Three trinuclear windwheel-shaped complexes were synthesized using M(II) (M = Mn, Co, Ni) ions, to give the easy-axis and easy-plane magnetic anisotropy, and the Co(II) complexes exhibited slow magnetic relaxation behavior.

Comprehensive Summary

A new family of trinuclear windwheel complexes with molecular formula [M^II ₃(tpa)₃(μ-ttc)](ClO₄)₃·n(sol) (ttc = 1,3,5-triazine-2,4,6-trithiol; tpa = tris(2-pyridylmethyl)amine; M = Mn, n = 2, sol = CH₃CN, 1; M = Co, n = 1, sol = CH₃CN, 2; M = Ni, n = 0, 3) were synthesized and characterized. Single-crystal X-ray diffraction revealed that three metal centers in 1—3 are connected by ttc bridge, forming a regular triangular M^II ₃ core. Each metal center is bonded by chelating S, N atoms from ttc and by N atoms from tpa. Magnetic studies showed that 1—3 displayed antiferromagnetic behavior and further gave the easy-axis anisotropy (D = −0.77 cm⁻¹ for 1 and −8.13 cm⁻¹ for 2) and easy-plane anisotropy (D = 5.08 cm⁻¹ for 3). Moreover, 2 exhibited field-induced slow magnetic relaxation behavior and their effective energy barriers were roughly evaluated U _eff = 6.9 K.

Here, we proposed one type of CDs doped with nitrogen and sulfur through the hydrothermal method, which exhibited the obvious yellow-fluorescence in aqueous solution. Importantly, the fluorescence intensity of CDs decreased with pH decreasing in the acidic range, thus exhibiting the potential of pH sensing. Importantly, introducing tigecycline into these CDs resulted in their decreased fluorescence, thus we further established a strategy of detecting tigecycline.

Comprehensive Summary

Long-wavelength fluorescence carbon dots (CDs) show great importance in multiple fields, especially for the biochemical sensing. Here, we proposed one type of CDs doped with nitrogen and sulfur through the hydrothermal method, which exhibited obvious yellow-fluorescence in aqueous solution. Importantly, the fluorescence intensity of CDs decreased with pH decreasing in the acidic range, thus a linear relationship between pH and fluorescence intensity was established, exhibiting the potential of pH sensing. Additionally, introducing tigecycline into CDs resulted in their decreased fluorescence, thus, we further established a strategy of detecting tigecycline with the concentration range of 200 μM to 7 nM. Meanwhile, we elucidated the static quenching as the major mechanism for CDs responding tigecycline, which was induced by the formed new complex between CDs and tigecycline. Furthermore, the practicality of the method was verified by examining the recovery of tigecycline in the actual lake-water samples.

Modern methods for producing CaC₂ are associated with a large amount of CO₂ emissions and energy costs. The use of metallic Ca as a starting reagent can affect both the complete removal of CO₂ emissions and the reduction of energy costs due to a lower reaction temperature.

Comprehensive Summary

Calcium carbide is considered a possible key component in the sustainable carbon cycle, including convenient recycling of carbon wastes to industrial uptake. However, currently employed CaC₂ manufacturing process produces significant amounts of CO₂. One of the main factors of its appearance is the formation of carbon oxide during the reaction. The reaction of lime ore with coal inevitably results in the formation of CO and the loss of one carbon atom. CO is usually burnt, forming CO₂ to maintain the required high temperature during synthesis – 2200 °C. In the present study, we discuss that the use of calcium metal instead of lime represents a good opportunity to prevent CO₂ emission since the reaction of Ca with carbon occurs in an atom-efficient manner and results in only CaC₂ at a much lower temperature of 1100 °C. Here, the reaction of Ca with carbon was successfully tested to synthesize CaC₂. The desired product was isolated in gram-scale amounts in 97.2% yield and 99% purity. The environmental friendliness of the proposed method originates from the calculations of the E-factor. Rationalization is provided concerning the cost factor of Ca within the considered process.

A new CXCR4-inhibiting nanomedicine PAMD/Zn@siPAI-1 was designed to synergistically regulate the hepatic stellate cells (HSCs) activation and extracellular matrix (ECM) deposition.

Comprehensive Summary

Inflammation is associated with different stages of liver disease, including acute injury, fibrosis, cirrhosis, and hepatoma. During the progression of liver inflammation, activation of hepatic stellate cells (HSCs) and extracellular matrix (ECM) deposition are critical pathologies, and thus the combined therapy using HSCs and ECM as targets represents a promising strategy in the treatment of liver injury. Here, a novel CXCR4-inhibiting nanomedicine that can simultaneously deliver AMD3100 (CXCR4 antagonist) and siPAI-1 (siRNA of plasminogen activator inhibitor-1) was designed and developed to reverse liver fibrosis by inhibiting HSCs activation and degrading ECM deposition. With this goal in mind, a Zn(II) coordinated polymeric AMD3100 named PAMD/Zn polymer with siRNA delivery and CXCR4 antagonism capabilities was synthesized. Overall, our results suggest that PAMD/Zn recruits pro-inflammatory cells for fibrogenesis and inhibits the activation of HSCs for fibrolysis at various stages of liver injury. Its use in conjunction with PAI-1 silencing achieved satisfactory therapeutic efficacy in liver injury and fibrosis. The derivative CXCR4-inhibiting nanomedicine is a versatile platform that offers valuable benefits for the treatment of liver diseases.

Molecular conformations play a crucial role in fields such as materials science and drug design. Traditional methods like molecular dynamics and Monte Carlo simulations are limited in speed and accuracy. Deep learning models offer a promising solution by rapidly generating accurate molecular conformations. This Emerging Topic highlights recent progresses in using deep learning for predicting molecular conformations and explores the potential and challenges of this emerging field.

Abstract

The accurate prediction of molecular conformations with high efficiency is crucial in various fields such as materials science, computational chemistry and computer-aided drug design, as the three-dimensional structures accessible at a given condition usually determine the specific physical, chemical, and biological properties of a molecule. Traditional approaches for the conformational sampling of molecules such as molecular dynamics simulations and Markov chain Monte Carlo methods either require an exponentially increasing amount of time as the degree of freedom of the molecule increases or suffer from systematic errors that fail to obtain important conformations, thus presenting significant challenges for conformation sampling with both high efficiency and high accuracy. Recently, deep learning-based generative models have emerged as a promising solution to this problem. These models can generate a large number of molecular conformations in a short time, and their accuracy is comparable and, in some cases, even better than that of current popular open-source and commercial software. This Emerging Topic introduces the recent progresses of using deep learning for predicting molecular conformations and briefly discusses the potential and challenges of this emerging field.

Comprehensive Summary

One dihydride-bridged dimeric Dy(III) guanidinate complex, formulated as [{(Me₃Si)₂NC(NⁱPr)₂}₂Dy(μ-H)]₂ (1Dy), was successfully isolated and the introduction of hydride bridges significantly reduces the intramolecular Dy(III)···Dy(III) distance to only 3.688(1) Å. To investigate the effect of such a short Dy(III)···Dy(III) distance for magnetism, we also prepared its dibromide-bridged analogue [{(Me₃Si)₂NC(NⁱPr)₂}₂Dy(μ-Br)]₂ (2Dy), which has a much longer Dy(III)···Dy(III) distance of 4.605(4) Å. Surprisingly, 2Dy demonstrates much larger effective energy barrier for magnetization reversal (U _eff) and higher blocking temperature (T _B). The worse performance of 1Dy is attributed to the concerted effect of strong antiferromagnetic interactions between Dy(III) ions (J _total = -2.683 cm^-1) and the unparallel arrangement of magnetic principle axes of the Dy(III) ions for 1Dy.

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Comprehensive Summary

Herein we report a condition-controlled divergent synthesis of spiro indene-2,1'-isoindolinones and spiro isochroman-3,1'-isoindolinones through cobalt-catalyzed formal [4 + 1] and [4 + 1 + 1] spirocyclization of aromatic amides with 2-diazo-1H-indene-1,3(2H)-dione. When the reaction is carried out under air in ethyl acetate, spiro indene-2,1'-isoindolinones are formed through Co(II)-catalyzed C−H/N−H [4 + 1] spirocyclization. When the reaction is run under O₂ in CH₃CN, on the other hand, spiro isochroman-3,1'-isoindolinones are generated through Baeyer-Villiger oxidation of the in situ formed spiro indene-2,1'-isoindolinones with O₂ as a cheaper and environmental-friendly oxygen source. In general, these protocols have advantages such as using non-precious and earth-abundant metal catalyst, no extra additive, high efficiency and regioselectivity. A gram-scale synthesis and the removal of the directing group further highlight its utility.

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A series of octahedral metallo-cages that are capable of tolerating with five metal cations (Pd²⁺, Cu²⁺, Ni²⁺, Co²⁺ and Zn²⁺), and five counter anions (ClO₄ ^–, OTf^–, BF₄ ^–, NTf₂ ^– and NO₃ ^–) are constructed by the coordination-driven self-assembly of a well-designed tritopic isoquinoline-based ligand with corresponding metal salts. Structural stability studies show that metal cations and counter anions play a critical role in the stability of the resulting cages depending on their coordination abilities and stacking manners.

Comprehensive Summary

Metallo-supramolecular architectures that are constructed by coordination-driven self-assembly have received tremendous attention on account of their diverse yet molecular-level precise structures and broad applications. Of particular, metal cations and counter anions are fundamentally important in terms of self-assembly, characterization and property; however, their effects on the structural stabilities of metallo-supramolecular architectures have seldom been investigated. To address this issue, herein, a series of octahedral metallo-cages that are capable of tolerating with five metal cations (Pd²⁺, Cu²⁺, Ni²⁺, Co²⁺ and Zn²⁺), and five counter anions (ClO₄ ^–, OTf^–, BF₄ ^–, NTf₂ ^– and NO₃ ^–) are constructed by the coordination-driven self-assembly of a well-designed tritopic isoquinoline-based ligand with corresponding metal salts. Structural stability studies show that metal cations and counter anions play a critical role in the stability of the resulting cages depending on their coordination abilities and stacking manners. This work provides deep insights in the ever-diversifying field of metallo-supramolecular chemistry, and will enable us to design more sophisticated assembled structure with desired function.

Three novel isotope-economic synthetic paths to ¹³C₂-labeled heterocycles are proposed. Using calcium carbide-¹³C₂ a number of 4,5-¹³C₂-triazoles, 4,5-¹³C₂-isoxazoles and 3,6-di(pyridin-2-yl)pyridazine-4,5-¹³C₂ were synthesized. New data on ¹H and ¹³C NMR spectra of ¹³C₂-labeled triazoles, isoxazoles and symmetrical pyridazine are described in details.

Comprehensive Summary

¹³C-Carbon is the most available source of carbon-13. It is a relatively inexpensive solid material, which can be easily converted to calcium carbide-¹³C₂. In current work, Ca¹³C₂ was used for in situ generation of ¹³C₂-acetylene in 1,3-dipolar cycloaddition and [4+2] cycloaddition reaction. For the first time, 1H-1,2,3-triazoles-4,5-¹³C₂ and isoxazoles-4,5-¹³C₂ were synthesized using calcium carbide-¹³C₂. A Diels-Alder type cycloaddition of 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine and Ca¹³C₂ was investigated, and the best way for the synthesis of 3,6-di(pyridin-2-yl)pyridazine-4,5-¹³C₂ was proposed for the first time. Here we perform a detailled description of NMR spectra of ¹³C₂-labeled triazoles, isoxazoles and 3,6-di(pyridin-2-yl)pyridazine.

New nickel(II) dibromide complexes with bis(azolyl)methane ligands with Et₂AlCl or Et₃Al₂Cl₃ resulted in the formation of catalytic systems active both in ethylene oligomerization and Friedel-Crafts alkylation of toluene. Catalytic systems activated with Et₃Al₂Cl₃ also produced small amounts of odd carbon number olefins (up to 0.8%). The Friedel-Crafts alkylation was used as a trap for previously undetected short-chain odd carbon number olefins (C₃ and C₅).

Comprehensive Summary

Nickel(II) complexes with pyrazole-based ligands are widely employed in catalysis of ethylene oligomerization and subsequent Friedel-Crafts alkylation of toluene. We have prepared ten new nickel(II) dibromide complexes with various substituted bis(azolyl)methanes. They have been characterized using ¹H NMR, IR, high resolution mass spectrometry and elemental analysis. The structures of three complexes have been unambiguously established using X-ray diffraction. It was found that these complexes in the presence of Et₂AlCl or Et₃Al₂Cl₃ are active both in ethylene oligomerization and Friedel-Crafts alkylation processes (activity up to 3720 kg_oligomer·mol[Ni]⁻¹·h⁻¹). The use of Et₃Al₂Cl₃ results in a higher share of alkylated products (up to 60%). Moreover, catalytic systems activated with Et₃Al₂Cl₃ produced small amounts of odd carbon number olefins (up to 0.8%). The Friedel-Crafts alkylation was used as a trap for previously undetected short-chain odd carbon number olefins (C₃ and C₅).