Sharif Digital Repository

This article describes the synthesis and characterization of electronegative oxovanadium(IV) complexes containing tetradentate Schiff-base ligands derived from condensation of 1,3-propanediamine and 1,8-naphthylamine with 5-bromo-3-nitro-2-hydroxybenzaldehyde. New VOL1: [VO(5-Br-3-NO2salnaph)] and VOL2: [VO(5-Br-3-NO2salpn)] complexes were obtained in orange polymeric form with (V=O) stretching bands at 884 and 876 cm-1, respectively. The orange VOL1 and VOL2 complexes turn dark brown and green, respectively, when ground thoroughly in mortars. X-ray powder diffraction patterns of the ground VOL1 complex (VOL1g) scarcely show diffraction peaks. The data suggest that the linear chain polymeric... 

In this paper, the second and third order corrections of the curvature tensor to the holographic complexity of a temperature state are studied in Hamdis field theory. The dual geometry in this temperature state is the geometry of the Schwarzschild black hole. The calculations made in this paper show that the consideration of these new terms only appears as a constant coefficient in the final result, the rate of growth of complexity over long periods of time. © 2020, Isfahan University of Technology. All rights reserved  

One of the main objectives of all watermarking algorithms is to provide a secure method for detecting all or part of the watermark pattern in case of usual attacks to a watermarked image. In this paper we introduce a method that is suitable for any spatial domain watermarking algorithms, such that, it can provide a measure for the level of robustness when a given watermark is supposed to be embedded in a known host image. In order to increase the robustness of the watermarked image, for a watermark of n bits, we embed it s times. Doing this, the entire image is divided into 16 equal size blocks. For each block the complexity of the sub-image in that block is measured. The number of... 

Oxone® (2KHSO5·KHSO4·K 2SO4) in the presence of mer-tris[(2-oxazolinyl)phenolato] manganese(III), Mn(phox)3, as catalyst under biphasic reaction conditions (CH2Cl2/H2O) and tetra-n-butylammonium bromide as phase transfer agent efficiently oxidises alcohols to their corresponding aldehydes and ketones at room temperature with very short reaction times (5 min) and good to quantitative yields. © 2003 Elsevier Ltd. All rights reserved  

Conventional implementation of multi-dimensional wavelet transform (e.g. 3-D wavelet) requires whether a high amount of "in access" memory or a continual access to slow memory of a processor which makes it infeasible for most applications. In this paper, we proposed a novel algorithm for computation of an n-D discrete wavelet transform (DWT) based on lifting scheme. In addition to benefits of lifting scheme (which causes a major reduction in computational complexity and performs the total computations in time domain), our real-time approach computes the coefficients for all kinds of 1st and 2 nd generation wavelets with short delay and optimized utilization of the slow and fast memories of a... 

Echo cancellers with long impulse responses are usually used in networks with long echoes. Since long adaptive filters with sparse target filters usually converge very slowly, adaptation algorithms with fast convergence rate are needed. PNLMS [2] is one of the algorithms that is designed for fast convergence on sparse impulse responses. But there are some disadvantages to this algorithm. The computational complexity of this algorithm is prohibitive, especially for long echo tails. Another disadvantage is that its convergence rate slows down significantly after the adaptation of large taps. In this paper we propose new algorithms to solve both these problems. In another part of this paper, we... 

Tris[(2-oxazolinyl)phenolato]manganese(III), Mn(phox)3, catalysed oxidation of dialkyl, diaryl, dibenzyl, and alkyl aryl sulfides to the corresponding sulfones is carried out by Oxone® in biphasic conditions (CH2Cl2/H2O), in the presence of tetra n-butylammonium bromide as phase transfer agent at room temperature in very short reaction times (5 min.) with quantitative yields  

The novel unsymmetrical tetradentate Schiff base complexes of Co(II) and Pd(II) with the general formula M(SaI.Phen.Acac.) and M(Sal.Phen. Naph.), have been synthesised by template and non-template method  

In this note, we introduce and investigate the notion of (Formula presented.) monomial ideals. We give an explicit relation of the (Formula presented.) property to a monomial ideal and its polarization. Further, we characterize the (Formula presented.) property of the ordinary as well as the symbolic third or more powers of squarefree monomial ideals. © 2022 Taylor & Francis Group, LLC  

This paper investigates the accumulation of technological capability in latecomer suppliers of complex capital goods by exploring the issue in an Iranian supplier of large hydro electricity generation systems. The findings suggest that, contrary to the conventional paths of catch-up in Asian and Latin American mass-producing electronics firms, and instead of starting from early stages of product lifecycle, the technological capabilities in this case were acquired through a non-linear movement within the stages of designing and installing complex capital goods in projects: starting from the middle stage (engineering and realisation of complex goods in projects), moving to the last stage... 

The reaction between [MoO2(acac)2] and an ONO type Schiff-base ligand (L = 4-bromo-2-((2-hydroxy-5-methylphenylimino)methyl)phenol) resulted a new oligomer molybdenum complex ([MoO2(L)]n). The oligomer complex was characterized by elemental analysis, FT-IR, 1H and 13C NMR spectroscopies. A suitable single crystal of the complex was grown in DMSO and characterized by X-ray single crystal diffraction as monomer stabilized by one DMSO molecule, [MoO2L(DMSO)]. The [MoO2(L)]n complex was used as a catalyst in epoxidation of olefins. Besides the high activity and selectivity, very high turnover numbers were a remarkable advantage of the catalytic system. © 2017  

Two copper(II)complexes were synthesized through the reaction of Cu(OAc)2·H2O with a Schiff-base ligand (1-(((3,4-dichlorophenyl)imino)methyl)naphthalen-2-ol)and a diazo ligand (1-((3,4-dichlorophenyl)diazenyl)naphthalen-2-ol)in methanol. The complexes and ligands were characterized employing elemental analysis and electronic spectra. In addition, the ligands were fully characterized by using several 1D and 2D NMR techniques. Single crystal X-ray crystallography was also used for the characterization of some of these materials. Due to finding out the effect of Schiff-base and diazo ligands nature on the catalytic activity, the complexes were catalytically compared in one-pot azide-alkyne... 

Tridentate Schiff-base ligands derived from condensation of 3-formyl-4-hydroxybenzyl-triphenylphosphonium chloride with glycine, L-alanine, L-valine, L-leucine and L-phenylalanine in the presence of Zn(OAc)2·2H2O form five new water-soluble Zn(II) complexes, which were characterized by elemental analyses, IR, electronic absorption and 1H, 13C NMR spectroscopies. In the IR spectra of the complexes, the difference between the asymmetric and the symmetric carboxylate stretching frequencies is larger than ∼210 cm-1, which implies that the carboxylate groups are monodentate. UV-Vis electronic absorption studies show that Zn(II) functions as a trap for the Schiff-base intermediate. Schiff-base... 

New water-soluble zinc(II) Schiff-base complexes derived from amino acids (glycine, L-phenylalanine, and L-valine) and salicylaldehyde-5-sulfonates (sodium salicylaldehyde-5-sulfonate and sodium 3-methoxy-salicylaldehyde-5- sulfonate) have been synthesized. The complexes were characterized by elemental analysis, IR, electronic, 1H NMR, and 13C NMR spectra. In the IR spectra of the complexes, the large difference between the asymmetric νas(COO) and symmetric νs(COO) carboxylate stretch, Δν(νas(COO)-νs(COO)) of 199-247 cm-1, indicates monodentate coordination of the carboxylate group. Spectral data showed that in these complexes the ligand is a tridentate ONO moiety, coordinating to the metal... 

A5/1 is a stream cipher used in GSM to provide over-the-air communication privacy. Biham and Dunkelman proposed an attack on A5/1 with time complexity of 2∧(39.91) and data complexity of 2∧(21.1) known bits and memory complexity of 32 GB. In this paper, we propose an improvement on their attack. Our improvement is identification and elimination of useless states from the precomputed table. Furthermore, we propose another way for use of table in online phase of attack that causes decreasing in the time complexity to 2∧(37.89) and memory complexity decreases to half  

The six-coordinated silver(I) complex [Au2Ag(μ-(PPh2)2py)2(OTf)2](OTf), 4 (py = pyridine, OTf = CF3SO3), and the five-coordinated silver(I) complex [Au2Ag(acetone)(μ-(PPh2)2py)2](PF6)3, 6, were prepared by the reaction of the precursor complexes 1(OTf)2 and 1(PF6)2, in which 1 = [Au2(μ-(PPh2)2py)2]2+, with 1 equiv of Ag(OTf) in dichloromethane and excess of Ag(PF6) in a mixture of dichloromethane/acetone, respectively. Also, the five-coordinated silver(I) complex [Au2Ag(μ-(PPh2)2py)2(py)(OTf)](OTf)2, 5, was obtained by the reaction of 4 with pyridine. The clusters 4-6 were characterized using multinuclear NMR spectroscopy and elemental microanalysis. The single-crystal X-ray diffraction... 

A series of previously reported mononuclear Cu(II) and homodinuclear Cu(II)Cu(II) complexes, as well as, novel mononuclear Cu(II), homodinuclear Cu(II)Cu(II), and heterodinuclear Cu(II)Ni(II) complexes of a phenol-based dinucleating ligand with two different N(amine)2O2 and N(imine)2O2 coordination sites, were synthesized and characterized by elemental analyses, infrared and electronic absorption spectroscopies and conductivity measurements. The electrochemical behavior and catecholase-like activity of the complexes were also studied using cyclic voltammetry and UV-vis spectrophotometry, respectively. Our results show that the dinuclear complexes are more effective catalysts in the oxidation...