Date of Award

Spring 5-11-2019

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Advisor

Howard H. Patterson

Second Committee Member

Scott D. Collins

Third Committee Member

Robert D. Pike

Additional Committee Members

Alice Bruce

Matthew Brichacek

Mohammad Omary

Abstract

This dissertation is divided into three sections: (1) optical memory, (2) metallophilic-based luminescence, and (3) chemical sensors. (1) Optical memory behavior of d10metal Cu(I) thiocyanate salts are investigated to explore their potential use in the development of digital data storage devices. From this study we have discovered a new class of CuSCN(3-BrPy)2optical memory material which undergo a reduction in emission intensity upon laser irradiation. This loss of emission intensity can be reversed simply by heating the sample to room temperature. The mechanism by which this emission loss occurs has been studied, revealing a migrating Br atom which forms a metastable interaction with an adjacent SCN group. (2) To explore the dependence of luminescence behavior on the metallophilic interactions within solid state materials, we have synthesized a series of analogous AuCN2-/AgCN2-crystals which possess and lack metallophilic interactions. Where metallophilic interactions are present we observe enhanced luminescence behavior, including charge transfer and dual singlet/triplet emission. (3) We have also demonstrated the importance of metallophilic interactions by exploring chemical sensing capabilities of pure and mixed iodocuprate(I)/iodoargenate(I) nanoparticles toward soft nucleophilic vapors. Upon exposure, these nanoparticles display vapochromic behavior where the emission energy is specific to the bound nucleophile. These materials are promising in the development of wearable sensors. Kinetic studies have been performed to map the reaction mechanism by which these nanoparticle materials operate. Measurements reveal that reaction rates are a factor of 10 times faster in cases with high Ag content.

To measure these photophysical behaviors, temperature variable and time-dependent luminescence measurements were used with other spectroscopic techniques including diffuse reflectance, UV-vis, and infrared. X-ray diffraction measurements on single crystals and nanoparticle samples were performed to corroborate the photophysical observations and structure. Transmission electron microscopy was used to measure nanoparticle size and morphology. Experimental data was interpreted with the help of Density Function Theory (DFT) molecular modelling.

In this study we have investigated new materials which have unique photophysical and photochemical behavior. Our findings enhance the experimental and theoretical understanding of these transition metal materials in the use of optical memory and chemical sensing based optoelectronic devices.

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