Discipline: Chemistry and Chemical Sciences
Subcategory: Materials Science
Sergio Jacinto - California State University San Bernardino
Co-Author(s): Kimberley Cousins and Timothy Usher, California State University San Bernardino
Dielectric materials are important because they have the potential to serve as components for electronic devices, such as computer processors and solid-state memory. The development and use of organic ferroelectric and piezoelectric materials would eliminate the need to use rare earth metals, and reduce toxicity in the production of dielectrics. Croconic Acid and Diisopropylamine (DIPA) were selected for this study, because they are components of known organic ferroelectric crystals. A computational and experimental investigation was conducted on whether the two species would exhibit hydrogen bonding interactions and form a co-crystalline salt, and whether the new compound would display interesting dielectric behavior. Using tools from the Cambridge Crystallographic Data Center, including ConQuest v1.6-8 and Mercury v3.6-3.8, and Wavefunction’s Spartan ’14 software, an initial complex was constructed of DIPA cation interacting with Croconate dianion. Mercury software was used in order to find the interaction sites of each molecule, which served as a guide in the development of the initial complex. The molecules were then placed together in a boxed system on Wavefunction’s Spartan ’14 software. Using Spartan ‘14, geometry and energy optimization calculations were run using Hartree-Fock method, with the 6-311G* and 6-311+G** basis sets. This was done in order to find a stable and low-energy geometry of the trimeric salt. Spartan ‘14 was then used to generate a theoretical NMR spectrum of the trimeric salt. Concurrently, two molar equivalents of Diisopropylamine were added to one molar equivalent of Croconic Acid using a pestle and mortar, and a reaction was immediately observed. The NMR spectrum of the resulting powder was compared to the predicted NMR spectrum that was produced by Spartan ’14, and the two graphs aligned well. When the product was recrystallized from isopropyl alcohol, the results crystals provided a cleaner NMR spectrum that more closely matched the predicted NMR spectrum generated by Spartan ’14. The co-crystal structure that provided the closest match to the experimental NMR was placed in a unit cell and prepared for calculations under VASP v5.4 software. Geometry and energy calculations were conducted through VASP in order to find a stable, low-energy theoretical unit cell of the crystal structure. The next steps in this study will be to obtain the X-Ray crystal structure and compare it to the theoretical unit cell, and to test the single crystals for dielectric behaviors.
Funder Acknowledgement(s): NSF-HRD 1435163
Faculty Advisor: Kimberley Cousins, firstname.lastname@example.org
Role: Performed all of the calculations, synthesized and crystallized and characterized the salt.