomerization process with an interconversion energy barrier of about 11.7 kcal mol−1 at coalescence temperature (273 K), and two more lower‐barrier dynamic processes involving flipping of the 1,4‐phenyl rings on the backbone and rotation of the mesityl substituents. Its dication ([8]CPPM‐Mes2+) adopts a bowl‐like geometry with a smaller depth of the cavity, and a slow bowl inversion process was observed by dynamic NMR. The bond lengths of the benzenoid/quinoid rings are more averaged via electron delocalization and the molecule shows global aromaticity, which was further validated by NMR and theoretical analysis. [8]CPPM‐Mes2+ exhibits open‐shell diradical character with a small singlet‐triplet energy gap (−1.8 kcal mol−1). [ABSTRACT FROM AUTHOR]

Synthesis of triangulene and its derivatives is challenging due to their intrinsic high spin nature. Herein, we report solution‐phase synthesis and isolation of a nitrogen‐doped triangulene (i.e. aza‐triangulene) (NT) and its cation (NT+) in single‐crystal form. Notably, the cation NT+ can be regarded as an isoelectronic structure of the corresponding all‐carbon triangulene. Both NT and NT+ show reasonable stability due to kinetic blocking by bulky and electron‐withdrawing aryl substituents, and intramolecular donor‐acceptor interaction. Bond length analysis, magnetic measurements and theoretical calculations reveal that the neutral NT has a doublet ground state with a zwitterionic character, while the cation NT+ exhibits a triplet ground state with a singlet‐triplet energy gap of +0.84 kcal mol−1. This study provides a rational strategy to access high‐spin systems by heteroatom doping of pure π‐conjugated polycyclic hydrocarbons. [ABSTRACT FROM AUTHOR]

Synthesis of triangulene and its derivatives is challenging due to their intrinsic high spin nature. Herein, we report solution‐phase synthesis and isolation of a nitrogen‐doped triangulene (i.e. aza‐triangulene) (NT) and its cation (NT+) in single‐crystal form. Notably, the cation NT+ can be regarded as an isoelectronic structure of the corresponding all‐carbon triangulene. Both NT and NT+ show reasonable stability due to kinetic blocking by bulky and electron‐withdrawing aryl substituents, and intramolecular donor‐acceptor interaction. Bond length analysis, magnetic measurements and theoretical calculations reveal that the neutral NT has a doublet ground state with a zwitterionic character, while the cation NT+ exhibits a triplet ground state with a singlet‐triplet energy gap of +0.84 kcal mol−1. This study provides a rational strategy to access high‐spin systems by heteroatom doping of pure π‐conjugated polycyclic hydrocarbons. [ABSTRACT FROM AUTHOR]

The incorporation of organic radicals into coordination polymers was considered as a promising strategy to promote metal‐ligand exchange interactions, but there are only a very limited number of stable organic radical‐based ligands that can serve well such a purpose. Herein, we report two new tris(2,4,6‐trichlorophenyl)methyl (TTM) radical‐based ligands L1 and L2 with two and three imidazole substituents, respectively. The imidazole unit serves as a coordination site and it can also stabilize the TTM radical by intramolecular donor–acceptor interaction. Coordination of L1 and L2 with cobalt(II) ions gave the corresponding one‐ (CoCP‐1) and two‐dimensional (CoCP‐2) coordination polymers, the structures of which were confirmed by X‐ray crystallographic analysis. Magnetic measurements and theoretical calculations suggest antiferromagnetic coupling between the paramagnetic cobalt(II) ions and the radical ligands. Our study provides a rational design for stable organic radical‐based ligands and further demonstrated the feasibility of a metal–radical approach toward magnetic materials. [ABSTRACT FROM AUTHOR]

The study of through‐space electronic coupling in π‐conjugated systems remains an underexplored area. In this work, we present the facile synthesis of two isomeric macrocycles (1 and 2) bridged by [2,2]paracyclophane (pCp) and based on thiophene. The structures of these macrocycles have been confirmed through X‐ray crystallographic analysis. Our investigation centers on their electronic properties across various redox states, with a specific focus on potential through‐space electronic coupling and global aromaticity. Experimental measurements, including UV‐vis‐NIR electronic absorption, NMR, ESR spectra, and X‐ray diffraction, combined with theoretical calculations, reveal that both the neutral compounds and their tetracations exhibit a closed‐shell ground state. However, their dications manifest as diradical dications with a subtle magnetic exchange interaction. Consequently, the through‐space electronic coupling facilitated by the pCp unit in their respective ground states appears to be weak. [ABSTRACT FROM AUTHOR]

Keywords: Antiaromaticity; Aromaticity; Diradicaloid; Indacene; Polycyclic Hydrocarbon EN Antiaromaticity Aromaticity Diradicaloid Indacene Polycyclic Hydrocarbon 1 1 1 09/14/23 20230918 NES 230918 B Polycyclic Hydrocarbons b . Both isomers display an open-shell singlet ground state. In their Communication (e202304937), Chunyan Chi et al. report the synthesis and isolation in single-crystal form of two fused indacene dimer isomers. [Extracted from the article]

Both isomers display an open-shell singlet ground state. In their Communication (e202304937), Chunyan Chi et al. report the synthesis and isolation in single-crystal form of two fused indacene dimer isomers. [Extracted from the article]

Highlights • 25 mg/L GA 3 +10 mg/L CPPU can nearly eliminated russet on grape berry peel. • The changes of enzyme activity (PAL) can effect the russet on grape berry peel. • Coatomer subunit beta'-2 (like) genes may participate in the elimination of russet. Abstract Russet on grape peel is a physiological disorder that effects grape quality and can be reduced or eliminated by different concentrations of GA 3 (gibberellic acid) + CPPU (N-(2-chloro-4-pyridyl)-N'-phenylurea). We have performed transcriptome and differential transcript expression analyses in 'Shine Muscat' grape at fruiting stage using Illumina RNA-seq to elucidate the mechanisms of russet elimination. 'Shine Muscat' clusters were treated with 25 mg/L GA 3 (GA) at full-bloom stage and 15 days after the full-bloom stage had a far less rusted appearance (˜5% of total peel) as compared to control treatment (CK) (> 20% of total peel). Approximately all russeted peel was eliminated after treatment with (25 mg/L GA3 + 10 mg/L CPPU) at full-bloom stage and 15 days after full-bloom stage (GA + CPPU). Measurement of enzyme activity indicated the GA + CPPU treatment had the lowest phenylalanine ammonia-lyase (PAL), 4-coumarate (4CL), and peroxidase (POD) enzyme activity. Analyses of three RNA-seq libraries identified 2385 transcripts (1271 up-regulated transcripts and 1114 down-regulated transcripts) with significant expression changes. RNA-seq and qRT-PCR following GA3 and CPPU application identified two putative mechanisms responsible for reducing or eliminating russet at berry pericarp: PAL activity was positively correlated with russet on peel and up-regulation of condition-specific genes expressed in the endoplasmic reticulum and Golgi non-clathrin-coated vesicles genes are potentially involved in the elimination of russet. GA 3 coupled with CPPU can approximately eliminate russet after application of above mentioned treatments.and PAL activity is shown to positively correlated with the elimination of russet. Furthermore, other factors are likely to be involved in the elimination of russet due to up-regulation of condition-specific coatomer subunit beta'-2 like genes. [ABSTRACT FROM AUTHOR]

Physiological (metabolite analysis) and molecular (gene expression) approaches were used to understand the mechanism underlying russet formation in response to the application of GA3 and CPPU (Forchlorfenuron) in a Japanese table grape cultivar 'Shine Muscat'. Several different concentrations of GA3 and GA3 + CPPU [25 mg L−1 GA3 (A), 25 mg L−1 GA3 + 5 mg L−1 CPPU (B), 25 mg L−1 GA3 + 10 mg L−1 CPPU (C), and 25 mg L−1 GA3 + 15 mg L−1 CPPU (D)] were applied to grape berry clusters at two weeks after flowering (WAF). No russet was observed on the berries treated with the 'C' combination. Lower levels of phenylalanine ammonia-lyase (PAL) activity was observed in the treated samples, relative to the untreated material. Reduced peroxide (POD) activity was also observed in response to different treatments, while the expression of Peroxidase 17 and Phenylalanine ammonia-lyase G1 genes mirrored lignin content. Increased activity of 4-coenzyme A ligase (4CL) may contribute to decreasing the level of russet and help to improve grape berry quality. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) with a one‐dimensional (1D), ribbon‐like structure have the potential to serve as both model compounds for corresponding graphene nanoribbons (GNRs) and as materials for optoelectronics applications. However, synthesizing molecules of this type with extended π‐conjugation presents a significant challenge. In this study, we present a straightforward synthetic method for a series of bis‐peri‐dinaphtho‐rylene molecules, wherein the peri‐positions of perylene, quaterrylene, and hexarylene are fused with naphtho‐units. These molecules were efficiently synthesized primarily through intramolecular or intermolecular radical coupling of in situ generated organic radical species. Their structures were confirmed using X‐ray crystallographic analysis, which also revealed a slightly bent geometry due to the incorporation of a cyclopentadiene ring at the bay regions of the rylene backbones. Bond lengh analysis and theoretical calculations indicate that their electronic structures resemble pyrenacenes more than quinoidal rylenes. That is, the aromatic sextets are predominantly localized along the long axis of the skeletones. As the chain length increases, these molecules exhibit enhanced electronic absorption with a bathochromic shift, and multiple amphoteric redox waves. This study introduces a novel synthetic approach for generating 1D extended PAHs and GNRs, along with their structure‐dependent electronic properties. [ABSTRACT FROM AUTHOR]

Polycyclic aromatic hydrocarbons (PAHs) with a one‐dimensional (1D), ribbon‐like structure have the potential to serve as both model compounds for corresponding graphene nanoribbons (GNRs) and as materials for optoelectronics applications. However, synthesizing molecules of this type with extended π‐conjugation presents a significant challenge. In this study, we present a straightforward synthetic method for a series of bis‐peri‐dinaphtho‐rylene molecules, wherein the peri‐positions of perylene, quaterrylene, and hexarylene are fused with naphtho‐units. These molecules were efficiently synthesized primarily through intramolecular or intermolecular radical coupling of in situ generated organic radical species. Their structures were confirmed using X‐ray crystallographic analysis, which also revealed a slightly bent geometry due to the incorporation of a cyclopentadiene ring at the bay regions of the rylene backbones. Bond lengh analysis and theoretical calculations indicate that their electronic structures resemble pyrenacenes more than quinoidal rylenes. That is, the aromatic sextets are predominantly localized along the long axis of the skeletones. As the chain length increases, these molecules exhibit enhanced electronic absorption with a bathochromic shift, and multiple amphoteric redox waves. This study introduces a novel synthetic approach for generating 1D extended PAHs and GNRs, along with their structure‐dependent electronic properties. [ABSTRACT FROM AUTHOR]

We demonstrated a facile and efficient method for the preparation of a magnetic and porous Ni@MOF-74(Ni) [Ni 2 (DOBDC), DOBDC = 2, 5-dihydroxyterephthalate] composite by one-step solvothermal reaction of Raney Ni and DOBDC. Ni in the reaction not only acted as the core of the composite, but also provided metal source for the formation of MOF-74(Ni). The Ni@MOF-74(Ni) composite exhibits both magnetic characteristics and high porosity, enabling it an efficient candidate for dye removal and target drug delivery system. The adsorption amount of rhodamine b reached up to 177.8 mg g −1 , and 4.1 mg g −1 for ibuprofen. [ABSTRACT FROM AUTHOR]

We present a facile and one-step synthesis of a N-doped porous carbon (NPC) material by direct heating of dicyanobenzene in the presence of ZnCl2, free from any pre- or post-treatment. The resultant NPC material features graphite-like monolayers with a thickness of approximately 1.4 nm, as proven by microscopy technology. NPC shows a BET surface area of 3038.5 m2 g−1 and a narrow pore-size distribution centered at 0.51 nm. As a consequence, NPC displays a high H2 uptake of up to 2.96 wt % at 77 K and a CO2 adsorption capability of 23.4 wt % at 278 K and 0.1 MPa. N-doping leads to extension of the optical absorption of NPC into the near-infrared (NIR) region. This N-decorated carbon material, as the first example of a NIR-triggered carbon photocatalyst, exhibits pronounced H2 production capabilities. Carbonization of aromatic multinitriles would be a general and facile approach to prepare multifunctional N-doped carbon materials for gas storage and full solar spectrum driven photocatalysts. [ABSTRACT FROM AUTHOR]

We present a gigantic polyoxozirconate nanocluster (Zr18O21(μ2-OH)2(OOCPh)28), involving 6, 7 and 8-coordinated Zr atoms. It exhibits visible light driven photocatalytic activity for H2 evolution. The current results could represent a prelude of polyoxozirconate-based photocatalysis. [ABSTRACT FROM AUTHOR]

Circumacenes (CAs) are a distinctive type of benzenoid polycyclic aromatic hydrocarbons where an acene unit is completely enclosed by a layer of outer fused benzene rings. Despite their unique structures, the synthesis of CAs is challenging, and until recently, the largest CA molecule synthesized was circumanthracene. In this study, we report the successful synthesis of an extended circumpentacene derivative 1, which represents the largest CA molecule synthesized to date. Its structure was confirmed by X‐ray crystallographic analysis and its electronic properties were systematically investigated by both experiments and theoretical calculations. It shows a unique open‐shell diradical character due to the existence of extended zigzag edges, with a moderate diradical character index (y0=39.7 %) and a small singlet‐triplet energy gap (ΔES‐T=−4.47 kcal/mol). It exhibits a dominant local aromatic character with π‐electrons delocalized in the individual aromatic sextet rings. It has a small HOMO–LUMO energy gap and displays amphoteric redox behavior. The electronic structures of its dication and dianion can be considered as doubly charged structures in which two coronene units are fused with a central aromatic benzene ring. This study provides a new route toward stable multizigzag‐edged graphene‐like molecules with open‐shell di/polyradical character. [ABSTRACT FROM AUTHOR]

Circumacenes (CAs) are a distinctive type of benzenoid polycyclic aromatic hydrocarbons where an acene unit is completely enclosed by a layer of outer fused benzene rings. Despite their unique structures, the synthesis of CAs is challenging, and until recently, the largest CA molecule synthesized was circumanthracene. In this study, we report the successful synthesis of an extended circumpentacene derivative 1, which represents the largest CA molecule synthesized to date. Its structure was confirmed by X‐ray crystallographic analysis and its electronic properties were systematically investigated by both experiments and theoretical calculations. It shows a unique open‐shell diradical character due to the existence of extended zigzag edges, with a moderate diradical character index (y0=39.7 %) and a small singlet‐triplet energy gap (ΔES‐T=−4.47 kcal/mol). It exhibits a dominant local aromatic character with π‐electrons delocalized in the individual aromatic sextet rings. It has a small HOMO–LUMO energy gap and displays amphoteric redox behavior. The electronic structures of its dication and dianion can be considered as doubly charged structures in which two coronene units are fused with a central aromatic benzene ring. This study provides a new route toward stable multizigzag‐edged graphene‐like molecules with open‐shell di/polyradical character. [ABSTRACT FROM AUTHOR]

Expanded helicenes are expected to show enhanced chiroptical properties as compared to the classical helicenes but the synthesis is very challenging. Herein, we report the facile synthesis of a series of expanded helicenes Hn (n=1–4) containing 11, 19, 27 and 35 cata‐fused benzene rings through Suzuki coupling‐based oligomerization followed by Bi(OTf)3‐mediated regioselective cyclization of vinyl ethers. Their structures were determined by X‐ray crystallographic analysis. Enantiopure H2, H3, and H4 can be isolated by chiral HPLC and they all exhibit strong chiroptical responses with high absorption dissymmetry factor (|gabs|) values (0.020 for H2, 0.021 for H3, and 0.021–0.024 for H4). [ABSTRACT FROM AUTHOR]

Expanded helicenes are expected to show enhanced chiroptical properties as compared to the classical helicenes but the synthesis is very challenging. Herein, we report the facile synthesis of a series of expanded helicenes Hn (n=1–4) containing 11, 19, 27 and 35 cata‐fused benzene rings through Suzuki coupling‐based oligomerization followed by Bi(OTf)3‐mediated regioselective cyclization of vinyl ethers. Their structures were determined by X‐ray crystallographic analysis. Enantiopure H2, H3, and H4 can be isolated by chiral HPLC and they all exhibit strong chiroptical responses with high absorption dissymmetry factor (|gabs|) values (0.020 for H2, 0.021 for H3, and 0.021–0.024 for H4). [ABSTRACT FROM AUTHOR]

The Geobiodiversity Database (GBDB) Project is dedicated to the construction and maintenance of a web-enabled taxonomic, stratigraphic and geographic database for information gathered from the fossil record. Its goal is to facilitate regional and global scientific collaborations focused on studying the history, diversity, geography and environmental context of life on Earth. After 7 years of development, its abundant data resources and diverse integrated functions make it a useful platform for stratigraphic, palaeontological and palaeogeographic analysis. Graptolites are the first major fossil group that has been the focus of our efforts to compile, standardize, digitize and analyse over the past several years. Here, we use the graptolite group as an example to introduce the major data resources and functionality of the GBDB. [ABSTRACT FROM AUTHOR]

Hydrogen spillover, involving the transfer of H atoms from metal sites onto the catalyst support, is ubiquitous in chemical processes such as catalytic hydrogenation and hydrogen storage. Atomic level information concerning the kinetics of this process, the structural evolution of catalysts during hydrogen spillover, as well as the nature of participation of the spilled over H in catalysis, remain vastly lacking. Here, we provide insights to those questions with a solubilized polyoxometalate‐supported single‐atom catalyst which allows for the use of characterization techniques generally inaccessible to the study of heterogeneous catalysts. Hydrogenation kinetics together with poisoning studies further reveal that hydrogen spillover can be either detrimental or beneficial for catalysis, the direction and magnitude of which depends mostly on the nature of the reducible functional group. Similar trends were observed on one of the most prototypical hydrogen spillover catalysts—Pt/WO3. [ABSTRACT FROM AUTHOR]

Hydrogen spillover, involving the transfer of H atoms from metal sites onto the catalyst support, is ubiquitous in chemical processes such as catalytic hydrogenation and hydrogen storage. Atomic level information concerning the kinetics of this process, the structural evolution of catalysts during hydrogen spillover, as well as the nature of participation of the spilled over H in catalysis, remain vastly lacking. Here, we provide insights to those questions with a solubilized polyoxometalate‐supported single‐atom catalyst which allows for the use of characterization techniques generally inaccessible to the study of heterogeneous catalysts. Hydrogenation kinetics together with poisoning studies further reveal that hydrogen spillover can be either detrimental or beneficial for catalysis, the direction and magnitude of which depends mostly on the nature of the reducible functional group. Similar trends were observed on one of the most prototypical hydrogen spillover catalysts—Pt/WO3. [ABSTRACT FROM AUTHOR]

Synthesis of π‐conjugated crystalline two‐dimensional (2D) polymers remains largely unexplored due to limited synthetic methodology. Herein, we report the preparation of a 1,6‐anthrazoline (AZ)‐linked crystalline 2D polymer AZP via acid mediated Friedländer synthesis. The feasibility was examined first by two model reactions, followed by synthesis of three AZ‐based macrocycles MCn (n=5–7), in which hexagonal MC6 was isolated as the major product. The favorable macrocycle formation could be largely attributed to the dynamic feature of Friedländer synthesis, which involves both imine condensation and aldol condensation. The structure and crystallinity of AZP were confirmed by experiments and simulation. The skeletons of the macrocycles and polymer consist of all‐sp2 hybridized C/N atoms and are thus π‐conjugated and electro‐active. Our studies provide a rational way to access kinetically stable 2D crystalline polymers by combination of different dynamic covalent chemistries. [ABSTRACT FROM AUTHOR]

Synthesis of π‐conjugated crystalline two‐dimensional (2D) polymers remains largely unexplored due to limited synthetic methodology. Herein, we report the preparation of a 1,6‐anthrazoline (AZ)‐linked crystalline 2D polymer AZP via acid mediated Friedländer synthesis. The feasibility was examined first by two model reactions, followed by synthesis of three AZ‐based macrocycles MCn (n=5–7), in which hexagonal MC6 was isolated as the major product. The favorable macrocycle formation could be largely attributed to the dynamic feature of Friedländer synthesis, which involves both imine condensation and aldol condensation. The structure and crystallinity of AZP were confirmed by experiments and simulation. The skeletons of the macrocycles and polymer consist of all‐sp2 hybridized C/N atoms and are thus π‐conjugated and electro‐active. Our studies provide a rational way to access kinetically stable 2D crystalline polymers by combination of different dynamic covalent chemistries. [ABSTRACT FROM AUTHOR]

Expanded azahelicenes, as heteroanalogues of helically chiral helicenes, hold significant potential for chiroptical materials. Nevertheless, their investigation and research have remained largely unexplored. Herein, we present the facile synthesis of a series of expanded azahelicenes NHn (n=1–5) consisting of 11, 19, 27, 35, and 43 fused rings, mainly by Suzuki coupling followed by Bi(OTf)3‐mediated cyclization of vinyl ethers. The structures of NH2, NH3 and NH4 were confirmed through X‐ray crystallography analysis, and their (P)‐ and (M)‐ enantiomers were also isolated with chiral high performance liquid chromatography. The enantiomers exhibit large absorption (abs) and luminescence (lum) dissymmetry factors, with |gabs|max=0.044; |glum|max=0.003 for NH2, |gabs|max=0.048; |glum|=0.014 for NH3, and |gabs|max=0.043; |glum|max=0.021 for NH4, which are superior to their respective all‐carbon analogues. [ABSTRACT FROM AUTHOR]

Expanded azahelicenes, as heteroanalogues of helically chiral helicenes, hold significant potential for chiroptical materials. Nevertheless, their investigation and research have remained largely unexplored. Herein, we present the facile synthesis of a series of expanded azahelicenes NHn (n=1–5) consisting of 11, 19, 27, 35, and 43 fused rings, mainly by Suzuki coupling followed by Bi(OTf)3‐mediated cyclization of vinyl ethers. The structures of NH2, NH3 and NH4 were confirmed through X‐ray crystallography analysis, and their (P)‐ and (M)‐ enantiomers were also isolated with chiral high performance liquid chromatography. The enantiomers exhibit large absorption (abs) and luminescence (lum) dissymmetry factors, with |gabs|max=0.044; |glum|max=0.003 for NH2, |gabs|max=0.048; |glum|=0.014 for NH3, and |gabs|max=0.043; |glum|max=0.021 for NH4, which are superior to their respective all‐carbon analogues. [ABSTRACT FROM AUTHOR]

The exploration of annulene's conformation, electronic properties and aromaticity has generated enduring interest over the years, yet it continues to present formidable challenges for annulenes with more than ten carbon atoms. In this study, we present the synthesis of a stable [10]cyclo‐para‐phenylmethine derivative (1), which bears a resemblance to [10]annulene. 1 can be readily oxidized into its respective cations, wherein electrons are effectively delocalized along the backbone, resulting in different conformations and aromaticity. Both 1 and its tetracation (14+ ⋅ 4SbF6−) exhibit a nearly planar conformation with a rectangular shape, akin to the E,Z,E,Z,Z‐[10]annulene. In contrast, the radical cation (1⋅+ ⋅ SbCl6−) possesses a doubly twisted Hückel topology. Furthermore, the dication (12+ ⋅ 2SbCl6−) displays conformational flexibility in solution and crystalizes with the simultaneous presence of Möbius‐twisted (1a2+ ⋅ 2SbCl6−) and Hückel‐planar (1b2+ ⋅ 2SbCl6−) isomers in its unit cell. Detailed experimental measurements and theoretical calculations reveal that: (1) 1 demonstrates localized aromaticity with an alternating benzenoid/quinoid structure; (2) 1a2+ ⋅ 2SbCl6− and 1b2+ ⋅ 2SbCl6− with 48π electrons are weakly Möbius aromatic and Hückel antiaromatic, respectively; (3) 14+ ⋅ 4SbF6− exhibits Hückel aromaticity (46π) and open‐shell diradical character. [ABSTRACT FROM AUTHOR]

The exploration of annulene's conformation, electronic properties and aromaticity has generated enduring interest over the years, yet it continues to present formidable challenges for annulenes with more than ten carbon atoms. In this study, we present the synthesis of a stable [10]cyclo‐para‐phenylmethine derivative (1), which bears a resemblance to [10]annulene. 1 can be readily oxidized into its respective cations, wherein electrons are effectively delocalized along the backbone, resulting in different conformations and aromaticity. Both 1 and its tetracation (14+ ⋅ 4SbF6−) exhibit a nearly planar conformation with a rectangular shape, akin to the E,Z,E,Z,Z‐[10]annulene. In contrast, the radical cation (1⋅+ ⋅ SbCl6−) possesses a doubly twisted Hückel topology. Furthermore, the dication (12+ ⋅ 2SbCl6−) displays conformational flexibility in solution and crystalizes with the simultaneous presence of Möbius‐twisted (1a2+ ⋅ 2SbCl6−) and Hückel‐planar (1b2+ ⋅ 2SbCl6−) isomers in its unit cell. Detailed experimental measurements and theoretical calculations reveal that: (1) 1 demonstrates localized aromaticity with an alternating benzenoid/quinoid structure; (2) 1a2+ ⋅ 2SbCl6− and 1b2+ ⋅ 2SbCl6− with 48π electrons are weakly Möbius aromatic and Hückel antiaromatic, respectively; (3) 14+ ⋅ 4SbF6− exhibits Hückel aromaticity (46π) and open‐shell diradical character. [ABSTRACT FROM AUTHOR]

[Display omitted] Obesity is a growing global health problem and is associated with increased prevalence of many metabolic disorders, including diabetes, hypertension and cardiovascular disease. Pancreatic lipase (PL) has been validated as a key target for developing anti-obesity agents, owing to its crucial role in lipid digestion and absorption. In the past few decades, porcine PL (pPL) is always used as the enzyme source for screening PL inhibitors, which generate numerous pPL inhibitors but the potent inhibitors against human PL (hPL) are rarely reported. Herein, a series of salicylanilide derivatives were designed and synthesized, while their anti-hPL effects were assayed by a fluorescence-based biochemical approach. To investigate the structure–activity relationships of salicylanilide derivatives as hPL inhibitors in detail, structural modifications on three rings (A, B and C) of the salicylanilide skeleton were performed. Among all tested compounds, 2t and 2u were found possessing the most potent anti-PL activity, showing IC 50 values of 1.86 μM and 1.63 μM, respectively. Inhibition kinetic analyses suggested that both 2t and 2u could effectively inhibit hPL in a non-competitive manner, with the k i value of 1.67 μM and 1.70 μM, respectively. Fluorescence quenching assays suggested that two inhibitors could quench the fluorescence of hPL via a static quenching procedure. Molecular docking simulations suggested that 2t and 2u could tightly bind on an allosteric site of hPL. Collectively, the structure–activity relationships of salicylanilide derivatives as hPL inhibitors were carefully investigated, while two newly identified reversible hPL inhibitors (2t and 2u) could be used as promising lead compounds to develop novel anti-obesity drugs. [ABSTRACT FROM AUTHOR]

Large graphene‐like molecules with four zigzag edges are ideal gain medium materials for organic near‐infrared (NIR) lasers. However, synthesizing them becomes increasingly challenging as the molecular size increases. In this study, we introduce a new intramolecular radical‐radical coupling approach and successfully synthesize two fused triangulene dimers (1 a/1 b) efficiently. X‐ray crystallographic analysis of 1 a indicates that there is no intermolecular π‐π stacking in the solid state. When the more soluble derivative 1 b is dispersed in polystyrene thin films, amplified spontaneous emission in the NIR region is observed. Using 1 b as the active gain material, we fabricate solution‐processed distributed feedback lasers that exhibit a narrow emission linewidth at around 790 nm. The laser devices also exhibit low thresholds with high photostability. Our study provides a new synthetic strategy for extended nanographenes, which have diverse applications in electronics and photonics. [ABSTRACT FROM AUTHOR]

Large graphene‐like molecules with four zigzag edges are ideal gain medium materials for organic near‐infrared (NIR) lasers. However, synthesizing them becomes increasingly challenging as the molecular size increases. In this study, we introduce a new intramolecular radical‐radical coupling approach and successfully synthesize two fused triangulene dimers (1 a/1 b) efficiently. X‐ray crystallographic analysis of 1 a indicates that there is no intermolecular π‐π stacking in the solid state. When the more soluble derivative 1 b is dispersed in polystyrene thin films, amplified spontaneous emission in the NIR region is observed. Using 1 b as the active gain material, we fabricate solution‐processed distributed feedback lasers that exhibit a narrow emission linewidth at around 790 nm. The laser devices also exhibit low thresholds with high photostability. Our study provides a new synthetic strategy for extended nanographenes, which have diverse applications in electronics and photonics. [ABSTRACT FROM AUTHOR]

Back Cover: Hydrogen Spillover and Its Relation to Hydrogenation: Observations on Structurally Defined Single-Atom Sites (Angew. Keywords: Mass Spectrometry; Polyoxometalates; Reaction Kinetics; Single-Site Catalysis; Structure-Activity Correlations EN Mass Spectrometry Polyoxometalates Reaction Kinetics Single-Site Catalysis Structure-Activity Correlations 1 1 1 09/28/22 20221004 NES 221004 B A palladium single-atom model catalyst b was used by Ning Yan and co-workers in their Research Article (e202208237) to shed light on the kinetics and structural evolution of catalysts in hydrogen spillover, as well as the nature of participation of the spilled-over H in hydrogenation. Mass Spectrometry, Polyoxometalates, Reaction Kinetics, Single-Site Catalysis, Structure-Activity Correlations. [Extracted from the article]

Global aromaticity in 3D π‐conjugated molecular cages remains largely unexplored. Herein, we report the facile synthesis of a fully conjugated molecular cage (1) containing two bridged triphenylamine units and three quinoidal bithiophene arms. X‐ray crystallographic analysis, NMR/ESR measurements and theoretical calculations reveal that: 1) its dication (12+) has an open‐shell singlet ground state and is 3D globally aromatic, with individual macrocycles being 2D Hückel aromatic; 2) its tetracation (14+) has a triplet ground state and is also 3D globally aromatic, with individual macrocycles being 2D Baird aromatic; and 3) its hexacation (16+) has a closed‐shell nature and shows local aromaticity. The study demonstrated a close relationship between 2D Hückel/Baird aromaticity and 3D global π‐aromaticity. [ABSTRACT FROM AUTHOR]

Despite rapid progress over the past decade, most polycondensation systems even upon a small structural variation of the building units eventually result in amorphous polymers other than the desired crystalline covalent organic frameworks. This synthetic dilemma is a central and challenging issue of the field. Here we report a novel approach based on module‐patterned polymerization to enable efficient and designed synthesis of crystalline porous polymeric frameworks. This strategy features a wide applicability to allow the use of various knots of different structures, enables polycondensation with diverse linkers, and develops a diversity of novel crystalline 2D polymers and frameworks, as demonstrated by using the C=C bond‐formation polycondensation reaction. The new sp2‐carbon frameworks are highly emissive and enable up‐conversion luminescence, offer low band gap semiconductors with tunable band structures, and achieve ultrahigh charge mobilities close to theoretically predicted maxima. [ABSTRACT FROM AUTHOR]

Global aromaticity in 3D π‐conjugated molecular cages remains largely unexplored. Herein, we report the facile synthesis of a fully conjugated molecular cage (1) containing two bridged triphenylamine units and three quinoidal bithiophene arms. X‐ray crystallographic analysis, NMR/ESR measurements and theoretical calculations reveal that: 1) its dication (12+) has an open‐shell singlet ground state and is 3D globally aromatic, with individual macrocycles being 2D Hückel aromatic; 2) its tetracation (14+) has a triplet ground state and is also 3D globally aromatic, with individual macrocycles being 2D Baird aromatic; and 3) its hexacation (16+) has a closed‐shell nature and shows local aromaticity. The study demonstrated a close relationship between 2D Hückel/Baird aromaticity and 3D global π‐aromaticity. [ABSTRACT FROM AUTHOR]

Despite rapid progress over the past decade, most polycondensation systems even upon a small structural variation of the building units eventually result in amorphous polymers other than the desired crystalline covalent organic frameworks. This synthetic dilemma is a central and challenging issue of the field. Here we report a novel approach based on module‐patterned polymerization to enable efficient and designed synthesis of crystalline porous polymeric frameworks. This strategy features a wide applicability to allow the use of various knots of different structures, enables polycondensation with diverse linkers, and develops a diversity of novel crystalline 2D polymers and frameworks, as demonstrated by using the C=C bond‐formation polycondensation reaction. The new sp2‐carbon frameworks are highly emissive and enable up‐conversion luminescence, offer low band gap semiconductors with tunable band structures, and achieve ultrahigh charge mobilities close to theoretically predicted maxima. [ABSTRACT FROM AUTHOR]

Human serum albumin (HSA) is one of the most important serum carrier proteins that deliver small-molecule drugs to their specific targets. Clarifying the molecular mechanism of the interaction between natural HSA and drugs in an aqueous solution has been a hot topic in pharmaceutical chemistry, clinical medicine, and biochemistry in recent years, but it is still challenging. In this paper, the details of molecular interactions of HSA with a variety of therapeutic drugs including ibuprofen, indomethacin, phenylbutazone, and warfarin are systematically investigated using a mass spectrometry (MS)-based lysine reactivity profiling (LRP) strategy. The results reaffirm that the major ligand binding sites (including Sites I and II) of HSA are located in subdomains IIA and IIIA, while several potential drug-binding areas at subdomain IIIB and α helix IIB-IIIA are newly characterized. The MS-LRP strategy may have important application prospects in pharmacodynamics, pharmacokinetics, and safety evaluation of small-molecule drugs. [ABSTRACT FROM AUTHOR]

A planar dibenzo‐peri‐hexacene derivative (2) was synthesized via FeCl3‐mediated Scholl reaction from a cyclopenta‐fused perylene (CP) based polyphenylene precursor (1). However, an unexpected octagon‐containing, negatively curved molecule (3) was obtained in nearly quantitative yield when 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) and methanesulfonic acid (MeSO3H) were used. Similar results were observed when two smaller‐sized precursors containing one (4) or two CP units (5) were tested. X‐ray crystallographic analysis also revealed that there is no close π–π stacking between neighboring π‐conjugated skeletons. DFT calculations suggest a radical cation mechanism in the presence of FeCl3 while an arenium ion pathway for the DDQ/MeSO3H mediated Scholl reaction, which can well explain the selective formation of hexagons and octagons under different conditions. The obtained compounds showed tunable optical and electrochemical properties. [ABSTRACT FROM AUTHOR]

A planar dibenzo‐peri‐hexacene derivative (2) was synthesized via FeCl3‐mediated Scholl reaction from a cyclopenta‐fused perylene (CP) based polyphenylene precursor (1). However, an unexpected octagon‐containing, negatively curved molecule (3) was obtained in nearly quantitative yield when 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) and methanesulfonic acid (MeSO3H) were used. Similar results were observed when two smaller‐sized precursors containing one (4) or two CP units (5) were tested. X‐ray crystallographic analysis also revealed that there is no close π–π stacking between neighboring π‐conjugated skeletons. DFT calculations suggest a radical cation mechanism in the presence of FeCl3 while an arenium ion pathway for the DDQ/MeSO3H mediated Scholl reaction, which can well explain the selective formation of hexagons and octagons under different conditions. The obtained compounds showed tunable optical and electrochemical properties. [ABSTRACT FROM AUTHOR]

• The cellulose colorimetric sensor (cellulose-DTu) for Ag+ and Cu2+ was synthesized. • The sensor exhibits an advantage of rapidity for in-situ detection of Ag+ and Cu2+. • A mechanism for the selective detection of Ag+ and Cu2+ by the sensor was proposed. A biomass cellulose-based colorimetric sensor for Ag+ and Cu2+ was prepared by grafting 2,5-dithiourea (DTu) onto biomass-pulp cellulose. The as-prepared sensor (cellulose-DTu) showed excellent selectivity and sensitivity towards Cu2+ over other common metal ions (Pb2+, Mn2+, Mg2+, Zn2+, Hg2+, K+, Al3+, Ca2+, Na+, Cd2+, Ni2+, Ba2+, and Li+), exhibiting a color change from white to light grey. However, the sensor exhibited a remarkable color change from white to yellow-red upon the addition of Ag+. The naked-eye-detection concentration limits for Ag+ and Cu2+ were 10−3 and 10-4 mol/L, respectively. Furthermore, cellulose-DTu responded to both Ag+ and Cu2+ within 5 s. A mechanism for the selective identification of Ag+ and Cu2+ by cellulose-DTu was proposed based on 13C solid NMR, XPS, and TEM analyses. In addition, the application of cellulose-DTu in real water confirmed that it exhibits the advantages of simplicity, rapidity, and high selectivity for in-situ identification of Ag+ and Cu2+. [ABSTRACT FROM AUTHOR]

Two new chromium and manganese bimetallic nanoclusters, [Cr8−xMnx(OH)8−x(H2O)x(OOCC6H5)16, x = 1.11] (1) and [Cr4Mn4O4(OOCC6H5)12·3CH3CN·H2O] (2), have been synthesized in a one-pot solvothermal reaction in this work. Under visible irradiation, cluster 1 can produce an increased photocurrent and exhibits significant visible-light-driven photocatalytic activity for H2 evolution in an aqueous system. Most importantly, it exhibits ultrahigh stability in both acid and base aqueous solutions, making it an excellent synthon for preparing functional materials. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Hylophalangopsis chinensis Lin and Huang, 2006 is attributed to Zeuneropterinae. • Hylophalangopsis chinensis Lin and Huang, 2006 is considered transitional species. • The zeuneropterines suggest a warm and humid climate. Abstract In the Dazhuoma stratigraphic section near the Gangni Township, Amdo County, northern Tibet, China, the Paleocene-lower Eocene Niubao Formation yields plenty of well-preserved microfossils and insects. A restudy of Hylophalangopsis chinensis Lin and Huang, 2006, an orthopteran insect from this formation, indicates that it should be attributed to Zeuneropterinae of Stenopelmatidae instead of Prophalangopsidae of Hagloidea in the original study. Some characters preserved in this species are herein considered transitional between Aboilinae (Prophalangopsidae) and Stenopelmatoidea, supporting the deduction that a close relationship exists between Stenopelmatoidea and Aboilinae. The close relationship of Hylophalangopsis with the other zeuneropterines in Canada and Scotland indicates a middle-late Paleocene age for the lower Niubao Formation, supported by some previous studies, and further suggests a warm and humid climate in the Dazhuoma area in the middle-late Paleocene, supported by some important evidence. [ABSTRACT FROM AUTHOR]

We report the exfoliation of two‐dimensional polyoxometalate‐encapsulating MOF (POM−Co‐MOF) into atomically thick nanosheets for highly efficient desulfurization application. Two‐dimensional layer‐structured MOF [Co2(H2O)4(BTX)3][PMo12O40] (BTX=1,4‐Bis(1,2,4‐triazol‐1‐ylmethyl)benzene) is featured with Keggin‐type POM wrapped in MOF skeleton via coordinating to cobalt with terminal oxygen. Wet ball‐milling and sonication assisted top‐down exfoliation in acetonitrile successfully delaminates POM‐MOF into nanosheets, which creates more accessible active sites and efficiently decreases the restriction of mass transfer during the reaction, and thus enhances the desulfurization efficiency. In comparison with bulk POM‐MOF, delaminated nanosheets exhibit a 14‐fold higher desulfurization efficiency via monitoring dibenzothiophene oxidation process (TON value of ca. 400) using H2O2 as oxidant. Meanwhile, POM−Co‐MOF nanosheets also show superior desulfurization performance in model oil system. Get skinny with ultrasheets: Inaccessible active sites and limited mass transfer restrict the catalytic performance of bulk MOF. We report the exfoliation of 2D POM−Co‐MOF into ultrathin nanosheets via a top‐down delamination strategy. Compared with the pristine MOF, the delaminated nanosheets possess more accessible active sites and much less restriction of mass transfer, which give rise to the superior catalytic performance on oxidative desulfurization reaction. [ABSTRACT FROM AUTHOR]