Date Thesis Awarded

5-2017

Access Type

Honors Thesis -- Access Restricted On-Campus Only

Degree Name

Bachelors of Science (BS)

Department

Chemistry

Advisor

Robert D. Pike

Committee Members

William R. McNamara

Deborah C. Bebout

David F. Grandis

Abstract

Twenty-one novel complexes of copper(II) thiocyanate pyridine were synthesized in methanol from the source material Cu(NO­3)2•2.5H2O and a diverse series of substituted pyridines (XPy). These complexes typically formed according to the formula trans-[Cu(NCS)2(XPy)2], with square-planar geometries that exhibited thiocyanate bridging via long Cu–S bonds. The length of this long bridging bond appears to loosely correlate to the substitution position of the pyridine ligand used, and resulted in square planar molecules forming edge-sharing chain networks of Jahn-Teller distorted octahedra. Several other structural types were also observed, resulting in part from the tendency of some complexes to form methanol solvates. Several species displayed polymorphism with known complexes or each other. Methanol-solvate structures include square-pyramidal monomers and networks of the form trans-[Cu(NCS)2(XPy)2(MeOH)], as well as Jahn-Teller distorted octrahedral monomers of the form trans-[Cu(NCS)2(XPy)­2(MeOH)­2]. The ligand 2-NH2Py produced an unusual network of methoxy-bridge dimers, trans-[Cu(NCS)2(2-NH2Py)2(µ-OMe)2], that are further linked via bridging thiocyanate to form a sheet structure. Furthermore, a mixed-ligand solution of (2-BrPy) and (3-BrPy) formed the surprising complex trans-[Cu(NCS)2(2-BrPy)(3-BrPy)]. Bridging complexes, trans-[Cu(NCS)2(LL)], were also formed from the ligands LL = 4,4ʹ-bipyridyl (Bpy) and pyrazine (Pyz); in these cases, bridging by both the organic and thiocyanate ligands produced sheet networks.

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