New Applications of the CD Exciton Chirality Method. Stereochemical Assignment of Organic Compounds Containing Carboxylic Acid Groups

Summary. CD exciton chirality methods are described for the stereochemical assignment of organic compounds containing carboxylic acid groups. Using the chromophoric combination 2-naphthoate or 2-anthroate and 9-anthrylmethyl group the absolute stereochemistry of - and -hydroxy carboxylic acids can be deduced from a single CD measurement. Furthermore, as demonstrated with cyclic and acylic dicarboxylic acids, the direct esterification of sterically hindered carboxyl groups with 2-naphthol also allows the stereochemical assignment via CD spectroscopy.     

Three New Coordination Compounds with Neodymium Based on Tetrazole Containing Carboxylic Acid Ligands

Reactions of three tetrazole containing carboxylic acid ligands, namely, Hpztza, Htzpya, and Hpytza [Hpztza = 5‐(2‐pyrazinyl)tetrazole‐2‐acetic acid, Htzpya = 3‐(5‐tetrazolyl)pyridine‐1‐acetic acid, Hpytza = 5‐(3‐pyridyl)tetrazole‐2‐acetic acid] with NdCl₃ · 6H₂O under hydrothermal conditions, afforded the complexes [Nd(pztza)₂(H₂O)₆] · pztza · 3H₂O ( 1 ), [Nd₂(tzpya)₂(H₂O)₁₂]Cl₄ · 2H₂O ( 2 ), and [Nd(pytza)₂Cl(H₂O)₂] ( 3 ). The compounds were structurally characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction. X‐ray diffraction analyses revealed that compound 1 displays a mononuclear structure, 2 shows a dinuclear structure, and 3 features a 1D polymeric chain structure via pytza as linker. Furthermore, the luminescent properties investigated at room temperature in the solid state show that compound 2 has an obvious decrease in its luminescence, when compared to the ligand.     

Characterization of Aromatic Polyamide Particles Containing Carboxylic Acid and Carboxylic Acid Chloride Groups and Their Modification in Water

Two types of aromatic polyamide particles were prepared from 4,4′-diphenyldicarbonyl chloride and 3,5-diaminobenzoic acid in a reaction solution containing water or pyridine. Particles obtained using water (PA-water) were coarse spheres containing COOH groups with a diameter of 1 µm. Particles obtained using pyridine (PA-pyridine) were smooth spheres containing COOH and COCl groups with a diameter of 80 nm. The molecular weight of PA-pyridine was less than that of PA-water. During modification of PA-pyridine using 4′-aminobenzo-15-crown-5-ether, the COCl groups reacted with NH₂ groups of the crown ether in water, resulting in attachment of the crown ether to the particle surface.     

Synthesis and Biological Activity of Amide Compounds Containing Pyrazole Mandelic Acid Groups

A series of novel mandelic acid pyrazole amide compounds were synthesized and characterized. Moreover, their antiviral activities against tobacco mosaic virus were evaluated. The bioassay results indicated that as‐prepared compounds showed antiviral activity against tobacco mosaic virus at a concentration of 500 g/mL. The curative activity of compound 4g is 59.5%, which was comparable with positive control (Ningnanmycin, 61.0%). The inactivation activity of the compound 4l exhibited 80.1%, which was higher than that of Ningnanmycin (75.0%), and its protective activity was 88.7%, which is comparable with that of Ningnanmycin (90.7%).     

Application of the Organic Photosensitizers Bearing Two Carboxylic Acid Groups to Dye‐Sensitized Solar Cells

Three electron donor‐?? bridge‐electron acceptor (D‐π‐A) organic dyes bearing two carboxylic acid groups were applied to dye‐sensitized solar cells (DSSC) as sensitizers, in which one triphenylamine or modified triphenylamine and two rhodanine‐3‐acetic acid fragments act as D and A, respectively. It was found that the introduction of t‐butyl or methoxy group in the triphenylamine subunit could lead to more efficient photoinduced intramolecular charge transfer, thus improving the overall photoelectric conversion efficiency of the resultant DSSC. Under global AM 1.5 solar irradiation (73 mW·cm^?2), the dye molecule based on methoxy‐substituted triphenylamine achieved the best photovoltaic performance: a short circuit photocurrent density (J_sc) of 12.63 mA·cm^?2, an open circuit voltage (V_oc) of 0.55 V, a fill factor (FF) of 0.62, corresponding to an overall efficiency (η) of 5.9%.     

Organic Selenium Compounds,Part IV: Synthesis and Applications of Some New Diaryl Selenides Containing Azomethine and Oxazole Moieties

3,3′-Diacetyloxy (2), 3,3′-dihydroxy (3), 4,4′-diamino (4), and 4-amino (5) diphenylselenide derivatives were prepared as new precursors for the title studies. Compound 6 was obtained by condensation of 4 with an appropriate aromatic aldehyde. Unsymmetrical diphenylselenides 7 and 8 were obtained by condensation of 4 and/or 5 with an aromatic aldehyde. Compound 7 undergoes facile condensation with the same aldehyde present in its arylidene moiety to yield 6, while condensation with another different aromatic aldehyde yielded unsymmetrical 4-arylideneamino diphenylselenide derivative 9. Oxidation of 6, 8, and 9 using lead tetra acetate and/or N-bromosuccinimide yielded symmetrical bis-(2-aryl benzoxazol-6-yl) (10), unsymmetrical 3′-hydroxy, 2-aryl benzoxazol-6-yl selenides (11), and 2-aryl benzoxazol-6-yl, 2′-aryl′ benzoxazol-6′-yl selenide derivatives (12), respectively. Compound 10 was prepared in one-pot unequivocal synthesis by fusion of 4 with the appropriate aromatic aldehyde, while 12 was prepared by fusion of 4 with two different aromatic aldehydes. In certain cases, 6 and 9 were heated on a direct flame until complete homogeneity afforded the corresponding 10 and 12. The structures of the synthesized compounds are based on physical data, IR, ¹H NMR, ¹³C NMR, chemical means, and mass spectral data. Some of the synthesized compounds were biologically tested.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Exciton Chirality. (A) Origins of and (B) Applications from Strongly Fluorescent Dipyrrinone Chromophores

(A) The origin of exciton interaction and examples of its application to organic stereochemistry are presented. (B) N,N-Carbonyl-bridged dipyrrinones constitute a new class of highly fluorescent chromophores suitable for investigations of stereochemistry and absolute configuration. N,N-Carbonylxanthobilirubic acid esters are strongly fluorescent, with a fluorescence quantum yield (_F) 0.8, but produce only weak exciton CD from the trans-1,2-cyclohexanediol template. The ester of an analog with benzoic acid replacing propionic, N,N-carbonyl-8-(4-carboxyphenyl)-3-ethyl-2,7,9-trimethyl-(10H)-dipyrrin-1-one, exhibits strong fluorescence (_F=0.68, _em=493nm, _ex=422nm in CHCl₃) and UV-Vis absorption (21000 at 424nm) in organic solvents. Its diester with (1S,2S)-cyclohexanediol is fluorescent and exhibits exciton circular dichroism (=+15dm³·mol^–1·cm^–1, =432nm; =–4dm³·mol^–1cm^–1, =380nm) that correlates with the Exciton Chirality Rule.     

Exciton Chirality. (A) Origins of and (B) Applications from Strongly Fluorescent Dipyrrinone Chromophores

Summary. (A) The origin of exciton interaction and examples of its application to organic stereochemistry are presented. (B) N,N-Carbonyl-bridged dipyrrinones constitute a new class of highly fluorescent chromophores suitable for investigations of stereochemistry and absolute configuration. N,N-Carbonylxanthobilirubic acid esters are strongly fluorescent, with a fluorescence quantum yield (_F) 0.8, but produce only weak exciton CD from the trans-1,2-cyclohexanediol template. The ester of an analog with benzoic acid replacing propionic, N,N-carbonyl-8-(4-carboxyphenyl)-3-ethyl-2,7,9-trimethyl-(10H)-dipyrrin-1-one, exhibits strong fluorescence (_F=0.68, _em=493nm, _ex=422nm in CHCl₃) and UV-Vis absorption (21000 at 424nm) in organic solvents. Its diester with (1S,2S)-cyclohexanediol is fluorescent and exhibits exciton circular dichroism (=+15dm³·mol^–1·cm^–1, =432nm; =–4dm³·mol^–1cm^–1, =380nm) that correlates with the Exciton Chirality Rule.     

New Oscillatory Process in Aqueous Solutions of Compounds Containing Carbonyl and Amino Groups1

Frequency-correlated oscillations of chemiluminescence and the redox potential are observed during the amino-carbonyl reaction, which occurs in aqueous solutions of methylglyoxal and various amino-containing compounds (ethanolamine, glycine, and -alanine) at room temperature. The duration and amplitude of oscillations depend on the composition and concentration of the starting reactants, pH, stirring, and surface area through which oxygen diffuses into the system.     

Assignment of the Absolute-Handedness Chirality of Single-Walled Carbon Nanotubes by Using Organic Molecule Supramolecular Structures

Supramolecular structures of organic molecules on planar nanocarbon surfaces, such as highly oriented pyrolytic graphite (HOPG), have been extensively studied and the factors that control them are generally well-established. In contrast, the properties of supramolecular structures on curved nanocarbon surfaces like carbon nanotubes remain challenging to predict and/or to understand. This paper reports an investigation into the first study of the supramolecular structures of 5,15-bisdodecylporphyrin (C12P) on chiral, concentrated single-walled carbon nanotubes (SWNTs; with right-handed helix P- and left-handed helix M-) surfaces using STM. Furthermore, the study is the first of its kind to experimentally assign the absolute-handedness chirality of SWNTs, as well as to understand their effect on the supramolecular structures of organic molecules on their surfaces. Interestingly, these SWNT enantiomers resulted in supramolecular structures of opposite chirality based on the handedness chirality. With molecular modelling, we predicted the absolute-handedness chirality of SWNTs, before demonstrating this experimentally.     

计算有机化合物脂水分配系数的新方法

A new method is presented for the calculation of octanol/water partition coefficients. On the basis of summation of atomic contributions, our algorithm, namely; XLOGP, also incorporate correction factors into the calculation. Multivariate regression analysis was performed on a training database of 1831 organic compounds with diverse structures to give the final model. The correlation coefficients for the whole set fitting is 0.968 and the standard deviation is 0.37. The result shows that our model is accurate enough for logP estimation in QSAR studies. Compared to other similar approaches, our method gives better results and is more convenient to use.     

Low-dimensional Compounds Containing Cyano Groups. XIII. Structural–spectral Correlation of Copper Dicyanoargentates

The new mixed-valence mixed-metal complex Cu(py)₆Cu₂Ag₂(CN)₆ (py = pyridine) possesses a three dimensional polymeric crystal structure. The Cu(I) atom is tetrahedrally coordinated by two nitrogen atoms of pyridine molecules, by one nitrogen atom of the dicyanoargentate anion and by one carbon atom of the cyano group. Both the dicyanoargentate anion and the cyano group bridge the Cu(I) atom with neighboring Cu(II) atoms. These are hexacoordinated in the form of an elongated tetragonal bipyramid. The equatorial plane is formed by two nitrogen atoms from two pyridine molecules and two nitrogen atoms from bridging cyano groups. Axial positions are occupied by nitrogen atoms of the bridging [Ag(CN₂]⁻ anions. Correlation between structures of the title compound and seven other dicyanoargentates with their i.r. spectra has been studied. The coordination mode of [Ag(CN₂]⁻ anions in compounds Cu_8-xAg_x(tn)₃(CN)₁₀ x = 0.25, Cu(3-Mepy)₂Ag₂(CN)₄, Cu(py)₂Ag₂(CN)₄ and Cu(py)₄Ag₂(CN)₄ (tn is 1,3-diaminopropane, 3-Mepy is 3-methylpyridine) is predicted based on this correlation.     

羟基和甲氧基对羧酸酸性的影响分析

归纳和演绎法是有机化学学习中的重要方法,通过分析讨论羟基和甲氧基在几种体系中对羧酸酸性的影响,得出了氢键效应在不同体系中对羧酸酸性的影响并不一致的结论.     

激子手性方法用于多氧取代环己烯类化合物的研究

多氧取代环己烯是一类比较独特的天然产物,分子中多具有四个手性中心,立体化学多变,尽管用化学衍生物方法确定了部分化合物的绝对构型,但对已报道的化合物中仍有大部分未能确定其构型。在阐明分子相对构型的基础上,应用激子手性方法确定此类化合物的绝对构型,并利用Alchemy程序进行了分子动力学计算,对此类化合物的圆二色性规律进行了总结。     

常见有机化合物中英文命名的新教学法*

基于英文命名的新有机化合物命名规则于2017年颁布以来,掌握有机化合物的英文命名就变得更加重要。介绍了有机化合物中英文命名的一种新教学方法,含单种特性基团化合物可以分为烃和非烃2类,根据官能团编号的特点,按照链状和环状化合物分类。含多种特性基团化合物主要考虑基团作为母体基团的优先顺序,以及醛和羧酸及其衍生物为取代基时其碳原子是否作为主链和环母体部分,分别开展有机化合物中英文命名教学,便于教师教和方便学生学,在教学实践中深受师生欢迎。