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.

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.

scholarly journals Alkyl substituted 4-pyrrolidinopyridinium salts encapsulated in the cavity of cucurbit[10]uril

2019 ◽  
Vol 43 (18) ◽  
pp. 7028-7034 ◽  
Author(s):  
Weitao Xu ◽  
Ming Liu ◽  
Mary Clare Escaño ◽  
Carl Redshaw ◽  
Bing Bian ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Aqueous Solution ◽  
Nmr Spectroscopy ◽  
Absorption Spectroscopy ◽  
Electronic Absorption ◽  
Electronic Absorption Spectroscopy ◽  
H Nmr ◽  
Pyridinium Nitrogen

The interaction between cucuribit[10]uril (Q[10]) and a series of 4-pyrrolidinopyridinium salts bearing aliphatic substituents at the pyridinium nitrogen, namely 4-(C4H8N)C5H5NRBr, where R = Et (g1), n-butyl (g2), n-pentyl (g3), n-hexyl (g4), n-octyl (g5), n-dodecyl (g6), has been studied in aqueous solution by 1H NMR spectroscopy, electronic absorption spectroscopy and mass spectrometry.

Complexations of the hydrophilic and hydrophobic moieties of benzethonium chloride by cucurbit[7]uril in aqueous solution

2012 ◽  
Vol 90 (10) ◽  
pp. 851-857 ◽  
Author(s):  
Brendan C. MacGillivray ◽  
Donal H. Macartney
Keyword(s):  
Mass Spectrometry ◽  
Aqueous Solution ◽  
Nmr Spectroscopy ◽  
Stability Constant ◽  
Guest Molecule ◽  
Ionization Mass ◽  
H Nmr ◽  
Benzethonium Chloride ◽  
End Groups ◽  
Initial Binding

The sequential complexations of the hydrophilic and hydrophobic end groups of benzethonium chloride by cucurbit[7]uril (CB[7]) in aqueous solution have been investigated using 1H NMR spectroscopy and electrospray ionization mass spectrometry. The initial binding is to the benzyldimethylammonium group, with a stability constant of (8.7 ± 3.1) × 107 (mol/L)–1. This binding constant and the complexation-induced upfield shifts of the benzyl guest protons are similar to those values observed with other cationic guests containing benzyl moieties. This equilibrium is followed by the binding of a second equivalent of the host to the hydrophobic 2-(2,4,4-trimethylpentyl) group, with a stability constant of (4.0 ± 1.9) × 103 (mol/L)–1. The relatively strong binding of this uncharged hydrophobic end of the guest molecule is consistent with the inclusion of eight heavy (nonhydrogen) atoms within the inner cavity of CB[7], with its low polarizability. The packing coefficient for the 2-(2,4,4-trimethylpentyl) group with the inner cavity is calculated to be 61%, close to Rebek’s ideal value of 55%.

Chemie polyfunktioneller Liganden, 69 [1] Über drei Organo-Arsen-Käfigverbindungen mit Noradamantanstruktur / Chemistry of Polyfunctional Ligands, 69 [1] Three Organo-Arsenic Cage Compounds with Noradamantane Structure

1981 ◽  
Vol 36 (12) ◽  
pp. 1532-1537 ◽  
Author(s):  
Jochen Ellermann ◽  
Martin Lietz
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Cage Compounds ◽  
H Nmr ◽  
New Compounds

Abstract The reaction of l.l.l-tris(diiodarsinomethyl)ethane, CH3C(CH2Asl2)3 (1), with H2C(COOC2H5)2, H2C(COOCH3)2 and H2C(COC6H5)2 in presence of the auxiliary base (C2H5)3N gives the noradamantane structured compounds CH3C(CH2As)3E2 [E=C(COOC2H 5)2 (2), C(COOCH3)2 (3) and C(COC6H5)2 (4)].The new compounds have been characterized by mass spectrometry and infrared, Raman and 1H NMR spectroscopy.

scholarly journals Where Are the tpy Embraces in [Zn{4′-(EtO)2OPC6H4tpy}2][CF3SO3]2?

Crystals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 461 ◽  
Author(s):  
Davood Zare ◽  
Alessandro Prescimone ◽  
Edwin C. Constable ◽  
Catherine E. Housecroft
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Electrospray Mass Spectrometry ◽  
Stacking Interactions ◽  
Adjacent Pair ◽  
Single Crystal Structures ◽  
Π Stacking ◽  
Multinuclear Nmr Spectroscopy ◽  
Packing Interactions

In this paper, the bromo- and phosphonate-ester-functionalized complexes [Zn(1)2][CF3SO3]2 and [Zn(2)2][CF3SO3]2 (1 = 4′-(4-bromophenyl)-2,2′:6′,2″-terpyridine, 2 = diethyl (4-([2,2′:6′,2″-terpyridin]-4′-yl)phenyl)phosphonate) are reported. The complexes have been characterized by electrospray mass spectrometry, IR and absorption spectroscopies, and multinuclear NMR spectroscopy. The single-crystal structures of [Zn(1)2][CF3SO3]2.MeCN.1/2Et2O and [Zn(2)2][CF3SO3]2 have been determined and they confirm {Zn(tpy)2}2+ cores (tpy = 2,2′:6′,2″-terpyridine). Ongoing from X = Br to P(O)(OEt)2, the {Zn(4′-XC6H4tpy)2}2+ unit exhibits significant “bowing” of the backbone, which is associated with changes in packing interactions. The [Zn(1)2]2+ cations engage in head-to-tail 4′-Phtpy...4′-Phtpy embraces with efficient pyridine...phenylene π-stacking interactions. The [Zn(2)2]2+ cations pack with one of the two ligands involved in pyridine...pyridine π-stacking; steric hindrance between one C6H4PO(OEt)2 group and an adjacent pair of π-stacked pyridine rings results in distortion of backbone of the ligand. This report is the first crystallographic determination of a salt of a homoleptic [M{4′-(RO)2OPC6H4tpy}2]n+ cation.

Formation and hydrolysis of polynuclear Th(IV) complexes – a nano-electrospray mass-spectrometry study

2008 ◽  
Vol 96 (7) ◽  
Author(s):  
C. Walther ◽  
M. Fuss ◽  
S. Büchner
Keyword(s):  
Mass Spectrometry ◽  
Aqueous Solution ◽  
Electrospray Mass Spectrometry ◽  
Mass Spectrometry Study ◽  
Hydrolysis Of

Polynuclear hydroxide complexes play an important role for the hydrolysis of tetravalent thorium ions in aqueous solution, in particular for Th(IV) concentrations exceeding some [Th(IV)]=10

Rhodium(I)–(N-heterocyclic carbene)–diphosphine complexes

2009 ◽  
Vol 87 (9) ◽  
pp. 1248-1254 ◽  
Author(s):  
Hongsui Sun ◽  
Xiao-Yan Yu ◽  
Paolo Marcazzan ◽  
Brian O. Patrick ◽  
Brian R. James
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Elemental Analysis ◽  
Benzene Solution ◽  
H Nmr ◽  
Diphosphine Dioxide

Reactions of [RhCl(COE)(IPr)]2 (1) and [RhCl(COE)(IMes)]2 (2) (COE = cyclooctene; IPr = N,N′-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene; IMes = N,N′-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene) with the diphosphines Ph2P(CH2)nPPh2 and 1,2-bis(diphenylphosphino)benzene (dppbz) give the N-heterocyclic carbene (NHC) – diphosphine – rhodium(I) complexes: RhCl(NHC)[Ph2P(CH2)nPPh2] [NHC = IPr, n = 1 (3); NHC = IMes, n = 1 (4); NHC = IPr, n = 2 (5); NHC = IMes, n = 2 (6); NHC = IPr, n = 4 (7); NHC = IMes, n = 4 (8)] and RhCl(NHC)(dppbz) [NHC = IPr (9); NHC = IMes (10)]. All the complexes are characterized by 1H, 31P{1H}, and 13C{1H} NMR spectroscopy, elemental analysis, and mass spectrometry. Complexes 3, 7, and 9 are also characterized crystallographically. In benzene solution, the complexes decompose in the presence of O2 with formation of the diphosphine dioxide, whereas reaction with CO leads to replacement of the NHC ligand to give known carbonyl–diphosphine complexes.

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.

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