Synthesis, Characterization, Crystallography, and Antimicrobial Activity of Novel Gold(I) Complexes with Phosphine Ligands (L1) tris(4-methoxy-3,5-dimethylphenyl)phosphine and (L2) Bis(2-methoxyphenyl) Chlorophosphine

Graduate #37
Discipline: Chemistry and Chemical Sciences
Subcategory: Chemistry (not Biochemistry)

Kwame Brown - North Carolina A&T State University

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With the success of the metal based cancer drug Cisplatin, there has been increased interest in metal complexes. Along with studying metal complexes for anti-cancer properties, the application as antimicrobial agents is growing. The increasing problem of microbial resistance to antibiotics is fueling the need for new methods in fighting microbes, with metal complexes proving to be promising alternatives. Biological activity of metal complexes is governed by the physicochemical properties of the ligands, in which group 11 metal complexes are showing to be highly effective. In this research, two novel gold (I) complexes are synthesized using phosphine ligands (L1) tris(4-methoxy-3,5-dimethylphenyl)phosphine and (L2) Bis(2-methoxyphenyl) Chlorophosphine. The mono coordinate forms of the complexes (L1)AuCl and (L2)AuCl were achieved by reacting precursor complex (tht)AuCl, (tht= tetrahydrothiophene), in dichloromethane with 1-equivalent of respective ligand. Higher coordinate forms of the respective complexes are done using stepwise addition of the ligand with appropriate molar ratio equivalence. Schlenk Line technique was used in the synthesis for solvent removal, generating the precipitate product. Recrystallization was done using slow cooling, liquid-liquid diffusion method, producing large colorless crystals. Characterization of the crystals are conducted with FT-IR, Ramen Spectroscopy, UV-Vis spectroscopy, NMR (31P & 1H), and crystallography using single crystal X-ray diffraction. Antimicrobial effect is examined using Minimum Inhibition Concentration (MIC) testing on several bacteria. Structural factors possibly affecting antimicrobial activity are discussed.

Not Submitted

Funder Acknowledgement(s): MBRS Research Initiative for Scientific Enhancement program (RISE) at North Carolina Agricultural and Technical State University- Funded by the National Institute of Health (NIH)

Faculty Advisor: Zerihun Assefa, zassefa@ncat.edu