Research Progress on Synthesis of Superoxide Dismutase Mimics

Research on the synthesis of superoxide dismutase mimics by chemical and biologi-cal synthetic methods were reviewed.The advantages and limitations were analyzed.A prospect for the future development of superoxide dismutase mimics is proposed.

Thermodynamics for chemical vapor synthesis of Nb nanopowder in NbCl_5-H_2-Ar system

Thermodynamics for chemical vapor synthesis （CVS） of Nb nanopowder in NbCl5-H2-Ar system was investigated by using FactSage software. The validation experiments were conducted to confirm the thermodynamics points. The results indicate that under the atmospheric pressure, the reduction approach from NbCl5（g） to Nb（s） is a stage-wise process with the formation of complex sub-chlorides, and is controllable at low hydrogen ratio （mole ratio of n（NbCl5）：n（H2）＆lt;1：180） and low temperature （＆lt;1050 ＆#176;C）. Furthermore, a reasonable amount of inert loading gas is favorable to increase the reduction ratio of NbCl5 and the powder yield. The as-synthesized Nb nanopowder with the homogeneous size of 30-50 nm and the powder yield of 85% （mass fraction） is obtained by the CVS process under n（NbCl5）：n（H2）：n（Ar）=1：120：1 and 950 ＆#176;C with the NbCl5 reduction rate of 96.1%.

Chemical synthesis of nanocrystalline ZrO_2-SnO_2 composite powders

ZrO_2-SnO_2 composite nanoparticles were prepared by heating the hydrateprecursors synthesized by the chemical co-precipitation reaction of ZrOCl_2 and SnCl_4. Theprecursors were examined by differential thermal analysis (DTA) and thermogravimetric analysis(TGA). The composite powder was characterized using X-ray diffraction (XRD), transmission electronmicroscopy (TEM) and desorption isotherm (Barrett-Joyner-Halenda method). The average crystal sizeof the nanoparticle ranges from 15 to 30 nm for the sample containing 5%-25% ZrO_2 (mass fraction).Most of the pores in the ZrO_2-SnO_2 nanoparticles are about 10-20 nm in diameter. The compositepowder is promising for chemical sensors.

Synthesis of Cell Adhesive Motif RGD Tripeptide by a Novel Chemical Method and Its Purification

The cell adhesive motif RGD tripeptide was synthesized by using a novel chemical method. First, Gly-Asp（GD） was synthesized in two steps including the chloroacetylation of free L-aspartic acid and the ammonolysis of the chloroacetylated L-aspartic acid. The yield of chloroacetylated L-aspartic acid was 83.0%. For the ammonolysis of chloroacetylated L-aspartic acid, the yield of the ammonolyzed product was 92. 3%. Second, the coupling between Arg and Gly-Asp was carried out by using the NCA method. The maximum yield of RGD was about 50% at 0℃ and pH = 9. 5. The prepared RGD tripeptide was confirmed by using amino acid component analysis and mass spectrographic analysis.

Preparation and characterization of calcium aluminate by chemical synthesis

Saturated Ca（OH）2 and AlCl3 solutions were used to synthesize calcium aluminate hydrate precipitates at room temperature; high purity calcium aluminate powders with stable phases were made by calcination of the precursors at a temperature as low as 1100℃. PSD and BET analysis revealed the particles with sizes ranging from submicrometer to several micrometers and with a specific area of 13 m^2/g. The measurement of hydraulic exotherm revealed that the exothennal rate is in peak for about 2 h. The exothermal quantities are 449.24 J/g at 12 h and 488.38 J/g at 24 h. Its strength development is quick and the 1 day curing strength is almost equal to 100% of the 3 days curing strength in the mortar test.

Soft chemical synthesis and electrochemical properties of tin oxide-based materials as anodes for lithium ion batteries

A novel soft chemical approach was developed to synthesize tin oxide-based powders. The microstructure, morphology, and electrochemical performance of the materials were investigated by X-ray diffraction, scanning electron microscope and electrochemical methods. The results show that the particles of tin oxide-based materials form an interconnected network structure like mesoporous material. The average size of the particles is about 200 nm. The materials deliver a charge capacity of more than 570 mA·h·g-1. And the capacity loss per cycle is about 0.15% after being cycled for 30 times. The good electrochemical performance indicates that tin oxide-based materials are promising anodes for lithium ion batteries.

Soft chemical synthesis and luminescence properties of red long-lasting phosphors Y_2O_2S:Sm^(3+)

Sm3＋-activated Y2028 red phosphors were prepared by the combustion method and microemulsion method at the first time. X-ray characterization and electron diffraction show that, Y202S：Sm3＋, Ti4＋, Mg2＋ samples prepared by these two methods are pure hexagonal crystals in structure with a trivial change due to dopants. Scanning electron microscopy （SEM） results show that the product presents an almond-like sheet in uniform size. Under the excitation of 269 nm ultraviolet light, Y202S：Sm3＋ samples fabricated by these two methods exhibit three main groups of red emission lines located at 564, 604, and 656 nm, respectively, which are attributed to the transitions of 4G5/2 →6H5/2, 4G~/2 →6H7/2, 4G5/2 →6H9/2, respectively. The samples prepared by microemulsion are seven times higher in fluorescent emission intensity and half time longer in afterglow time than that prepared by combustion.

Chemical synthesis of magnetic nanocrystals:Recent progress

Colloidal chemical synthesis of various types of magnetic nanocrystals is discussed with regard to recent discoveries. We first outline the chemical preparation of single-component magnetic nanocrystals with controlled size, shape, and uniformity based on several solution-phase methods, especially thermal decomposition and/or reduction method. Then we discuss the synthetic strategies of multi-component nanocrystals incorporating at least one magnetic component by manipulating heterogeneous nucleation and growth process. Toward the end, approaches for preparing hollow/porous magnetic nanocrystals are highlighted. We believe that the summarized chemical synthesis will pave the way for the future development of extraordinary magnetic nanocrystals.

Chemical Synthesis and Magnetic Properties of Nanocrystalline (La_(0.67-X)Gd_X)Sr_(0.33)MnO_3 Using Amorphous Molecular Alloy as Precursors

A new route to synthesize nanosized crystalline of （La0.67-xGdx）Sr0.33MnO3 （X=0.05, 0.10, 0.15, 0.20） perovskite-type complex oxides at calcination temperature of 600-1000℃ using the amorphous molecular alloy as precursors was reported. The precursor could be completely decomposed into complex oxide at temperature below 500℃ according to the TGA and DTA results. XRD demonstrates that the decomposed species is composed of perovskite-type structure at calcination temperature of 600℃ for 2 h. The particle size that depends on the calcination temperature of the precursor is in a range of 30-120 nm as determined by transmission electron microscopy （TEM）. This method is effective and can be easily quantitatively controlled to synthesize nanosized perovskite-type complex oxides. The magnetic properties of （La0.67 xGdx）Sr0.33MnO3 nanocrystalline were preliminary studied.

A FACILE CHEMICAL SYNTHESIS of PENTADEOXYRIBONUCLEOTIDE d-TGGGT via PHOSPHOTRIESTER METHOD

In this paper,we report the chemical synthesis of oligonucleotide d-TGGGT using phosphotriester method.The protected pentamer d-MmtTGibGibGibT(=p-ClC6H_4-O(O)P)was deblocked by treatment with concentrated ammonium hydroxide and 80% acetic acid.The pure d-TGGGT obtained by chromatorgraphy on DEAE-Sephadex A-25 and Q-Sepharose FF could be hydrolyzed completely and confirmed by base ratio.

Progress in Chemical Synthesis of Peptides and Proteins

For the proteins that cannot be expressed exactly by cell expression technology (e.g., proteins with multiple posttranslational modifications or toxic proteins), chemical synthesis is an important substitute. Given the limited peptide length offered by solid-phase peptide synthesis invented by Professor Merrifield, peptide ligation plays a key role in long peptide or protein synthesis by ligating two small peptides to a long one. Moreover, high-molecular-weight proteins must be synthesized using two or more peptide ligation steps, and sequential peptide ligation is such an efficient way. In this paper, we reviewed the development of chemical protein synthesis, including solid-phase peptide synthesis, chemical ligation, and sequential chemical ligation. © 2017, The Author(s).

Chemical synthesis, spectroscopic properties and biochemical evaluation of an adenine nucleotide derivative 2-aminoadenosine 5＇-triphosphate

An adenine nucleotide derivative 2-aminoadenosine 5＇-triphosphate was chemically synthesized through four steps and was characterized with 1H NMR, 31p NMR, 13C NMR, EA and FT-IR. Its ultraviolet and fluorescence properties at various pH values were studied. Two pKa values for the compound were determined by the curves of UV absorption dependency on pH, Which were 0.68 and 4.83, respectively. The values were consistent with those calculated from ACD/Labs software. In addition, hydrolysis of the adenine nucleotide derivative in the catalysis of potato apyrase was studied. The competition of the ATP analogue with ATP for potato apyrase＇ active site was proved to be a sequential reaction mechanism.

SYNTHESIS OF PPCuPc FILM BY MICROWAVE PLASMA CHEMICAL VAPORIZATION DEPOSITION(MPCVD)

Using a low power microwave generator(W_(max)=100W) and a Surfatron discharge device, Plasma-polymerized copper phthalocyanine (PPCuPc) film was synthesised from monomer copper phthalocyanine(CuPc) by microwave plasma chemical vaporization deposition(MPCVD) with Ar as incorporation gas. The film was characterized by FTIR and ESCA. The role of dissociation of chemical bond in the polymerization process and the influence of substrate temperature and material on deposition were investigated in some detail.

NC310 Catalyst for Methanol Synthesis Developed by SINOPEC Research Institute of Nanjing Chemical Company

The NC310 type catalyst for methanol synthesis developedby the SINOPEC Research Institute of NanjingChemical Company has passed the appraisal of researchachievements organized by the Science and TechnologyDivision of the Sinopec Corp. The group of specialistsattending the appraisal meeting has recognized that thiscatalyst has reached the internationally advanced level interms of its overall catalytic performance.

Synthesis and optical properties of zinc phosphate microspheres

Monodisperse zinc phosphate microspheres were synthesized by a facile solvothermal method in the presence of oleic acid.X-ray powder diffraction（XRD）,Fourier transform infrared spectrum（FT-IR）,emission scanning electron microscopy（SEM）,and energy dispersive X-ray spectrum（EDX） were used to characterize the microstructures and morphologies of the as-obtained zinc phosphate samples.The experimental results indicate that the zinc phosphate products are well crystallized,and the morphologies of the samples can be easily controlled by the elaborate choice of oleic acid addition and the content of NaOH.Furthermore,self-activated luminescent properties of the products are observed.The as-obtained samples show an intense blue emission under a long-wavelength UV light excitation of 400 nm.The possible luminescent mechanism may be ascribed to the carbon-related surface impurities or defects.

Simple chemical synthesis and isotropic negative thermal expansion in MHfF_(6)(M=Ca,Mn,Fe,and Co)

The rapid progress of modern technologies has accelerated the prominence of thermal expansion mismatch between materials,and tunable thermal expansion materials will be a powerful safeguard against this challenge.Here,isotropic MHfF_(6)(M=Ca,Mn,Fe,and Co)compounds with tunable thermal expansion have been produced via a low-cost synthetic method and investigated.By utilizing temperature dependent X-ray diffraction(XRD)and Raman spectroscopy,combined with first principles calculations,it was revealed that the transverse thermal vibrations of the F atoms are dominated by low-frequency phonons with negative Grüneisen parameters and are therefore the origin of the negative thermal expansion(NTE).Very interestingly,with the increase of the M atomic number,the metal…F atomic linkages become stiffer,reducing the number of vibrational modes with negative Grüneisen parameters,so that the strong NTE can be gradually adjusted to moderate NTE and to near zero thermal expansion.The present study achieves the tunable thermal expansion in a new compound family and shed light on the internal mechanism from the perspective of lattice vibrational dynamics.

Synthesis of Phenylpropanoid Glycoside Analogs

The regioselective acylation of unprotected phenylethyl glucoside withcinnamoyl chloride leads to 6-OH cin-namoylated glucoside. In this manner, thirteen phenylpropanoidglycoside analogs were designed and prepared. Their structure was confirmed by ~1H NMR and ^(13)CNMR spectra.

Recent advances in chemical protein synthesis:method developments and biological applications

The central dogma of modern biology underscores the pivotal roles proteins play in diverse biological processes,the study of which necessitates advanced methods to produce proteins with precision and versatility.Chemical protein synthesis,a powerful approach utilizing chemical reactions for the de novo construction of structurally accurate proteins,has emerged as a transformative tool for studying proteins and generating protein derivatives/mimics inaccessible by natural biological machinery,including post-translationally modified proteins,proteins comprised of unnatural amino acids,as well as mirror-image proteins.This review summarizes recent strides in synthetic method developments for chemical protein synthesis,including innovative techniques in solid-phase peptide synthesis,the challenges presented by difficult sequences in either synthesis or folding and the exploration of novel ligation reactions using both chemical and enzymatic methods.Furthermore,the review also delves into newly developed protocols for site-selective protein modifications and the generation of stapled or macrocyclized peptides/miniproteins,highlighting the power of chemical methods to make structurally diverse proteins.Recent applications of synthetic proteins in investigating post-translational modifications(phosphorylation,lipidation,glycosylation,ubiquitination,etc.),mirror-image biological processes and drug development are further discussed.Together,these topics provide a comprehensive overview of the current landscape of chemical protein synthesis.

Efficient Chemical Synthesis and Folding of Mirror-Image Tropomyosin Receptor Kinase A Using the Strategy of Removable Glycosylation Modification

Comprehensive Summary The strategy of removable glycosylation modification was used to overcome the low-efficiency problem encountered in the chemical synthesis of the mirror-image D-version of the immunoglobulin(Ig)-like domain of tropomyosin receptor kinase A(DlgCTrkA),a protein molecule needed for mirror-image screening of D-peptide ligands targeting this cell membrane receptor.It was found that O-linked-β-N-acetyl-D-glucosamine(O-GlcNAc)modification at^(D)Ser^(312),or^(D)Ser^(320)can significantly improve the efficiency of DlgCTrkA synthesis and folding,while O-GlcNAc modification at^(D)Ser^(330)showed barely any improvement.This study provides a new example demonstrating the power of the removable glycosylation modification strategy in the chemical synthesis and folding of difficult-to-obtain proteins.It also presents evidence that removable glycosylation modification at different sites would significantly affect the efficiency of protein folding promoted by this strategy.

An improved installation of 2-hydroxy-4-methoxybenzyl(iHmb)method for chemical protein synthesis

The 2-hydroxy-4-methoxybenzyl(Hmb)backbone modification can prevent amide bond-mediated sidereactions(e.g.,aspartimide formation,peptide aggregation)by installing the removable Hmb group into a peptide bond,thus improving the synthesis of long and challenging peptides and proteins.However,its use is largely precluded by the limited Hmb’s installation sites.In this report,an improved installation of Hmb(iHmb)method was developed to achieve the flexible installation and the convenient removal of Hmb.The iHmb method involves two critical steps:(1)oxidative diazotization of the readily installed 2-hydroxy-4-methoxy-5-amino-benzyl(Hmab)to give 2-hydroxy-4-methoxy-5-diazonium-benzyl(Hmdab)by combining soamyl nitrite(IAN)/HBF_(4),and(2)reductive elimination of Hmdab to give the desired Hmb by 1,2-ethanedithiol(EDT).The iHmb method enables the installation of Hmb at any primary amino acid including the highly sterically hindered amino acids(e.g.,valine and isoleucine).The practicality and utility of the iHmb method was demonstrated by one-shot solid-phase synthesis of a challenging aspartimide-prone peptide,the mirror-image version of a hydrophobic peptide and a long-chain peptide up to 76-residue.Furthermore,the iHmb method can be utilized to facilitate chemical protein ligation,as exemplified by the synthesis of the single-spanning membrane protein sarcolipin.The iHmb method expands the toolkit for peptide synthesis and ligation and facilitates the preparation of peptides/proteins.