Search for dissertations about: "aromaticity"

Showing result 1 - 5 of 11 swedish dissertations containing the word aromaticity.

2. 1. Ground and Excited State Aromaticity : Design Tools for π-Conjugated Functional Molecules and Materials

   Author : Christian Dahlstrand; Henrik Ottosson; Miguel Solà; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; fulvene; fulvalene; polyfulvene; aromaticity; triplet state; excited state; Clar structure; polybenzenoid hydrocarbons PBH ; conjugated polymers; computational chemistry; optical spectroscopy; Kemi med inriktning mot organisk kemi; Chemistry with specialization in Organic Chemistry;

   Abstract : The main focus of this thesis is on the aromaticity of the ground state and electronically excited states of π-conjugated molecules and polymers, as well as how aromaticity is connected to their properties.The electronic structures of polybenzenoid hydrocarbons (PBHs) were explored through density functional theory (DFT) calculations and the π-component of the electron localization function (ELFπ). READ MORE

4. 2. Excited State Aromaticity and Antiaromaticity : Fundamental Studies and Applications

   Author : Rabia Ayub; Henrik Ottosson; Manabu Abe; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Baird s rule; Clar s rule; Computational quantum chemistry; Excited state aromaticity; Excited state aromaticity indicators; Organic photochemistry; Polycyclic conjugated hydrocarbons; Chemistry with specialization in Organic Chemistry; Kemi med inriktning mot organisk kemi;

   Abstract : The central theme of this thesis is the ability to tune various molecular properties by controlling and utilizing aromaticity and antiaromaticity in the lowest electronically excited states. This investigation is based on qualitative theory, quantum chemical (QC) calculations and experimental work. READ MORE

5. 3. Influence of Aromaticity on Excited State Structure, Reactivity and Properties

   Author : Kjell Jorner; Henrik Ottosson; Rainer Herges; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; photochemistry; aromaticity; computational chemistry; Chemistry with specialization in Organic Chemistry; Kemi med inriktning mot organisk kemi;

   Abstract : This thesis describes work that could help development of new photochemical reactions and light-absorbing materials. Focus is on the chemical concept "aromaticity" which is a proven conceptual tool in developing thermal chemical reactions. It is here shown that aromaticity is also valuable for photochemistry. READ MORE

6. 4. Hyperconjugation in Group 14 Organic Compounds : Design and Property Investigations

   Author : Aleksandra Denisova; Henrik Ottosson; Thomas Müller; Uppsala universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; 1; 4-disilacyclohexa-2; 5-diene; aromaticity; computational chemistry; conjugation; cross-hyperconjugation; hyperconjugation; group 14 elements; organosilicon chemistry; silole;

   Abstract : Nowadays π-conjugated molecules are widely used as materials for devices in organic and molecular electronics. This is due to the ability of such molecules to conduct electricity. However, π-conjugation leads to molecular rigidness and associated lower solubility, which limits possible applications. READ MORE

7. 5. Catalysis of Quantum Chain Photoisomerizations: Calculations of Triplet Energy Surfaces and Measurements of Quantum Yields

   Author : Maria Brink; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; triplet state; density functional theory; potential energy surface; cis-trans isomerization; adiabatic isomerization; catalysis;

   Abstract : Triplet state cis-trans photoisomerizations of olefins is the theme of this thesis, and the goal is to make the isomerizations as efficient as possible. The shape of the triplet potential energy surface (T1 PES) is essential for this, and the possibility of calculating these T1 PESs for two smaller olefins, using the computationally inexpensive density functional theory (DFT) methods, was investigated. READ MORE