A modular approach for molecular recognition by zinc dipicolinate complexes

2015 ◽  
Vol 44 (32) ◽  
pp. 14411-14423 ◽  
Author(s):  
Krapa Shankar ◽  
Alexander M. Kirillov ◽  
Jubaraj B. Baruah
Keyword(s):  
Molecular Recognition ◽  
Modular Approach ◽  
Guest Molecules

Recognition of 4-nitrophenol guest molecules by stacking and H-bonding interactions with a 4,4′-bipyridinium zinc dipicolinate host was found and investigated in detail.

The trisubstituted-triazole approach to extended functional naphthalocyanines

2011 ◽  
Vol 15 (09n10) ◽  
pp. 898-907 ◽  
Author(s):  
Michal Juríček ◽  
Kathleen Stout ◽  
Paul H.J. Kouwer ◽  
Alan E. Rowan
Keyword(s):  
Model System ◽  
Modular Approach ◽  
Core Size ◽  
Guest Molecules ◽  
Synthetic Routes ◽  
Atomically Flat

Recently, a novel modular approach to octatriazole-derived phthalocyanines (Pcs; 1) was developed and optimized in our group; herein, the pool of the functional Pc materials was expanded for an additional candidate (2), a fused derivative of 1. Compared with 1, the aromaticity in 2 is extended by an additional four benzene and eight triazole rings and, in addition, the triazole units and the Pc core co-create four functional, in-plane cavities. Various methods to link the unsubstituted carbon atoms of the neighboring triazoles in 1 to afford atomically flat naphthalocyanine (Nc) analogs (2), containing eight fused triazole moieties, were studied. Several synthetic routes were designed, among them the trisubstituted-triazole approach, which was found to be the most suitable route. The crucial steps of this approach, the copper-catalyzed azide-haloalkyne cycloaddition and the intramolecular homocoupling reactions, were first studied on a model system; subsequently, this methodology was applied in the synthesis of the desired Nc 2. The increased core size and the π-electron deficient structure predict this class of Ncs to possess very strong aggregation properties. Moreover, owing to the presence of four tridentate half-cavities, the final properties of the molecule or the assembly can, in principle, be further tuned by doping with metals or guest molecules.

scholarly journals Molecular recognition of N-acetyltryptophan enantiomers by β-cyclodextrin

2017 ◽  
Vol 13 ◽  
pp. 1572-1582 ◽  
Author(s):  
Spyros D Chatziefthimiou ◽  
Mario Inclán ◽  
Petros Giastas ◽  
Athanasios Papakyriakou ◽  
Konstantina Yannakopoulou ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Molecular Recognition ◽  
Aqueous Solutions ◽  
Crystalline State ◽  
Dimeric Complex ◽  
Nmr Studies ◽  
Guest Molecules ◽  
Crystallographic Order

The enantioselectivity of β-cyclodextrin (β-CD) towards L- and D-N-acetyltryptophan (NAcTrp) has been studied in aqueous solution and the crystalline state. NMR studies in solution show that β-CD forms complexes of very similar but not identical geometry with both L- and D-NAcTrp and exhibits stronger binding with L-NAcTrp. In the crystalline state, only β-CD–L-NAcTrp crystallizes readily from aqueous solutions as a dimeric complex (two hosts enclosing two guest molecules). In contrast, crystals of the complex β-CD–D-NAcTrp were never obtained, although numerous conditions were tried. In aqueous solution, the orientation of the guest in both complexes is different than in the β-CD–L-NAcTrp complex in the crystal. Overall, the study shows that subtle differences observed between the β-CD–L,D-NAcTrp complexes in aqueous solution are magnified at the onset of crystallization, as a consequence of accumulation of many soft host–guest interactions and of the imposed crystallographic order, thus resulting in very dissimilar propensity of each enantiomer to produce crystals with β-CD.

Synthesis of a Novel Hollow Sphere Having Rigid Binaphthyl Macrocycle as Shell

2007 ◽  
Vol 121-123 ◽  
pp. 219-222 ◽  
Author(s):  
Na Liu ◽  
Xing Wang ◽  
Hui Cao ◽  
Chun Hai Chen ◽  
Wan Jin Zhang
Keyword(s):  
Molecular Recognition ◽  
Hollow Sphere ◽  
Coupling Agent ◽  
Colloidal Silica ◽  
Hollow Spheres ◽  
Silica Particles ◽  
Important Class ◽  
Guest Molecules ◽  
Sem And Tem ◽  
Silica Core

A novel hollow sphere having rigid binaphthyl macrocycle as shell was prepared by means of sacrifice the silica core. The synthesis of hollow sphere from rigid colloidal silica particles occurs in three steps: a) modification of silica particles with vinyltriethoxysilane as coupling agent, b) immersion in the solution of monomer having rigid binaphthyl macrocycle and polymerization, and c) removal of silica particles. These macrocycles contained in the shell of hollow spheres belong to an important class of host-guest macrocyclic material in which the rigid backbone and C2 symmetry of the binaphthyl unit play an important role in complexing guest molecules. This will endow hollow sphere with new opportunities in molecular recognition and separation.The morphology of colloidal silica particles and hollow spheres was characterized by SEM and TEM.

scholarly journals Insights into molecular recognition from the crystal structures of p-tert-butylcalix[6]arene complexed with different solvents

IUCrJ ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Maura Malinska
Keyword(s):  
Molecular Recognition ◽  
Ethyl Acetate ◽  
Inclusion Complexes ◽  
Methyl Acetate ◽  
Crystal Packing ◽  
X Ray Diffraction ◽  
Polar Solvents ◽  
Guest Molecules ◽  
X Ray ◽  
Fill Percentage

Calixarenes are host molecules that can form complexes with one or more guest molecules, and molecular recognition in calixarenes can be affected by many factors. With a view to establishing molecular recognition rules, the host p-tert-butylcalix[6]arene (TBC6) was crystallized with different guest molecules (cyclohexane, anisole, heptane, toluene, benzene, methyl acetate, ethyl acetate, dichloromethane, tetrahydrofuran and pyridine) and the obtained structures were characterized by X-ray diffraction. With most solvents, 1:1 and/or 1:3 host–guest complexes were formed, although other stoichiometries were also observed with small guest molecules, and crystallization from ethyl acetate produced the unsolvated form. The calculated fill percentage of the TBC6 cavity was ∼55% for apolar guests and significantly lower for polar solvents, indicating that polar molecules can bind to apolar cavities with significantly lower packing coefficients. The most stable crystals were formed by 1:1 host–guest inclusion complexes. The ratio between the apolar surface area and the volume was used to predict the formation of inclusion versus exclusion complexes, with inclusion complexes observed at ratios <40. These findings allow the binding of potential guest molecules to be predicted and a suitable crystal packing for the designed properties to be obtained.

Self-Assembly of Gels through Molecular Recognition of Cyclodextrins: Shape Selectivity for Linear and Cyclic Guest Molecules

2011 ◽  
Vol 44 (8) ◽  
pp. 2395-2399 ◽  
Author(s):  
Hiroyasu Yamaguchi ◽  
Ryosuke Kobayashi ◽  
Yoshinori Takashima ◽  
Akihito Hashidzume ◽  
Akira Harada
Keyword(s):  
Molecular Recognition ◽  
Self Assembly ◽  
Shape Selectivity ◽  
Guest Molecules
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