Chemistry - A European Journal最新文献

A networked supramolecular logic AND gate system is accomplished using precise chemical communication within a multicomponent ensemble via metal ion-driven self-sorting processes. The cybernetic AND gate is composed of a copper(I)-loaded nanoswitch, an aza-crown ether and a rhodamine receptor. The modus operandi of the AND gate, from state (0,0), was induced with stoichiometric amounts of two inputs (IN-1 = Hg2+, IN-2 = Li+) generating copper(I) ions as output only in state (1,1). Generation of state (1,1) from state (0,0) involves selective Cu+ ion translocation from the nanoswitch to the aza-crown ether in the first step (IN-1) and then from the aza-crown ether to the rhodamine receptor in the second step (IN-2). The released copper(I) output acts as a messenger that binds to the rhodamine receptor, triggering it's spiro-lactam ring opening, which leads to a diagnostic FRET emission from the copper(I)-loaded Rhodamine scaffold accompanied by a remarkable fluorescence and colour change from pale yellow to pink.

Two new non-centrosymmetric chalcogenides, ACuGa6S10 (A = Rb, Cs) have been successfully synthesized by an "iterative substitution" strategy based on chalcopyrite CuFeS2 structural template. Benefiting from the substitution of Fe3+ cations by Ga3+ cations, ACuGa6S10 (A = Rb, Cs) exhibit wide suitable band gap of 2.48 and 2.40 eV, respectively, which is about five times higher than their structure template CuFeS2, and the large second harmonic generation response (1.5 and 1.8 × AgGaS2). Combining theoretical calculation and structural analysis confirm that the [GaS4] tetrahedra make the main contribution on their good liner and nonlinear optical (NLO) performances. The "iterative substitution" strategy expands the design idea of materials and can lead to the discovery of a large number of IR NLO compounds.

The copper-catalyzed azide-alkyne cycloaddition (CuAAC) has heralded a new era of chemical biology and biomedicine. However, caveats of CuAAC include formation of reactive oxygen species (ROS) and other copper-related toxicity. This limits utility in sensitive biological samples and matrices. Towards addressing these caveats, we synthesized and fully characterized two air and water stable trinuclear Cu (I) dimer complexes. The complexes were stable to oxidation in the presence of hydrogen peroxide, acid, base, and other chelators, which was reasoned to be due to the linear benzimidazole-Cu-benzimidazole geometry. Computational investigations of the catalytic cycle implicated two of the three coppers in the trimer complex as the active metal centers. The complexes were shown to catalyze the reaction at far below sub-toxic concentrations for intracellular click reactions to label triple negative breast cancer cells and compared to the current CuSO-4-THPTA standard.

Aqueous Zn ion batteries (AZIBs) are promising candidates of next-generation energy storage devices with high safety and theoretical capacity. However, the irreversibility of metallic Zn anode, attributed to dendrite growth and water decomposition, severely limits the cycling durability of AZIBs and restricts their further development. Herein, a facile surface engineering strategy is put forward to tackle the issue of poor reversibility of the Zn anode. Benzotriazole (BTA) is employed as a functional additive of ZnSO4 electrolyte to confine the reactivity of free water situated in the electric double layer (EDL). Experimental results and theoretical simulation reveal that BTA can preferiencially adsorb onto the Zn surface to uniform Zn2+ ion distribution and alleviate H2O-involved side reactions like hydrogen evolution, and surface passivation. Consequently, in BTA-modulated aqueous electrolyte, the lifespan of the Zn anode is extended from 170 h to 1092 h at 1 mA cm-2/1 mAh cm-2. The reversibility improvement of Zn anode also benefits the cycling durability of full devices including supercapacitors and batteries. Zn||I₂ batteries assembled in as-designed electrolyte witness only 11.3% capacity decay over 17000 cycles at 1 A g-1, far outstripping that observed in ZnSO4 counterpart (~ 4675 cycles).

Increasing cut-off voltage of lithium cobalt oxide (LCO) (> 4.6 V) is an effective strategy to satisfy the ever-increasing demand for high energy density. However, the irreversible phase transition significantly destroys the structure of high-voltage LCO, especially the surface lattice. Considering that the structural stability of LCO is primarily dominated by the intrinsic merits of electrode-electrolyte interface (EEI), we explored and disclosed the operating mechanism of anion chelating agent tris(pentafluorophenyl) borane (TPFPB) and regulate the CEI layer on LCO electrode. Benefiting from the high HOMO energy level and preferential decomposition of TPFPB-PF6-, a robust LiF-rich CEI layer is constructed and greatly improves the stability of electrode/electrolyte interface. The well-designed electrolyte composed of 1 mol L-1 LiPF6 in EC/EMC with TPFPB additives endows Li/LCO half cells and 4 Ah Gr/LCO pouch cell with enhanced cycling stability under a high voltage condition. This work provides pave a new direction for the development of economical high-voltage LIBs.

Organic dyes are interesting building blocks for the preparation of organic semiconductors as they possess synthetic handles that can be used to functionalize them and, consequently, change their electronic properties. However, reactions to extend their π-conjugated framework through ring annulation have only been scarcely tested. Herein, we report the use of alkyne benzannulation on 2,8-dibromo-dibenzo[def,mno]chrysene (vat orange 3) and 2,9-dibromo-dibenzo[b,def]chrysene (vat orange 1) to extend the conjugation and reduce their bandgap. Unexpectedly, the ring closure reaction takes place at the most sterically hindered positions (peri to the substituent) to yield contorted polycyclic compounds. More surprisingly, both TIPS-acetylene-functionalized derivatives underwent a tandem dearomative spirocyclization to form bent polycyclic compounds. Absorption spectroscopy reveals that ring annulation on both 2,9-dibromo-dibenzo[b,def]chrysene and 2,8-dibromo-dibenzo[def,mno]chrysene resulted in a decrease of 0.38 and 0.12 eV in bandgap values, respectively, despite inducing a contorted conformation.

We investigated the Diels-Alder reaction of 6,13-bis(triisopropylsilyl)pentacene (1) with small dienophiles such as (bridged) dihydronaphthalenes/cyclohexenes that yielded adducts at the central ring, the other dienophiles predominantly or exclusively attacked the unsubstituted off-center ring. The difference in regioselectivity was investigated by DFT calculations. Apart from dispersion interactions, it is due to the steric demand of the dienophiles, which need to fit in between the silylethynyl substituents to react at the central ring. Epoxynaphthalene adducts of 1 as well as its anthracene and tetracene congeners were deoxygenated, easily furnishing triarenobarrelenes with TIPS-ethynyl substituents at the bridge heads, attractive building blocks for porous solids and higher acene-based trimers.

A library of novel π-extended porphyrin-hexabenzo-coronene (HBC) architectures is presented. Two distinct synthetic pathways were utilized to obtain either phenyl- or HBC-fused compounds. Absorption experiments reveal the species' exciting photophysical and optoelectronic properties. Depending on the degree of π-extension, the number of porphyrins, and their relative position, a decisive change in shape, panchromatic broadening, and red-shifting of the absorption curves is observed. Theoretical studies give more profound insight into the molecule's electronic structures, showing vast decreases in band energy gaps.

Helicenes and helicenoid structures are promising candidates for future applications exploiting circularly polarized light. Ideal candidates should possess near-quantitative photoluminescence quantum yield, high a luminescence dissymmetry factor and an adjustable HOMO-LUMO gap. However, carbo[n]helicenes are poorly luminescent compounds and they absorb light mainly in the ultraviolet region. Here we show that the incorporation of a carbonyl group into helical scaffold significantly improves the fluorescence quantum yield and shifts the absorption to visible region. Although the carbonyl group is commonly considered as detrimental to efficient emission, fluorescence quantum yields up to Φ = 0.43 were recorded. A straightforward synthetic approach to a highly luminescent tetraceno[6]helicenone and an aza analogue has been developed. The key step is a radical cyclization which is achieving dehydrative π-extension. The aza-analogue was incorporated as an emitter in organic light emitting diodes (OLEDs) and showed good performance.

Carboxylic acids are attractive synthetic feedstocks with stable, non-toxic, and inexpensive properties that can be easily obtained from natural sources or through synthesis. Carboxylic acids have long been considered environmentally friendly coupling agents in various organic transformations. In recent years, electrochemically mediated decarboxylation reactions of decarboxylic acids and their derivatives (NHPI) have emerged as effective new methods for constructing carbon-carbon or carbon-heterocarbon chemical bonds. Compared with transition metal and photochemistry-mediated catalytic reactions, which do not require the addition of oxidants and strong bases, electrochemically-mediated decarboxylative transformations are considered a sustainable strategy. In addition, various functional groups tolerate the electrochemical decarboxylation conversion strategy well. Here, we summarize the recent electrochemical decarboxylation reactions to better elucidate the advantages of electrochemical decarboxylation reactions.