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October 9th-12th, 2014 Pamporovo, BULGARIA The influence of the magnetic field on the kinetic of the chemical reaction Antonella De Ninno ENEA – Italian National Agency for New Technologies, Energy and Sustainable Economic Development October 9th -12th, 2014 Pamporovo, BULGARIA Summary 1. The supra-molecular structure of liquid water 2. Non-isolated systems out of equilibrium 3. The effect of weak magnetic field on hydration of molecules 4. Low Energy/matter exchanges in aqueous systems Models of liquid water Röngten: floating low density clusters in high density matrix Robinson: domains of different density. The mixture model provides for the specific volume the simple expression: Bernal and Fowler : the revenge of the thermodynamics Linus Pauling: the idea of hydrogen bond Stanley and Teixeira the concept of infinite connected network or gel In the last decades a great number of Molecular Dynamics (MD) simulations have been carried on these bases. V ( p, T ) f ( p, T )VI ( p, T ) 1 f ( p, T )VII ( p, T ) Philippa Wiggins and Martin Chaplin extended this two phase liquid concept to room temperature water in terms of: Low Density Water LDW is the hydrating water around cell membranes and DNA double helix and High Density Water HDW is the “bulk” water. Electrodynamic coherence Later on, the existence of water in two different populations made up by molecules having different degree of mutual correlation has been demonstrated according to first principles: it can be proved that when the temperature T is lower than a critical T crit and the density N is higher than a critical Ncrit an ensemble of particles is subjected to a collective coherent oscillation between a couple of internal levels of its components, thus generating a collective behaviour. These collective behaviour is responsible for the long-range forces which account for the actual existence of the condensed state. Water represents a remarkable example of such a general principle: at room temperature a dynamical superposition of two populations, Fc , Fnc of coherent and non-coherent molecules is thereby established, depending on temperature. According to this view, each atom or molecule belongs to one of the two fractions in a dynamical sense, i.e. it fluctuates between a coherent and a non-coherent state with a characteristic time life ~ 5·10-15 sec. The coherent fraction represents the lowest energy, ordered state while the non coherent fraction is populated by monomers and dimers such as the gas phase. The vibrational spectra of liquid water can be easily interpreted in agreement with this theory . Very recent time-resolved optical Kerr effect investigation (pub, on Nature Comm.) have shown the evidence of the coexistence of two local configuration, interpreted as high density and low density water form from ambient to supercooled conditions Non-isolated systems out of equilibrium Nanoaggregates – Alexander Konovalov EZ water – Jerry Pollack Aquaphotomics – Roumiana Tsenkova Stable aggregates of water at room temperature – Vittorio Elia … Actually, we know that the Temperature is not the only parameter influencing the fraction of coherent population: Temperature (“ab initio” calculations) Contact with surfaces (Pollack, Konovalov, Tsenkova) Exchange of low amount of mechanical energy with the environment (Elia) Electromagnetic fields (will see in the following) Water • • • Gases are fully non coherent systems Liquids are systems where electron clouds are coherent Solids are systems where nuclei, too, are coherent • Liquid water is peculiar, since the coherent oscillation connects two electronic configurations that have extreme features: F (T ) F (T ) 1 1) The ground configuration where all electrons are tightly bound (the ionization potential is 12.60 eV, corresponding to soft X-rays and to an excitation temperature ofc145.000 °C !) nc 2) The excited configuration has an energy E=12.06 eV, only 0.54 eV below the ionization threshold. So for each molecule there is an almost free electron! Ө Ө Ө Ө Ө Ө Ө Ө Ө Ө Ө Ө ( ) r ( ) i i ( ) Let’s have a look on the surface of solutes in water, or, what is the same on a wet surface. Negatively charged surface ( ) r ( ) i i ( ) Positively charged surface The general theory of the Van der Waals Forces (1961) The basic idea of the theory is that the interactions between nonpolar bodies is considered to take place through a fluctuating electro magnetic field. These fluctuations are all the spectral components which have wavelengths large compared to the atomic dimensions. All the properties of these long wavelength fluctuations, are completely specified through the complex dielectric permeability of the body. The only limitation is that all the characteristic dimensions of the bodies must be large compared to the inter-atomic distances. Thus it applies to the macromolecules involved in the biological reactions. Forces between two bodies separated by a medium depend on the dielectric constant of 1, 2 of the two bodies and 3 of the medium which fills the gap d<l l ~ 1-2 mm l 1 2 l characterize the absorption spectrum of the body F (d ) 8 d 2 3 d 1 (i ) 3 (i ) 2 (i ) 3 (i ) d (i ) 3 (i ) 2 (i ) 3 (i ) 0 1 Suppose that both bodies are sufficiently rarefied. From the point of view of macroscopic electrodynamics this means that their dielectric permeability are close to 1. We obtain the classical London formula (1930) 3 1 3 e4 U (d ) 2 6 2m d f1 (1 ) f 2 2 0 0 12 1 2 d1d2 Attraction and repulsion depend on the medium which fills the gap It has to be noted that if the two bodies differ and the medium between them is water the interaction can be either an attraction or a repulsion: If 1 3 and 2 3 have opposite sign then F < 0 and the bodies will repel each other. If 1 3 and 2 3 have the same sign then F > 0 and the bodies will attract for “large” separation, the forces are determined by the electrostatic values of the dielectric constants. Two atoms in water (Pitaevskii, 1959) Weak solution of N1 and N2 atoms in the same solvent Gap filled with pure water For small concentrations the dielectric permeabilities ε1 and ε2 differ little from that of pure solvent ε3= ε 1 i 2 i 1 F ( R) N1 N 2 d 2 3 2 32 R N1 N 10 N 2 N 20 i 0 This force corresponds to an interaction energy of the dissolved atoms equal to: 1 i 2 i 1 U ( R) d 3 6 2 16 R 0 N1 N 10 N 2 N 20 i 3 We see that when the dissolved molecules interact strongly with the solvent the interaction forces between them are no longer determined by their polarizability but depend on the dielectric constant of the solvent ! Static dielectric constant Dielectric properties of water (T ) Fcoh (T ) coh (T ) Fnoncoh (T ) noncoh (T ) exp T 298 K 79 experimental value calc T 298K 12 non interacting dipoles coh T 0 K 160 coherent domains * with respect to the wavelength of the em fluctuation large distances * Aqueous solutions used by Prof. Konovalov ‘s group have typical absorption line in their spectrum in the range of 200-600 nm. Hence, whenever the average distance among particles exceed such a length the following formula holds 23 c 1 1 N 0 2 U (d ) ( ) N 0 3 3 7 64 R 2 N 0 Energy is decreased by the formation of aggregates of coherent water having a higher static dielectric constant (Konovalov nanoaggregates) The magnetic field may protect the pile-up of the energy aligning the magnetic dipoles associated to the CDs thus stabilizing the aggregates. Average distance less than l 200/400 nm depending on the substances Average distance greater than l 200/400 nm depending on the substances The observed stable nano objects have a size of hundreds of nanometers which is in the same range of the wavelength characteristic of the spectrum of the solute. We suggest that whenever the dilution exceed a certain threshold where the average distance among solutes d ≫ l water Coherent Domains gather to form a mesoscopic region in order to decrease the free energy of the system. Stable water cluster may have a permanent electric charge (ζpotential) due to the quasi-free electrons at the border of the CDs. In bulk water such a feature cannot be observed because the lifetime of a CD is too short (10-15 sec) We are talking about the arrangement of extended structures formed by the water coherent domains and the solutes. It is also possible that their collective vibrations could become coherent due to the principle of minimization of energy, this implies that water shift its oscillation frequency or (what is the same) its energy gap. Experimental hints: Blu shift of the IR spectrum of EZ water aquaphotomics Water permittivity short distances Hic sunt leones ! (here are the lions!) * with respect to the wavelength of the em fluctuation * A film of water on the surface of a solid body (EZ water) The chemical potential of the film per unit volume of the liquid is: m 8 R 2 F (i w ( ), i s ( )) 3 For “large” thickness m ( R) is proportional to R-4 with a coefficient depending on the electrostatic dielectric constants of the film and of the solid surface solid water The function may change sign and be non-monotonic according to the sign of the difference ( w s ) Open the way for a theory for EZ water Permittivity vs frequency at 25°C for Nafion 117 ( coh Nafion ) ( noncoh Nafion ) The collective vibration of dangling charges (SO 3- sulfonic groups) of the surface and of the coherent water molecules could become coherent (blue shift) in order to further reduce the energy of the system water + Nafion 0 0 Dielectric constant 160 Nafion Dielectric constant 12 Non coherent molecules can enter into the Nafion structure. After a threshold of hydration they are attracted toward the surface Nafion Nafion acts as a phase separator EZ water The effect of weak magnetic field on hydration of molecules FTIR spectra of aqueous solution of L-phe Phenylalanine Exposure to a static magnetic field 1 Gauss – 30 minutes pH pK a log unprotonatedform(base) protonatedform(acid ) pKa1 = 2.88± 0.03 MAGNETIC FIELD pKa1 = 3.31± 0.04 TheDexposure of L-Phe to the magnetic field has an effect similar =+0.43 to the exposure to NIR radiation, which is known to cause significant changes in the hydration properties of such molecules. 1 pKa2= 9.51±0.04 MAGNETIC FIELD pKa2= 9.41±0.04 D2=-0.1 H 2O modifications aggregation pKa shift The unusual property of EDTA is its ability to chelate or complex metal ions in 1:1 metal-to-EDTA complexes C r ( H O ) E D T A C r ( E D T A ) 6 H O 3 4 2 6 a q . a q . Classic form (H4y) EDTA l i q . a q . 2 Cr-EDTA Following the formation of the complex via the UV-vis spectroscopy Two cuvettes C1 and C2. To the C2 cuvette have been applied two permanent, rare earth oxides, magnets having dimensions 52 x 13x 7 mm. The magnitude of the field is 2800±100 Gauss inside the cuvette. Absorbance at l = 540.0 nm of the EDTA-Cr(III) complex. Kinetic of formation of EDTA-Cr (III) complex: difference in the absorbance of exposed – not exposed samples. Kinetic data, available in the literature, show that the rate constant for the reaction is accelerated with increasing the EDTA: concentration, pH, temperature, decreasing ionic strength and dielectric constant of the reaction medium These results point towards an associative mechanism supported by the decrease of enthalpy and a large negative entropy for substitution of water by ligand compared to water exchange. Substitution of water by a ligand 1 D H 5 7 . 2 3 K J m o l 1 D S 1 2 8 8 J K m o l Water exchange 1 D H 1 0 9 . 6 K J m o l 1 D S 1 2 J K m o l The much higher entropy gain of the reaction implies a larger scale ordering realized in the construction of the complex The magnetic field increases the kinetic constant affecting the ordered structures of water molecules surrounding the hydrophobic chains. It increases the fraction of non coherent molecules available for the substitution of water by a ligand. The energy of the system water + solute is decreased. Other experimental reports 1. Very High field: 10T 1. 2. High field: 6T 1. 3. Refraction index increases of 0.1% (Hosoda et al.- J. of Phys Cem A, 2004, 108, 1461) Modifications when O2 is dissolved: Raman bands, contact angle, electrolytic potential (Otsuka and Ozeki – J. of Phys Chem B Lett 2006,110,1509-1512) Low field: 45-65 mT 1. Vaporization enthalpy increases 2. Viscosity increases 3. Surface tension increases (Toledo et al. – J. of Mol Struct 2008, 888, 409-425) Energy/matter exchanges in aqueous systems The spontaneous evolution of the system is influenced by the environment (temperature, energy exchange, magnetic field). In general it can be said that a system doesn’t reach the thermodynamic equilibrium unless the system is isolated. This principle is valid not only for the living matter but also for the inanimate one. These considerations have been the basis of the experimental work of an Italian chemist, Giorgio Piccardi, in the ‘50s. we suggest that water is the medium in which these exchanges at very low energy occur. Thank you for your attention