Role of Planar Conformations in Aggregation Induced Spectral Shifts of   Supermolecular Oligofluorenols in Solutions and Films: A Combined   Experimental and MD/TD-DFT Study

doi:10.1021/acs.jpcb.5b04558

CORC > 北京大学 > 化学与分子工程学院

	Role of Planar Conformations in Aggregation Induced Spectral Shifts of Supermolecular Oligofluorenols in Solutions and Films: A Combined Experimental and MD/TD-DFT Study
	Yuan, Xiangai ; Zhang, Wanwan ; Xie, Ling-Hai ; Ma, Jing ; Huang, Wei ; Liu, Wenjian
刊名	JOURNAL OF PHYSICAL CHEMISTRY B
	2015
关键词	MOLECULAR-DYNAMICS SIMULATIONS BETA-PHASE FORMATION CONJUGATED POLYMER POLY(9,9-DIOCTYLFLUORENE) LIGHT-EMITTING MATERIALS AB-INITIO CALCULATIONS GROUND-STATE ENERGIES POLYFLUORENE DERIVATIVES FRAGMENTATION APPROACH EXCITATION-ENERGIES ELECTRONIC-STRUCTURES
DOI	10.1021/acs.jpcb.5b04558
英文摘要	The supramolecular approach of fluorenol polymers brings about excellent self-assembly behavior to fabricate organogels and superstructured thin films through highly directional noncovalent interactions. To understand the aggregation effects on electronic structures, the packing structures and the UV/vis absorption spectra of oligofluorenols (PFOHn, n = 1/3-8), with and without OC8H17 side chains, were studied experimentally and theoretically in crystal, amorphous solids, and solutions, respectively. For the ground state in vacuum the steric repulsion between two adjacent fluorenol units renders the PFOH oligomers twisted in a helix conformation, while the molecular aggregation favors the appearance of planar pi-conjugated structures. In comparison with the crystal packing, the content of planar conformation (with the torsion angle less than 20 degrees) is increased in amorphous solids. The hydroxyl groups in oligofluorenols facilitate the formation of hydrogen bonding networks. The red shift in absorption spectra was observed in a systematic experimental study of unsubstituted and substituted oligofluorenols with the increasing concentration both in toluene and chloroform solutions. The subsitituted oligofluorenol R-PFOH1 with only one OC8H17 side chain exhibited a shoulder peak at 430-440 nm, which is different from PFOH1 without side chain and 3R-PFO1 with three OC8H17 side chain. Time-dependent density functional theory (TDDFT) calculations, which were carried out on conformation ensembles taken from a series of molecular dynamics (MD) simulations, revealed that the increase in the content of planar pi-conjugated conformations is correlated to the red shift in the absorption spectra upon increasing the solution concentrations. The aggregation-induced red-shift in absorption spectra of oligofluorenols, as well as the blue-shift for oligothiophenes, was rationalized in a unified way from the increased (and reduced) content of planar conformations in molecular aggregates.; National Basic Research Program [2011CB808604]; National Natural Science Foundation of China [21290192, 21273102, U1301243, 21274064]; National Natural Science Funds for Excellent Young Scholar [21322402]; Program for New Century Excellent Talents in University [NCET-11-0992]; Ministry of Education of China [20133223110007]; Excellent science and technology innovation team of Jiangsu Higher Education Institutions; State Key Laboratory of Supramolecular Structure and Materials at Jilin University [sklssm2015022]; Priority Academic Program Development of Jiangsu Higher Education Institutions; SCI(E); ARTICLE; iamlhxie@njupt.edu.cn; majing@nju.edu.cn; liuwj@pku.edu.cn; 32; 10316-10333; 119
语种	英语
内容类型	期刊论文
源URL	[http://ir.pku.edu.cn/handle/20.500.11897/417200]
专题	化学与分子工程学院
推荐引用方式 GB/T 7714	Yuan, Xiangai,Zhang, Wanwan,Xie, Ling-Hai,et al. Role of Planar Conformations in Aggregation Induced Spectral Shifts of Supermolecular Oligofluorenols in Solutions and Films: A Combined Experimental and MD/TD-DFT Study[J]. JOURNAL OF PHYSICAL CHEMISTRY B,2015.
APA	Yuan, Xiangai,Zhang, Wanwan,Xie, Ling-Hai,Ma, Jing,Huang, Wei,&Liu, Wenjian.(2015).Role of Planar Conformations in Aggregation Induced Spectral Shifts of Supermolecular Oligofluorenols in Solutions and Films: A Combined Experimental and MD/TD-DFT Study.JOURNAL OF PHYSICAL CHEMISTRY B.
MLA	Yuan, Xiangai,et al."Role of Planar Conformations in Aggregation Induced Spectral Shifts of Supermolecular Oligofluorenols in Solutions and Films: A Combined Experimental and MD/TD-DFT Study".JOURNAL OF PHYSICAL CHEMISTRY B (2015).