CHEMISTRY Publication Record Al-Ghoul, M. 2000. Dynamics and dissipation of externally
forced system. Physical Chemistry Chemical Physics 2:3773. . 2001. Generalized hydrodynamic theory of shock waves: Mach
number dependence of inverse shock width for nitrogen gas. Physical Review
Letters 86:4294. Haddadin, M. J., M. J. Kurth, and M. M. Olmstead. 2000. One step synthesis of new heterocyclic azacyanines. Tetrahedron Letter 41:5613. Haung, K. S., M. J. Haddadin, M. M. Olmstead, and M. J. Kurth.
2001. Synthesis and reactions of heterocyclic azacyanines (dedicated to
Professor Costas H. Issidorides on the occasion of his Eightieth birthday).
Journal of Organic Chemistry 66:1310. Kortz, U. 2000. Polyoxometalate-diphosphate complexes. 5. The
cigar-shaped 30-molybdob]ispyrophosphate: Structure of (N(C4H9)4)2H9[{(P2O7)
Mo15O45}2 [PMo12O40]. Inorganic
Chemistry 39:623. . 2000. Polyoxometalate-diphosphate complexes. 6. Possible intermediates in the molybdate-catalyzed hydrolysis of pyrophosphate. Structure of hexamolybdopyrophosphate, [(O3POPO3)Mo6O18(H2O)4]4-. Inorganic Chemistry 39:625. Kortz, U., and M. H. Dickman*. 2000. Cadmium copper tetrachloride tetrahydrate. Acta Crystallographica C56:265. Kortz, U., S. Isber, M. H. Dickman*, and D. Ravot*. 2000.
Sandwich-type silicotungstates: Structure and magnetic properties of the
dimeric polyoxoanions [{SiM2W9O34(H2O)}2]12-
(M = Mn2+, Cu2+, Zn2+). Inorganic
Chemistry 39:2915. Kortz, U., Y. P. Jeannin*, A. Tιzι*, G. Hervι*, and S. Isber.
1999. A novel dimeric Ni-substituted beta-keggin silicotungstate: Structure
and magnetic properties of K12 [{β-SiNi2W10O36(OH)2(H2O)}2]·20H2O.
Inorganic Chemistry 38:3670. Kortz, U., and S. Matta. 2001. Novel, triangular Mn-substituted undecatungstosilicate, [(SiW11MnO39)3]18-. Inorganic Chemistry 40:815. Kortz, U., A. Tιzι*, and G. Hervι*. 1999. A Cubane-substituted
Polyoxoanion: Structure and Magnetic Properties of Cs2[H2PW9Ni4O34(OH)3(H2O)6]·
5H2O. Inorganic Chemistry. Nazer, M. Z., and M. J. Haddadin. 2000. Reactions of TCU with
0-Nitrobenzaldehye. Heterocycles 53 (10):2221. Panjarian, S., and R. Sultan. 2001. Crystal selection and
Liesegang banding in dynamic precipitate systems. Collection of the
Czechoslovak Chemical Communications 66:514541. Sammelson, R. E., M. M. Olmstead, M. J. Haddadin, and M. J.
Kurth. 2000. 1, 2, 4, 5-tetrazines as oxidant and reactant with DBU: An
unexpected formation of novel fused tetraheterocyclic azepine. Journal of
Organic Chemistry 65:9265. Sultan, R. F., N. K. Al-Kassem, A. A. H. Sultan, and N. M.
Salem. 2000. Periodic trends in precipitate patterning schemes involving two
salts. Physical Chemistry Chemical Physics (PCCP) 2:31553162. Sultan, R., and R. Halabieh. 2000. Effect of an electric field
on propagating Co(OH)2 liesegang patterns. Chemical Physics
Letters 332:331338. Sultan, R., and S. Jaafar. 1999. Static and swinging chemical waves in a two-interface dynamics on a ring. Physical Chemistry Chemical Physics (PCCP) 1:49314936. Abstracts, Conferences, and Proceedings Al-Ghoul, M. March 2000.
Shock waves in monatomic gases: A continuum theory. The international
conference on research trends in science and technology, Beirut, Lebanon. . June 2001. Generalized
hydrodynamic theory of shock waves in nitrogen gas. Dynamics Days
Europe 2001, Dresden, Germany. Assaf-Diab, M., M. J. Haddadin,
and H. Ghali-Mouhtaseb. April 2001. Quinoxaline 1,4-dioxides
after epithelial cell proliferation via changes in transforming growth
factors expression. 5th Middle East Oncology Congress, Beirut, Lebanon. . April 2001.
Quinoxaline 1,4-dioxides a new class of hypoxia-selective drugs. 5th Middle
East Oncology Congress, Beirut, Lebanon. Kortz, U. October 1999. Novel
structures in transition metal-substituted polyoxometalate chemistry.
Polyoxometalates: From Topology to Industrial Applications, Bielefeld,
Germany. . August 2000. Synthesis
and characterization of novel transition metal-substituted silicotungstates.
220th American Chemical Society National Meeting, Washington, DC, USA. Kurth, M. J., R. E. Sammelson,
K. S. Haung, and M. J. Haddadin. April 2001. Solution and solid phase
synthesis of unsymmetrical azacyanines. The 221st National Meeting of
American Chemical Society, San Diego, California, USA. Nazer, M. Z., S. Abu
Eid, M. J. Haddadin, and M. T. Kurth. April 2001. Tandem cycloaddition,
retrocycloaddition reaction:Formation of a diazadioxabicyclononene system.
The 221st National Meeting of the American Chemical Society, April 1-5,
2001, San Diego, California, USA. Sultan, R., and Sh. Panjarian. August 2000. Crystal selection and
liesegang banding in dynamic precipitate systems. Gordon Research
Conference/Oscillations and Dynamic Instabilities in Chemical Systems, Bristol,
Rhode Island, USA. . August 2000. Propagating
fronts in 2D Cr(OH)3 precipitate systems in gelled media. Gordon
Research Conference/Oscillations and Dynamic Instabilities in Chemical
Systems, Bristol, Rhode Island, USA. Miscellaneous Kortz, U. September
2000. Novel structures in polyoxometalate chemistry. Georgetown
University, Department of Chemistry, Washington, DC, USA. Graduate Theses and Projects Abou Ghali, F. June 2001. Synthesis of novel, transition
metal-substituted polyoxotungstates, [M4(H2O)10(ί-XW9O33)2]n- ( X = AsIII,
SbIII, SeIV, TeIV; M = Mn2+, Co2+, Ni2+, Zn2+, Cd2+, Hg2+, Cr3+, V5+). U.
Kortz. Khalil, L. June 2001. Synthesis of dimeric, transition
metal-substituted arsenotungstates, [M4(H2O)2(B-alpha-AsW9O34)2]10- (M = Mn2+,
Co2+, Ni2+, Cu2+). U. Kortz. Research Projects Dissipation and efficiency in a biochemical oscillator We study the dissipation and the efficiency of a
biochemical oscillator driven by periodic signals and by noise. Such systems
are described by stochastic differential equations which, in this work, are
solved numerically or semi-analytically. Entropy production is used as a
criterion for dissipation. Al-Ghoul, M. Shock waves in diatomic gases We developed a continuum hydrodynamic theory of shock
waves which yields shock structures (shock widths) for supersonic waves in a
diatomic gas. The theory is based on the Boltzmann-Curtiss kinetic equation,
which is solved using the modified moment method. The results are in
excellent agreement with experiments. Al-Ghoul, M. (PL), and Byung Chan (EU). Completed or in progress at AUB
We modeled a complex precipitate system that exhibits
Liesegang patterns using a set of reaction-diffusion equations. The model is then
solved numerically, and the results are compared with experiments. An
excellent agreement was found. Al-Ghoul, M. (PL), and R. Sultan. Synthesis of biodegradable macromolecular drug delivery
vehicles The goal of our research is to develop new approaches to
increase the circulation of anticancer agents in the body while minimizing
their side effects. A number of these agents, when complexed or
attached to a biodegradable macromolecular moiety, can be delivered
systemically. These complexes have relatively high molecular weights
and are not easily excreted by the kidney. The initial high molecular
weight of the polymer can be exploited to facilitate site-specific
accumulation of anticancer agents in solid tumors via the enhanced
permeability and retention (EPR) effect. The enhanced permeability of
the microvascular within solid tumors allows the passage of high molecular
weight conjugates that are restricted to normal tissue. Drugs are then
released slowly from the macromolecular drug carrier at the desired
site. This approach could potentially be used to deliver multiple
agents and could be useful in preventing the development of multi-drug
resistance (MDR). Bouhadir, K. Supported by URB Quinoxalin 1,4- dioxides as hypoxia
selective therapeutic agents
Number of quinoxaline 1,4-dioxides have been found to be
effective hypoxia selective agents with 2- benzyl-3-phenyl-6, 7-dichloro
quinoxaline 1,4-dioxide being the most effective. One paper is in the press,
another was submitted recently; and a third is in the last phase of being
written up. Ghali-Mouhtaseb, H. U., M. J. Haddadin, and M. Diab-Assaf. Supported by AUB Synthesis of water-soluble quinoxaline 1,4-dioxides For the purpose of a more efficient drug delivery, the
synthesis of water-soluble quinoxaline 1,4-dioxides is in its initial stage.
It is planned to have this work as the M.S. thesis of Mr. Roland Bou Chedid.
Haddadin, M. J. Supported by AUB and potentially University of California,
Davis Volta metric measurements of some Azacyanines The redox potetials of a number of Azacyanines will be
determined for the first time. Some preliminary results are at hand and more
are planned for. Haddadin, M. J. and L. Halaoui. Supported by AUB Synthesis and reactions of azacyanines A continuation of this project in collaboration with
Professor Mark J. Kurth of the University of California at Davis is being
pursued. New azacyanines have been prepared, and their reactions are being
studied. Two papers have been published (see Publication Record below) and
more are in preparation. Haddadin, M. J., and M. J. Kurth. Supported by AUB and University of California, Davis Reactions of 0-nitrobenzaldehyde with TCU: Formation of
heterocyclic clefts As a continuation of our previous work on the synthesis of
heterocyclic clefts, we investigated the reactions of 0-nitrobenzaldehyde
with TCU and isolated and identified, with X-Ray structural confirmation,
eight new derivatives. One paper was published and the second is ready for
submission for publication. Other products will be pursued further. Haddadin,
M. J., and M. Z. Nazer. Supported by AUB and University of Jordan Interaction of ethylenediphosphonate with tungstate,
molybdate and vanadate The anionic, ditetrahedral heterogroup,
ethylenediphosphonate, (O3PCH2CH2PO3)4-, was reacted in an aqueous medium
with tungstate, WO42-, molybdate, MoO42-, and vanadate, VO43-, respectively,
at a variety of ratios and at different pH. The reactions were monitored by
31P-NMR (at Georgetown University), and it was apparent that compounds were
formed, but until now, it has not been possible to isolate and crystallize a
pure product. This work is still in progress. Kortz, U. (PL). Interaction of phosphonocarboxylates with tungstate,
molybdate and vanadate The interaction of three phosphonocarboxylates,
(O3P(CH2)nCOOH)2- (n = 0, 1, 2), with tungstate, WO42-, and molybdate,
MoO42-, were studied by 31P-NMR. As expected, there is an indication that
novel polyoxometalates are formed. Currently, attempts are being made to
crystallize these compounds so that structural characterization by
single-crystal X-ray diffraction becomes possible. Kortz, U. (PL). Interaction of the dilacunary
gamma-decatungstophosphate, [gamma-PW10O36]7-, with first-row transition
metals We were able to synthesize and also crystallize products
by reacting [-PW10O36]7- with a variety of transition metal ions,
e.g., Fe3+, Co2+, Ni2+, and Zn2+. Last summer, while at Georgetown University
working on a Long-Term Faculty Development Grant, I used single-crystal X-ray
crystallography to collect data sets on different crystalline samples.
Unfortunately, it turned out that the respective transition metals were
incorporated in the well-known Keggin ion, most likely corresponding to the
formula [PW10M2O40]11- or [PW11MO40]7- (M = Co2+, Zn2+, Ni2+). Elemental
analysis for the cobalt derivative indicates that the latter formula is
correct. However, it is still possible that a mixture of rotational isomers
(e.g., [-PW11CoO40]7- vs. [-PW11CoO40]7-) is present.
Crystals of the Co2+ containing product are of sufficient size for
single-crystal electron paramagnetic resonance (EPR). This technique could
perhaps allow us to determine if indeed two or more different isomers are
present. Kortz, U. (PL). Introduction of second and third-row transition metals
in lacunary heteropolyanions We were able to synthesize a very interesting
ruthenium-substituted polyoxotungstate. A detailed study of its catalytic
properties (redox, electrocatalysis) is currently under way. Synthesis of transition metal substituted
molybdopyrophosphate heteropolyanions It was attempted to introduce first-row transition metals
(e.g. Ni) in-between the two half-units of the 30-molybdobispyrophosphate
during the synthesis of the polyanion (in situ), but so far without success.
On the other hand, it might be possible to synthesize a lacunary version of
the 30-molybdobispyrophosphate. e.g., by loss of a Mo3O6 cap through
controlled action of strong base. This will be further investigated this
coming summer at Georgetown University by using 31P-NMR. Kortz, U. (PL). The interaction of dinuclear and trinuclear
heterogroups with tungstate, molybdate, and vanadate During the summers of 1998 and 1999, I worked in the laboratory of Prof. M. T. Pope at Georgetown University, and I reacted the two tritetrahedral heterogroups, namely, tripolyphosphate, (O3POPO3PO3)4-, and nitrilotrismethylenephosphonate, {N(CH2PO3)3}6-, with tungstate, WO42-, molybdate, MoO42-, and vanadate, VO43-, respectively, at a variety of ratios and at different pH. The reactions were monitored by 31P-NMR, and it was apparent that a variety of products formed, but until now, it has not been possible to isolate and crystallize a pure product. This work is still in progress.
Supported by URB Cycloaddition reactions of symmetrical tetrazines;
formation of a new heterocyclic system The reaction of 3,5-diphenyl tetrazine with aldahydes with
only one proton on the carbon alpha to the carbonyl group gave a host of products,
the most interesting of which is the isolation and the X-Ray confirmation of
the a new heterocyclic system: Diazadioxabicyclonoene. These results were
orally presented at the 221st National Meeting of the American Chemical
Society in San Diego, April 1-5, 2001. More work is in progress in
collaboration with Professor Musa Z. Nazer of the University of Jordan and
Professor Mark J. Kurth of the University of California at Davis. Nazer, M.
Z., M. J. Haddadin, and M. J. Kurth. Supported by AUB, University of Jordan, and University of
California, Davis Front propagation in patterned precipitation I:
Simulation of a migrating Co(OH)2 Liesegang pattern The propagation of a stratum of Co(OH)2 Liesegang bands is
simulated using the Supported by URB Liesegang banding and the particle size distribution A Liesegang pattern is a stratification of parallel bands
that appear when two co-precipitate ions inter-diffuse in a gel. In some
cases, the bands are themselves composed of tiny particles of different
sizes. We study the particle size distribution in a cobalt oxinate
precipitate system. The sizes of the particles are measured in every band,
and the average particle size and the number of particles within a given band
are determined. The measurement and count are repeated by image analysis of
an enlarged picture of each separate band. Then, the average particle size
and the number of bands are plotted versus band number. As the band number
increases, the system is shown to evolve toward a state of fewer and
larger particles, thus directly verifying the Ostwald ripening phenomenon. We
look for other possible trends by exploring the various conditions under
which the pattern is prepared. Sultan, R. (PL), and M. Al-Ghoul. Completed or in progress at AUB Fractal structures in lead fluoride precipitate systems Tree-like aggregates (dendrites) have been reported in a
variety of precipitate systems. We here explored different routes for the
growth of dendrites of PbF2 in Liesegang-type and some other experiments. The
latter include interdiffusion of co-precipitates in microslides, evaporation,
and infiltration of electrolyte through cracks, thus simulating geochemical
fractals. Images of the various patterns obtained are analyzed, and their
fractal dimensions are determined. A comparison between the properties of the
patterns obtained through the different routes is finally made. Sultan, R.
(PL), and L. Mandalian (RA). Propagating fronts in 2D Cr(OH)3 precipitate
systems in gelled media The propagation of a circular Cr(OH)3 precipitate ring in
2D is studied, and the velocities are measured at different concentrations.
The effect of an electric field on the propagation is investigated.
Interesting deformations in the ring are obtained when the field is applied
in a non-uniform manner. Paper in press (Physica D). Sultan, R.
(PL), and Sh. Panjarian (RA). Effect of competitive complex formation on
patterning and front propagation in periodic precipitation The Co(OH)2 Liesegang pattern (from Co2+ and NH4OH)
propagates in space via periodic band formation ahead due to precipitation
and band disappearance at the tail due to dissolution in excess NH4OH. Ni2+
(which competes with Co2+ for complex formation with ammonia) was introduced
into the system, resulting in many interesting observations: slowing down of
the propagation, decrease in the number of bands, and increase in the spacing
between them. At high concentrations of Ni2+, only a uniform precipitate zone
was observed. The difference in the distance of last band in the system with
nickel relative to that without nickel attained at a fixed time (89 hours)
was found to oscillate as the initial concentration of NH4OH is varied. It
was shown that the concentration of intermediate NH4+ is a precursor for
those oscillations. Project completed and paper being written. Sultan, R.
(PL), and Z. Shreif (undergraduate student). |