Electrostatic Insights into the Molecular Hydration Process: A Case Study of Crown Ethers

Pingale, Shirish S.; Gadre, Shridhar R.; Bartolotti, Libero J.

doi:10.1021/jp982444b

Cited by 56 publications

(49 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…31 The shifted parallel geometry has EPIC interaction energy of −0.97 kcal/ mol, while for T-shaped it is −0.71 kcal/ mol. ͑2͒, using EPIC program.…”

Section: A Co 2 Homoclusters and The Effect On Asymmetric Stretchingmentioning

confidence: 99%

An ab initio investigation on (CO2)n and CO2(Ar)m clusters: Geometries and IR spectra

Jose

Gadre

2008

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

An ab initio investigation on CO(2) homoclusters is done at MPWB1K6-31++G(2d) level of theory. Electrostatic guidelines are found to be useful for generating initial structures of (CO(2))(n) clusters. The ab initio minimum energy geometries of (CO(2))(n) with n=2-8 are T shaped, cyclic, trigonal pyramidal, tetragonal pyramidal, tetragonal bipyramidal, pentagonal bipyramidal, and pentagonal bipyramid with one CO(2) molecule attached to it. A test calculation on (CO(2))(20) cluster is also reported. The geometric parameters of the energetically most favored (CO(2))(n) clusters match quite well their experimental counterparts (wherever available) as well as those derived from molecular dynamics studies. The effect of clustering is quantified through the asymmetric C-O stretching frequency shift relative to the single CO(2) molecule. (CO(2))(n) clusters show an increasing blueshift from 1.8 to 9.6 cm(-1) on increasing number of CO(2) molecules from n=2 to 8. The energetics and geometries of CO(2)(Ar)(m) clusters have also been explored at the same level of theory. The geometries for m=1-6 show a predominant T type of the argon-CO(2) molecule interaction. Higher clusters with m=7-12 show that the argon atoms cluster around the oxygen atom after the saturation of the central carbon atom. The CO(2)(Ar)(m) clusters exhibit an increasing redshift in the C-O asymmetric stretch relative to CO(2) molecule of 0.7-5.6 cm(-1) with increasing number of argon atoms through m=1-8.

show abstract

“…31 The shifted parallel geometry has EPIC interaction energy of −0.97 kcal/ mol, while for T-shaped it is −0.71 kcal/ mol. ͑2͒, using EPIC program.…”

Section: A Co 2 Homoclusters and The Effect On Asymmetric Stretchingmentioning

confidence: 99%

An ab initio investigation on (CO2)n and CO2(Ar)m clusters: Geometries and IR spectra

Jose

Gadre

2008

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

show abstract

“…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

View full text Add to dashboard Cite

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 ...

show abstract

“…This interaction energy is minimized by rotating and translating the guest molecule such that the van der Waals surfaces of the guest and the host do not interpenetrate. The EPIC model was applied successfully to many systems such as DNA base dimers and trimers [86], hydration of crown ether [87] and stacked and H-bonded cytosine dimer [88]. Previous studies performed in our laboratory generally demonstrated striking similarities between the geometries obtained from ab initio and EPIC calculations.…”

Section: Use Of Molecular Electrostatic Potential For Probing Lone Pamentioning

confidence: 79%

Understanding Lone Pair-π Interactions from Electrostatic Viewpoint

Gadre

Kumar

2015

Challenges and Advances in Computational Chemistry and Physics

Self Cite

View full text Add to dashboard Cite

Over the last two decades, studies on lone pair-π interaction have attracted lot of attention of experimental as well as theoretical chemists due to its intriguing nature and its suspected presence in biological systems. The present Chapter begins with a brief overview of the earlier theoretical and experimental work done in this area. This is followed by exploration of the nuances of bonding in lone pair-π interaction, employing the tool of molecular electrostatic potential (MESP) since such weak interactions are mainly dominated by electrostatic features of host and guest molecules. The critical points associated with the scalar field of MESP are exploited for scrutinizing the directionality and bonding sites involved in the lone pair-π complexes. Furthermore, the electrostatic potential for intermolecular complexation (EPIC) model developed by Gadre et al., has been employed for finding out the electrostatically optimized structures and interaction energies of these complexes. The outcomes of EPIC model are compared with the results obtained from quantum chemical calculations of the complexes employing M06L/6-311++G(d,p) level of theory. The present study details out four different cases of lone pair-π complexes, which are currently in vogue. Hexafluorobenzene, one of the most explored π -deficient host in the present context, is initially taken up to demonstrate various facets of MESP for gaining insights into this interaction. This is followed by the scrutiny of special classes of recently synthesized highly π -deficient molecules, viz. tetraoxacalix [2]arene[2]triazine and naphthalenediimide, which are known to have specificity and large affinity, respectively, towards the electron rich species. The chapter ends with the description of lone pair-π interaction in the case of urate oxidase, an enzyme present in biological systems.

show abstract

Electrostatic Insights into the Molecular Hydration Process: A Case Study of Crown Ethers

Cited by 56 publications

References 60 publications

An ab initio investigation on (CO2)n and CO2(Ar)m clusters: Geometries and IR spectra

An ab initio investigation on (CO2)n and CO2(Ar)m clusters: Geometries and IR spectra

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

Understanding Lone Pair-π Interactions from Electrostatic Viewpoint

Contact Info

Product

Resources

About