Haky, Jerome E.

This research is part of a long-term project aimed at elucidating important structural
features, of both ligands and metals, that are needed to produce effective anti-cancer agents.
The specific goal is the synthesis of organotin polymers containing amino acids, in this
case the diamino acid diglycine. The desired materials were synthesized with percent yields
ranging from 32-99%. The products were synthesized employing the interfacial
polymerization technique. The polymers were then characterized utilizing the following
physical characterization techniques: light scattering photometry (LS), Infrared
spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR), and matrix assisted
laser desorption mass spectroscopy (MALDI). Physical characterization showed evidence
of formation of desired adducts in addition to data that was consistent with the formation
of materials containing multiple repeat units. The materials were then analyzed for
biological activity. The synthesized materials displayed the ability to inhibit tested cancer
cell lines.

A web-based learning system for Organic Chemistry is being integrated into a Peer-Led Team Learning (PLTL) environment to restructure the existing Organic Chemistry I discussion (OrgoBOND) sections to enhance student learning, improve overall grades, and lower the Organic Chemistry I DFW rates. Students taking Organic Chemistry I are required to participate in a section of OrgoBOND utilizing the web-based learning system in a smaller classroom than in previous discussion sessions. Student performance will be compared to that of students in future semesters participating in the same small PLTL setting, but with traditional recitation format. The advantages of introducing a web-based learning system into PLTL discussion sessions are (1) providing “hints,” (2) offering multiple attempts per question, and (3) instant grading and feedback. The computer assignments are unique to each student and reflect the topic recently reviewed in lecture. We will report on the preliminary results from data being collected on student performance, satisfaction levels, and retention rate changes.

Dynamically coated alumina (DCA) was prepared by pumping mobile phase containing methanol and concentration of 10mM Sodium Lauryl Sulphate (SLS), an anionic surfactant prepared in water, through a bare alumina column. The mechanism of separation of a test mixture were characteristic of reversed phase chromatography as evident in the decreased retention time as the percentage of methanol increased. However, the effects of changing the pH of the mobile phase on retention of solutes were different than that expected in reversed phase separations, indicating the presence of another retention mechanism. Excellent resolutions, peak shapes and peak symmetries were obtained using the DCA conditions and were comparable to similar separations performed on an ODA (octadecylalumina) column. Comparisons of retentions of a variety of organic compounds on DCA with those of commercial ODS (octadecylsilica) and ODA phases were also performed.

Surface-modified alumina containing covalently-bonded p-aminophenyl groups was prepared by refluxing chromatographic grade alumina with p-aminophenylphosphonic acid in n-butanol. The resulting material, p-aminophenylalumina (PAPA), was evaluated for use as a stationary phase in high performance liquid chromatography (HPLC). When used with mobile phases consisting of acetonitrile and water, retention of solutes on the PAPA phase exhibited normal phase behavior, as evidenced by the increases in solute retention times with increasing percentages of acetonitrile. Excellent separations of carbohydrate mixtures were obtained on the PAPA stationary phase. Comparisons of the chromatographic properties the PAPA phase with those of commercial aminoalkyl silica stationary phases were also performed.

Ultraviolet spectrophotometry was employed to investigate the adsorption of phenylphosphonic acid onto the surface of alumina from aqueous solution. It was found that an initial chemisorption occurred with monolayer coverage, reaching a maximum at a solution pH of 3.0. The results were interpreted as indicating that this and related adsorptions are controlled by ligand exchange processes involving electrostatic attraction between oppositely-charged species. In a separate project, high performance liquid chromatography was employed for the quantitative analysis of aminophylline in commercial thigh cream formulations. The analysis required derivatization of the compound by dansylation under carefully-controlled conditions. This enhanced its detection and separation from other cream components.

A novel simplex method was applied for the systematic selection of optimal concentrations of two matrix modifiers, nitric acid and magnesium nitrate, for aluminum analysis in aqueous samples using electrothermal atomic absorption spectrometry. Independent optimizations of sensitivity were performed over several practical concentration ranges for each matrix modifier and optimum concentrations were chosen by comparison of data obtained for the resulting simplexes. The results indicate a strong interdependency between magnesium and nitric acid in the achievement of conditions for optimum sensitivity. Using the optimized conditions, detection limits of less than 7 parts per billion of aluminum were achieved, with relative standard deviations of less than 10%. A variety of aqueous samples were analyzed yielding relative standard deviations from 2 to 10%.

A new aluminum phenylphosphonate compound, AlH(C6H5P03)2 was obtained by refluxing a mixture of aluminum nitrate and excess phenylphosphonic acid in water. The compound was characterized by elemental analysis, thermogravimetric analysis, infrared spectroscopy, x-ray powder diffraction and nuclear magnetic resonance spectroscopy. The data indicates that an intercalation compound formed, with an interlayer spacing of 15 angstroms. The compound contains both tetrahedrally and octahedrally coordinated aluminum atoms, suggesting the presence of two or more crystalline phases or a complex unit cell structure. The compound also possesses some unique ion-exchange properties.

The applicability of a recently developed octadecylalumina (ODA) stationary phase for the preparative separations of proteins and peptides is compared with that of conventional Octadecylsilica (ODS) phases. Chromatographic peak widths, peaks areas, and recoveries of polypeptides were obtained from both types of phases. The ODA phase compares favorably with the ODS phase on small peptides, but exhibits low recoveries on high molecular weight proteins. The results are attributed to the unique fused-microplatelet shape of the ODA particles.

27Al nuclear magnetic resonance (NMR) has been employed to study the structure of aqueous aluminum nitrate solutions in the presence of phenylphosphonic acid, potassium dihydrogen phosphate and phosphoric acid. Evidence has been obtained which indicates that in aqueous solution, aluminum ions can be complexed with phosphonate or phosphate in either a 1:1 or 2:1 molar ratio, respectively. The relative percentages of these complexes in solution are shown to be dependent on the ratio of aluminum nitrate to phosphonate or phosphate as well as the degree of ionization of the phosphorus species.

The general chromatographic properties of perfluoroalkyl-bonded alumina-based stationary phases were evaluated by comparing hydrophobicities and selectivities to octadecyl-bonded silica phases. Potential applications for the perfluoroalkyl-bonded alumina-based stationary phases were also investigated by analyzing octapeptide mixtures as well as separations which employed totally aqueous mobile phases. The fluorinated alumina-based stationary phases investigated in this study were found to possess different chromatographic properties compared to octadecylsilica columns.