Catalyst-free synthesis of functionalized dihydro-2-oxypyrroles by the reaction of enaminones and N,N′-bis(phenylmethylidene)phenylmethane

A catalyst-free and convenient approach for the preparation of substituted dihydro-2-oxypyrrole is described. This three-component reaction between primary amines, dialkyl acetylenedicarboxylate, and N,N′-bis(phenylmethylidene)phenylmethane proceeds in MeOH under reflux conditions in good to excellent yields.     

Theoretical investigation of azo dyes adsorbed on cellulose fibers: 1. Electronic and bonding structures

Structural, bonding and electronic characteristics of complexes of anthraquinone and 1-arylazo-2-naphtol dyes and cellulose I _β are studied using B3LYP density functional method with 6-31G** basis set based on the partially and fully optimized structures. Results reveal that for both partially and fully optimized complexes, there is a stabilizing attraction between dyes and cellulose surface. The hydrazone (Hy) tautomer in anionic state (Hy–SO₃ ^?) shows the strongest interaction with the cellulose surface. Natural bond orbital (NBO) and atoms-in-molecules (AIM) analyses have been carried out to study the nature of azo dyes-cellulose bonds in detail. According to NBO analysis, a remarkable charge transfer occurs between the –SO₃ ^? and –SO₃H functional groups of the dye and the cellulose surface which can be regarded as the main source of the large dye–cellulose interaction energy. AIM analysis confirms the existence of hydrogen and van der Waals bonds between the azo dyes and cellulose. Furthermore, a very good agreement is observed between the number of hydrogen bonding sites and dye–cellulose interaction energies.     

Iron(III) hetero-ligand complexes containing 1,10-phenanthroline derivatives, chloride and dimethyl sulfoxide: synthesis, characterization, crystal structure determination and luminescent properties

[Fe(Me-phen)Cl₄][Me-phen·H] (1) and [Fe(Cl-phen)Cl₄][Cl-phen·H] (2) complexes were prepared from the reactions of FeCl₃·6H₂O with 5-methyl-1,10-phenanthroline (Me-phen) and 5-chloro-1,10-phenanthroline (Cl-phen), respectively, in a 0.1 M aqueous solution of HCl. Stepwise addition of dimethyl sulfoxide to the solution of 1 in methanol results in a mixed ligand complex, [Fe(Me-phen)Cl₃(DMSO)] (3). Complex 3 was also prepared by two other methods. The reaction of a methanol solution of [Fe(Me-phen)Cl₄][Me-phen·H] (1) with [Fe(DMSO)₄Cl₂][FeCl₄] in 1:6 ratio led to 3. Complex 3 was also prepared from the reaction of 5-methyl-1,10-phenanthroline with [Fe(DMSO)₄Cl₂][FeCl₄] in 1:1 ratio in methanol. The three complexes were characterized by IR, UV–Vis, ¹H NMR and luminescence spectroscopy and their structures were studied by the single-crystal diffraction method. Calculation methods were employed to study the isomerization of (3) in solution.     

Synthesis and Multinuclear NMR Study of Benzoyl Methylene Triparatolylphosphorane Ylide and the Reaction of this Ylide with Mercury(II) Halides

The reaction of the title ylide {PhCOCHP(p-tolyl)₃} with Pd(II), Pt(II). Hg(II), and Ag(I) in equimolar ratios using CH₃CN, CH₃OH, and CH₂Cl₂ as solvents have yielded [{(p-tolyl)₃PCHCOC₆H₅} PdCl₂]₂ (I), [{(p-tolyl)₃ PCHCOC₆H₅} PtCl₂]₂(2), [Hg(NO₃)₂ {(p-tolyl)₃ PCHCOC₆H₅}](3), and [Ag{(p-tolyl)₃ PCHCOC₆H₅ < eqid1 > ₂]⁺ (4). The IR, ¹H ¹³C, and ³¹P NMR together with micro analysis data of the products were obtained.     

Structural,Theoretical, and Spectroscopic Study of Mercury(II) Complexes of two New Unsymmetric Phosphorus Ylides

Abstract

The reaction of Ph₂PCH₂PPh₂ (dppm) with 4-methylphenacyl bromide and 2-(bromoacetyl)naphthalene in chloroform produce the new phosphonium salts [Ph₂PCH₂PPh₂CH₂C(O)C₆H₄Me]Br (1) and [Ph₂PCH₂PPh₂CH₂C(O)C₁₀H₇]Br (2). Further, by reaction of the monophosphonium salts of dppm with the strong base Et₃N the corresponding bidentate phosphorus ylides, Ph₂PCH₂P(Ph)₂ = C(H)C(O)C₆H₄Me (3) and Ph₂PCH₂P(Ph)₂ = C(H)C(O)C₁₀H₇ (4) were obtained. The reaction of these ligands with mercury(II) halides in dry methanol led to the formation of the mononuclear complexes {HgX ₂[(Ph₂PCH₂PPh₂C(H)C(O)C₆H₄Me)]} [X = Cl (5), Br (6), and I (7)] and {HgX ₂[(Ph₂PCH₂PPh₂C(H)C(O)C₁₀H₇)]} [X = Cl (8), Br (9), and I (10)]. Characterization of the obtained compounds was performed by elemental analysis, IR, ¹H, ³¹P, and ¹³C NMR spectra. The structure of compounds 3 and 10 are unequivocally determined by single crystal X-ray diffraction techniques. X-ray analysis of 10 reveals the presence of mononuclear complex containing Hg atom in a distorted tetrahedral environment. In all complexes, the title ylides are coordinated through the ylidic carbon and the phosphine phosphorus. Computational studies on ligand 4 and complexes 8, 9, and 10 at DFT (B3LYP) level of theory are also reported. It was shown that the formation of P,C-coordinated 1+1 complex 10 is energetically more favored than corresponding P,P-coordinated 1+2 product.

[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 following free supplemental files: Additional figures]     

Cosmological Constraints on Polytropic Gas Model

We study the polytropic gas scenario as the unification of dark matter and dark energy. We fit the model parameters by using the latest observational data including type Ia supernovae, baryon acoustic oscillation, cosmic microwave background, and Hubble parameter data. At 68.3 % and 95.4 % confidence levels, we find the best fit values of the model parameters as $\tilde{K}=0.742_{-0.024}^{+0.024}(1\sigma)_{-0.049}^{+0.048}(2\sigma)$ and $n=-1.05_{-0.08}^{+0.08}(1\sigma)_{-0.16}^{+0.15}(2\sigma)$ . Using the best fit values of the model, we obtain the evolutionary behaviors of the equation of state parameters of the polytropic gas model and dark energy, the deceleration parameter of the universe, the dimensionless density parameters of dark matter and dark energy as well as the growth factor of structure formation. Then, we investigate different energy conditions in the polytropic gas model and obtain that only the strong energy condition is violated for the special ranges of the redshift. We also conclude that in the this model, the universe starts from the matter dominated epoch and approaches a de Sitter phase at late times, as expected. Further, the universe begins to accelerate at redshift z _t=0.74. Furthermore, in contrary to the ΛCDM model, the cosmic coincidence problem is solved naturally in the polytropic gas scenario. Moreover, this model fits the data of the growth factor well as the ΛCDM model.     

Note on “Inverse minimum cost flow problems under the weighted Hamming distance”

Jiang et al. proposed an algorithm to solve the inverse minimum cost flow problems under the bottleneck-type weighted Hamming distance [Y. Jiang, L. Liu, B. Wuc, E. Yao, Inverse minimum cost flow problems under the weighted Hamming distance, European Journal of Operational Research 207 (2010) 50–54]. In this note, it is shown that their proposed algorithm does not solve correctly the inverse problem in the general case due to some incorrect results in that article. Then, a new algorithm is proposed to solve the inverse problem in strongly polynomial time. The algorithm uses the linear search technique and solves a shortest path problem in each iteration.     

Determination of cyanide using a chemiluminescence system composed of permanganate,rhodamine B,and gold nanoparticles

We describe a new chemiluminescence (CL) system based on the oxidation of rhodamine B (RhoB) with alkaline potassium permanganate in the presence of gold nanoparticles (Au-NPs) and anionic detergent sodium dodecyl sulfate. Free RhoB is weakly chemiluminescent when oxidized with permanganate at alkaline pH values. However, a remarkably strong enhancement of CL is observed in the presence of Au-NPs, probably due to a strong interaction between RhoB and the NPs. The possible mechanism was studied via recording the CL emission. It is also found that the intensity of CL gradually decreases in the presence of cyanide due to its interaction with the Au-NPs. The relation between the decreased CL intensity and cyanide concentration was exploited to develop a method for the determination of cyanide in the 0.01–0.5 μM concentration range, with a detection limit of 2.8 nM. The method was used to determine cyanide in spiked water, urine, and serum. Figure

Alkaline permanganate-rhodamine B-SDS CL reaction is dramatically enhanced by gold nanoparticles. Based on the inhibiting effect of cyanide on this system, a sensitive CL method was developed for its determination     

In vitro anti-proliferative activity of novel hexacoordinated triphenyltin(IV) trifluoroacetate containing a bidentate N-donor ligand

The discovery of the antitumor activity of cisplatin led several research groups to investigate the possible therapeutic applications of other metal based compounds. In an attempt to develop novel metal based drugs with a different therapeutic profile to cisplatin, we have synthesized a new N,N-chelated organotin(IV) trifluoroacetate by the reaction of Ph₃SnOCOCF₃ with equimolar amounts of 2,9-dimethyl-1,10-phenanthroline (Neocuproine). The complex is characterized by FT-IR and multinuclear NMR (¹H, ¹³C, ¹⁹F and ¹¹⁹Sn). FT-IR results authenticate the ligand coordination to the organotin moiety via nitrogen atoms. Furthermore, the cytotoxic activity of the free ligand (Neocuproine) and triorganotin(IV) complex towards human cervix carcinoma HeLa, human myelogenous leukemia K562 and normal immunocompetent cells, peripheral blood mononuclear cells PBMC is evaluated by the MTT (3-[4,5-dimetylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) method. The complex exhibits higher activities than antitumor drug cisplatin in all the tested cell lines. These results indicate that the studied triorganotin(IV) complex can be a potential anticancer agent for further stages of screening in vitro and/or in vivo.