Doctor of Philosophy
Date of Defense
Dr. Alicia Beatty
Dr. Janet Braddock-Wilking
Dr. George Gokel
Dr. Stephen Holmes
Inorganic-organic hybrid metal halide materials have been of great interest recently due to the useful properties offered by such a combination. The inorganic portions usually consisting of MX62- subunits, (M = Pb, Sn, Cd, Cu; X = Cl, Br, I) most often form 2-D perovskite layers where the metals are bridged by corner sharing halides. The organic portion, usually consisting of primary amines or anilines provides a template for the inorganic framework and in some cases, dictates the dimensionality (2-D, 1-D, 0-D) of the network. These materials have various applications in host-guest chemistry catalysis, and gas storage, or as superconductors or quantum dots.
It has been established by the Beatty group that it is possible to alter the metal halide assembly by changing the size of the substituent ortho to an aniline/amine group. Cadmium chloride complexes can be transformed from 2-D to 0-D based on the size of the substituent ortho to the nitrogen on a dianilinium complex. When the substituent in the ortho position is small (H) a perovskite layer is formed (Cd-Cl distance 2.4-2.7 Å). If the substituent is changed to a methyl group the [CdCl6]2- layer expands (Cd-Cl distance 3.14-3.87 Å). If the group is changed to a larger ethyl group, the steric bulkiness of the group causes the layer to collapse into a hexameric cluster with Cd-Cl distances that are slightly shorter than that of the expanded layer while still being longer than that of a normal perovskite layer (2.8-3.04 Å). To determine if this phenomenon occurs generally, we have used metal halides such as CdX2 and CuX2 (where X = Cl, Br, I) with a number of ortho-substituted anilines and dianilines (ortho = H, Cl, CH3, CH2CH3, CH(CH3)2, C(CH3)3, C6H5).
Cernicek, Stephanie, "Cadmium Chloride Dimensionality Changes From Ortho-Substituted Anilines" (2017). Dissertations. 668.