Multidimensional Frameworks Assembled from Silver(I) Coordination Polymers Containing Flexible Bis(thioquinolyl) Ligands:  Role of the Intra- and Intermolecular Aromatic Stacking Interactions

2003 ◽  
Vol 42 (12) ◽  
pp. 3738-3750 ◽  
Author(s):  
Chun-Long Chen ◽  
Cheng-Yong Su ◽  
Yue-Peng Cai ◽  
Hua-Xin Zhang ◽  
An-Wu Xu ◽  
...  
2009 ◽  
Vol 64 (10) ◽  
pp. 1093-1097 ◽  
Author(s):  
Irena Stein ◽  
Uwe Ruschewitz

By slow diffusion of pyridine (py) into an aqueous solution containing the respective metal salt and acetylenedicarboxylic acid (H2ADC), single crystals of coordination polymers of composition 1∞[MII(H2O)2(py)2ADC] with MII = Zn (1) and Cd (2) were obtained. The crystal structures consist of octahedral MIIN2O4 units, which are connected to chains via acetylenedicarboxylate dianions. Hydrogen bonds between O atoms of the dianions and of the water molecules lead to the formation of layers perpendicular to [010]. The structure is further held together by weak aromatic stacking interactions between the pyridine ligands.


2015 ◽  
Vol 68 (1) ◽  
pp. 113
Author(s):  
Min Chen ◽  
Zhuo-Wei Wang ◽  
Hui Zhao ◽  
Chun-Sen Liu

Three new ZnII coordination polymers, namely [Zn(ndc)]n (1), {[Zn(ndc)(bpe)]·1.25H2O}n (2), and {[Zn(ndc)(bpee)]·1.25H2O}n (3), were prepared based on in situ reaction of 1,2-naphthalenedicarboxylic anhydride (ndca) with two different 4,4′-bipyridyl-like bridging co-ligands, bpe and bpee (ndc = 1,2-naphthalenedicarboxylate, bpe = 1,2-bis(4-pyridyl)ethane, and bpee = trans-1,2-bis(4-pyridyl)ethylene). In 1, the ZnII and ndc ligands are directly involved in the polymeric frameworks, forming a 2D (43.63) layered network. Complexes 2 and 3 similarly consist of Zn2(ndc)2 binuclear units that are linked by bpe and bpee ligands, respectively, into a 2D (44.62) sheet. However, further analysis indicates that 2 and 3 feature the similar 2-fold interpenetrating structure linked via hydrogen bonding interactions for 2 and aromatic stacking interactions for 3. In addition, the resultant 2D→3D supramolecular frameworks of 2 and 3 are both constructed via aromatic stacking interactions. Also, the fluorescent and thermal properties of the complexes were investigated.


2017 ◽  
Vol 139 (42) ◽  
pp. 14931-14946 ◽  
Author(s):  
Siddharth Goyal ◽  
Aditya Chattopadhyay ◽  
Koushik Kasavajhala ◽  
U. Deva Priyakumar

2011 ◽  
Vol 40 (7) ◽  
pp. 3218-3231 ◽  
Author(s):  
Takako Ohyama ◽  
Takashi Nagata ◽  
Kengo Tsuda ◽  
Naohiro Kobayashi ◽  
Takao Imai ◽  
...  

2020 ◽  
Author(s):  
Nidhi Gour ◽  
Bharti Koshti

Aggregation of amyloid beeta 1-42 (Aβ<sub>42</sub>) peptide causes the formation of clustered deposits knows as amyloid plaques in the brain which leads to neuronal dysfunction and memory loss and associated with many neurological disorders including Alzheimer’s and Parkinson’s. Aβ<sub>42</sub> has core structural motif with phenylalanine at the 19 and 20 positions. The diphenylalanine (FF) residue plays a crucial role in the formation of amyloid fibers and serves as model peptide for studying Aβ<sub>42 </sub>aggregation. FF self-assembles to well-ordered tubular morphology via aromatic pi-pi stackings. Our studies, suggest that the aromatic rings present in the anti-amyloidogenic compounds may interact with the pi-pi stacking interactions present in the FF. Even the compounds which do not have aromatic rings, like cyclodextrin and cucurbituril show anti-amyloid property due to the binding of aromatic ring inside the guest cavity. Hence, our studies also suggest that compounds which may have a functional moiety capable of interacting with the aromatic stacking interactions might be tested for their anti-amyloidogenic properties. Further, in this manuscript, we have proposed two novel nanoparticle based assays for the rapid screening of amyloid inhibitors. In the first assay, interaction between biotin-tagged FF peptide and the streptavidin labelled gold nanoparticles (s-AuNPs) were used. In another assay, thiol-Au interactions were used to develop an assay for detection of amyloid inhibitors. It is envisaged that the proposed analytical method will provide a simple, facile and cost effective technique for the screening of amyloid inhibitors and may be of immense practical implications to find the therapeutic remedies for the diseases associated with the protein aggregation.


Inorganics ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 54
Author(s):  
Giacomo Manfroni ◽  
Simona S. Capomolla ◽  
Alessandro Prescimone ◽  
Edwin C. Constable ◽  
Catherine E. Housecroft

The isomers 4′-(4-(trifluoromethyl)phenyl)-4,2′:6′,4″-terpyridine (1), 4′-(3-(trifluoromethyl)phenyl)-4,2′:6′,4″-terpyridine (2), 4′-(4-(trifluoromethyl)phenyl)-3,2′:6′,3″-terpyridine (3), and 4′-(3-(trifluoromethyl)phenyl)-3,2′:6′,3″-terpyridine (4) have been prepared and characterized. The single crystal structures of 1 and 2 were determined. The 1D-polymers [Cu2(hfacac)4(1)2]n.2nC6H4Cl2 (Hhfacac = 1,1,1,5,5,5-hexafluoropentane-2,4-dione), [Cu(hfacac)2(2)]n.2nC6H5Me, [Cu2(hfacac)4(3)2]n.nC6H4Cl2, [Cu2(hfacac)4(3)2]n.nC6H5Cl, and [Cu(hfacac)2(4)]n.nC6H5Cl have been formed by reactions of 1, 2, 3 and 4 with [Cu(hfacac)2].H2O under conditions of crystal growth by layering and four of these coordination polymers have been formed on a preparative scale. [Cu2(hfacac)4(1)2]n.2nC6H4Cl2 and [Cu(hfacac)2(2)]n.2nC6H5Me are zig-zag chains and the different substitution position of the CF3 group in 1 and 2 does not affect this motif. Packing of the polymer chains is governed mainly by C–F...F–C contacts, and there are no inter-polymer π-stacking interactions. The conformation of the 3,2′:6′,3″-tpy unit in [Cu2(hfacac)4(3)2]n.nC6H4Cl2 and [Cu(hfacac)2(4)]n.nC6H5Cl differs, leading to different structural motifs in the 1D-polymer backbones. In [Cu(hfacac)2(4)]n.nC6H5Cl, the peripheral 3-CF3C6H4 unit is accommodated in a pocket between two {Cu(hfacac)2} units and engages in four C–Hphenyl...F–Chfacac contacts which lock the phenylpyridine unit in a near planar conformation. In [Cu2(hfacac)4(3)2]n.nC6H4Cl2 and [Cu(hfacac)2(4)]n.nC6H5Cl, π-stacking interactions between 4′-trifluoromethylphenyl-3,2′:6′,3″-tpy domains are key packing interactions, and this contrasts with the packing of polymers incorporating 1 and 2. We use powder X-ray diffraction to demonstrate that the assemblies of the coordination polymers are reproducible, and that a switch from a 4,2′:6′,4″- to 3,2′:6′,3″-tpy metal-binding unit is accompanied by a change from dominant C–F...F–C and C–F...H–C contacts to π-stacking of arene domains between ligands 3 or 4.


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