Solvent fluctuations in the solvation shell determine the activation barrier for crystal growth rates

Solution crystallization is a common technique to grow advanced, functional crystalline materials. Supersaturation, temperature, and solvent composition are known to influence the growth rates and thereby properties of crystalline materials; however, a satisfactory explanation of how these factors affect the activation barrier for growth rates has not been developed. We report here that these effects can be attributed to a previously unrecognized consequence of solvent fluctuations in the solvation shell of solute molecules attaching to the crystal surface. With increasing supersaturation, the average hydration number of the glutamic acid molecule decreases and can reach an asymptotic limit corresponding to the number of adsorption sites on the molecule. The hydration number of the glutamic acid molecule also fluctuates due to the rapid exchange of solvent in the solvation shell and local variation in the supersaturation. These rapid fluctuations allow quasi-equilibrium between fully solvated and partially desolvated states of molecules, which can be used to construct a double-well potential and thereby to identify the transition state and the required activation barrier. The partially desolvated molecules are not stable and can attach spontaneously to the crystal surface. The activation barrier versus hydration number follows the Evans–Polanyi relation. The predicted absolute growth rates of the α-glutamic acid crystal at lower supersaturations are in reasonable agreement with the experimental observations.

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Coverage dependent adsorption sites in the K/Cu(100) system: A crystal truncation rod analysis

Zeitschrift für Kristallographie - Crystalline Materials ◽

10.1524/zkri.1993.208.part-1.73 ◽

1993 ◽

Vol 208 (1) ◽

Cited By ~ 9

Author(s):

H. L. Meyerheim ◽

I. K. Robinson ◽

V. Jahns ◽

P. J. Eng ◽

W. Moritz

Keyword(s):

Crystal Surface ◽

High Coverage ◽

Adsorption Sites ◽

System A ◽

Crystal Truncation Rod ◽

Surface Crystal

AbstractThe analysis of the intensity along the diffraction rods normal to the crystal surface (crystal truncation rods) has been used to analyse the adsorption sites of potassium atoms adsorbed atAt high coverage (

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Examination of inequivalent wetting on the crystal habit surfaces of RS-ibuprofen using grid-based molecular modelling

Physical Chemistry Chemical Physics ◽

10.1039/c7cp08354h ◽

2018 ◽

Vol 20 (17) ◽

pp. 11622-11633 ◽

Cited By ~ 7

Author(s):

I. Rosbottom ◽

J. H. Pickering ◽

B. Etbon ◽

R. B. Hammond ◽

K. J. Roberts

Keyword(s):

Molecular Modelling ◽

Growth Rates ◽

Crystal Surface ◽

Surface Interactions ◽

Surface Growth ◽

Crystal Habit ◽

Grid Based

Novel grid-based searching of solvent/crystal-surface interactions to investigate solution wetting impact upon crystal surface growth rates.

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Microsecond Molecular Dynamics Simulations of Proteins Using a Quasi-Equilibrium Solvation Shell Model

Journal of Chemical Theory and Computation ◽

10.1021/acs.jctc.9b01072 ◽

2020 ◽

Vol 16 (3) ◽

pp. 1866-1881 ◽

Cited By ~ 2

Author(s):

Victor Ovchinnikov ◽

Simone Conti ◽

Edmond Y. Lau ◽

Felice C. Lightstone ◽

Martin Karplus

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Simulations ◽

Shell Model ◽

Solvation Shell ◽

Quasi Equilibrium ◽

Dynamics Simulations

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Adsorption of iron tetraphenylporphyrin on (111) surfaces of coinage metals: a density functional theory study

Beilstein Journal of Nanotechnology ◽

10.3762/bjnano.8.248 ◽

2017 ◽

Vol 8 ◽

pp. 2484-2491 ◽

Cited By ~ 3

Author(s):

Hao Tang ◽

Nathalie Tarrat ◽

Véronique Langlais ◽

Yongfeng Wang

Keyword(s):

Density Functional Theory ◽

High Spin ◽

Density Functional ◽

Activation Barrier ◽

High Spin State ◽

Coulomb Repulsion ◽

Functional Theory ◽

Adsorption Sites ◽

Intermediate Spin ◽

Magnetic States

The adsorption of the iron tetraphenylporphyrin (FeTPP) molecule in its deckchair conformation was investigated on Au(111), Ag(111) and Cu(111) surfaces by performing spin-polarized density functional theory (DFT) calculations taking into account both van der Waals (vdW) interaction and on-site Coulomb repulsion. The deckchair conformation of the molecule favours intermolecular π–π-type interactions in a less densely packed monolayer than the saddle conformation. The activation barrier between the two stable magnetic states (high spin, S = 2 and intermediate spin, S = 1) of the molecule in vacuum disappears upon adsorption on the metal surfaces. The high-spin state of physisorbed FeTPP is stable on all adsorption sites. This result reveals that an external permanent element such as a STM tip or an additional molecule is needed to use FeTPP or similar molecules as model system for molecular spin switches.

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Kinetic aspects of major and trace elements in olivines from variably cooled basaltic melts

10.5194/egusphere-egu2020-19696 ◽

2020 ◽

Author(s):

Sarah Lang ◽

Silvio Mollo ◽

Lyderic France ◽

Manuela Nazzari ◽

Valeria Misiti ◽

...

Keyword(s):

Boundary Layer ◽

Trace Elements ◽

Crystal Growth ◽

Cooling Rate ◽

Crystallization Kinetics ◽

Growth Rates ◽

Crystal Surface ◽

Major And Trace Elements ◽

Diffusive Boundary Layer ◽

Diffusive Boundary

<p>Olivine is an important mineral phase in naturally cooled basaltic rocks. The texture and composition of olivine are strictly related to the interplay between the degree of magma undercooling and crystal growth rate. Crystals formed at low undercoolings and growth rates generally show polyhedral-hopper textures and quite homogeneous compositions, while skeletal-dendritic textures and evident crystal zonations occur at high undercoolings and growth rates. In this context, we have performed equilibrium and disequilibrium (i.e., cooling rate) experiments to better understand, by a comparatively approach, the effects of crystallization kinetics on the incorporation of major and trace cations in olivine lattice. The experiments were carried out in a 1 atm vertical tube CO-CO2 gas-mixing furnace to perform experiment at atmospheric pressure and oxygen fugacity of QFM-2 using a basaltic glass (i.e., OIB) as starting materials. The equilibrium experiment was performed at 1175 &#176;C. These target temperatures were kept constant for 240 h and then quenched. Conversely, the disequilibrium experiments were performed at the superliquidus temperature of 1250, and 1300 &#176;C, which was kept constant for 2 h before cooling. The final target temperatures of 1150 (undercooling -&#916;T = 50 &#176;C), and 1175 &#176;C (-&#916;T = 25 &#176;C) were attained by applying cooling rates of 2 &#176;C/h, 20 &#176;C/h, and 60 &#176;C/h. Then the experimental charges were quenched. Results show that the olivine texture shifts from euhedral (i.e., equilibrium) to anhedral (i.e., disequilibrium) under the effect of cooling rate and rapid crystal growth. In equilibrium experiments, the composition of olivine is homogeneous and non chemical gradients are found in the melt next to the crystal surface. In contrast, a diffusive boundary layer develops in the melt surrounding the olivine crystals growing rapidly under the effect of cooling rate and degree of undercooling. The compositional gradient in the melt increases with increasing cooling rate and undercooling, causing the diffusive boundary layer to expand towards the far field melt. Because of the effects of crystallization kinetics, skeletal-dendritic olivines incorporates higher proportions of major and trace elements that are generally incompatible within their crystal lattice under equilibrium conditions.</p>

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Proton Magnetic Resonance Studies of Ionic Solvation in Ion-exchange Resins. Part III. Multivalent Counterions

Canadian Journal of Chemistry ◽

10.1139/v71-661 ◽

1971 ◽

Vol 49 (24) ◽

pp. 3948-3955 ◽

Cited By ~ 4

Author(s):

H. D. Sharma ◽

N. Subramanian

Keyword(s):

Ion Exchange ◽

Chemical Shifts ◽

Hydration Number ◽

Water Structure ◽

Ion Association ◽

Solvation Shell ◽

Ion Pair ◽

Ion Exchange Resins ◽

Long Range Ordering ◽

Exchange Resins

The p.m.r. spectra of Dowex AG 50W, X8, resins containing multivalent counterions have been measured. The ionic molal shifts in the exchanger phase are compared with those reported in homogeneous aqueous solutions. The spectral results are consistent with the concentrated electrolyte model of ion-exchange resins. Concentration and temperature dependence of proton chemical shifts in multivalent ionic forms of the resin suggests that ion association at high crosslinkages is more pronounced for counterions with high charge densities. The shapes of the shift-molality plots are explained by postulating that, at high crosslinkages, Mg2+ ion and the fixed —SO3− group form "contact-ion pair" while the formation of "solvent-separated ion pair" is important in Be2+ and Al3+ forms of the resin. The anomalous trend in the hydration number values for magnesium and aluminum resinates can be understood as due to the long-range ordering of water structure in the presence of structure-forming ions. The p.m.r. spectra of resin–methanol system have been recorded at room temperature and at −65 °C. Failure to observe the resonance signal due to the cationic solvation shell at low temperature is attributed to the high degree of ion association under the conditions prevailing in the resin medium.

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Cooperativity of Three Fragments : Protonated or Methylated Makaluvamine, Water Molecule and Glutamic Acid Molecule in Twelve Complexes and their Stabilities. A Study Performed at B3LYP/6-31+G(D,P) Level

Global Journal of Science Frontier Research ◽

10.34257/gjsfrbvol20is1pg1 ◽

2020 ◽

pp. 1-10

Author(s):

Soleymane Koné ◽

Sékou Diomandé ◽

El-Hadji Sawaliho Bamba

Keyword(s):

Water Molecule ◽

Glutamic Acid ◽

Density Functional ◽

Topoisomerase Ii ◽

Geometrical Parameters ◽

Acid Molecule ◽

Functional Theory ◽

Cancer Breast ◽

Total Interaction ◽

The Stability

Makaluvamines are used by intercalation in the DNA for the treatment of cancer cells such as colon cancer, prostate cancer, breast cancer.... This work studies energetic and geometrical parameters of stability of the 3-body complexes formed by six Makaluvamines, first protonated and then methylated by interactions with a water molecule and a glutamic acid molecule (Glu. Ac), a protein residue of topoisomerase II. This study was carried out by the quantum chemistry method of density functional theory (DFT). Firstly, we determined the energy of each super-molecule, the energies of all units of two fragments and one fragment in the geometries of the complexes. We have also determined the energies of 2-body and 3-body interaction, cooperativity, relaxation and total interaction. The results of these calculations helped to appreciate the rigidity of each fragment between the isolated and complex states. They also allowed knowing the stability of each complex and the contribution of each interaction term to this stability.

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FURTHER OBSERVATIONS ON THE SPECIFICITY OF THE FOLIC ACID MOLECULE

Blood ◽

10.1182/blood.v3.1.121.121 ◽

1948 ◽

Vol 3 (1) ◽

pp. 121-126 ◽

Cited By ~ 3

Author(s):

TOM D. SPIES ◽

GUILLERMO GARCIA LOPEZ ◽

ROBERT E. STONE ◽

FERNANDO MILANES ◽

ROBERT O. BRANDENBURG ◽

...

Keyword(s):

Folic Acid ◽

Glutamic Acid ◽

Blood Cells ◽

White Blood Cells ◽

Macrocytic Anemia ◽

The Body ◽

Acid Molecule ◽

Streptococcus Lactis ◽

Great Specificity ◽

Pteroic Acid

Abstract Methyl folic acid,2 N-(4-(4-quinazoline) amino) benzoyl)-glutamic acid, the Mg salt of formyl pteroyl glutamic acid, the Mg salt of formyl pteroic acid, pteroyl aspartic acid, oxyfolic acid and oxypteroic acid have been studied as to their effect on blood regeneration in selected cases of Addisonian pernicious anemia, nutritional macrocytic anemia and tropical sprue. In the amounts administered, only the Mg salt of formyl pteroyl glutamic acid was effective in producing reticulocytosis and an increase in red blood cells, hemoglobin, white blood cells and platelets, and it was not as effective per unit of weight as was folic acid per se. Presumably this compound is slowly changed into folic acid in the body. It is of special interest that the Mg salt of formyl pteroic acid (Streptococcus lactis factor) was negative in producing hemopoiesis. These observations show the very great specificity of the folic acid molecule.

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Phase transformation of calcium phosphates in the presence of glutamic acid

Canadian Journal of Chemistry ◽

10.1139/v11-032 ◽

2011 ◽

Vol 89 (7) ◽

pp. 885-891 ◽

Cited By ~ 3

Author(s):

Tim W. T. Tsai ◽

Wei-Ya Chen ◽

Yao-Hung Tseng ◽

Jerry C. C. Chan

Keyword(s):

Phase Transformation ◽

Calcium Phosphate ◽

Glutamic Acid ◽

Crystal Surface ◽

Calcium Phosphates ◽

Water Layer ◽

Octacalcium Phosphate ◽

Growth Direction ◽

Transformation Kinetics ◽

Transformation Pathway

This work describes a phase-transformation pathway of calcium phosphate in the presence of glutamic acid. The route follows the order starting from amorphous calcium phosphate and brushite, then octacalcium phosphate (OCP), and finally hydroxyapatite (HAp). The preferred growth direction of the intermediate OCP and the final HAp phases lies along the c axis. On the basis of our scanning electron microscopy, X-ray powder diffraction, and 31P solid-state NMR data, we suggest that the transformation is via the dissolution–reprecipitation process, which is facilitated in the presence of glutamic acid. The effect on the transformation kinetics is rationalized by the disruption of the water layer bound on the crystal surface.

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