scholarly journals Host-Guest Complexations of Amine Boranes and Isoelectronic/Isostructural Quaternary Alkylammonium Cations by Cucurbit[7]uril in Aqueous Solution

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Mona A. Gamal-Eldin ◽  
Donal H. Macartney
Keyword(s):  
Aqueous Solution ◽  
Hydrophobic Effect ◽  
Host Molecule ◽  
Guest Complex ◽  
H Nmr ◽  
Hydrophobic Cavity ◽  
Host Guest Complex ◽  
Dipole Interactions ◽  
The Stability ◽  
Amine Boranes

The host-guest complexation of six amine boranes (R3NBH3) by the macrocyclic host molecule cucurbit[7]uril (CB[7]) in aqueous solution has been investigated using 1H and 11B NMR spectroscopy. The limiting complexation-induced 1H and 11B chemical shift changes indicate that the amine boranes are included in the hydrophobic cavity of the host molecule. The host-guest stability constants for neutral  R3NBH3∙CB[7]  complexes (in the range of 105-107M-1) have been determined by 1H NMR competition experiments and are compared with the corresponding values for the isoelectronic/isostructural  R3NCH3∙CB[7] + complexes. Ammonia borane (H3NBH3) does not form a host-guest complex with CB[7]. The trends in the host-guest stability constant with the guest molar volume are examined, and the stability is ascribed to the hydrophobic effect (packing coefficient) and quadrupole-dipole interactions.

Cucurbit[7]uril host-guest complexes with cationic bis(4,5-dihydro-1H-imidazol-2-yl) guests in aqueous solution

2006 ◽  
Vol 84 (6) ◽  
pp. 905-914 ◽  
Author(s):  
D Saroja N Hettiarachchi ◽  
Donal H Macartney
Keyword(s):  
Mass Spectrometry ◽  
Aqueous Solution ◽  
Nmr Spectroscopy ◽  
Stability Constants ◽  
Electrospray Mass Spectrometry ◽  
Hydrophobic Core ◽  
Guest Complex ◽  
H Nmr ◽  
Host Guest Complex ◽  
Proton Resonances

The host–guest interactions between cucurbit[7]uril and a series of novel cationic bis(4,5-dihydro-1H-imidazol-2-yl)arene and 1-(4,5-dihydro-1H-imidazol-2-yl)- and 1,3-bis(4,5-dihydro-1H-imidazol-2-yl)-adamantane guests have been investigated in aqueous solution using UV–vis and NMR spectroscopy, and electrospray mass spectrometry. With the exception of the 1,3-bis(4,5-dihydro-1H-imidazol-2-yl)adamantane (which binds externally to the CB[7]), these guests form very stable inclusion complexes with slow exchange on the 1H NMR timescale. The direction and magnitude of the complexation-induced shifts (CIS) in the proton resonances of the guests are indicative of the residence of the hydrophobic core of the guest within the CB[7] cavity and the charged 4,5-dihydro-1H-imidazol-2-yl units outside the cavity adjacent to the carbonyl-lined portals of the host. The CIS values and the inclusion stability constants have been correlated with the nature of the guest core and with the distance between the charges on the terminal 4,5-dihydro-1H-imidazol-2-yl rings.Key words: cucurbit[7]uril, host–guest complex, dihydroimidazolyl, inclusion stability constants.

Cucurbit[7]uril host−guest complexations of steroidal neuromuscular blocking agents in aqueous solution

2014 ◽  
Vol 92 (3) ◽  
pp. 243-249 ◽  
Author(s):  
Mona A. Gamal-Eldin ◽  
Donal H. Macartney
Keyword(s):  
Aqueous Solution ◽  
Neuromuscular Blocking ◽  
Neuromuscular Blocking Agents ◽  
Host Molecule ◽  
Reversal Agent ◽  
H Nmr ◽  
Blocking Agents ◽  
Dipole Interactions ◽  
Neuromuscular Blockade Reversal ◽  
Esi Mass Spectrometry

The complexations of three steroidal neuromuscular blocking agents, rocuronium, vecuronium, and pancuronium, by the cucurbit[7]uril host molecule have been investigated in aqueous solution using 1H NMR spectroscopy and ESI mass spectrometry. The CB[7] binds to each of the two terminal cationic N-heterocyclic groups by means of ion-dipole interactions and hydrophobic effects, with stability constants in the order of vecuronium > pancuronium > rocuronium. This trend is different from those observed for the anionic substituted γ-cyclodextrin (Sugammadex), currently employed as a neuromuscular blockade reversal agent, and an acylic glycoluril tetramer (Calabadion), recently reported to reverse both steroidal and benzylisoquinolium neuromuscular blocking agents in rats.

Study on the Supramolecular Interaction of Dibenzoyl Peroxide(BPO) and ß-Cyclodextrin(ß-CD) by Spectrophtometry and its Analytical Application

2012 ◽  
Vol 554-556 ◽  
pp. 27-30
Author(s):  
Hui Xie ◽  
Yan Min Wang
Keyword(s):  
Aqueous Solution ◽  
Complex Formation ◽  
Benzoic Acid ◽  
Supramolecular Interaction ◽  
Guest Complex ◽  
Host Guest Complex ◽  
Molecule Recognition ◽  
Excellent Selectivity ◽  
Principal Advantage ◽  
Dibenzoyl Peroxide

The supramolecular interaction of BPO and ß-CD has been studied by spectrophtometry. The mechanism of the inclusion was studied. The results showed that ß-CD react with BPO to form a 2:1 or 1:1 host-guest complex.The ß-CD reacts with benzoic acid to form a 1:1 host-guest complex after the BPO was reduced by hydroxyl ammonium chloride.Based on the enhancement of the absorbance of BPO produced through complex formation, a spectrophotometric method for determination BPO in bulk aqueous solution in the presence of ß-CD was developed. A linear relationship between the absorbance and BPO concentration was obtained in the range of 0.2～50 μg.ml-1. The proposed method was used to determine the BPO in the flour with satisfactory results. The principal advantage of the proposed method is its excellent selectivity based on molecule recognition of ß-CD and simple.

Host-Guest Complexation of Aromatic Carboxylic Acids and their Conjugate Bases by β-Cyclodextrins Monosubstituted at C 6 by Linear and Cyclic Alkyl Triamines in Aqueous Solution

1999 ◽  
Vol 52 (12) ◽  
pp. 1157 ◽  
Author(s):  
Suzanna D. Kean ◽  
Bruce L. May ◽  
Philip Clements ◽  
Christopher J. Easton ◽  
Stephen F. Lincoln
Keyword(s):  
Aqueous Solution ◽  
Carboxylic Acid ◽  
Complex Stability ◽  
Guest Complex ◽  
Acid Complex ◽  
K Value ◽  
Host Guest Complex ◽  
Ph Range ◽  
Conjugate Bases ◽  
Significant Factors

A pH titrimetric study of the complexation of the guests benzoic acid, 4-methylbenzoic acid and (R)- and (S)-2-phenylpropanoic acids and their conjugate bases by the host 6A-[2-(2-aminoethylamino)ethylamino]-, 6A-[3-(3-aminopropylamino)propylamino]-, 6A-(1,4,7-triazacyclononan-1-yl)-, and 6A-(1,5,9-triazacyclododecan-1-yl)-6A-deoxy-β-cyclodextrins (βCDdien, βCDdipn, βCDtacn and βCDtacdo, respectively) is reported. Over the pH range 3.0–11.0, 49 host–guest complexes were detected. Their stability constants (K) range from 220±50 dm3 mol–1 for the βCDdienH22+ ·benzoate– complex to 48000±11000 dm3 mol–1 for the βCDdipnH22+·(S)-2-phenylpropanoic acid complex at 298.2 K and I = 0.10 mol dm–3 (NaClO4). The latter K value is among the highest reported for a complex of a simple carboxylic acid with a substituted β-cyclodextrin. The charge, hydrophobicity and stereochemistry of both host and guest appear to be significant factors in the variation of host–guest complex stability. 1H ROESY n.m.r. studies of some of the complexes formed are also reported.

Molecular Tweezer and Clip in Aqueous Solution:  Unexpected Self-Assembly, Powerful Host−Guest Complex Formation, Quantum Chemical1H NMR Shift Calculation

2006 ◽  
Vol 128 (14) ◽  
pp. 4831-4841 ◽  
Author(s):  
Frank-Gerrit Klärner ◽  
Björn Kahlert ◽  
Anke Nellesen ◽  
Jan Zienau ◽  
Christian Ochsenfeld ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Complex Formation ◽  
Self Assembly ◽  
Guest Complex ◽  
Host Guest Complex ◽  
Molecular Tweezer ◽  
Shift Calculation

scholarly journals Water-soluble host–guest complexes between fullerenes and a sugar-functionalized tribenzotriquinacene assembling to microspheres

2020 ◽  
Vol 16 ◽  
pp. 2551-2561
Author(s):  
Si-Yuan Liu ◽  
Xin-Rui Wang ◽  
Man-Ping Li ◽  
Wen-Rong Xu ◽  
Dietmar Kuck
Keyword(s):  
Electron Microscopy ◽  
Driving Force ◽  
Hydrophobic Effect ◽  
Binding Constants ◽  
Hydrophobic Surface ◽  
Water Soluble ◽  
Visible Spectroscopy ◽  
Guest Complex ◽  
Host Guest Complex ◽  
Scanning Electron

A sugar-functionalized water-soluble tribenzotriquinacene derivative bearing six glucose residues, TBTQ-(OG) 6 , was synthesized and its interaction with C60 and C70-fullerene in co-organic solvents and aqueous solution was investigated by fluorescence spectroscopy and ultraviolet-visible spectroscopy. The association stoichiometry of the complexes TBTQ-(OG) 6 with C60 and TBTQ-(OG) 6 with C70 was found to be 1:1 with binding constants of K a = (1.50 ± 0.10) × 105 M−1 and K a = (2.20 ± 0.16) × 105 M−1, respectively. The binding affinity between TBTQ-(OG) 6 and C60 was further verified by Raman spectroscopy. The geometry of the complex of TBTQ-(OG) 6 with C60 deduced from DFT calculations indicates that the driving force of the complexation is mainly due to the hydrophobic effect and to host–guest π–π interactions. Hydrophobic surface simulations showed that TBTQ-(OG) 6 and C60 forms an amphiphilic supramolecular host–guest complex, which further assembles to microspheres with diameters of 0.3–3.5 μm, as determined by scanning electron microscopy.

β-Cyclodextrin Based Nanosponges in Organic Synthesis

2020 ◽  
Vol 23 (21) ◽  
pp. 2366-2377
Author(s):  
Ali R. Kiasat ◽  
Seyyed J. Saghanezhad ◽  
Samaneh Noori
Keyword(s):  
Drug Delivery ◽  
Aqueous Solution ◽  
Organic Synthesis ◽  
Flame Retardants ◽  
3D Structure ◽  
Gas Storage ◽  
Hydrophilic Surface ◽  
Guest Complex ◽  
Smart Fabrics ◽  
Host Guest Complex

The particular β-cyclodextrin 3D structure, with its hydrophilic surface and apolar cavity, has enabled to partially or totally encapsulate hydrophobic molecules of appropriated size and shape in aqueous solution as well as in solid-state through the formation of a reversible host–guest complex. Accordingly, β-cyclodextrin based nanosponges have been prepared and used in previous years for the synthesis of organic compounds. In this review, we are going to mention some of the recent reports on the application of β- cyclodextrin 3D nanosponges in organic synthesis catalysis. Furthermore, it should be mentioned that these compounds have also been utilized for numerous applications including drug delivery, gas storage, rubber manufacture, diagnostics, cosmetics, agriculture, smart fabrics, water purification, and flame retardants.

High-affinity host–guest complex of cucurbit[7]uril with a bis(thiazolium) salt

RSC Advances ◽  
2015 ◽  
Vol 5 (69) ◽  
pp. 56110-56115 ◽  
Author(s):  
Shengke Li ◽  
Xiaoqing Miao ◽  
Ian W. Wyman ◽  
Ye Li ◽  
Ying Zheng ◽  
...  
Keyword(s):  
Guest Complex ◽  
High Affinity ◽  
Host Guest Complex ◽  
The Stability

The stability of a bis(thiazolium) dication was improved upon inclusion by cucurbit[7]uril, as demonstrated by the slowed-down C(2)-H/D exchange.

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