Intramolecular π-Stacking Interactions of Bridged Bis-p-Phenylenediamine Radical Cations and Diradical Dications: Charge-Transfer versus Spin-Coupling

2011 ◽  
Vol 123 (30) ◽  
pp. 6992-6995 ◽  
Author(s):  
Almaz S. Jalilov ◽  
Stephen F. Nelsen ◽  
Ilia A. Guzei ◽  
Qin Wu
2020 ◽  
Vol 7 (6) ◽  
pp. 1451-1466 ◽  
Author(s):  
Wei Wu ◽  
Xiang-Ling Lin ◽  
Qian Liu ◽  
Yan He ◽  
You-Ren Huang ◽  
...  

Good electrical bistability performances in stilbazolium/iodocuprate hybrids stem from the better face-to-face π⋯π stacking interactions induced by the substituents with appropriate lengths and electronic natures.


2021 ◽  
Vol 22 (17) ◽  
pp. 9510
Author(s):  
Kévan Pérez de Carvasal ◽  
Claudia Riccardi ◽  
Irene Russo Krauss ◽  
Domenico Cavasso ◽  
Jean-Jacques Vasseur ◽  
...  

In the search for optimized thrombin binding aptamers (TBAs), we herein describe the synthesis of a library of TBA analogues obtained by end-functionalization with the electron-rich 1,5-dialkoxy naphthalene (DAN) and the electron-deficient 1,8,4,5-naphthalenetetra-carboxylic diimide (NDI) moieties. Indeed, when these G-rich oligonucleotides were folded into the peculiar TBA G-quadruplex (G4) structure, effective donor–acceptor charge transfer interactions between the DAN and NDI residues attached to the extremities of the sequence were induced, providing pseudo-cyclic structures. Alternatively, insertion of NDI groups at both extremities produced TBA analogues stabilized by π–π stacking interactions. All the doubly-modified TBAs were characterized by different biophysical techniques and compared with the analogues carrying only the DAN or NDI residue and unmodified TBA. These modified TBAs exhibited higher nuclease resistance, and their G4 structures were markedly stabilized, as evidenced by increased Tm values compared to TBA. These favorable properties were also associated with improved anticoagulant activity for one DAN/NDI-modified TBA, and for one NDI/NDI-modified TBA. Our results indicated that TBA pseudo-cyclic structuring by ad hoc designed end-functionalization represents an efficient approach to improve the aptamer features, while pre-organizing and stabilizing the G4 structure but allowing sufficient flexibility to the aptamer folding, which is necessary for optimal thrombin recognition.


2019 ◽  
Author(s):  
KAIKAI MA ◽  
Peng Li ◽  
John Xin ◽  
Yongwei Chen ◽  
Zhijie Chen ◽  
...  

Creating crystalline porous materials with large pores is typically challenging due to undesired interpen-etration, staggered stacking, or weakened framework stability. Here, we report a pore size expansion strategy by self-recognizing π-π stacking interactions in a series of two-dimensional (2D) hydrogen–bonded organic frameworks (HOFs), HOF-10x (x=0,1,2), self-assembled from pyrene-based tectons with systematic elongation of π-conjugated molecular arms. This strategy successfully avoids interpene-tration or staggered stacking and expands the pore size of HOF materials to access mesoporous HOF-102, which features a surface area of ~ 2,500 m2/g and the largest pore volume (1.3 cm3/g) to date among all reported HOFs. More importantly, HOF-102 shows significantly enhanced thermal and chemical stability as evidenced by powder x-ray diffraction and N2 isotherms after treatments in chal-lenging conditions. Such stability enables the adsorption of dyes and cytochrome c from aqueous media by HOF-102 and affords a processible HOF-102/fiber composite for the efficient photochemical detox-ification of a mustard gas simulant.


Author(s):  
Gul Yakali

Fluorescent organic small molecules with the property of aggregation induced enhanced emission in the solid phase (crystall or thin film) have great attention for the design of optoelectronic materials. Generally,...


1999 ◽  
Vol 11 (3) ◽  
pp. 530-532 ◽  
Author(s):  
Yue Wang ◽  
Weixing Zhang ◽  
Yanqin Li ◽  
Ling Ye ◽  
Guangdi Yang

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