The Nature of K+/Crown Ether Interactions: A Hybrid Quantum Mechanical-Molecular Mechanical Study

Thompson, M. A.; Glendening, Eric D.; Feller, David

doi:10.1021/j100092a015

Cited by 185 publications

(151 citation statements)

References 33 publications

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“…21,22 On the other hand, in recent years, hydration of the crown ether molecules and complexes has been also studied by both the theoretical [23][24][25][26][27][28][29][30][31] and experimental [32][33][34][35][36][37] approaches, but most of these studies were in aqueous solution. Studies concerning hydration in the wet-organic solvents for the crown ether system are scarce.…”

Section: Introductionmentioning

confidence: 99%

Hydration to Benzo-15-crown-5, Benzo-18-crown-6 and the Benzo-18-crown-6-Potassium Ion Complex in the Low-Polar Organic Solvents

2001

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The water in the organic solvents sometimes exerts quite a large effect on the equilibria, the existing state and the structure of solutes. [1][2][3][4][5][6][7][8][9][10] Particularly, in the solvent extraction study, since the solutes in the water-saturated organic solution are discussed, hydration of the solutes in the organic phase is a very important subject. It has been demonstrated that the water molecules are coextracted with the metal ions, 11-14 the metal complexes, [14][15][16][17] and the inorganic anions 2,3,[18][19][20] into the organic solvents, and the mean hydration numbers of these solutes in the organic phase were determined.There have been numerous studies about the ion-pair extraction of the crown ether complexes; extractability and selectivity of the metal ions have been discussed by using the overall extraction equilibrium constant and its component equilibrium constants. 21,22 On the other hand, in recent years, hydration of the crown ether molecules and complexes has been also studied by both the theoretical 23-31 and experimental [32][33][34][35][36][37] approaches, but most of these studies were in aqueous solution. Studies concerning hydration in the wet-organic solvents for the crown ether system are scarce.Iwachido et al. 14 reported on the hydration number of the alkali and alkaline earth metal ions and of those complexes with several crown ethers or cryptands in the water-saturated NB. We reported on the hydration number of the alkali metal ions and barium ion complexes with the non-cyclic poly-(oxyethylene) compounds (POE compounds) or 18-crown-6 (18C6) in the water-saturated 1,2-DCE. 17 However, the information for hydration in the wet-organic solvents for the crown ether system is still insufficient, and particularly information is lacking about hydration in various organic solvents. Therefore, in this study, we have investigated the coextraction of water with B15C5, B18C6 and the B18C6-K + complex into seven relatively low-polar solvents which are usually employed for the extraction study of crown ethers. The mean hydration number and hydration equilibrium in the solvents saturated with water are discussed. Experimental ReagentsB15C5 and B18C6 were purchased from Tokyo Kasei, and were used without further purification. Organic solvents (Wako Pure Chemicals): CTC, CF, DCM, 1,2-DCE, BZ, CB and o-DCB, were washed three times with distilled water. Potassium picrate was prepared from its hydroxide and picric acid (Wako), and was recrystallized twice from distilled water. Other chemicals were of analytical reagent grade. ProcedureFor distribution of free crown ethers, a portion of an organic solution (20 ml) containing B18C6 (0 -0.06 mol dm -3 ) or B15C5 (0 -0.1 mol dm -3 ) was shaken with an equal volume of water in a centrifuge tube (50 ml) in a thermostated water bath for 1 h at 25.0 ± 0.1˚C. After centrifugation, the water concentration of the organic phase was determined by the coulometric Karl-Fischer titration (Kyoto Electronics MKC-210).For distribution of potassium picrate ...

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Section: Introductionmentioning

confidence: 99%

Hydration to Benzo-15-crown-5, Benzo-18-crown-6 and the Benzo-18-crown-6-Potassium Ion Complex in the Low-Polar Organic Solvents

2001

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“…The high negative value of entropy of activation is suggestive of associative mechanism being observed. This mechanism is further confirmed from the molecular modelling method in which the energy as well as the heat of formation of the zwitterionic form and protonated form has been calculated [14][15][16][17][18]. Values of the energies as well as heat of formation were calculated after optimizing the geometry of the molecules.…”

Section: Ni(ii)-d-22-(ethylenediimino)-di-1-butanol Complexationmentioning

confidence: 84%

A Kinetic Studies of Interaction of Ni(II) with d-2,2-(Ethylenediimino)-di-1-butanol

Sharma¹,

Malhotra²,

Sharma³

2018

Asian J. Chem.

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The complexation kinetics between Ni(II) with d-2,2-(ethylenediimino)-di-1-butanol has been investigated at 25, 30, 35 and 40 ± 0.05 °C in the pH range 6.18-7.41 using Aminco Morrow stopped flow spectrophotometer. The ionic strength was maintained at 0.1 M KNO3. The anionic form of d-2,2-(ethylenediimino)-di-1-butanol is more reactive and the protonated form interacts only to a small extent. Kinetic results indicate that the ligand is not involved in the rate determining step which is, in fact, associated with the release of a water molecule from the shell of the metal ions prior to complexation with the ligand. Enthalpy, entropy of activation, energy of the molecule and heat of formation were also calculated. A mechanism consistent with the kinetic data has been suggested.

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“…Computational models capable of reliably predicting ligand selectivity in a variety of cations have been shown to be valuable tools for the advancement of practical works. [26][27][28][29] …”

Section: Resultsmentioning

confidence: 99%

Application of pyridine-2-carbaldehyde-2-(4-methyl-1,3-benzo thiazol-2-yl)hydrazone as a neutral ionophore in the construction of a novel Er(III) sensor

Ganjali¹,

Rezapour²,

Rasoolipour³

et al. 2007

J. Braz. Chem. Soc.

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A piridina-2-carbaldeído-2-(4-metil-1,3-benzotiazol-2-il) hidrazona (PCMHT) pode ser usada como um ionóforo neutro apropriado à preparação de uma membrana sensora a Er(III), com alta seletividade. A composição ótima encontrada foi PCMHT-PVC-KTpClPB-BA com as razões de 6,0:30,0:5,0:59,0 . A excelente seletividade a Er(III) do sensor proposto, frente aos íons metálicos mais comuns e, especialmente íons lantanídeos, é uma outra vantagem. O sensor foi usado com sucesso como eletrodo indicador na titulação de 25 mL de 1,0 × 10 -4 mol L -1 de íons Er(III) com 1,0 × 10 -2 mol L -1 de EDTA. O sensor proposto foi usado na monitoração direta de Er(III) em misturas binárias e na determinação indireta de íons fluoreto em duas preparações de enxágüe bucal.We found that pyridine-2-carbaldehyde-2-(4-methyl-1,3-benzothiazol-2-yl) hydrazone (PCMHT) can be used as a suitable neutral ionophore for preparing an Er(III) membrane sensor with high selectivity. The optimum composition was found to be PCMHT-PVC-KTpClPB-BA with the ratios of 6.0:30.0:5.0:59.0, respectively. The Nernstian response was of 21.8 ± 0.5 mV decade -1 of Er(III) activity, the linear range of the sensor was found to be relatively wide (from 1.0×10 -5 to 1.0 ×10 -2 mol L -1). Its applicability pH range of 2.5-12.0 seems to make it suitable for analytical applications. EDTA. The proposed sensor was used for direct monitoring of Er(III) in binary mixtures and indirect determination of fluoride ions in two mouth wash preparations.

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The Nature of K+/Crown Ether Interactions: A Hybrid Quantum Mechanical-Molecular Mechanical Study

Cited by 185 publications

References 33 publications

Hydration to Benzo-15-crown-5, Benzo-18-crown-6 and the Benzo-18-crown-6-Potassium Ion Complex in the Low-Polar Organic Solvents

Hydration to Benzo-15-crown-5, Benzo-18-crown-6 and the Benzo-18-crown-6-Potassium Ion Complex in the Low-Polar Organic Solvents

A Kinetic Studies of Interaction of Ni(II) with d-2,2-(Ethylenediimino)-di-1-butanol

Application of pyridine-2-carbaldehyde-2-(4-methyl-1,3-benzo thiazol-2-yl)hydrazone as a neutral ionophore in the construction of a novel Er(III) sensor

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