Date on Senior Honors Thesis

3-2019

Document Type

Senior Honors Thesis

Degree Name

B.S.

Department

Chemistry

Committee Chair

Grapperhaus, Craig

Committee Member

Riedel, Thomas

Committee Member

Rich, Christine

Author's Keywords

transamination; ligand; amine; thiosemicarbazone

Abstract

Bis-thiosemicarbazones are an important class of ligands for the synthesis of transition metal complexes with applications in medicine and electrochemistry.1,2 Among the most studied of these complexation ligands is diacetyl-2,3-bis(N4-methyl-3-thiosemicarbazone) (denoted as ATSM, 1, Figure 1).2,3 Derivatives of 1 with various amines in place of the methylamine of ATSM have previously been reported, including diacetyl (N4-methylthiosemicarbazone-N4′-dimethylthio-semicarbazone) (denoted as ATSM/DM, 2).4 In this work, we pursue the development of a library of ATSM derivatives with a variety of functionalized pendant amines with a range of electronic and steric properties through the transamination of 2 with primary amines (molecules with an –NH2 group). The synthesis, yields, melting points, and 1H NMR spectra of a variety of new ATSM derivative ligands are reported.

Lay Summary

Bis-thiosemicarbazone derivative ligands are a class of molecules, that, when complexed with certain metal atoms, have important medicinal and industrial applications. Among these applications are treatments for cancer, tuberculosis, malaria, and stroke, as well as medical imaging and environmentally sustainable production of gases for industrial use. The highly studied and well-known bis-thiosemicarbazone ligand with which this research is concerned is diacetyl(N(4)-methylthiosemicarbazone-N’(4)-dimethylthiosemicarbazone), otherwise known as ATSM/DM. Specialization of the ATSM/DM for each of these purposes is done by attaching different molecules with different properties to its molecular structure. This is done through a reaction called transamination. Transamination involves attachment of molecules with a primary amine (--NH2 group) to the end of the ATSM/DM. The aim of this research was twofold: to examine the scope of the transamination reaction, that is, how many different molecules with varying properties and chemical behaviors can be attached to the ATSM/DM, as well as optimization of the reaction conditions, which involved testing the reaction in different solvents and at varying reactant ratios to discover which was the most efficient and successful. To do this, molecules with varying chemical properties were attached to the ATSM/DM under varying conditions. In cases where the aforementioned reaction conditions failed to produce pure products of substantial yields, new reaction conditions were devised through analysis of how the reaction is known to proceed.

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