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Dihydrogen Oxide. That means… 2 hydrogens And one oxygen! Aka: Water, aka: H “two” O. All Behavior from Simple Geometry. Electronic Properties. 10 electrons completely filling the valence shell Hydrogens donate their electrons to the more electronegative Oxygen
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Dihydrogen Oxide That means… 2 hydrogens And one oxygen! Aka: Water, aka: H “two” O
Electronic Properties • 10 electrons completely filling the valence shell • Hydrogens donate their electrons to the more electronegative Oxygen • Oxygen has two lone pairs that make a tetrahedral arrangement with the Hydrogens below • The bond character is “resonant”, i.e. a mixture of ionic and covalent character • Overall dipole moment of 1.86 Debye. • * 1 Debye = 10−18 esu centimeter or about 3.336 × 10−30 coulomb meters
Strange Temperature Dependence • When Cold water (~ 0 ̊ C) is increasing temperature
Strange Temperature Dependence • When Hot Water is increasing temperature: There is a completely opposite effect
Anomalous behavior(not predictable from Group 6A [i.e. H2S] and Group 4A [i.e. CH4] hydrides)
Continuing Anomalous behavior • Expansion upon Freezing!
17 polymorphs of H2O as IceSee http://www.lsbu.ac.uk/water/phase.html
Potential of hydrogen bonding • The potential as a function of distance between two 4-molecule tetramers of water • First minimum is from non-bonded interactions. Second is highly directional in nature Thus, low-T H-bonded water networks hold molecules apart as well as provide a strong geometry. More of these types of polymers follow.
Pretty pictures of these molecular structures (one of highest possible symmetries in nature) Icosahedron symmetries 15 2-fold axes 10 3-fold axes 6 5-fold axes Faces are: 12 regular pentagons 20 regular triangles 30 rectangles Cyclic pentamer Bicyclo-octamer Tricyclo-decamer
Icosahedra predicted……and found! • Proposed by: M. F. Chaplin, A proposal for the structuring of water, Biophys. Chem.83 (2000) 211-221. • Found from X-ray diffraction of water nanodrops by: A. Müller, H. Bögge and E. Diemann, Structure of a cavity-encapsulated nanodrop of water, Inorg. Chem. Commun.6 (2003) 52-53; Corrigendum: A. Müller, H. Bögge and E. Diemann, Inorg. Chem. Commun.6 (2003) 329 • The calculations with the collapsed and extended structures of the icosahedral states can predict: temperature-density and pressure-viscosity behavior, the radial distribution pattern of Oxygen-Oxygen distances, the presence of both cyclic pentamers and hexamers, the change in properties on supercooling and the solvation and hydration properties of ions, hydrophobic molecules, carbohydrates and macromolecules.
Vibrational Modes and Absorption SpectraMost likely the most relevant to material discussed in this class…
Some absorption notes… • Blue hue of water due to least absorption of blue frequencies… • Infrared peaks would be most notable in contribution to biophysical processes since all living organisms maintain autonomous thermodynamic work cycles at temperatures corresponding to the liquid phase of water. • Farther below the scale of the plot is the microwave absorption spectrum which primarily interacts with the dipole moment of the water molecule. Energy loss as friction provides the heat generated in your microwave. • Note: The absorption spectra maintained in this figure and in the following numbers is for bulk water. Some spectra calculations for nanoscale droplets will follow.
Nanoscale droplets(may have far reaching consequences for biological molecules since water is ubiquitous and often is present within proteins) Plot of absorption coefficient in droplets at specific radii of micelles (water droplets stabilized in heptane by surfactant sodium bis(2-ethylhexyl) sulfosuccinate {AOT}) -Smallest micelles show absorption coefficient ~8 times that of bulk water.
This plot is the calculated Density of Modes as a function of frequency a) R = 2 nm, b) R = 5 nm, c) R = 9 nm Arrow signifies cutoff from Surface Modes. This plot shows measured Peak absorption frequency and the solid line is the expected absorption due to dominant surface modes. As micelle size decreases, the water pool radius drops and the water inside becomes more structured. This internal structure seems to be providing the large absorption.
The integrated absorption strength of the measured spectra as a function of water pool radius. The authors write: “It should be noted that narrow well-resolved resonances are almost unprecedented in far-infrared liquid-state spectroscopy. These observations have important implications for any chemical, biological, or catalytic processes in which sequestered water plays a role. Since solvent vibrations are crucial in determining the rates of many chemical reactions, these results raise the intriguing possibility that the design of certain active biomolecular subunits may be optimized to exploit the enhanced vibrational density of states induced by the confinement.” J. Boyd, A. Briskman, V. Colvin, and D. Mittleman, Phys. Rev. Lett. 87, 147401(2003)
Protein-Water Simulations inconclusive and not worth including • Several papers currently published suggesting that hydrogen-bond dynamics are correlated with protein structural relaxation… ummm… yeah. • If we restrict the water molecules, proteins respond similar to dehydration. • Complete structural relaxation necessitates relaxation of the hydrogen-bond network. This is known to occur relative to Acid-Base chemistry (pH dependence on folding). Note to self: Acid-Base chemistry doesn’t exist without water. • One paper in particular used Molecular Dynamics Simulations starting with RNase in a crystal at 100, 150, 200, 250, and 300K. Also included was a powder with slight hydration at 300K. M. Tarek and D.J. Tobias, Phys. Rev. Lett. 88, 138101(2002)
Reactive Oxygen Species • Necessary for Respiration in Mitochondria, BUT… only a little! Large numbers can create chains of causal reactions creating more and more reactive species breaking down structures of nearby proteins. • Some of these reactive species are :
Outside of Hypochlorite, All ROS are simple Hydrogen and Oxygen inclusive molecular ions. • It is known that ROS may be created in Water through its homolytic dissociation from a mild impetus such as streaming, filtration, sonication, microwave irradiation, etc. • Considering the spatio-temporal locations of specific biochemical reactions within a cell, it is not implausible to suggest that the typical approach to the analysis of ROS dependent processes is flawed considering the basis of average concentration.
Last but Not LEAST… The present belief of causation of Biological Processes Key-Keyhole interactions… Quantitative Structure Activity Relationship (QSAR) A slowly evolving belief of potential causation of Biological Processes EM signal interactions… Aren’t all processes outside of nuclear interactions QED?
Water Memory and Homeopathy Back in 1988… Benveniste published results of an experiment in which he tried homeopathy. The Facts: • A type of human white blood cell, polymorphonuclear basophils with antibodies of the immunoglobulin E (IgE) type on its surface , release histamine upon engaging anti-IgE antibodies. • From calculated dilutions from 102 through 10120, over that range, there are successive peaks of degranulation front 40 to 60% of the basophils, despite the calculated absence of any anti-IgE molecules at the highest dilutions. • Upon publishing his findings, he was expelled from his professorship and funding was withdrawn.
Since that Time… • Benveniste has continued his research and is publishing his findings in the FASEB Journal • His most recent claim is that he can have a solution of a biochemical that causes a specific phenomena, wrap a copper loop with a white noise signal played into it, record the signal with a second copper loop onto any data recording device, then take that signal, play into a second sample of pure water with another partnered White noise signal, shake vigorously, and reveal the same effect on biological function that the solution in the first sample caused. Science is still attempting to resolve the issue from 1988, and one taker, namely, Professor Madeleine Ennis of Queen's University Belfast is suggesting that Benveniste’s original results were correct. She is conducting a similar basophil activation using 4 labs spread across Europe that are receiving “ghost” solutions of an antibody produced in 3 completely separate labs. A final independent researcher who coded the solutions and collated the data though having no part in the testing and analysis to prevent any bias whatsoever. Her Result: Histamine solutions, both at pharmacological concentrations and diluted out of existence, lead to statistically significant inhibition of basophile activation by aIgE, confirming previous work in this area.
Summary • Water is Life… Without its anomalous behavior, Life can potentially be negated. • Water is weird… But apparently all due to hydrogen-bonding and its subsequent networks. • Vibrational modes of water still under investigation yet not quite accounted for in protein dynamics. • Reactive Oxygen Species still a burgeoning child of BioPhysics thanks to the discovery of electron and proton transport in ATP synthase. Water will surely play a role in the evolution of this subject. • Homeopathy still neglected by most, under investigation by others and blindly swallowed by many, BUT, true scientific evidence is being gathered now. • An unbiased eye is necessary for true interpretation of water’s role in Life.