Synthesis and characterization of new meso -substituted unsymmetrical metalloporphyrins

The synthesis and characterization of new meso-substituted unsymmetrical metalloporphyrins has been described. A new modified Adler method was used for the synthesis of two unsymmetrical porphyrins. Reactions of these unsymmetrical porphyrins with metal acetates afforded the corresponding metalloporphyrins in high yields with excellent purity. These porphyrins and their metal derivatives were characterized by spectroscopic methods. However, the copper complexes were further studied by ESR spectra and zinc complex by fluorescence spectrum.     

Synthesis, characterization, and spectroscopic analysis of antiaromatic benzofused metalloporphyrins

A two-electron oxidation of the Cu(II) (9) and Zn(II) (12) complexes of tetraphenyltetrabenzoporphyrin (TPTBP) results in the formation of stable antiaromatic [(TPTBP)Cu(II)(H(2)O)](2+)?2?[SbF(6)](-) (10) and [(TPTBP)Zn(II)(H(2)O)(2)](2+)?2?[SbF(6)](-) (13) with 16π electrons on the inner ligand perimeter. X-ray structures of the parent TPTBP complexes, the dications, and singly oxidized species [(TPTBP)Cu(II)](?+)[SbF(6)](-) (11) reveal that the use of TPTBP rather than a porphyrin ligand reduces the degree of nonplanarity in the 16π-electron species relative to the parent 18π complex. Significant high-field shifts of the (1)H?NMR signals of the outer ring protons and large positive values in calculations of nucleus-independent chemical shifts on the central cavity of the porphyrin ring provide unambiguous evidence for the antiaromatic character of the 16π Zn(II) species. A combination of magnetic circular dichroism spectroscopic studies and TD-DFT calculations on both the Zn(II) and Cu(II) species demonstrates that the main electronic bands of the dicationic species can be readily assigned by using Michl's 4N perimeter model. Femtosecond transient absorption studies clearly demonstrated that the number of π electrons on the inner ligand perimeter and the configuration of the central metal ion play a critical role in the excited-state relaxation dynamics. Redox potentials for conversion between the 16π, 17π, and 18π systems were measured by cyclic voltammetry in dichloromethane and benzonitrile, and UV/Vis spectra of each oxidation/reduction product were monitored by thin-layer spectroelectrochemistry.     

Crown ether-appended Fe (III) porphyrin: Synthesis, characterization and catalytic oxidation of cyclohexene with molecular oxygen

A new crown ether appended Fe(Ⅲ) porphyrin complex was prepared by sulfuryl chloride appended benzo-15-crown-5 to the meso position of meso-5,10,15,20-tetra(4-hydrophenyl)porphyrin,and it was applied to catalytic oxidation of cyclohexene with molecular oxygen without reductant,showing a remarkable catalytic activity(conversion is up to 94%) and selectivity for 2-cyclohexen-1-ol(73%).     

Synthesis, electrochemistry, absorption and electro-polymerization of aniline-ethynyl metalloporphyrins

Free-base, nickel(II), zinc(II) and iron(III) mono(4-aniline-ethynyl)biphenylporphines (AEBPPs) were synthesized and their electro-polymerization reactions were studied. Electrochemical and UV-Visible experiments showed that AEBPPs were electro-polymerized onto Pt and indium tin oxide (ITO) surfaces without significantly changing their redox and spectral properties. This suggests that the pi-conjugations of these porphyrins were not greatly affected upon electro-polymerization. SEM images indicated the formation of porphyrin films on the electrode surfaces, while EDS spectra of the metallo-AEBPP films confirmed deposits of the corresponding metals. Upon closer inspection, the AFM images revealed nano-scale fine structure of these porphyrin films. Both SEM and AFM images of the porphyrin films showed similar trends of porphyrin accumulation.     

Studies of tailed metalloporphyrins VI. Synthesis,characterization and catalysis of benzimidazole-linked iron(III) porphyrins

Transition Metal Chemistry -     

The effect of dimerization on the resonance raman excitation profiles of metalloporphyrins

Model calculations are reported showing the effect of dimerization on the absorption spectra and resonance Raman excitation profiles of metalloporhyrins. This effect, which qualitatively resembles that of metal atom substitution or solvent change, is mainly due to mixing of the monomer Q and B states.     

疏水性金属卟啉的合成及催化性能研究

本文合成了一类带疏水性长链的对称卟啉及其金属配合物, 研究了该类金属卟啉在CH2Cl2/H2O两相体系中催化苯乙烯的环氧化反应性能。通过以上研究, 发现催化反应体系中水相PH值对烯烃环氧化反应有很大影响; 改变金属卟啉的疏水性对催化反应影响不大; 具不同中心金属离子的金属卟啉有不同的催化活性, 催化活性顺序为:Mn>Co>Ni>Cu。     

Synthesis and study of crown ether-appended boron dipyrrin chemosensors for cation detection

Boron dipyrrin (BDP) bearing crown ethers of varying cavity sizes, namely, 15-crown-5, 18-crown-6, and 21-crown-7, at the meso-position are synthesized and employed as chemosensors for cation detection in solution. In the absence of metal cations, the emission of the BDP moiety is found to be quenched to some extent by an intramolecular charge transfer (ICT) process from the donor oxygen atoms to the acceptor BDP unit. Coordination of metal ions to the oxygen donor atoms in the crown ether cavity inhibits intramolecular charge transfer to the BDP acceptor, leading to cation-induced fluorescence enhancement. The fluorescence enhancement is systematically probed as a function of crown ether cavity and metal ion sizes to achieve metal ion selectivity.     

Synthesis, characterization, and biological evaluation of new oxime-phosphazenes

Hexachlorocylotriphosphazene (1) was reacted with 4-hydroxy-3-methoxybenzaldehyde to give hexakis[(4-formyl-2-methoxy)phenoxy]cyclotriphosphazene (2). Hexakis[(4-(hydroxyimino)2-methoxy)phenoxy]cyclotriphosphazene (3) was synthesized by reaction of 2 with hydroxlamine hydrochloride in pyridine. Compound 3 was reacted with benzyl chloride, acetyl chloride, allyl bromide, benzoyl chloride, propanoyl chloride, 4-methoxybenzoyl chloride, 2-chlorobenzoyl chloride, chloroacetyl chloride, methyl iodide, and thiophene-2-carbonyl chloride. From these reactions, full or partially substituted compounds were obtained, usually in high yields. Pure or defined products could not be obtained from reaction of 3 with methacryloyl chloride and O-acetylsalicyloyl chloride. The structures of the compounds were determined by elemental analysis, and IR, ¹H, ¹³C, and ³¹P NMR spectroscopy. The synthesized compounds were screened for in-vitro antimicrobial activity against two Gram-positive bacteria (Staphylococcus aureus and Enterococcus faecalis), two gram-negative bacteria (Escherichia coli and Klebsiella pneumonia), and fungal strains (Aspergillus niger, and Candida albicans) by the agar well diffusion method. Few compounds had significant activity against both Gram-positive and Gram-negative bacteria. None of the compounds had antifungal activity except compounds 7 and 9, which had moderate activity.     

Synthesis,characterization, and antimicrobial activity of new benzofuran derivatives

Russian Journal of General Chemistry - A novel series of (5-substituted-1-benzofuran-2-yl)(2,4-substituted phenyl)methanones (4a–4i) have been prepared by the Knoevenagel condensation of...     

Synthesis,characterization, and thermal properties of new flavor compounds

Synthesis, characterization, and thermal properties of new, flavor, long chain esters were presented. The new compounds were obtained in the catalytic esterification process of a stoichiometric ratio of trans-3,7-dimethyl-2,6-octadien-1-ol, succinic anhydride, and aliphatic chain diol. As diols ethylene glycol, 1,4-buthylene glycol, 1,5-pentylene glycol, and 1,6-hexylene glycol were applied. The spectroscopic analyses completely confirmed that the applied synthesis conditions allowed obtaining the new compounds with high yield and purity. Their thermal properties were studied in inert and oxidative atmospheres. The esters were less thermally stable in inert (IDT 186–195 °C) than in oxidative (IDT 210–228 °C) atmosphere. Two, non-completely divided decomposition steps were visible during their pyrolysis. In contrast, the new, long chain compounds decompose in three major steps in air. The analyses of the volatile products emitted during their pyrolysis indicated on the asymmetrical disrupt of their bonds. The formation of acyclic and alicyclic monoterpene hydrocarbons, succinic anhydride, diols, alcohols, alkenes, and water was observed. It indicated mainly on the β-elimination reactions during their pyrolysis. Also, β-elimination reactions of esters are mainly expected in air. Initially, it resulted in the formation of acyclic and alicyclic monoterpene hydrocarbons, hydroxyl compounds (diols, alcohols), and its β-elimination products: aldehydes, alkenes, and water. However, the presence of oxygen in the medium causes the partial decarboxylation and oxygenation of aldehydes and thus the formation of alkenes and carbon dioxide. In addition, the beginning of evaporation of succinic anhydride was detected at T _max1. At T _max2 the evaporation of succinic anhydride, their partial decarboxylation to CO₂, the small amounts of diols, alcohols, and aldehyde fragments were indicated. Finally, succinic anhydride, water, and carbon dioxide were only observed during decomposition of studied esters in air.     

Synthesis, characterization, and thermal properties of new silarylene-siloxane-acetylene polymers

New silarylene-siloxane-acetylene polymers have been synthesized by coupling reactions employing 1,3-bis(p-ethynylphenyl)-1,1,3,3-tetraphenyldisiloxane (3) as the key monomer. Their thermal properties have been evaluated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). All of the new polymers showed good thermal stability, with their temperatures at 5% weight loss (T_d5) being higher than 540 °C under nitrogen and higher than 460 °C in air. Their char yields at 1000 °C under N₂ were above 80%. Broad exothermic peaks, attributable to reaction of the acetylenic units, were observed by DSC analysis in the temperature range 270-450 °C.     

Synthesis,characterization, and antimicrobial activity of new benzoylthiourea ligands

In this study, new benzoylthiourea derivatives, (E)-N-[(2-benzamidomethyleneamino)ethylcarbamothioyl]benzamide H₃L′, N-(1-(3-benzoylthioureido)propan-2-ylcarbamothioyl)-benzamide H₄L″, (E)-N-[4-(benzamidomethyleneamino)phenylcarbamothioyl]benzamide H₃L‴, were synthesized. Structures of the compounds were identified by spectroscopic techniques. In addition, all synthesized compounds were evaluated for in vitro antibacterial and antifungal activity. Compound H₃L‴ exhibited antibacterial activity.     

Synthesis,characterization and antimicrobial activities of new bis-hydrazonothioxothiazolidinone derivatives

New bis-hydrazonothioxothiazolidinone derivatives based on 2-thioxothiazolidin-4-one were synthesized in good yields using a simplified experimental condition. The structure of synthesized compounds was established with the help of common physico-chemical analysis and various spectroscopic techniques like FT-IR, mass and ¹H NMR. The results of characterizations are in good agreement with the proposed structure of all the synthesized compounds. Further, the antimicrobial (antibacterial and antifungal) activities of all the synthesized derivatives were carried out against various species like Bacillus subtilis, Escherichia coli, Aspergillous niger and Aspergillous flavus by using agar-cup method. The results of antimicrobial screening showed that all the compounds have mild to moderate activity. However, some of the compounds (3a, 3b, 3d, 3e, 3f, 3g, 3i and 3j) have shown better activity than the other.     

Synthesis, characterization and herbicidal activity of new thiazoline derivatives

A series of new thiazoline derivatives 2-alkyl(aryl) imino-4-amino-5-ethoxycarbonyl-3-phenyl-3Hthiazoline (3) and bis(2-imino-4-amino-5-ethoxycarbonyl-3-phenyl-3H-thiazoline alkylene (4) have been synthesized by reactions of intermediate 4-amino-5-ethoxycarbonyl-2-methylthio-3-phenyl-3H-thiazolinium sulphate (2) with alkylamines or arylamine in 64%-89% yields. The structures of 3 and 4 have been confirmed by 1H NMR, EI-MS, IR spectroscopy and elemental analyses. Some compounds exhibited high or moderate herbicidal activities against the roots of rapeseed and barnyard grass at 100 mg/L.     

Synthesis, characterization and cytotoxicity of new rotundic acid derivatives

Rotundic acid (RA, 1), a natural compound, exhibits potent tumor cell growth inhibiting properties. To date there are no reports on derivatives of RA. Furthermore, the 28-COOH position of RA might make it unstable and induced serious gastrointestinal side effects when it was applied in vivo. Therefore, in order to explore and make use of this compound, eight new amino acid derivatives of RA at the 28-COOH position were synthesized and evaluated for their cytotoxicities in vitro on three tumor cell lines including A375, HepG2 and NCI-H446. As a result, a few of these new amino acid derivatives showed stronger cytotoxicity. Compound 5a was found to have the best inhibition activity on the three tested human tumor cell lines with IC(50) values of less than 10 μM compared with RA treatment. Meanwhile, the cytotoxicity of compound 6b was significantly higher than that of RA on the A375 cell line and almost the same as RA on the HepG2 and NCI-H446 cell lines. Hence, compounds 5a and 6b may serve as potential lead compounds for the development of new anti-tumor drugs.     

Synthesis, characterization and antimicrobial activity of new 1,2,3-selenadiazoles

The commercially available aromatic polyketones 1a-d were utilized for the synthesis of the multi-arm1,2,3-selenadiazole derivatives 3a-d. The preparation starts with the reaction between compounds 1a-d and p-toluenesulfonyl hydrazide to give the corresponding tosylhydrazones 2a-d. Subsequent reaction with selenium dioxide leads to regiospecific ring closure of the tosylhydrazones to give the target multi-arm 1,2,3-selenadiazole derivatives in high yield. A 1,2,3-selenadiazole derivative 3e containing an epoxide ring was also prepared. The structures of all the synthesized compounds were confirmed on the basis of spectral and analytical data. The compounds were screened in vitro for their antimicrobial activity against various pathogenic bacterial and Candida strains obtained from King Abdullah Hospital in Irbid -Jordan. Compounds 3a, 3c and 3e were found to be highly active against all the selected pathogens. Compound 3e showed an inhibition zone of 13 mm against the highly resistant P. aruginosa.     

Synthesis and characterization of new mono-, bis-, and tris-oxamato proligands

This communication presents the synthesis and the characterization of new organic molecules bearing up to three N-phenyl-oxalamic acid ethyl esters. The syntheses are based on Sonogashira-type cross-coupling reactions with preformed oxalamic ester intermediate building blocks. The short synthetic pathways lead easily to valuable potential oxamato-bridging ligands with overall interesting yields.     

Synthesis of lysine derivatives containing aza-crown ethers and a chromophore unit

The synthesis of a lysine-like chromo-ionophore and its derivatives, useful in peptide chemistry, is described. The influence of the peptide framework on the anthraquinone properties is examined with spectroscopic and electrochemical methods.     

金属卟啉分子印迹聚合物的合成与性能研究

以5-(4-羟基苯基)-10,15,20-三苯基卟啉锌为印迹分子,4-乙烯基吡啶为功能单体,乙二醇二甲基丙烯酸酯为交联剂,合成了具有金属卟啉识别能力的分子印迹聚合物.紫外可见滴定光谱研究表明,功能单体与印迹分子在聚合前形成1:1的配合物.通过吸附试验、荧光光谱及斯卡查特分析法,考察了分子印迹聚合物对锌卟啉化合物的识别性能.结果表明,印迹聚合物对结构类似的卟啉化合物具有良好的识别能力,对印迹分子荧光性能的影响远大于其对应的非印迹聚合物.在浓度较低时,印迹聚合物对印迹分子的结合常数和最大结合量分别为:1.61×106L/mol和3.22×10-5mol/g.