Dynamic Aspects in Host-Guest Interactions. 3. Kinetics and Mechanism of Molecular Recognition by Hexakis(2,6-di-O-methyl)-.alpha.-cyclodextrin of Some Azo Guest Molecules

1995 ◽  
Vol 99 (11) ◽  
pp. 3671-3677 ◽  
Author(s):  
Noboru Yoshida ◽  
Yuji Fujita
Keyword(s):  
Molecular Recognition ◽  
Kinetics And Mechanism ◽  
Guest Molecules

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.

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

scholarly journals Towards the sequence-specific multivalent molecular recognition of cyclodextrin oligomers

2014 ◽  
Vol 10 ◽  
pp. 2428-2440 ◽  
Author(s):  
Michael Kurlemann ◽  
Bart Jan Ravoo
Keyword(s):  
Molecular Recognition ◽  
Titration Calorimetry ◽  
Biological Processes ◽  
Sequence Specificity ◽  
New Materials ◽  
Guest Molecules ◽  
Binding Motifs ◽  
Specific Recognition ◽  
Recognition Motifs ◽  
Complementary Binding

Sequence-specific multivalent molecular recognition has been recognized to play a major role in biological processes. Furthermore, sequence-specific recognition motifs have been used in various artificial systems in the last years, e.g., to emulate biological processes or to build up new materials with highly specific recognition domains. In this article, we present the preparation of cyclodextrin (CD)-based strands and complementary and non-complementary strands modified with guest molecules and the investigation of their complexation behavior towards each other by isothermal titration calorimetry (ITC). As complementary binding motifs n-butyl and α-CD and adamantane and β-CD were selected. It was found that it is possible to realize sequence-specific molecular recognition by the use of host–guest chemistry, but the recognition motifs as well as the linkages have to be chosen very carefully. In the case of trivalent systems one adamantane moiety must be included to induce preferred formation of 1:1 adducts. Due to the too weak interaction between n-butyl and α-CD these systems have a negative chelate cooperativity and open adducts are preferentially formed. As soon as two adamantane moieties are present, the complementary systems have a positive chelate cooperativity and double-stranded structures are favored over open adducts. In this system the n-butyl moiety provides insufficient discrimination towards α- and β-CD and no sequence specificity is observed. By the combination of three adamantane moieties sequence specificity can be generated. Exclusively with the complementary CD sequence double-stranded structures are formed, with non-complementary strands aggregates of higher stoichiometry are generated.

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