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Associate Professor and Chair Department of Chemistry Buffalo State College 1300 Elmwood Ave. Buffalo, NY 14222 Phone: (716) 878-5204 Professional
Information/Research |
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I am largely responsible for
teaching the Organic discipline in the Chemistry Department. I teach
Organic Chemistry I (CHE 201), Organic Chemistry II (CHE 202), and
Advanced Synthetic techniques (CHE 630). I also teach Biological
Chemistry (CHE 322) in the Spring and occasionally teach 100-level
courses, most recently CHE 100, a general chemistry course for
students with little chemistry or science background.
Advising
I am the Coordinator and an academic advisor for the forensic chemistry major.
Research
My research interests fall into two main categories:
My primary research interests involve molecular recognition. At present, we are working on the synthesis and characterization of calixarene-based host molecules that can form complexes with guest molecules through specific, non-covalent interactions. Several different interactions must be brought to bear on the guest molecule to gain a specific interaction with the host. Among the possibilities are hydrogen bonding, and hydrophobic or electrostatic interactions. We are currently taking an exciting new direction in this research. We are synthesizing calix-[4] and -[5]arenes with reporter groups on the upper rim. Our current focus is to synthesis calixarenes with a verdazyl (a stable radical) attached to the upper rim. (Figure 1). Since this molecule has an unpaired electron, binding in the calixarene cavity can be potentially monitored by ESR, NMR, or UV-vis.
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The tris(pyrazolyl)borates (Tp) are a versatile class of nitrogen-donor ligands, first employed about 30 years ago, that are still receiving considerable attention today. These anionic ligands consist of a tetrahedral boron bonded to 3 pyrazoles, with the remaining group on the boron usually being a hydride (Figure 1, Z=B&endash;). More recently, the tris(pyrazolyl)methanes (Tpm) have been developed as ligands. (Figure 1, Z=C). The Tpm ligands contain a carbon in place of the boron and are therefore neutral analogues of the Tp ligands.
Previous syntheses of 3- and 5-substituted Tpm ligands produced a
mixture of regioisomers, which were typically equilibrated under
acidic conditions giving the most stable regioisomer. We reasoned
that under similar conditions, substitution of the pyrazoles with
other nucleophiles would also be possible. In this paper we show that
simple tris(pyrazolyl)methanes 1 can be equilibrated with
substituted pyrazoles (a-d) to form new "mixed"
tris(pyrazolyl)methanes 2 (Scheme 1). The composition of the
product depends on the nature of the starting tris(pyrazolyl)methane,
the nature of the substituted pyrazole, and the relative amount of
these two reagents.
These results were then applied to the synthesis of a Tpm ligand containing 3 different pyrazoles. (Scheme 2). Equilibration of 1b with c (3 equiv.) and d (1 equiv.) leads to a mixture containing all 10 possible Tpm ligands, with the desired racemic-2bcd being present at about 20% by NMR. Column chromatography lead to the isolation of the pure ligand.
In the course of this project we have also produced several new crystal structures, a few of which are shown below
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