Proton schematic representation

Fig. 3. Mechanisms for polymer degradation. The illustration is a schematic representation of three degradation mechanisms I, cleavage of cross-links II, hydrolysis, ionisa tion, or protonation of pendent groups III, backbone cleavage. Actual biodegradation may be a combination of these mechanisms.

Figure 12.17 Schematic representation of proton-switch conduction mechanism involving [U2PO4I phosphoric acid.

Figure 5.34 Schematic representation of the coupling interactions of the H, and Hf, protons of Klibromobenzene. The H and protons are split into double doublets due to their couplings with //j and is split into a triplet by the two...

Figure 6.3 Schematic representation of the resolution advantages of 3D NMR spectroscopy, (a) Both pairs of protons have the same resonance frequency, (b) Due to the same resonance frequency, both pairs exhibit overlapping crosspeaks in the 2D NOESY spectrum, (c) When the frequency of the carbon atoms is plotted as the third dimension, the problem of overlapping is solved, since their resonance frequencies are different. The NOESY cross-peaks are thus distributed in different planes.

Figure 15.2 Schematic representation of different electrochemical cell types used in studies of electrocatalytic reactions (a) proton exchange membrane single cell, comprising a membrane electrode assembly (b) electrochemical cell with a gas diffusion electrode (c) electrochemical cell with a thin-layer working electrode (d) electrochemical cell with a model nonporous electrode. CE, counter-electrode RE, reference electrode WE, working electrode.

Fig. 27. A schematic representation of the seven transmembrane helical peptide chains (A-G) viewed from inside the cell. The numbering denotes the first and last amino acid residues. The proton channel is believed to be the volume between helices C, D, F and G...

Figure 1 Schematic representation of the 13C (or 15N) spin-lattice relaxation times (7"i), spin-spin relaxation (T2), and H spin-lattice relaxation time in the rotating frame (Tlp) for the liquid-like and solid-like domains, as a function of the correlation times of local motions. 13C (or 15N) NMR signals from the solid-like domains undergoing incoherent fluctuation motions with the correlation times of 10 4-10 5 s (indicated by the grey colour) could be lost due to failure of attempted peak-narrowing due to interference of frequency with proton decoupling or magic angle spinning.

Fig. 1. Schematic representation of a Gdm complex with one inner sphere water molecule, which is the origin of the inner sphere contribution to proton relaxivity. The complex is surrounded by bulk water, giving rise to the outer sphere relaxation mechanism.

Fig. 25. Protonation and ligand dissociation mechanism for 0-TRENSOX (26) (176). (A) Four-step hydrolysis mechanism of O-TRENSOX where Q represents 8-hydroxyquinolyl and S the corresponding salicylate coordinating moiety. Charge on the complex has been omitted for clarity. (B) Schematic representation of the salicylate shift of the 8-hydroxyquinolyl donor groups of O-TRENSOX.

A number of factors must be taken into account when the diagrammatic representation of mixed proton conductivity is attempted. The behavior of the solid depends upon the temperature, the dopant concentration, the partial pressure of oxygen, and the partial pressure of hydrogen or water vapor. Schematic representation of defect concentrations in mixed proton conductors on a Brouwer diagram therefore requires a four-dimensional depiction. A three-dimensional plot can be constructed if two variables, often temperature and dopant concentration, are fixed (Fig. 8.18a). It is often clearer to use two-dimensional sections of such a plot, constructed with three variables fixed (Fig. 8.18h-8.18<7). 

Figure 8.18 Schematic representation of defect concentrations in mixed proton conductors on a Brouwer diagram (a) three-dimensional plot with two variables fixed (b)-(d) two-dimensional plots with three variables fixed.

Figure 8.6 Schematic representation of the newly developed proton-transfer polymerization as a route to hyperbranched polymers [27]...

Schematic representation of the various reaction modes for the dissolution of Fe(III)(hydr)oxides a) by protons b) by bidentate complex formers that form surface chelates. The resulting solute Fe(III) complexes may subsequently become reduced, e.g., by HS c) by reductants (ligands with oxygen donor atoms) such as ascorbate that can form surface complexes and transfer electrons inner-spheri-cally d) catalytic dissolution of Fe(III)(hydr)oxides by Fe(II) in the presence of a complex former e) light-induced dissolution of Fe(III)(hydr)oxides in the presence of an electron donor such as oxalate. In all of the above examples, surface coordination controls the dissolution process. (Adapted from Sulzberger et al., 1989, and from Hering and Stumm, 1990.)...

Figure 2.5 Schematic representation of the Au/MPS/PAH-Os/solution interface modeled in Refs. [118-120] using the molecular theory for modified polyelectrolyte electrodes described in Section 2.5. The red arrows indicate the chemical equilibria considered by the theory. The redox polymer, PAH-Os (see Figure 2.4), is divided into the poly(allyl-amine) backbone (depicted as blue and light blue solid lines) and the pyridine-bipyridine osmium complexes. Each osmium complex is in redox equilibrium with the gold substrate and, dependingon its potential, can be in an oxidized Os(lll) (red spheres) or in a reduced Os(ll) (blue sphere) state. The allyl-amine units can be in a positively charged protonated state (plus signs on the polymer...

Fig. 11. Schematic representation showing the network of mobile protons close to a negatively charged Gd(III) complex bound to a protein.

The COSY spectrum shows which pairs of protons in a molecule are coupled to each other. The COSY speetrum is a symmetrieal speetrum that has the NMR spectrum of the substanee as both of the chemical shift axes (Fi and F2). A schematic representation of COSY spectmm is given below. 

The HSC spectrum is the heteronuclear analogue of the COSY spectrum and identifies which protons are coupled to which carbons in the molecule. The HSC spectrum has the NMR spectrum of the substance on one axis (F2) and the i C spectrum (or the spectrum of some other nucleus) on the second axis (Fi). A schematic representation of an HSC spectrum is given below. It is usual to plot a normal (one-dimensional) H NMR spectmm along the proton dimension and a normal (one-dimensional) C NMR spectmm along the C dimension to give reference spectra for the peaks that appear in the two-dimensional spectmm. 

Scheme 2.2 Schematic representation of a proton-jumping molecular system with fast enol-enolic equilibrium between structures la and lb.

FIG. 5. Schematic representation of the orbital overlap between the chromium d, v orbital and the ligand protons Ha and Hb for oxo-Cr(V) complexes of 6 (left) and 7 (right). 

Fig. 12.1 Schematic representation of the consecutive steps of dissolution by protonation of a M " oxide. In the lower part the activation energy, Eg, levels of the corresponding steps are shown (Stumm Furrer, 1987, with permission).

Fig. 11. Proposed schematic representation of the swiveling movement of helices in the Fq portion of ATP synthase. Since deprotonation of the Asp-61 residue can only occur at the periphery of the c-rotor at the a-c interface, twisting and swiveling of the helices composing the c subunits is caused by the rotation of the c-rotor. Since all protonated c subunits are identical, untwisted (protonated) c subunit helices should twist when the c-rotor rotates as a result of proton binding and unbinding during ATP synthesis...

Figure 1 Schematic representation of the geometrical parameters for the [HjN-H-NHst ion. The reaction coordinatefor the proton transfer is defined as = l/2[Ri-RJ.

Figure 9. (a) Schematic representation of the five-module format of a photoactive triad which is switchable only by the simultaneous presence of a pair of ions. This design involves the multiple application of the ideas in Figure 1. The four distinct situations are shown. Note that the presence of each guest ion in its selective receptor only suppresses that particular electron transfer path. The mutually exclusive selectivity of each receptor is symbolized by the different hole sizes. All electron transfer activity ceases when both guest ions have been received by the appropriate receptors. The case is an AND logic gate at the molecular scale. While this uses only two ionic inputs, the principle established here should be extensible to accommodate three inputs or more, (b) An example illustrating the principles of part (a) from an extension of the aminomethyl aromatic family. The case shown applies to the situation (iv) in part (a) where both receptors are occupied. It is only then that luminescence is switched "on". Protons and sodium ions are the relevant ionic inputs.

Figure 13. Schematic representations of the geometries of host-guest complexes, (a) Two possible geometries of the host-guest complex between calix[6jarene hexaester (29) and a protonated primary amine guest, (b) Plausible geometry of the host-guest complex between dibenzo-18-crown-6 (32) and a protonated primary amine guest...

Fig. 2.7 Schematic representation of electrochemical processes (reduction) for organic solids able to experience coupled proton transport/electron transport processes...

Schematic representation of hot hydrogen burning via the CNO tricycle. Branching is shown for four different temperatures designated using the symbol T9, which means 10 9 K. Widths of arrows are proportional to reaction rate. At temperatures >10 8 K, the proton reaction rates on 13C, 150,17F, and 1SF begin to compete effectively with the (,p+ v) reactions. Isotopes such as 13C and 1SN are bypassed and a different equilibrium is established. If this equilibrium is quenched, such as in a nova explosion, the unstable nuclei p-decay to their respective stable daughters, resulting in low 12C/13C and 14N/15N, and 12C/160 can be greater than one, very different from the outcome of normal CNO burning. After Champaign and Wiescher (1992).

Fig. 7. 112. Schematic representation of the first and second (rate-determining) steps of the mechanism of the evolution of 02 on perovskites, involving a series of proton transfers. (Reprinted from J. O M. Bockris and T. Ottagawa, J. Phys. Chem. 87 2964,1983.)...

Figure 6.1 Schematic representations of a general neutron-nucleus potential and a proton...

Figure 4. Schematic representation of proton relaxation rates as function of frequencies. No measurements were made in the 0.1 MHz range which is between the domain of the Tlp and Tt techniques.

Figure 1. Schematic representation of solvent effect on proton transfer from naphthols.

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