Mild, convenient and efficient synthesis of novel 2,2-dichloro-1,3-diarylaziridines from Schiff bases by phase transfer CTAB catalysis under low concentration alkaline conditions

A mild and efficient method for preparation of novel 2,2-dichloro-1,3-diarylaziridines from Schiff base compounds in the presence of Ar-cetyl-N,N,N-trimethyl ammonium bromide(CTAB) as phase transfer catalyst has been described.The reaction is dramatically enhanced in the presence of quaternary ammonium salt.The corresponding products have been obtained in excellent yields,high purity and short reaction times.     

Indentation analysis of nano-particle using nano-contact mechanics models during nano-manipulation based on atomic force microscopy

Atomic force microscopy is applied to measure intermolecular forces and mechanical properties of materials, nano-particle manipulation, surface scanning and imaging with atomic accuracy in the nano-world. During nano-manipulation process, contact forces cause indentation in contact area between nano-particle and tip/substrate which is considerable at nano-scale and affects the nano-manipulation process. Several nano-contact mechanics models such as Hertz, Derjaguin–Muller–Toporov (DMT), Johnson–Kendall–Roberts–Sperling (JKRS), Burnham–Colton–Pollock (BCP), Maugis–Dugdale (MD), Carpick–Ogletree–Salmeron (COS), Pietrement–Troyon (PT), and Sun et al. have been applied as the continuum mechanics approaches at nano-scale. In this article, indentation depth and contact radius between tip and substrate with nano-particle for both spherical and conical tip shape during nano-manipulation process are analyzed and compared by applying theoretical, semiempirical, and empirical nano-contact mechanics models. The effects of adhesion force, as the main contrast point in different nano-contact mechanics models, on nano-manipulation analysis is investigated for different contact radius, and the critical point is discussed for mentioned models.     

Spectral and crystallography studies of new palladacycle complexes with P,C‐ and C,C‐donor ligands; Application of (OAL16) to optimizing the yield of Mizoroki‐Heck reaction

The new symmetrical diphosphonium salt [Ph₂P(CH₂)₂PPh₂(CH₂C(O)C₆H₄Br)₂] Br₂ ( S ) was synthesized in the reaction of 1,2‐bis (diphenylphosphino) ethane (dppe) and related ketone. Further treatment with NEt₃ gave the symmetrical α‐keto stabilized diphosphine ylide [Ph₂P(CH₂)₂PPh₂(CHC(O)C₆H₄Br)₂] ( Y ¹ ). The unsymmetrical α‐keto stabilized diphosphine ylide [Ph₂P(CH₂)₂PPh₂(CHC(O)C₆H₄Br)] ( Y ² ) was synthesized in the reaction of diphosphine in 1:1 ratio with 2.3′‐dibromoacetophenone, then treatment with NEt_3. The reaction of dibromo (1,5‐cyclooctadiene)palladium (II), [PdBr₂(COD)] with this ligand ( Y ¹ ) in equimolar ratio gave the new C,C‐chelated [PdBr₂(Ph₂P(CH₂)₂PPh₂(C(H)C(O)C₆H₄Br)₂)] ( 1 ) and with unsymmetrical phosphorus ylide [Ph₂P(CH₂)₂PPh₂C(H)C(O)C₆H₄Br] ( Y ² ) gave the new P, C‐chelated palladacycle complex [PdBr₂(Ph₂P(CH₂)₂PPh₂C(H)C(O)Br)] ( 2 ). These compounds were characterized successfully by FT‐IR, NMR (¹H, ¹³C and ³¹P) spectroscopic methods and the crystal structure of Y ¹ and 2 were elucidated by single crystal X‐ray diffraction. The results indicated that the complex 1 was C, C‐chelated whereas complex 2 was P, C‐chelated. These air/moisture stable complexes were employed as efficient catalysts for the Mizoroki‐Heck cross‐coupling reaction of several aryl chlorides, and the Taguchi method was used to optimize the yield of Mizoroki‐Heck coupling. The optimum condition was found to be as followed: base; K₂CO₃, solvent; DMF and loading of catalyst; 0.005 mmol.     

Au(III) complexes loaded pH‐responsive magnetic nanogels for cancer therapy

A novel pH‐responsive magnetic nanogels were developed with the aim of targeted delivering and simultaneously releasing of newly synthesized Au(III)‐based anticancer drug, Au(1,7‐Phen)Br₃. The obtained nanogels were characterized by FT‐IR, DLS, EDAX, TEM, XRD, ICP‐Ms and MRI. The TEM images showed that the nanogels had a spherical shape with a mean diameter of 20 nm. The in vitro release studies of Au (III)‐loaded nanogels showed a pH‐triggered controlled release of drugs. The in vitro cytotoxicity assay of samples to human cervical cancer HeLa cell lines indicated that the Au(III)‐loaded magnetic nanogels exert higher cytotoxicity in comparison with free Au(III) complex. Fluorescent microscope images indicated that these magnetic nanogels possessed notable cell specific targeting in vitro in the presence of an external magnetic field. The results show that this superparamagnetic nanocarrier is a promising candidate for inhibiting growth of tumor cells.     

When a line graph associated to annihilating-ideal graph of a lattice is planar or projective

Let (L,∧, ∨) be a finite lattice with a least element 0. AG(L) is an annihilating-ideal graph of L in which the vertex set is the set of all nontrivial ideals of L, and two distinct vertices I and J are adjacent if and only if I ∧ J = 0. We completely characterize all finite lattices L whose line graph associated to an annihilating-ideal graph, denoted by L(AG(L)), is a planar or projective graph.     

A non-commutative cryptosystem based on quaternion algebras

We propose BQTRU, a non-commutative NTRU-like cryptosystem over quaternion algebras. This cryptosystem uses bivariate polynomials as the underling ring. The multiplication operation in our cryptosystem can be performed with high speed using quaternions algebras over finite rings. As a consequence, the key generation and encryption process of our cryptosystem is faster than NTRU in comparable parameters. Typically using Strassen’s method, the key generation and encryption process is approximately 16 / 7 times faster than NTRU for an equivalent parameter set. Moreover, the BQTRU lattice has a hybrid structure that makes inefficient standard lattice attacks on the private key. This entails a higher computational complexity for attackers providing the opportunity of having smaller key sizes. Consequently, in this sense, BQTRU is more resistant than NTRU against known attacks at an equivalent parameter set. Moreover, message protection is feasible through larger polynomials and this allows us to obtain the same security level as other NTRU-like cryptosystems but using lower dimensions.     

TWO-VARIABLE JACOBI POLYNOMIALS FOR SOLVING SOME FRACTIONAL PARTIAL DIFFERENTIAL EQUATIONS

Two-variable Jacobi polynomials, as a two-dimensional basis, are applied to solve a class of temporal fractional partial differential equations. The fractional derivative operators are in the Caputo sense. The operational matrices of the integration of integer and fractional orders are presented. Using these matrices together with the Tau Jacobi method converts the main problem into the corresponding system of algebraic equations. An error bound is obtained in a two-dimensional Jacobi-weighted Sobolev space. Finally, the efficiency of the proposed method is demonstrated by implementing the algorithm to several illustrative examples. Results will be compared with those obtained from some existing methods.     

MnCl2‐Promoted synthesis of quinoxaline derivatives at room temperature

MnCl₂ efficiently catalyzes the condensation of o‐phenylenediamine derivatives with 1,2‐diketones at room temperature to afford the corresponding quinoxaline derivatives in high yields. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:218–220, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20401     

Preparation of ion-imprinted polyvinyl sulfonate-grafted silica particles for trace enrichment of Th(IV) prior to determination by inductively coupled plasma-mass spectrometry

Grafting from polymerisation technique has been used to prepare Th(IV) ion-imprinted polyvinyl sulfonate (IIPVS)-bonded silica particles. The graft polymerisation of vinyl sulfonate (VS) on the surface of silica particles was achieved in aqueous medium through thermal decomposition of surface-bound azo initiators (60°C) in the presence of thorium ion. The prepared material was characterised by Fourier transform infrared spectroscopy, differential scanning calorimetry and thermogravimetric analysis. The entrapped template ion was then removed using 2 M HCl. The experimental batch rebinding data were successfully described by the Langmuir–Freundlich model. The prepared material was then packed to a PTFE micro-column (20 mm × 3.0 mm, id) to evaluate its efficiency in column operations prior to determination by inductively coupled plasma-mass spectrometry (ICP-MS). The limit of detection of the method and breakthrough capacity of the column was evaluated as 0.074 µg L^?1 and 0.83 mg g^?1, respectively. The selectivity of the prepared polymer towards Th(IV) ion was investigated in the presence of some foreign competitor ions, including U(VI). Finally, the proposed method has been used to determine Th(IV) ion in real samples.