Metal-free inorganic ligands for colloidal nanocrystals: S2-, HS-, Se2-, HSe-, Te2-, HTe-, TeS3(2-), OH-, and NH2- as surface ligands

All-inorganic colloidal nanocrystals were synthesized by replacing organic capping ligands on chemically synthesized nanocrystals with metal-free inorganic ions such as S(2-), HS(-), Se(2-), HSe(-), Te(2-), HTe(-), TeS(3)(2-), OH(-) and NH(2)(-). These simple ligands adhered to the NC surface and provided colloidal stability in polar solvents. The versatility of such ligand exchange has been demonstrated for various semiconductor and metal nanocrystals of different size and shape. We showed that the key aspects of Pearson's hard and soft acids and bases (HSAB) principle, originally developed for metal coordination compounds, can be applied to the bonding of molecular species to the nanocrystal surface. The use of small inorganic ligands instead of traditional ligands with long hydrocarbon tails facilitated the charge transport between individual nanocrystals and opened up interesting opportunities for device integration of colloidal nanostructures.     

Generation, translocation, and action of nitric oxide in living systems

Nitric oxide (NO) is a gaseous diatomic radical that is involved in a wide range of physiological and pathological functions in biology. Conceptually, the biochemistry of NO can be separated into three stages: generation (stage 1), translocation (stage 2), and action (stage 3). In stage 1 the oxygenase domain of NO synthase converts L-arginine to L-citrulline and NO (g). Owing to its short-lived nature, this molecule is converted into a different nitrogen oxide such as NO(2), an organonitrosyl such as a nitrosothiol, or a metal nitrosyl such as a heme-nitrosyl, for transportation in stage 2. Each of these derivatives features unique physical characteristics, chemical reactivity, and biological activity. Upon delivery in stage 3, NO exerts its physiological or pathological function by reaction with biomolecules containing redox-active metals or other residues.     

Photochemical molecular storage of Cl2, HCl, and COCl2: synthesis of organochlorine compounds, salts, ureas, and polycarbonate with photodecomposed chloroform

Chloroform is available as not only an organic solvent but also photochemical molecular storage for synthetically important chemicals such as Cl(2), HCl, and COCl(2). We have succeeded in synthesizing organochlorine compounds, hydrochloric salt of amines, ureas, organic carbonates, and polycarbonate in practical high yields with photodecomposed chloroform.     

淀粉—g—PGMA与甘氨酸反应产物对金,钯,铬,镉的吸附性能

淀粉改性官能团化作为金属离子的吸附剂用于废水处理已有报道,但吸附效果不理想,应用范围受限制。本文将玉米淀粉接枝甲基丙烯酸缩水甘油酯共聚物(Cs-g-PGMA)与甘氨酸反应,得到Cs-g-PGMA-Gly作为吸附剂,可以去除水中的Cd~(2 )、Cr~(3 )等有害元素,而且在适当的pH条件下还可富集分离Au~(3 )、Pd~(2 )。     

Design,Synthesis, and Biological Evaluation of Novel Pyrazole,Oxazole, and Pyridine Derivatives as Potential Anticancer Agents Using Mixed Chalcone

New pyrazole, oxazole, and pyridine derivatives bearing naphthalene and furan moieties have been prepared by condensing 3‐(furan‐2‐yl)‐1‐(naphthalen‐2‐yl)prop‐2‐en‐1‐one 1 with different nitrogen and carbon nucleophiles such as hydrazine, hydroxylamine, cyclohexanone, cyclopentanone, ethyl cyanoacetate, and malononitrile, respectively. Cyclization of chalcone 1 with malononitrile in refluxing ethanol and ammonium acetate gave the corresponding dihydropyridine, which was condensed with different carbon electrophilic reagents such as ethyl cyanoacetate, ethyl acetoacetate, formamide, and acetic anhydride to yield the pyridine derivatives 13 – 16 . Elemental and spectroscopic evidences characterized all the newly synthesized compounds. All of the newly synthesized compounds were tested in vitro for their anti‐proliferative activities against HePG‐2 and MCF‐7 cell lines. Compounds 11 , 8 , and 15 displayed promising growth inhibitory effect toward the two cell lines compared with the standard drug doxorubicin.     

Neutral-ligand complexes of bis(imino)pyridine iron: synthesis, structure, and spectroscopy

A family of bis(imino)pyridine iron neutral-ligand derivatives, ((iPr)PDI)FeL(n) ((iPr)PDI = 2,6-(2,6-iPr2-C6H3N=CMe)2C6H3N), has been synthesized from the corresponding bis(dinitrogen) complex, ((iPr)PDI)Fe(N2)2. When L is a strong-field ligand such as tBuNC or a chelating alkyl diphosphine such as DEPE (DEPE = 1,2-bis(diethylphosphino)ethane), a five-coordinate, diamagnetic compound results with no spectroscopic evidence for mixing of paramagnetic states. Reducing the field strength of the neutral donor to principally sigma-type ligands such as tBuNH2 or THT (THT = tetrahydrothiophene) also yielded diamagnetic compounds. However, the 1H NMR chemical shifts of the in-plane bis(imino)pyridine hydrogens exhibit a large chemical shift dispersion indicative of temperature-independent paramagnetism (TIP) arising from mixing of an S = 1 excited state via spin-orbit coupling. Metrical data from X-ray diffraction establish bis(imino)pyridine chelate reduction for each structural type, while M?ssbauer parameters and NMR spectroscopic data differentiate the spin states of the iron and identify contributions from paramagnetic excited states.     

Thiazolidinones: Synthesis,Reactivity, and Their Biological Applications

Thiazolidinone is a biologically important five‐membered heterocyclic ring having almost all types of biological activities. This review covers various types of thiazolidinones, such as 2‐thiazolidinones, 4‐thiazolidinones, 5‐thiazolidinones, 2‐thioxo‐4‐thiazolidinones, and thiazolidiene‐2,4‐dione. The literature related to the physical properties, chemical reactions, and synthesis for these derivatives has been included. Recent advances in the biological activities reported for 4‐thiazolidinone derivatives, such as peroxisome proliferator‐activated receptor γ binders, follicle‐stimulating hormone agonists, cystic fibrosis transmembrane conductance regulator inhibitors, and antioxidants, have been covered in this review. Thus, this study may help in further optimizing these thiazolidinone derivatives as more effective drug agents.     

Reversible Uptake of COS,CS2, and SO2: Ionic Liquids with O‐Alkylxanthate,O‐Alkylthiocarbonyl,and O‐Alkylsulfite Anions

CO₂‐binding organic liquids (CO₂BOLs) are mixtures of a base (typically an amidine or guanidine) and an alcohol, and have been shown to reversibly capture and release CO₂ with low reaction energies and high gravimetric CO₂ capacity. We now report the ability of such liquid blends to chemically bind and release other acid gases such as CS₂, COS, and SO₂ analogously to CO₂. These systems bind with sulfur‐containing acid gases to form colored ionic liquids with new O‐alkylxanthate, O‐alkylthiocarbonyl, and O‐alkylsulfite anions. The capture and thermal stripping of each acid gas from these systems and their applicability towards flue gas desulfurization is discussed.     

Osmium diboride, an ultra-incompressible, hard material

The need for wear- and scratch-resistant materials drives the quest for new superhard materials. In this work, we apply two design parameters to identify ultra-incompressible, superhard materials-high valence electron density and high bond covalency. Our first example of such a material is OsB2. The bulk modulus of OsB2 was measured using in situ high-pressure X-ray diffraction and was determined to be in the range of 365-395 GPa. While this value is slightly less than that of the bulk modulus of diamond, due to the anisotropic crystal structure of OsB2, the axis compressibility in the orthorhombic c-direction is less than the axis compressibility found in diamond. OsB2 also scratches the surface of a sapphire window, indicating that the hardness of OsB2 exceeds 2000 kg/mm2.     

Synthesis of Fluoro-, Monofluoromethyl-, Difluoromethyl-, and Trifluoromethyl-Substituted Three-Membered Rings

This Minireview describes recent advances toward the synthesis of fluoro-, monofluoromethyl-, difluoromethyl-, and trifluoromethyl-substituted three-membered rings such as cyclopropanes, aziridines, epoxides, episulfides, cyclopropenes, and 2 H-azirines. The main synthetic methodologies since 2016 for cyclopropanes and since 2010 for the other three-membered rings are reported.     

B−Hb←:X (X= N,O, P,S, F,Cl, Br) interactions: A density functional study

Density functional theory calculation on B H_b←:X interaction (X= N, O, P, S, F, Cl, Br) is performed. HOMO energy predicts the feasibility of such complexation. Steric and electronic effects play significant role on geometry of the complexes. Interaction energy suggests that the interaction is moderately strong (< 5.00 kcal mol⁻¹) in nature and the complexes are stable in both gas and solvent phase. Electron donating group on: X facilitates the interaction whereas electron withdrawing group impedes the same. MP2 and CCSD(T) calculations further confirm the suitability of ωB97X‐D and M06‐2X functional for studying such interactions. Dispersive interaction is the primary mode of interaction in stabilizing the complexes. ¹H NMR and IR study are also performed. Thermochemical analysis advocates exothermic nature of complexation.     

Controlled synthesis, characterization, and crystallization of Ni-P nanospheres

The size- and composition-controlled synthesis of Ni-P nanospheres from nickel chloride and sodium hypophosphite has been systematically investigated by changing the conditions, such as the ratio of the starting materials, pH value, and reduction temperature. It was found that when the starting ratio of H2PO2(-)/Ni2+ was changed the size and chemical composition of the nanoparticles changed simultaneously. Within a suitable pH range, the phosphorus content was altered without affecting the particle size. Increasing the reduction temperature resulted in smaller Ni-P nanospheres but invariable phosphorus content. The Ni-P nanospheres were amorphous when the phosphorus content was higher than 10.0 mol %, while lower phosphorus content led to a composite of amorphous Ni-P and face-centered cubic (fcc) Ni. During postsynthesis calcinations, amorphous Ni-P nanospheres with a low phosphorus content directly crystallized to Ni3P and fcc Ni. However, the specimens with high phosphorus content crystallized via some intermediate phases such as Ni5P2 and Ni12P5. In the latter, an amorphous P-rich shell was developed simultaneously. A preliminary catalytic test of growth of carbon nanofibers on the Ni-P nanospheres has been carried out.     

Photosensitizing Electron Transfer Processes of Fullerenes,Carbon Nanotubes,and Carbon Nanohorns

In this account, studies on the photosensitizing electron transfer of nanocarbons, such as fullerenes, single‐walled carbon nanotubes (SWCNTs), and carbon nanohorns (CNH), performed in our laboratory for about 15 years in the early 21st century have been briefly reviewed. These novel nanocarbons act as excellent electron acceptors, when they are linked to light‐absorbing electron donors, such as porphyrins or phthalocyanines. For such molecule–nanocarbon hybrids, the direct confirmation of fast, transient, electron‐transfer phenomena must be performed with time‐resolved spectroscopic methods, such as transient absorption spectral measurements, in addition to fluorescence time‐profile measurements in the wide‐wavelength regions. Careful use of these methods affords useful information to understand photoinduced electron‐transfer mechanisms. In addition, kinetic data obtained by these methods can assist in the construction of light‐active devices, such as photovoltaic cells and solar H₂‐generation systems.     

Integrated nanoparticle-biomolecule hybrid systems: synthesis, properties, and applications

Nanomaterials, such as metal or semiconductor nanoparticles and nanorods, exhibit similar dimensions to those of biomolecules, such as proteins (enzymes, antigens, antibodies) or DNA. The integration of nanoparticles, which exhibit unique electronic, photonic, and catalytic properties, with biomaterials, which display unique recognition, catalytic, and inhibition properties, yields novel hybrid nanobiomaterials of synergetic properties and functions. This review describes recent advances in the synthesis of biomolecule-nanoparticle/nanorod hybrid systems and the application of such assemblies in the generation of 2D and 3D ordered structures in solutions and on surfaces. Particular emphasis is directed to the use of biomolecule-nanoparticle (metallic or semiconductive) assemblies for bioanalytical applications and for the fabrication of bioelectronic devices.     

Carbocyclic Ring Closure of Unsaturated S-, Se-, and C-Aryl Glycosides

Triisobutylaluminum-promoted rearrangement of unsaturated glycosides containing electron-donating aglycons-such as C-aryl glycoside 1, or O-, S-, and Se-glycosides-provides direct access to highly functionalized cyclohexane derivatives such as 2.     

一步法合成取代-1, 2-苯醌类化合物

应用固定化多酚氧化酶催化的氧化-迈克尔加成反应,一步合成了4,5-二取代-1,2-苯醌类化合物:4,5-N,N-二(苯胺基)-1,2-苯醌,4,5-N,N-二(对甲苯胺基)-1,2-苯醌,4,5-N,N-二(间氯苯胺基)-1,2-苯醌,4,5-N,N-二(对溴苯胺基)-1,2-苯醌。用化学法(I~2-KI)进行氧化-迈克尔加成反应也成功地合成了4,5-二取代-1,2-苯醌类化合物。应用紫外光谱方法证明了氧化-迈克尔加成反应的机制。     

Sn/Cu-TiO2 nanoparticles produced via sol-gel method: Synthesis,characterization, and photocatalytic activity

TiO₂ and Sn/Cu-TiO₂ nanoparticles with different Sn/Cu contents have been synthesized and characterized by different analysis methods such as XRD, TEM, and BET. Sn/Cu-TiO₂ was preferential to TiO₂ with 2,5-fold increase in photodegradation rate of different types of dyes such as methyl orange, methylene blue and methyl red. This activity was relevant to the influences of co-doping on the physicochemical properties and surface interfacial charge transfer mechanisms. An optimum synergetic effect was found for a mass ratio of Sn/TiO₂ equal to 0.75% and Cu/TiO₂ equal to 0.5%. The degradation reaction fit well to a Langmuir-Hinshelwood kinetic model indicating the reaction rate is depended on initial adsorption step.     

微波消解-ICP-MS法同时测定木薯淀粉中铅、铜、镉、砷、汞的含量

用硝酸-过氧化氢溶液(3+3)作为消解剂,微波消解法处理木薯淀粉等样品,采用电感耦合等离子体质谱法,选择适合的同位素元素,运用碰撞池技术(CCT)降低元素Cu、As的多原子离子干扰,测定样品溶液中Pb、Cu、Cd、As、Hg等元素的含量,各元素线性相关系数为0.9997 ～0.9999,元素的检出限(3sd)分别为pb...     

RuCl(2)(p-cymene)](2) on carbon: an efficient,selective, reusable,and environmentally versatile heterogeneous catalyst

[reaction: see text] A heterogeneous ruthenium catalyst, easily prepared by adsorption of [RuCl(2)(p-cymene)](2) on activated carbon, exhibited a highly efficient and selective catalytic activity in various environmentally attractive transformations such as aerobic oxidation, hydrolytic oxidation, and dehydration processes with excellent recyclability.