neutral spin carrying hexabenzocoronene (HBC) derivative is described. The conjugated phenyl nitroxide substituted HBC with five alkyl chains exhibits a positive magneto-LC effect in columnar hexagonal liquid crystalline phase as probed by differential scanning calorimetry and electron paramagneticresonance spectroscopy. Surprisingly, at 140 K the ΔMS = 2 transition can be observed indicating a thermally
Long-Lived Charge Transfer Excited States in HBC-Polypyridyl Complex Hybrids
作者:Anastasia B. S. Elliott、Raphael Horvath、Xue-Zhong Sun、Michael G. Gardiner、Klaus Müllen、Nigel T. Lucas、Michael W. George、Keith C. Gordon
DOI:10.1021/acs.inorgchem.5b02602
日期:2016.5.16
calculations support the donor–acceptor chargetransfer character of these systems, in which HBC is the donor and bpy is the acceptor. The ground state optical properties are dominated by the HBC chromophore with additional distinct transitions of the complexes, one associated with MLCT 450 nm (ε > 17 000 L mol–1 cm–1) and another with a HBC/metal to bpy chargetransfer, termed the MLLCT band (373 nm, ε
报道了用t Bu或C 12 H 25功能化的两个联吡啶-六-周边-六苯并二氢呋喃(bpy-HBC)配体及其Re(I)三羰基氯配合物的合成,并使用光谱和计算方法研究了它们的电子性质。金属配合物表现出不同寻常的性质,我们使用时间分辨红外光谱观察到了长寿命激发态的形成。根据不同的溶剂,这似乎是形式Rebpy的• - HBC •+或以bpy为中心的π,π*状态。TD-DFT计算支持了这些系统的供体-受体电荷转移特性,其中HBC是供体,bpy是受体。基态的光学性质主要由HBC发色团主导,另外还有明显的复合物跃迁,一个跃迁与MLCT 450 nm(ε> 17000 L mol –1 cm –1)有关,另一个与HBC /金属向bpy的电荷转移有关,称为MLLCT谱带(373 nm,ε= 66 000 L mol –1 cm –1)。这些分配也得到共振拉曼光谱的支持。
Langmuir and Langmuir-Blodgett Films of Amphiphilic Hexa-peri-hexabenzocoronene: New Phase Transitions and Electronic Properties Controlled by Pressure
作者:Niels Reitzel、Tue Hassenkam、Konstantin Balashev、Torben R. Jensen、Paul B. Howes、Kristian Kjaer、Andreas Fechtenkötter、Natalia Tchebotareva、Shunji Ito、Klaus Müllen、Thomas Bjørnholm
= 71.9 A2 = 3 x 23.9 A2. Thin monolayer films can be transferred to solid supports by the Langmuir-Blodgett (LB) technique. Atomic force microscopy (AFM) with atomic resolution reveals the crystalline packing of alkyl chains in the high-pressure phase. Kelvin force microscopy (KFM) shows a clear potential difference between the high- and low-pressure phases. This is discussed in terms of orbital delocalization
Self-Assembly, Molecular Dynamics, and Kinetics of Structure Formation in Dipole-Functionalized Discotic Liquid Crystals
作者:Mahdy M. Elmahdy、Xi Dou、Mihail Mondeshki、George Floudas、Hans-Jürgen Butt、Hans W. Spiess、Klaus Müllen
DOI:10.1021/ja7113618
日期:2008.4.1
The self-assembly, the molecular dynamics, and the kinetics of structure formation are studied in dipole-functionalized hexabenzocoronene (HBC) derivatives. Dipole substitution destabilizes the columnar crystalline phase except for the dimethoxy- and monoethynyl-substituted HBCs that undergo a reversible transformation to the crystalline phase. The disk dynamics are studied by dielectric spectroscopy and site-specific NMR techniques that provide both the time-scale and geometry of motion. Application of pressure results in the thermodynamic phase diagram that shows increasing stability of the crystalline phase at elevated pressures. Long-lived metastability was found during the transformation between the two phases. These results suggest new thermodynamic and kinetic pathways that favor the phase with the highest charge carrier mobility.
Donor–acceptor optoelectronic molecules based on hexa-peri-hexabenzocoronene and benzothiadiazole units: effect of different combinations
Three donor-acceptor (D-A) conjugated molecules using hexa-peri-hexabenzocoronene (HBC) as D unit while benzo[2,1,3]thiadiazole (BT) as A unit have been synthesized. They have different D-A combination fashions, including D-A, A-D-A and D-A-D. Their thermal, optical, electrochemical properties and molecular interactions have been thoroughly studied, with particular attention paid on the effect of different D-A combinations. Property comparison reveals that the ADA molecule using HBC as core and two BT units as arms possesses a better light absorption property and a more ordered film structure than the other two. Finally, such ADA molecule displayed the best field-effect transistor and photovoltaic performances. (C) 2016 Elsevier Ltd. All rights reserved.