Master’s Theses Chlorosulphonation of carbonyl compounds Reaction of carbonyl (dicarbonyl) and a ,3-unsaturated compounds with chlorosulphonic acid are currently under investigation. The resulting products are further reacted to generate sulfur containing heterocyclic compounds. J. P. Bassin. (Supported by Bobst; URB.) Chlorosulphonation of styrylpyridine derivatives A series of styrylpyridine derivatives are being investigated with chlorosulphonic acid. Some of this work has been submitted for publication. J. P. Bassin. (Supported by Bobst; URB.) Heterocyclic clefts: Reaction of nitrobenzaldehydes and electrophilic heterocycles with polycyclo undecane diones The reaction of tetracyclo- and pentacyclo undecane diones with nitrobenzaldehydes, benzofurazan oxides, tetrazines, and related compounds, with the aim of synthesizing novel cleft compounds containing chelating centers is studied. The effect of bases and solvents on the rproducts is investigated. M. J. Haddadin and M. Z. Nazer. (Supported by URB.) The electrochemical etching of tungsten STM tips Factors influencing the electrochemical etching of tungsten under dc conditions to produce sharp, high aspect-ratio STM (Scanning Tunnelling Microscopy) tips have been investigated. The optimum conditions for tip fabrication were: a) use of a relatively low value of cell potential (< 5V); b) use of KOH or NaOH electrolyte concentrations of 2M; c) applying tension to the wire during etching, but making sure that the wire did not snap under the applied load. Tips should be initially screened using optical microscopy and then imaged by SEM to calculate the radius of curvature, a fundamental parameter for effective STM tips. S. Kerfriden*, A. Nahlé , S. A. Campbell*, F. C. Walsh* and J. R. Smith*. (Supported by URB.) Electrochemical studies of corrosion inhibition of a series of quaternary ammonium salts of iron in HCl solution The inhibition and the effect of concentration of a series of quaternary ammonium salts on corrosion of Fe in 1M HCl solution were electrochemically studied. These inhibitors were: tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetraheptylammonium bromide. The concentration of the inhibitors ranged from 1x10-6M to 1x10-2M. It was concluded that the percentage inhibition increased with the increase of the concentration in each inhibitor and with the increase of the chain length of the alkyl substituent. The efficiency of corrosion inhibition was 85.55% with 1x10-2M tetramethylammonium bromide and 99.46% with 1x10-2M tetraheptylammonium bromide. Furthermore, it was found that the degree of inhibition for all the inhibitors closely followed the absorption isotherm of the inhibition on the metal surface. This work has been submitted to Corrosion Prevention and Control. A. Nahlé. (Supported by URB.) The study of Ebonex electrodes for the simultaneous determination of Cd, Pb, and Cu ions by anodic stripping voltammetry (ASV) The use of Ebonex electrodes in the simultaneous determination of trace amounts of Cd, Pb, and Cu ions by ASV will be studied; and the results will be compared with those obtained from glassy carbon and RVC electrodes. This project has importance for the monitoring of trace amounts of poisonous ions in sea, river and rain waters. A. Nahlé. (Supported by URB.) Hydrogen bonding association of a ruthenium (II) bipyridine barbituric acid guest to complementary 2,6-diaminopyridine amide hosts: electrostatic, steric and electronic controls The binding between a ruthenium polypyridine guest RuG2 (where Ru = 4,4' -di-t-butyl-bpy)2Ru(bpy = 2,2' -bipyridine) and G2 = 5-[4-(4' -Methyl)-2, 2' -bipyridyl]methyl-2, 4, 6-(1H, 3H, 5H)-pyrimidinetrione) and a series of hosts, 3,5-bis [(6-aminopyrid-2-yl) amino] carbonyl pyridine acyl derivatives (R = n-Bu, Phenyl, CF3, t-Bu, OC-(CH2)3-CO2–)) and 3,5-bis [(6-amino-4-isopropoxypyrid-2-yl) amino] carbonyl pyridine diacetyl derivatives (R = CH3) was studied by NMR and fluorescence titrations. Ionization of RuG2 to the enolate form occurs upon binding of RuG2 to the hosts. This enolate form of RuG2 forms strong H-bonds with the series of hosts. Changes in the binding constants of the ruthenium guest RuG2 to these hosts from K ~ 105 M-1 to K ~ 109 M-1 can be attributed to steric, electronic, and electrostatic changes in the structure of the hosts. Submitted for publication to Supramolecular Chemistry. A. S. Salameh, T. Ghaddar*, and S.S. Isied*. The influence of some platinum (II), palladium (II) and rhodium (III) coordination compounds on humoral immune response on white mice The coordination compounds of platinum (II), palladium (II) and rhodium (III) with 2,6-diaminopyridine and its substitutions products 3-p-sodiumsulphophenylazo-2,6-diaminopyridine (SULPHAZDAP), have been investigated as potential anti-tumor compounds. Some novel compounds of Pd, Pt and Rh with SULPHAZDAP have been synthesized with the hope that water-solubility of these compounds would be improved over that of the unsubstituted DAP complexes. However, solubility in water was not enhanced by substitution on DAP and thus only DAP complexes were used in the biological activity investigation. DAP complexes of Pt, Pd and Rh exhibit significant effect on the humoral immune response in the animal system. The Pt complex was most consistent in enhancement of antibody forming cells since all groups injected with the complex showed positive response. Both Pd and Rh showed different antimitogenic activity but the effect depended on both time factor and conditions of injection. Submitted for publication to Arabian Journal for Science and Engineering. A. S. Salameh, N. Nassif*, and H. A. Tayim*. The synthesis of some 5, and 5,5' -substituted 2,2' -bipyridines 5-Methyl-2,2' -bipyridine has been utilized for the preparation of several 5-substituted bipyridines: carboxylic acid, methylcarboxylate, carboxamide, acetoxymethyl, hydroxymethyl, aminomethyl, carboxaldehyde. 5,5' -Dimethyl-2,2' bipyridine has been utilized for the preparation of 5,5' -disubstituted 2,2' -bipyridines: diacetoxymethyl bis (hydroxymethyl), dicarboxaldehyde, 5-methyl, 5' -hydroxymethyl, 5-methyl-5' -carboxaldehyde. A. Salameh and M. Al-Sayah. Multicomponent self-assembly: The construction of rigid-rack multimetallic pseudorotaxanes The spontaneous self-assembly of a new class of rigid rack-type multimetallic complexes comprising a linear array of metal ions has been achieved. Thus, macrocyclic phenanthroline ligands efficiently thread onto rigid-rod linear polytopic ligands as directed by copper (I) ions to yield multimetallic [3]- and [4]-pseudorotaxanes. This construction process is one of the few examples of inorganic self-assembly process where two different ligand types are brought together as directed by metal ions to form the final architecture. Submitted to Inorganic Chemistry. H. Sleiman, P. N. W. Baxter*, J-M. Lehn*, K. Airola* and K. Rissanen*. (Supported by University Louis Pasteur, Strasbourg; URB.) Synthesis and transition metal coordination of novel phenanthroline-based bridging ligands Our research focuses on the synthesis of multimetallic conjugated systems which can potentially serve as components of molecular electronic devices. For this purpose, a new class of polytopic phenanthroline-pyrazine ligands linked through a biphenyl group has been synthesized and complexation studies have been carried out. The ruthenium complexes of these ligands can potentially serve as pH-driven molecular light switches; spectroscopic studies are currently being carried out to fine-tune these properties in such systems. H. Sleiman. (Supported by URB.) Synthesis and transition metal coordination of substituted 2,2' -bipyrimidines A new class of substituted 2,2’-bipyrimidines has been synthesized. These complexes have been designed to undergo self-assembly with linear polytopic ligands as directed by tetrahedral metal ions. The spontaneous self-association process generates multimetallic ladder-type systems in high yield. H. Sleiman and J-M. Lehn*. Synthesis and electrochemistry of ferrocene-ruthenium phenanthroline systems Among our objectives in the generation of potential components of molecular electronic devices, we have synthesized bimetallic and trimetallic systems containing ruthenium-phenanthroline and ferrocene components. These units are linked together through a conjugated imine spacer functionality and can serve as electrochemically-driven molecular light switches. H. Sleiman. (Supported by URB.) Scanning probe microscopy studies of Ebonex electrodes The porosity of Ebonex electrodes is known to have a marked effect on their electrochemical properties. Atomic force microscopy (AFM) and scanning tunnelling microscopy (STM) have been used to investigate the topography of porous and fully-hardened (nonporous) Ebonex at high resolution. AFM has also been used to study the early stages of copper electrodeposition on porous Ebonex electrodes. Initial copper nucleation and growth were found to occur preferentially at surface pores. J. R. Smith*, A. Nahléand F. C. Walsh*. (Supported by URB.) Two-salt patterns in nonequilibrium precipitate systems Precipitation reactions in gelled media are known to exhibit a periodic behavior, forming the so-called “Liesegang” rings. We here investigate the types of precipitation patterns obtained when two insoluble salts (PbI2 and PbF2) are formed. Experiments are carried out in both one- (tubes) and two- (petri dishes) spatial dimension(s). The patterns are analyzed in terms of band precipitate content and characterized as periodic, stochastic or deterministically chaotic. Theoretical investigations are also made based on existing precipitation-diffusion models. The theoretical predictions are compared with the experimental results. R. Sultan. (Supported by URB.) Band morphology, dissolution fronts and chaotic variables in Co(OH)2 Liesegang patterns Various
characteristics of Co(OH)2 precipitate patterns in gelatin are
studied. While most patterns evolve in time by merely increasing their
overall number of bands as the co-precipitate ions interdiffuse, the Co(OH)2
pattern exhibits a random variation in its number of bands. The nature
and origin of those erratic oscillations are being characterized as either
chaotic dynamics or random fluctuations. A dissolution front is observed
to advance behind the diffusion-precipitation front, thus causing the whole
pattern to move down the tube. The band morphology ranges from regular
menisci to bell shapes to Saturn structures. The appearance of these shapes
is studied in the light of the system dynamics. R. Sultan. (Supported
by URB.)
Barker, B. D.*, Bond, P.*, Graham, P.*, Hoy,T.*, Nahle, A., Ottewill, G. A.* and Walsh, F. C.*, Phosphating of steel and the effects of galvanic coupling to zinc and zinc-based coatings. Arabian Journal for Science and Engineering, 20 (2), 343-359, 1995. Bassin, P. J., Reaction of benzoylacetone with chlorosulphonic acid. Phosphorus, Sulfur and Silicon, 112, 285-287, 1996. Bikhazi, A. B., Salameh, A. S., El-Kasti, M.M. and Awar, R. A., Comparative nephrotoxic effects of cis-platinum (II), cis-palladium (II), and cis-rhodium (III) metal coodination compounds in rat kidneys. Comparative Biochemistry and Physiology, IIIC (3), 423-427, 1995. El-Abadelah, M. M.*, Nazer, M. Z., El-Abadlah, N. S.* and Meier, H.*, Synthesis of methyl 4-amino-1-aryl-1,4,5,6-tetrahydro-6-oxo-1,2,4-triazine-3-carboxylate. Journal fü r Praktische Chemie, 339, 90-91, 1997. Nahlé , A., Reade, G. W.* and Walsh, F. C.*, Mass transport to reticulated vitreous carbon rotating cylinder electrodes. Journal of Applied Electrochemistry, 25, 450-455, 1995. Nahlé , A. and Walsh, F. C.*, The application of x-ray techniques to studies of corrosion and protection. Part I: Review and literature survey. Arabian Journal for Science and Engineering, 20 (2), 315-324, 1995. ———, The application of x-ray techniques to studies of corrosion and protection. Part II: Experimental x-ray diffraction measurements. Arabian Journal for Science and Engineering, 20 (2), 325-341, 1995. ———, Electrochemical study of two corrosion inhibitors for iron in HCl: Cetyltrimethyl ammonium bromide and tetraphenyl phosphonium chloride. Corrosion Prevention and Control, 42 (2), 30-34, 1995. Naud, D., Thermal decomposition of arylnitramines. Journal of the Chemical Society, Perkin Transaction 2 (7), 1321-1324, 1996. Sleiman, H., Baxter, P. N. W.*, Lehn, J-M.* and Rissanen, K.*, Multicomponent self-assembly: The construction of rigid-rack multimetallic complexes of rotaxane type. Journal of the Chemical Society, Chemical Communications, 715-716, 1995. Sultan, R. F., The structural variety of chemical spike-electric field interactions. Chemical Physics Letters, 266 (1,2), 145-152, 1997. Sultan,
R. and Sadek, S., Patterning trends and chaotic behavior in Co2+/NH4OH
Liesegang systems. Journal of Physical Chemistry, 100 (42), 16912-16920,
1996.
Abstracts, Presentations and Proceedings Sleiman, H., Baxter, P.N.W. *, Lehn, J. M. *, Airola, K.* and Rissanen, K.*, Multicomponent self-assembly: The construction of rigid-rack multimetallic pseudorotaxanes. American Chemical Society 213th National Meeting, Abstract INOR 116, San Francisco, USA, April 1997. Sleiman, H., Multicomponent self-assembly: The single-step construction of extended metal arrays. McGill University Department of Chemistry, January 1997. Sultan,
R. and Nasri, A., Computer visualization of atomic orbitals. First International
Conference on Computer Simulations, Beirut, Lebanon. Proceedings of
the Lebanese Association for the Advancement of Science (LAAS), 369, 1995.
Abdel-Malak, R., Synthesis of conjugated ferrocene-phenanthroline spacer ligands (1996). Advisor: H. Sleiman. Al-Sayah, M., The synthesis of 5- and 5,5' -substituted derivatives of 2,2' -bipyridines (1996). Advisor: A. Salameh. Ghaddar, T., The synthesis of novel pyridine and bipyridine receptor ligands for barbiturate donors (1995). Advisor: A. Salameh. Mansour, R., Synthesis and properties of substituted pyrimidines (1996). Advisor: H. Sleiman. Sadek, S., Liesegang banding and two-salt patterns in precipitate systems (1995). Advisor: R. Sultan. Zakhem,
G., Synthesis and transition metal coordination of substituted phenanthrolines
(1996). Advisor: H. Sleiman.
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