2016
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Item Reactivity and Mechanism of Phenoxide Anions Addition to 4-nitrobenzofurazan in Aqueous Solution(Canadian Science Publishing, 2016-09-12) Ben Salah, Saida; Boubaker, Taoufik; Goumont, RégisSecond-order rate constants (k1) for the -complexation of 4-nitrobenzofurazan 1 with four 4-X-substituted phenoxide anions 2a-d (X = OCH3, CH3, H and Cl) were measured in aqueous solution at 20 °C. Using this series of phenoxide anions as reference, the electrophilicity parameters E of this electrophile 1 has been evaluated according Mayr’s approach. With the E value of -9.42, equation of Mayr was found to correctly predict the rate constants for the reactions of the 4-nitrobenzofurazan 1 with hydroxide ion in H2O and 50% H2O - 50% CH3CN. On the other hand, the large βnuc value of 1.12 obtained in the present work is clearly consistent with a single transfer electrons mechanism (SET).Item Computational design of three Cu-induced triangular pyrimidines-based DNA motifs with improved conductivity(Canadian Science Publishing, 2016-12-27) Lu, Nan; Bu, YuxiangNovel DNA triangular pyrimidine derivatives are designed by metal-decoration through replacement of H-by-Cu in the Watson-Crick hydrogen bond region. The DFT method is used to examine the coordination of triangle-arranged Cu with three pyrimidines in nonplanar three-bladed turbine geometries. The Cu···Cu cuprophilic bonds are ascribed to the partially occupied d orbitals without direct molecular orbital (MO) interactions. Four-center bonds depend on Cu-N/O bonds, which are contributed by p orbitals of N/O atoms along or perpendicular to the bond axis. The activity of frontier MOs is modulated leading to the decrease of gaps, ionization potentials (IPs) and electron affinities (EAs) desired for the improvement of conductivity. The hole trapping ability is assured by virtue of the spin density distributed on Cu. The single electron density is located averagely on π orbitals of three aromatic base rings. There’s paramagnetic electron delocalization on the inner d orbitals of triangle region. The analysis of electron localization function ELF-π and electrostatic potential maps reveals that the outer strong π-π stacking interaction together with the inner d orbital channel enable effective transduction of electrical signals along the Cu-DNA nanowires. The 3Cu-induced triangular pyrimidines have great potential applications as structural motifs of molecular electronic devices.Item Electrochemical detection of chlorpheniramine maleate in the presence of an anionic surfactant and its analytical applications(Canadian Science Publishing, 2016-11-27) Shetti, Nagaraj P.; Nayak, Deepti S.Improvement of methods for the detection of an analyte at low concentration with high sensitivity has become an important point of interest. In reflection of this fact, an effort has been made to know the electrochemical behavior of chlorpheniramine maleate in the presence of an anionic surfactant. Voltammograms were obtained in the range of 6.0 - 11.2 pH and maximum peak current (Ip) was observed at pH 10.4. Various physico-chemical parameters such as, process on the surface of the electrode, which was found to be diffusion controlled, heterogeneous rate constant, number of electrons transferred and charge transfer coefficient were estimated. Square wave voltammetry of chlorpheniramine maleate at the modified electrode exhibited a linear calibration curve in the concentration range of 1.0-100 ÎźM, with a limit of detection of 28 nM. The proposed technique was successfully used for the determination of chlorpheniramine maleate in pharmaceuticals as well as in biological samples.Item [GaX2(dmpe)2][GaX4] (X = Cl, Br, I): A Synthetic, Solid State and Computational Study(Canadian Science Publishing, 2016-11-09) Gray, Paul A.; Saville, James W.; Krause, Katherine; Burford, Neil; McDonald, Robert; Ferguson, Michael J.Derivatives of [GaX2(dmpe)2][GaX4] (X = Cl,Br, I) were prepared and characterized. The salts contain a cation involving two diphosphine ligands bound to GaX2+, imposing a pseudo-octahedral geometry at gallium. A variety of possible structural alternatives for the equimolar combination of GaX3 and dmpe have been computationally modelled and shown to be energetically similar to the observed cations, indicating potential fluxionality in the system and are in agreement with spectroscopic characterization.Item Large pi-systems containing W-N=N-W groups(Canadian Science Publishing, 2016-11-12) Vilarrubias, PereAbstract The compound Cl-W(Mes)3-N=N-W(Mes)3-Cl can polymerize, giving large inorganic pi systems containing N2 and W(Mes)3 where Mes=mesityl. Some of these compounds have been studied in the present paper using B3LYP functional. A description of the molecular orbitals from the pi system is given, explaining the role of the mesityl groups, the terminal chlorines and the d atomic orbitals from W in the whole conjugated system. Other data such as bond order, atomic partial charges or geometry are studied.Item Synthesis, characterization, and anticancer properties of iminophosphineplatinum(II) complexes containing boronate esters(Canadian Science Publishing, 2016-11-17) St-Coeur, Patrick-Denis; Kinley, Samantha; Vogels, Christopher M.; Decken, Andreas; Morin, Pier Jr.; Westcott, Stephen A.Three new iminophosphines containing pinacol-derived boronate esters have been prepared and ligated to dichloridoplatinum(II) fragments. All compounds have been characterized fully, including an X-ray diffraction study carried out for the platinum complex 8, which is derived from 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline. These three new platinum complexes, along with the non-boron containing control, have been examined for their initial cytotoxic properties against two glioma cell lines using the MTT method.Item Structures and Properties of Saturn-Like Complexes Composed of Oligothiophene Macrocycle with Methano[60]fullerene and [70]Fullerene(Canadian Science Publishing, 2016-10-04) Iyoda, Masahiko; Shimizu, Hideyuki; Aoyagi, Shinobu; Okada, Hiroshi; Zhou, Biao; Matsuo, YutakaĎ -Expanded oligothienylene macrocycle with a large inner cavity incorporates fullerenes such as methano[60]fullerene (C61H2) and [70]fullerene (C70) inside to form Saturn-like complexes. Although the oligothiophene macrocycle weakly interacts with fullerenes in solution, it forms stable Saturn-like fullerene complexes in the solid state. X-ray analysis of the Saturn-like complexes exhibited short contacts between the sulfur atoms of the oligothiophene macrocycle and fullerene-carbons, which hinder the rotation of fullerenes. As a result, the non-covalent interaction between the oligothiophene macrocycle and fullerenes was employed in crystal structure determination of fullerenes. UV-vis-NIR spectra of the Saturn-like complexes showed weak donor-acceptor interaction between the oligothiophene macrocycle and fullerenes.Item Acidic ionic liquids, green and recyclable catalysts in the clean nitration of TAIW to CL-20 using HNO3 electrolyte(Canadian Science Publishing, 2016-11-15) Kai, Wang; Dong, Bo; Yang, Chaofei; Qian, HuaA novel method for the synthesis of CL-20 by nitration of TAIW was investigated. HNO3 electrolyte containing generated dinitrogen pentoxide and unreacted dinitrogen tetraoxide was directly used as nitrating agent and the result was encouraging. A series of SO3H-functionalized ionic liquids were utilized to further improve the result. The satisfactory yield of CL-20 (94%) makes it a useful method for the green and clean synthesis of CL-20.Item On the Irregularity of Some Molecular Structures(Canadian Science Publishing, 2016-10-19) Abdo, Hosam; Dimitrov, Darko; Gao, WeiMeasures of the irregularity of chemical graphs could be helpful for QSAR/QSPR studies and for the descriptive purposes of biological and chemical properties, such as melting and boiling points, toxicity and resistance. Here we consider the following four established irregularity measures: the irregularity index by Albertson, the total irregularity, the variance of vertex degrees and the Collatz-Sinogowitz index. Through the means of graph structural analysis and derivation, we study the above-mentioned irregularity measures of several chemical molecular graphs which frequently appear in chemical, medical and material engineering, as well as the nanotubes: $TUC_4 C_8(S)$, $TUC_4 C_8(R)$, Zig-Zag $TUHC_{6}$, $TUC_4$, Armchair $TUVC_{6}$, then dendrimers $T_{k,d}$ and the circumcoronene series of benzenoid $H_k$. In addition, the irregularities of Mycielski's constructions of cycle and path graphs are analyzed.Item Thin Flexible Lithium Ion Battery Featuring Graphite Paper Based Current Collectors with Enhanced Conductivity(Canadian Science Publishing, 2016-10-14) Qu, Hang; Hou, Jingshan; Tang, Yufeng; Semenikhin, Oleg; Skorobogatiy, MaksimA flexible, light weight and high conductivity current collector is the key element that enables fabrication of high performance flexible lithium ion battery. Here we report a thin, light weight and flexible lithium ion battery that uses graphite paper enhanced with nano-sized metallic layers as the current collector, LiFePO4 and Li4Ti5O12 as the cathode and anode materials, and a PE membrane soaked in LiPF6 as the separator. Using thin and flexible graphite paper as a substrate for the current collector instead of a rigid and heavy metal foil enables us to demonstrate a ultra-thin lithium-ion battery (total thickness including encapsulation layers of less than 250 Îźm) that also features light weight and high flexibility.Item Synthesis of zeolite/carbon nanotube composite for gas separation(Canadian Science Publishing, 2016-10-16) Babaei, Majideh; Anbia, Mansoor; Kazemipour, MaryamA hybrid composite of NaY zeolite and amine modified multi walled carbon nanotube (MWCNT) has been synthesized by hydrothermal method. The obtained NaY/CNT composite (NC composite) was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), Scanning electron microscopy (SEM) and BET analysis. CO2, CH4 and N2 adsorption at two different temperatures and PItem A Comparative Analysis of Empirical Equations Describing Pressure Dependence of Equilibrium and Reaction Rate Constants(Canadian Science Publishing, 2016-09-28) Spooner, Jacob Alan; Weinberg, NohamGeneral properties of the empirical analytical functions used to describe the effect of pressure on rate and equilibrium constants in solution are reviewed and the effects of experimental errors on the accuracy of activation and reaction volumes predicted by these equations are compared. When the error levels are low (1-2%) and pressure ranges are small (0-1kbar) all functions perform well, but when fitting data with high error or extending to higher pressures special care must be taken in order to obtain reliable results. Analysis of the results from fitting the equations to simulated data as well as experimental data for Diels-Alder, Menshutkin, and methanolysis reactions allows us to propose a set of general recommendations when using these equations as a tool for obtaining accurate activation and reaction volumes.Item A practical synthesis and X-ray crystal structure of tribenzo[a,d,j]corannulene(Canadian Science Publishing, 2016-10-17) Smith, Natalie Joy; Scott, LawrenceTribenzo[a,d,j]corannulene (5) has been synthesized in four linear steps from commercially available starting materials on a half-gram scale in 18% overall yield. An X-ray crystal structure of this triply benzannulated geodesic polyarene confirms the prediction that successive benzannulation of corannulene has a gradual flattening effect on the bowl-shaped core.Item A New Thiophene-Functionalized Pyrene, Peropyrene, and Teropyrene via a Two- or Four-fold Alkyne Annulation and Their Photophysical Properties(Canadian Science Publishing, 2016-10-13) Yang, Wenlong; Monteiro, Jorge H.S.K.; de Bettencourt-Dias, Ana; Chalifoux, Wesley A.A thiophene-functionalized pyrene, peropyrene, and teropyrene were synthesized through a two- or four-fold alkyne annulation reaction promoted by triflic acid. All of the target compounds were fully characterized spectroscopically and the structure of the peropyrene analogue was unambiguously confirmed by X-ray crystallography. A significant red-shift in the absorption and emission properties as a function of extended conjugation was observed by UV-vis and fluorescence spectroscopy. This alkyne annulation strategy is a useful method for the conversion of smaller polycyclic aromatics to larger ones, such as nanographenes.Item Synthesis and physical properties of [4]cyclo-3,7-dibenzo[b,d]thiophene and its S,S-dioxide(Canadian Science Publishing, 2016-09-28) Kayahara, Eiichi; Xue, Zhai; Yamago, ShigeruCyclic tetramers of 3,7-dibenzo[b,d]thiophene (DBT) and 3,7-dibenzo[b,d]thiophene-5,5-dioxide (DBTO), i.e., [4]cyclo-DBT ([4]CDBT) and [4]cyclo-DBTO ([4]CDBTO), respectively, are synthesized by the platinum-mediated assembly of bis-metallated DBT and DBTO and the subsequent reductive elimination of platinum. This is the first example of the synthesis of sulfur-containing cycloparaphenylene (CPP) derivatives. The structure of [4]CDBTO is unambiguously determined by the single crystal X-ray analysis. Theoretical and experimental analyses of their physical properties reveal the effect of the sulfur atom and sulfonyl group at the periphery of biphenyl units of the CPP.Item Super-size Cp! Tetrabenzo[a,c,g,i]fluorenyl Complexes of Yttrium(Canadian Science Publishing, 2016-11-01) Berg, David J.; Sun, Jianlong; Twamley, BrendanThe synthesis of the tetrabenzo[a,c,g,i]fluorenyl (Tbf) yttrium dialkyl complexes, (Tbf)Y(CH2SiMe3)2(L) (L = THF, 1; L = bipy, 2) by direct protonolysis of the tris(alkyl) complex, Y(CH2SiMe3)3(THF)2, are reported. The X-ray crystal structures of 1 and 2 display the helical twisting typically observed for the Tbf ligand. Dynamic NMR studies on 1 show a barrier to Tbf helical inversion (epimerization or ‘wagging’) of 38.1 ± 0.5 kJ molItem A Cyclopenta[hi]acephenanthrylene Bearing Two Benzoannelated [3.3.3]Propellane Units: Extension of Triptindane Chemistry(Canadian Science Publishing, 2016-11-15) Hackfort, Thorsten; Neumann, Beate; Stammler, Hans-Georg; Kuck, DietmarThe McMurry reaction of triptindan-9-one (2), a three-fold benzoannelated Cs-symmetrical [3.3.3]propellane ketone, gave trans-9,9’-bitriptindanylidene (5), a sterically crowded stilbene hydrocarbon bearing two E-oriented triptindane moieties, in good yield. Photoisomerization of 5 generated the corresponding cis-stilbene 8 in a photostationary E/Z-mixture (55 : 45), which adopts a similarly crowded C2-symmetrical conformation that is apparently static on the NMR timescale. Photocyclodehydrogenation of 5 via 8 in benzene solution afforded the title hydrocarbon 6, a 1,2,9,10-tetrahydrocyclopenta[hi]acephenanthrylene merged with two triptindane units, in 85% yield. X-ray structure analysis of 6 revealed an essentially planar phenanthrene unit but significant steric repulsion between the pairs of opposite methylene groups of the [3.3.3]propellane cores, giving rise to a C2-symmetrical conformation. Reaction of 2 under modified McMurry conditions (DME instead of THF as a solvent) gave the saturated dimer, 9,9’-bitriptindanyl 7, as a mixture of diastereomers. Attempts to synthesize “columnene” (4), an elusive barrelene derivative fused with two triptindane caps, by three-fold McMurry reaction of triptindane-9,10,11-trione (3) failed.Item Probing the Structural Features that Influence the Mesomorphic Properties of Substituted Dibenz[a,c]anthracenes(Canadian Science Publishing, 2016-10-24) Paquette, Joseph A.; Psutka, Katie M.; Yardley, Colin J.; Maly, KennethWe report the synthesis and mesophase characterization of a series of novel hexaalkoxydibenzanthracenes in order to probe the effect of side-chain length variation and substituents on the mesophase temperature range. A series of hexaalkoxydibenz[a,c]anthracenes (2a-i) with varying chain lengths were prepared by Suzuki coupling of the appropriate boronate ester with the corresponding dialkoxy-dibromonaphthalenes, followed by oxidative cyclization. Compounds 2a-i were also brominated in the 10 and 13-positions to yield the corresponding dibromo series 4a-i. While none of the compounds 2a-i exhibited columnar mesophases, all of the compounds in series 4a-i did exhibit columnar phases over broad temperature ranges. To further investigate the effect of substituents on the mesomorphic properties of hexaalkozydibenzanthracenes, we also prepared iodo-substituted 8, nitro-substituted 9, and amino-substituted 10. A comparison of the mesophase temperature range with previously reported compounds 3-7 shows that electron-withdrawing groups promote the formation of stable mesophases. However, our results also suggest that the substituents affect mesophase stability by participating in intermolecular contacts within the columnar stacks of the mesophase.Item Topological indices of rhombus type silicate and oxide networks(Canadian Science Publishing, 2016-10-27) Javaid, Muhammad; Rahman, Masood Ur; Cao, JindeFor a molecular graph, a numeric quantity which characterizes the whole structure of a graph is called a topological index. In the studies of quantitative structure-activity relationship (QSAR) and quantitative structure-property relationship (QSPR), topological indices are utilized to guess the bioactivity of chemical compounds. In this paper, we compute general Randic, first general Zagreb, generalized Zagreb, multiplicative Zagreb, atom-bond connectivity (ABC) and geometric-arithmetic (GA) indices for the rhombus silicate and rhombus oxide networks. In addition, we also compute the latest developed topological indices such as the fourth version of ABC (ABC4), the fifth version of GA (GA5), augmented Zagreb and Sanskruti indices for the foresaid networks. At the end, a comparison between all the indices is included and the result is shown with the help of a cartesian coordinate system.Item Branched-chain and dendritic lipids for nanoparticles(Canadian Science Publishing, 2016-10-28) Meanwell, Michael Weiwei; O'Sullivan, Connor; Howard, Perry; Fyles, Thomas M.Lipid nanoparticles (LNPs) for drug-delivery applications are largely derived from natural lipids. Synthetic lipids, particularly those incorporating branched hydrocarbons and hyper-branched hydrocarbon architectures may afford enhanced lipophilicity with enhanced fluidity and thereby lead to LNP stabilization. Hydrocarbon anchors based on serinol diesters were prepared from linear Cn (n = 14, 16, 18) and branched (n = 16) acids with Boc-protected serinol. These diesters were further dimerized on an iminodiacetamide backbone to provide eight branched-chain and dendritic lipid anchors. Derivatization of these core structures provided eight PEG-lipids and seven thiopurine linked lipid-drug conjugates. LNPs were prepared by microfluidic mixing from mixed lipids in ethanol diluted into aqueous media. The lipid-drug conjugates incorporated 5 mol% of a phosphocholine and 5 mol% of a commercial PEG-lipid to form LNPs with a thiopurine drug loading of 15 wt%. The PEG-lipids prepared were formulated at 1.5 mol% as a surface stabilizer to LNPs containing dsDNA lipoplexes. The stability of the LNPs was assessed under different storage conditions through monitoring of particle size. For both LNPs from lipid-thiopurine conjugates and the PEG-lipid systems there is strong preliminary evidence that hydrocarbon branching results in LNP stabilization. Four of the lipid-drug conjugate formulations were stable to cell culture conditions (10% serum, 37째C) and the toxicity of these LNPs was assessed in two cell lines relative to the free thiopurines in the medium. The observed toxicity is consistent with cellular uptake of the LNPs and reductive release of the cargo thiopurine within the cell.