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Graduation Term
Summer 2025
Degree Name
Master of Science (MS)
Department
Department of Chemistry
Committee Chair
Bhaskar Chilukuri
Committee Member
Jun-Hyun Kim
Committee Member
Susil Baral
Abstract
This thesis explores the self-assembly, adsorption behaviors, and interface stability of two molecular systems—phthalocyanines and a bent-core liquid crystal compound, denoted as IP31—using Density Functional Theory (DFT) simulations. Additionally, the gas-phase assembly of configuration-variable uracil-based clusters is investigated, focusing solely on their structural stability and molecular orientations. For phthalocyanines, we examined the parent, phenoxy, and ethoxy-substituted derivatives (M = Co, Mg, and H₂) adsorbed on highly ordered pyrolytic graphite (HOPG), highlighting the dominant role of peripheral substitutions in determining monolayer stability and morphology. Octa-substituted derivatives formed well-packed, stable monolayers, whereas tetra-substituted variants displayed weak phase segregation and disorder, further influenced by solvent interactions. In the case of IP31, adsorption onto HOPG revealed that surface interactions significantly alter the geometry of this bent-core liquid crystal. The orientation of terminal alkyl chains, whether parallel or anti-parallel, was found to impact the energetic stability and self-assembly of IP31 at the interface. For uracil-based clusters, we investigated their interactions with alkali metal cations (Li⁺, Na⁺, K⁺, Cs⁺), demonstrating a size-dependent relationship between cluster stability and hydrogen bonding. Smaller cations favored compact clusters with minimal bonding, while larger cations supported larger, more extended structures with enhanced intermolecular hydrogen bonding. Across these systems, we identified how molecular substituents, isomeric configurations, and external factors like solvents and metal cations drive the organization and stability of molecular assemblies. These insights provide a deeper understanding of the fundamental mechanisms of molecular self-assembly, offering implications for the design of functional materials in applications such as catalysis, molecular electronics, and supramolecular chemistry.
Access Type
Thesis-ISU Access Only
Recommended Citation
Suthaharan, Sivanujan, "Atomistic Insights into Molecular Self-Assembly Using Quantum Mechanical Simulations" (2025). Theses and Dissertations. 2194.
https://ir.library.illinoisstate.edu/etd/2194
DOI
https://doi.org/10.30707/ETD.1763755358.703998