Polyoxometalate-dependent Photocatalytic Activity of Radical-doped Perylenediimide-based Hybrid Materials.

Inorganic-organic hybrid materials are a kind of multiduty materials with high crystallinity and definite structures, built from functional inorganic and organic components with highly tunable photochemical properties. Perylenediimides (PDIs) are a kind of strong visible light-absorbing organic dyes with π-electron-deficient planes and photochemical properties depending on their micro-environment, which provides a platform for designing tunable and efficient hybrid photocatalytic materials. Herein, four radical-doped PDI-based crystalline hybrid materials, Cl4-PDI⋅SiW12O40 (1), Cl4-PDI⋅SiMo12O40 (2), Cl4-PDI⋅PW12O40 (3), and Cl4-PDI⋅PMo12O40 (4), were attained by slow diffusion of polyoxometalates (POMs) into acidified Cl4-PDI solutions. The obtained PDI-based crystalline hybrid materials not only exhibited prominent photochromism, but also possessed reactive organic radicals under ambient conditions. Furthermore, all hybrid materials could be easily photoreduced to their radical anions (Cl4-PDI⋅-), and then underwent a second photoexcitation to form energetic excited state radical anions (Cl4-PDI⋅-*). However, experiments and theoretical calculations demonstrated that the formed energetic Cl4-PDI⋅-* showed unusual POM-dependent photocatalytic efficiencies toward the oxidative coupling of amines and the iodoperfluoroalkylation of alkenes; higher photocatalytic efficiencies were found for hybrid materials 1 (anion: SiW12O40 4-) and 2 (anion: SiMo12O40 4-) compared to 3 (anion: PW12O40 3-) and 4 (anion: PMo12O40 3-). The photocatalytic efficiencies of these hybrid materials are mainly controlled by the energy differences between the SOMO-2 level of Cl4-PDI⋅-* and the LUMO level of the POMs. The structure-photocatalytic activity relationships established in present work provide new research directions to both the photocatalysis and hybrid material fields, and will promote the integration of these areas to explore new materials with interesting properties.

Ru(II)-Ru(II) and Ru(II)-Os(II) Homo-/Heterodinuclear Complexes and Ru3(II)-Ru(II) Homotetranuclear Complexes Based on Heteroditopic Bridging Ligands: Synthesis, Photophysics, and Effective Energy Transfer.

In this paper, the synthesis, photophysics, electrochemistry, and intramolecular energy transfer of two series of dinuclear and tetranuclear metallic complexes [(bpy)2M1LxM2(bpy)2]4+ (x = 1, 2; M1 = Ru, M2 = Ru/Os; M1 = Os, M2 = Ru) and {[Ru(bpy)2(Lx)]3Ru}8+ based on new heteroditopic bridging ligands (L1 = 6-phenyl-4-Hpip-2-2'-bipyridine, L2 = 6-Hpip-2-2'-bipyridine, Hpip = 2-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline) are reported. The dimetallic and tetrametallic complexes exhibit rich redox properties with successive reversible metal-centered oxidation and ligand-centered reduction couples. All complexes display intense absorption in the entire ultraviolet-visible spectral regions. The mononuclear [LxRu(bpy)2]2+ and homodinuclear [(bpy)2RuLxRu(bpy)2]4+ complexes display strong Ru-based characteristic emission at room temperature. Interestingly, the optical studies of heterodinuclear complexes reveal almost complete quenching of the RuII-based emission and efficient photoinduced energy transfer, resulting in an OsII-based emission in the near-infrared region. As a result of the intramolecular energy transfer from the center to the periphery and steric hindrance quenching of the peripheral RuII-centered emissive triplet metal-to-ligand charge transfer states, the tetranuclear complexes exhibit weak RuII-based emission with a short lifetime. Since the light absorbed by several chromophores is efficiently directed to the subunit with the lowest-energy excited state, the present multinuclear complexes can be used as well-visible-light-absorption antennas.

Enantioselective formal total synthesis of dihydrospirotryprostatin B.

Spirotryprostatins are representative members of medicinally interesting bioactive molecules of the spirooxindole natural products. In this communication, we present a novel enantioselective total synthesis of the spirooxindole alkaloid dihydrospirotryprostatin B. The synthesis takes advantage of copper-catalyzed tandem reaction of o-iodoanilide chiral sulfinamide derivatives with alkynone to rapidly construct the key quaternary carbon stereocenter of the natural product dihydrospirotryprostatin B.

Monomer-Promoting Asymmetric Kinetic Resolution-Alternating Copolymerization To Afford AAB-Type Copolyesters.

Living copolymerization of mixed monomers can enrich the diversity of copolymer materials with well-defined performance via controlling both monomers and stereosequences. However, periodic sequence-controlled living copolymerization of same-type monomers with more than two components in synthetic polymer science remains a challenge. In this work, a new method of monomer-promoting asymmetric kinetic resolution-alternating copolymerization can let a tricomponent mixture of l-lactide (S,S-LA or l-LA) and two enantiomeric isomers of racemic tropic acid cyclic esters (tropicolactone) be polymerized into sequence-controlled -(ASASBS)n- type biodegradable copolyesters (the subscript S presents the configuration and A and B present lactic acid units and tropic acid units, respectively), and diblock copolymers of -(ASASBS)n-b-(ARARBR)n- can further be obtained upon addition of R,R-LA (d-LA). Compared to previous asymmetric kinetic resolutions of racemic chemicals via polymerization or organic reactions, no enantiopure catalyst/initiator is required in this system. After the resolution and alternating copolymerization of S,S-LA and rac-tropicolactone, the ee value of unreacted tropicolactone can reach 99.4%. The alternating probability between tropicolactone and lactide monomers is more than 96% in periodic sequence polymers of -(ASASBS)n-. The tetracomponent mixture of rac-lactide and rac-tropicolactone can be copolymerized into an alternating copolymer with a -((ASASBS)x-ran-(ARARBR)y)n- structure, in which the stereoselective linkage probability of 95% after S,S-lactide (R,R-lactide) followed by S-tropicolactone (R-tropicolactone) keeps very high too.

Synthesis and antitumor activity of novel hybrid compounds between 1,4-benzodioxane and imidazolium salts.

A series of novel hybrid compounds between 1,4-benzodioxane and imidazolium salts was designed and prepared. The compounds were evaluated in vitro against a panel of human tumor cell lines (K562, SMMC-7721, and A-549). The structure-activity relationship results demonstrated that the 2-methyl-benzimidazole or 5,6-dimethyl-benzimidazole ring and substitution of the imidazolyl-3-position with a 4-phenylphenacyl substituent were critical for promoting cytotoxic activity. Particularly, compound 25 was found to be the most potent compound with IC50 values of 1.06-8.31 µM against the three human tumor cell lines and exhibited higher selectivity to K562 and SMMC-7721 cells with IC50 values 4.5- and 4.7-fold lower than cisplatin. Moreover, compound 25 inhibited cell proliferation by inducing the G0/G1 cell cycle arrest and apoptosis in SMMC-7721 cells.

Molecular Iodine Capture by Covalent Organic Frameworks.

The effective capture and storage of volatile molecular iodine from nuclear waste is of great significance. Covalent organic frameworks (COFs) are a class of extended crystalline porous polymers that possess unique architectures with high surface areas, long-range order, and permanent porosity. Substantial efforts have been devoted to the design and synthesis of COF materials for the capture of radioactive iodine. In this review, we first introduce research techniques for determining the mechanism of iodine capture by COF materials. Then, the influencing factors of iodine capture performance are classified, and the design principles and strategies for constructing COFs with potential for iodine capture are summarized on this basis. Finally, our personal insights on remaining challenges and future trends are outlined, in order to bring more inspiration to this hot topic of research.

Copper-Catalyzed Coupling of Sulfonamides with Alkylamines: Synthesis of (E)-N-Sulfonylformamidines.

Herein, we describe an efficient copper-catalyzed coupling of sulfonamides with alkylamines to synthesize (E)-N-sulfonylformamidines. The reaction is accomplished under mild conditions without the use of a corrosive acid or base as an additive. It tolerates a broad scope of substrates and generates the products with exclusive (E)-stereoselectivity.

A Novel Ruthenium(II) Polypyridyl Complex Bearing 1,8-Naphthyridine as a High Selectivity and Sensitivity Fluorescent Chemosensor for Cu2+ and Fe3+ Ions.

A novel ruthenium(II) polypyridyl complex bearing 1,8-naphthyridine was successfully designed and synthesized. This complex was fully characterized by EI-HRMS, NMR, and elemental analyses. The recognition properties of the complex for various metal ions were investigated. The results suggested that the complex displayed high selectivity and sensitivity for Cu2+ and Fe3+ ions with good anti-interference in the CH3CN/H2O (1:1, v/v) solution. The fluorescent chemosensor showed obvious fluorescence quenching when the Cu2+ and Fe3+ ions were added. The detection limits of Cu2+ and Fe3+ were 39.9 nmol/L and 6.68 nmol/L, respectively. This study suggested that this Ru(II) polypyridyl complex can be used as a high selectivity and sensitivity fluorescent chemosensor for Cu2+ and Fe3+ ions.

Two star-shaped tetranuclear Ru(II) complexes containing uncoordinated imidazole groups: synthesis, characterization, photophysical and pH sensing properties.

Tetrapodal ligands H4L(1) and H4L(2) containing imidazole groups have been synthesized by the reaction of 1,10-phenanthroline-5,6-dione with 1,2,4,5-tetrakis[(4-formylphenoxy)methyl]benzene and 1,2,4,5-tetrakis[(3-formylphenoxy)methyl]benzene, respectively, in presence of NH4OAc. Two star-shaped complexes [{Ru(bpy)2}4(µ4-H4L(1))](PF6)8 and [{Ru(bpy)2}4(µ4-H4L(2))](PF6)8 (bpy = 2,2'-bipyridine) have been prepared by refluxing Ru(bpy)2Cl2 ·2H2O and each ligand in ethylene glycol. The deprotonated complexes [{Ru(bpy)2}4(µ4-L(1))](PF6)4 and [{Ru(bpy)2}4(µ4-L(2))](PF6)4 have been obtained by the reaction of sodium methoxide with [{Ru(bpy)2}4(µ4-H4L(1))](PF6)8 and [{Ru(bpy)2}4(µ4-H4L(2))](PF6)8, respectively, in methanol. The pH effects on the UV-vis light absorption and emission spectra of both complexes have been studied, and ground- and excited-state ionization constants of both complexes have been derived. The photophysical properties of both complexes are strongly dependent on the solution pH. They act as proton-induced off-on-off luminescent sensors through two successive deprotonation processes of imidazole groups, with a maximum on-off ratio of 8 in buffer solution at room temperature. Theoretical calculations for the highest occupied molecular orbital (HOMO) and lowest occupied molecular orbital (LOMO) orbitals of bridging ligand are also presented for plausible explanations of the fluorescence changes.

[Analysis of the interaction between cefdinir and bovine serum albumin by spectrometry].

OBJECTIVE: To explore the interaction between cefdinir (CE) and bovine serum albumin (BSA) by fluorescence and ultraviolet-visible absorption spectrometry.
 METHODS: Under the optimal conditions, the interaction between CE and BSA was investigated by fluorescence and ultraviolet-visible absorption spectrometry.
 RESULTS: CE could quench (static quenching) the intrinsic fluorescence of BSA by forming the CE-BSA complex. The main binding forces were considered as hydrogen bonds and Van der Waals forces based on the calculated values of the thermodynamic parameter. The process of binding was spontaneous because Gibbs free energy change was negative. The primary binding site for CE was located at sub-domain II of BSA. The values of Hill's coefficients were less than 1, indicating a negative cooperative effect. Synchronous fluorescence spectra showed that the conjugation reaction between CE and BSA did not affect the conformation of BSA, and the binding site was close to the tyrosine residue.
 CONCLUSION: This test provides a theoretical basis for revealing the pharmacokinetic issue and the development for new drugs.

Gases and gas-releasing materials for the treatment of chronic diabetic wounds.

Chronic non-healing wounds are a common consequence of skin ulceration in diabetic patients, with severe cases such as diabetic foot even leading to amputations. The interplay between pathological factors like hypoxia-ischemia, chronic inflammation, bacterial infection, impaired angiogenesis, and accumulation of advanced glycosylation end products (AGEs), resulting from the dysregulation of the immune microenvironment caused by hyperglycemia, establishes an unending cycle that hampers wound healing. However, there remains a dearth of sufficient and effective approaches to break this vicious cycle within the complex immune microenvironment. Consequently, numerous scholars have directed their research efforts towards addressing chronic diabetic wound repair. In recent years, gases including Oxygen (O2), Nitric oxide (NO), Hydrogen (H2), Hydrogen sulfide (H2S), Ozone (O3), Carbon monoxide (CO) and Nitrous oxide (N2O), along with gas-releasing materials associated with them have emerged as promising therapeutic solutions due to their ability to regulate angiogenesis, intracellular oxygenation levels, exhibit antibacterial and anti-inflammatory effects while effectively minimizing drug residue-induced damage and circumventing drug resistance issues. In this review, we discuss the latest advances in the mechanisms of action and treatment of these gases and related gas-releasing materials in diabetic wound repair. We hope that this review can provide different ideas for the future design and application of gas therapy for chronic diabetic wounds.

Highly efficient photocatalytic hydrogen production by ZnCdS composite catalyst modified with NiCoP nanosheets prepared by LDH precursor.

The unique characteristics and diverse applications of 2D transition metal phosphides have aroused significant interest. In this paper, we successfully prepared 2D NiCoP modified ZnCdS composite. The NiCoP nanosheets were successfully obtained by phosphating layered double hydroxide (LDH) precursor. The results show that the ZnCdS-8%NiCoP has the highest photocatalytic performance among all the composite photocatalysts with the H2 evolution rate of 1370.1 µmol h-1, which is 17.9 folds higher than obtained with pure ZnCdS. Detailed analysis reveal that NiCoP nanosheets functions as an excellent electron acceptor, speeding up the directed migration of electrons. Furthermore, the rational mechanism of photocatalytic has been presented based on density function theory (DFT) calculations, which is well congruent with experimental results. Our research offers a simple, environmentally benign, and scalable technique for making highly effective photocatalysts, as well as a novel perspective on transition metal phosphides rational design.

Effect of electronic structure of energy transfer in bimetallic Ru(II)/Os(II) complexes.

Novel monometallic (µ-LL')Ru, Ru(µ-LL'), homobimetallic Ru(µ-LL')Ru, and heterodimetallic Ru(µ-LL')Os and Os(µ-LL')Ru complexes based on two asymmetrical ligands LL' (where LL' = L1L1', L2L2') have been synthesized and characterized. Spectroscopic analysis indicates that all complexes exhibit intense spin-allowed ligand-centered (LC) transitions at 288 nm and Ru-based moderate spin-allowed MLCT absorption between 440-450 nm. The Ru(µ-LL')Os and Os(µ-LL')Ru dinuclear complexes show Os-based unit absorption in the range of 565-583 nm. The Ru-based units of the complexes present different emission intensities due to differing steric hindrance at the coordination sites of the two bridging ligands. The Os(µ-LL')Ru dinuclear complexes present weaker emission intensity than their parent monometallic complexes (µ-LL')Ru. These results indicate that the emission of Os(µ-LL')Ru dinuclear complexes is quenched by the Os(II)-based units.

Energy transfer in metal-exchange binuclear complexes covalently linked by asymmetric ligands.

Nitrogen complexation with π-conjugated ligands is an effective strategy for synthesizing luminescent molecules. The asymmetric bridging ligands L (L1 and L2) have been designed. The terminal chelating sites of the L1 and L2 bridging ligands consisted of 2,2'-bipyridine (bpy) and 1,10-phenanthroline moieties (where L = L1 and L2; L1 = 2-(3-((4-([2,2'-bipyridin]-6-yl)benzyl)oxy)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline and L2 = 2-(3-((4-(6-phenyl-[2,2'-bipyridin]-4-yl)benzyl)oxy)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline). The full use of the synthetic strategy of the "complexes as ligands and complexes as metals" was expected to successfully design and synthesize a series of conjugated metal-exchange complexes linked by the asymmetric bridging ligands L1 and L2. These compounds included monometallic complexes Ru(L) and (L)Ru (C1, C2, C7, and C8), homometallic complexes Ru(L)Ru (C3 and C4), and heterometallic complexes Os(L)Ru and Ru(L)Os (C5, C6, C9, and C10) with Ru- or Os-based units. C3-C10 complexes exhibited various degrees of octahedral distortion around the Ru(II) or Os(II) center, which was consistent with the optimized geometry of the coordination complexes based on density functional theory calculation. These complexes exhibited intense spin-allowed ligand-centered transitions with high absorbance at around 288 nm upon absorbing visible light. Notably, all complexes exhibited spin-allowed metal-to-ligand charge transfer absorption of the Ru-based units in the 440-450 nm range. In addition, the heterometallic C5, C6, C9, and C10 complexes showed absorption of the Os-based units in the range of 565-583 nm. The intramolecular energy transfer of C3 and C5 was briefly discussed by comparing the emission intensity of monometallic C1 and C2 to that of binuclear complexes C3 and C5, respectively. The results indicated that the intramolecular energy transfer of the Ru(II)/Os(II) polypyridine complexes proceeded from the Ru(II)- to the Os(II)-based units in the heterometallic C5 and C6 complexes.

Discarded COVID-19 masks-derived-doped porous carbon for lithium-sulfur batteries.

Despite the high theoretical capacity and energy density of lithium-sulfur (Li-S) batteries, the development of Li-S batteries has been slow due to the poor electrical conductivity and the shuttle effect of the electrode materials, resulting in low sulfur utilization and fast long-term cycling capacity decay. The modified carbon materials are often used as sulfur hosts to significantly improve the cycling performance of the materials, but also bring high-cost issues. Here, the porous carbon materials are synthesized quickly and conveniently by the microwave cross-linking method using discarded medical masks as carbon sources and concentrated sulfuric acid as solvent. However, poor surface and structural properties limit the application of materials. The porous carbon material is modified with p-toluene disulfide and urea as the sulfur and nitrogen sources by the microwave cross-linking method, which not only improves the porosity and specific surface area of the porous carbon material, but also improved the electrical conductivity and interlayer spacing of the material. As synthesized SN-doped porous carbon is employed as the sulfur host, which exhibits a high discharge capacity (1349.3 mAh g-1) at 0.1°C, the S-porous C/S, N-porous C/S, and SN-porous C/S can maintain 78.1, 43.9, and 59.5% of the initial capacity after 500 cycles. The results indicate that the doping of S and N atoms provides sufficient active sites for the chemisorbed lithium polysulfides (LiPSs) to improve the reaction kinetics of the materials.

Merging of the photocatalyst decatungstate and naphthalene diimide in a hybrid structure for the oxidative coupling of amines.

Designing and developing novel hybrid materials for the effective photoconversion of organic substrates is of great importance. Crystalline hybrid heterostructures, as an attractive class of material, are composed of semiconducting organic and inorganic components with fast-responsive charge-separated properties and thus they are promising photocatalysts. Naphthalene diimides (NDIs) and decatungstate (W10O324-) are two versatile semiconductor components that have been utilized as building blocks for the construction of functional materials for various applications. In this context, we demonstrated that the combination of an electron-deficient NDI derivative with W10O324- resulted in an organic-inorganic hybrid compound, namely Zn2(DPNDI)(W10O32)(DMA)6 (DPNDI = N,N'-di-(4-pyridyl)-1,4,5,8-naphthalene diimide) (1). Because of consecutive photo-induced electron transfer processes among the components, this hybrid compound exhibits fast-responsive reversible photochromic properties, and it efficiently photocatalytically oxidizes amines to imines under mild conditions with high yields and an excellent substrate application range.

Perylenediimide-Based Hybrid Materials for the Iodoperfluoroalkylation of Alkenes and Oxidative Coupling of Amines: Bay-Substituent-Mediated Photocatalytic Activity.

Inorganic-organic donor-acceptor hybrid compounds are an emerging class of multifunctional crystalline materials with well-defined structures built from semiconductive inorganic and organic components. Perylenediimides (PDIs) are a prominent class of electron-deficient organic dyes, which can undergo consecutive photoinduced electron transfers to generate doublet excited-state radical anions for photoredox-inert chemical bonds. Thus, this is an excellent organic component for building hybrid materials to study the structure-property relationships in organic synthesis. In this context, three molecular structure modified PDI-based hybrid materials, (Me4-PDI)2·SiW12O40 (1), (Me4-Cl4-PDI)2·SiW12O40 (2), and (Me4-Br2-PDI)1.5·HSiW12O40 (3), were studied. By the introduction of different substituent groups at the bay positions, these three hybrid materials were successfully fabricated to investigate the impact of substituent groups on the photocatalytic activity. As expected, all PDI-based hybrid materials easily underwent consecutive photoexcitation to obtain their excited-state radical anions. However, experimental and theoretical analyses showed that these obtained excited-state radical anions displayed unusual bay-substituent-group-dependent photocatalytic conversion activities for the iodoperfluoroalkylation of alkenes and oxidative coupling of amines. Higher conversion yields were obtained for complexes 1 and 3 (bay-unsubstituted and Br-substituted PDI hybrid materials, respectively), and lower conversion was observed for complex 2 (Cl-substituted PDI hybrid material), which is attributed to the excited-state SOMO-1 energies of the PDI radical anions. The structure-property relationship established in this work provides insights for the further exploration of bay-substituted PDI hybrid materials in other small-molecule photocatalytic transformations.

Correction: A photochromic zinc-based coordination polymer for a Li-ion battery anode with high capacity and stable cycling stability.

Correction for 'A photochromic zinc-based coordination polymer for a Li-ion battery anode with high capacity and stable cycling stability' by Shu-Biao Xia et al., Dalton Trans., 2018, 47, 13222-13228, DOI: 10.1039/C8DT02930J.

Correction: Naphthalimide-containing coordination polymer with mechanoresponsive luminescence and excellent metal ion sensing properties.

Correction for 'Naphthalimide-containing coordination polymer with mechanoresponsive luminescence and excellent metal ion sensing properties' by Jian-Jun Liu et al., Dalton Trans., 2020, 49, 3174-3180, DOI: 10.1039/C9DT04928B.

Asymmetric epoxidation of olefins using novel chiral dinuclear Mn(III)-salen complexes with inherent phase-transfer capability in ionic liquids.

Two new chiral dinuclear Mn(III)-Salen complexes with inherent phase-transfer capability have been synthesized, which serve as catalysts in the asymmetric epoxidation of nonfunctionalized alkenes. Experimental results show these complexes are effective catalysts for the asymmetric epoxidation of some cyclic alkenes and the catalysts have certain inherent phase-transfer capability during the epoxidation because of their weak water solubility. In general, good enantioselectivity and acceptable yields were achieved when NaClO was used as oxidant under three different reaction systems. Among these alkenes, the catalyst 6a gave the highest ee (94%) for 6-chloro-2,2-dimethylchromene in the presence of ionic liquid 2. Additionally, the recovery and recycling of one dimeric Mn(III)-Salen complex were tested to investigate atom efficiency of the catalyst in different reaction systems on the alkenes epoxidations. The catalyst 6a could be recovered and recycled for six times without losing activity and selectivity.