Distinctive Substituent Effect on 3,9-Bis (p-(R)-diphenylamino) Perylene in Electron Push-Pull System for Emission Color Tuning = 페릴렌 도너 억셉터 분자 시스템에서의 전자 밀고 당김의 효과와 발광색 조절의 제한

다국어 초록 (Multilingual Abstract)

A series of perylene-based donor-acceptor-donor (D-A-D) compounds, 3,9-Bis(p-(R)-diphenylamino)perylene (R: CN (2a), F (2b), H (2c), Me (2d), and OMe (2e)), were synthesized by a Buchwald-Hartwig cross-coupling reaction using 3,9-dibromoperylene with p-(R)-diphenylamine and intramolecular charge transfer (ICT) on the D-A-D system with regards to electron push-pulled substituents effect was investigated. In this system, diphenylamine (DPA) and perylene (Peri) units act as an electron donor and acceptor, respectively. By introducing various p-(R)-diphenylamine derivatives with electron-donating or electron-withdrawing R groups, the energy band gap of the D-A-D compound were systematically controlled and the emission colors were efficiently tuned from green to red. Basically, the UV/Vis absorption origin of the 3,9-Bis(p-(R)-diphenylamino)perylene compounds were assigned to π−π* transition and ICT by using the steady state absorption spectra and DFT/TDDFT calculations. As expected, the steady state emission spectra of all D-A-D compounds were observed as well controlled emission color depending on the Hammett substituent constants (). However, the absorption spectrum of the CN substituted 2a was showed a different structure compared to 2b−2e compounds. Based on solvatochromic experiments, all of compounds were showed distinctive ICT character in order to increasing the solvent polarity. In the Lippert-Mataga plots, the different charge transfer character was observed depending on the electron push-pull substitution, which showing gradually increased ICT characters from the electron-withdrawing to donating substitution. However, exceptionally, the strong electron withdrawing group of CN substituted 2a was not correlated with other R group compounds. From the experimental data and DFT calculations, we concluded that the 2a compound emission is originated by reverse ICT character from arylamine to CN unit. As a result, we assumed that there is constraint on emission color tuning to make higher energy of blue emission in the D-A-D molecular system due to the reverse charge transfer property caused by strong electron withdrawing group.

국문 초록 (Abstract)

페릴렌을 활용한 도너 억셉터 분자 시스템은 주로 페릴렌 다이이마이드에 대한 응용 연구가 많이 이루어졌다. 그러나, 페릴렌 도너 억셉터 분자 시스템에서 치환기효과만으로 분자 내 전하이동을 미세하게 조절하는 연구는 아직까지 알려지지 않았다. 본 연구에서는 페릴렌 도너 억셉터 시스템을 기반으로 분자 내 결합을 통해 일어나는 전하이동의 효과와 그에 따른 발광색 조절에는 한계가 있음을 확인하였다. 도너로써 역할을 하는 다이페닐아민과 억셉터로써 역할을 하는 페릴렌을 결합한 도너-억셉터-도너 시스템에서 치환기효과가 없는 H를 기준으로 전자 당김 치환기인 CN 과 F, 전자 주개 치환기인 Me, OMe 를 사용하여 분자구조를 디자인하였고, 광물리학적 특성과 전기화학적 특성 그리고 DFT/TDDFT 계산을 통해서 치환기에 따른 5가지 발광물질들의 특징들을 비교해보았다. 일반적으로 알려져 있듯이, HOMO 와 LUMO 의 조절로 물질의 발광색을 변화시킬 수 있고, F, H, Me, OMe 물질의 경우, 치환기효과만으로 HOMO 와 LUMO 가 조절되는 경향성이 보이지만, CN 물질의 경우 그 경향성에서 벗어났고, 따라서 CN 물질로부터 HOMO 와 LUMO 조절의 한계점을 확인하였다.

목차 (Table of Contents)

• Ⅰ. Introduction 1
• Ⅱ. Experimental Section 5
• 1. General 5
• 2. Synthesis 6
• 1) 3,9-bis(N,N-bis(4’-cyanophenyl)amino)perylene (2a) 7
• 2) 3,9-bis(N,N-bis(4’-fluorophenyl)amino)perylene (2b) 8
• 3) 3,9-bis(N,N-diphenylamino)perylene (2c) 9
• 4) 3,9-bis(N,N-bis(4’-methylphenyl)amino)perylene (2d) 10
• 5) 3,9-bis(N,N-bis(4’-methoxyphenyl)amino)perylene (2e) 11
• 3. Analysis equipment and analysis method 12
• 1) UV/Vis absorption and emission spectra 12
• 2) Electrochemistry 12
• 3) Density functional theory calculations 13
• Ⅲ. Result and Discussion 14
• 1. Photophysical Properties 14
• 2. Electrochemical Properties 23
• 3. DFT Calculations 27
• Ⅳ. Conclusion 30
• Reference 31
• Abstract 36
• Appendix 37