Yonsei University · Materials Science
Professor Juwon Oh's research lab specializes in physical and structural organic chemistry, with a central focus on aromaticity and its dynamic behavior in excited electronic states. The lab investigates Baird's rule and aromaticity reversal—particularly the transition from Hückel to Möbius topology and from aromatic to antiaromatic character in triplet excited states—using advanced spectroscopic techniques and high-level quantum calculations. A key research direction involves designing and synthesizing large, flexible macrocyclic systems such as expanded porphyrins and carbaporphyrins to probe electronic delocalization, conformational switching, and photoresponsive behavior. The lab also explores functional molecular architectures, including nanographene-fused porphyrins and metal-complexed systems, to understand how electronic communication and steric effects govern photophysical and coordination properties.
Figures are computed from collected data and may differ slightly.
Aromaticity, the special energetic stability derived from cyclic [4 n + 2]π-conjugated electronic structures, has been the topic of intense interest in chemistry because it plays a critical role in rationalizing molecular stability, reactivity, and physical/chemical properties. Recently, the pioneering work by Colin Baird on aromaticity reversal, postulating that aromatic (antiaromatic) character in the ground state reverses to antiaromatic (aromatic) character in the lowest excited triplet stat
Recently, Baird (anti)aromaticity has been referred to as a description of excited-state (anti)aromaticity. With the term of Baird's rule, recent studies have intensively verified that the Hückel aromatic [4<i>n</i> + 2]π (or antiaromatic [4<i>n</i>]π) molecules in the ground state are reversed to give Baird aromatic [4<i>n</i>]π (or Baird antiaromatic [4<i>n</i> + 2]π) molecules in the excited states. Since the Hückel (anti)aromaticity has great influence on the molecular properties and reactio
The aromaticity reversal in the lowest triplet state (T1 ) of a comparable set of Hückel/Möbius aromatic metalated expanded porphyrins was explored by optical spectroscopy and quantum calculations. In the absorption spectra, the T1 states of the Möbius aromatic species showed broad, weak, and ill-defined spectral features with small extinction coefficients, which is in line with typical antiaromatic expanded porphyrins. In combination with quantum calculations, these results indicate that the Mö
A nanographene-fused expanded carbaporphyrin (<b>5</b>) and its BF<sub>2</sub> complex (<b>6</b>) were synthesized. Single-crystal X-ray structures revealed that <b>5</b> and <b>6</b> are connected by two hexa-<i>peri</i>-hexabenzocoronene (HBC) units and two dipyrromethene or BODIPY units, respectively. As prepared, <b>5</b> and <b>6</b> both show nonaromatic character with figure-of-eight carbaoctaphyrin (1.1.1.0.1.1.1.0) cores and adopt tweezers-like conformations characterized by a partially
N-(p-Methoxycarbonylbenzyl) triazole (BTz) substituents have been introduced to Ni(II) porphyrins (NiPs), in which their modulated axial-coordination processes have been investigated. For this study, the two types of ligands, neutral pyridine versus anionic cyanide, were employed to investigate an effect of BTz substituents. The unique microenvironments given by the BTz substituents provided two different effects on the axial-coordination processes of NiPs on the ground and excited states: (1) s
The switching phenomena of conformation with π-electronic network through deprotonation-protonation processes were investigated by employing a series of 5,20-bis(α-oligothienyl) substituted hexaphyrins(1.1.1.1.1.1). They showed significant changes in the absorption and emission spectra with deprotonation, and returned to the initial state with protonation. Through NMR measurements and single crystal X-ray diffraction analysis, we found that the 5,20-bis(α-oligothienyl) substituted hexaphyrins, w
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