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Property relationships cyclic

In conclusion, a variety of linear or cyclic oligo(phospholes)s and their derivatives are accessible via a set of efficient synthetic strategies. The potential of these compounds as advanced 71-conjugated systems is broadened by the presence of reactive trivalent P-centres, which allow a range of additional chemical modifications to be achieved. However, elucidation of structure-property relationships for these derivatives is still needed. [Pg.134]

If [A/R] = H, then the subset R c /f is cyclic over M. This is a dual relationship between the properties of cyclicity for an algebra and those of separation for the commutant. Thus, the following conditions are equivalent ... [Pg.388]

DMA is a very useful thermoanalytical tool for studying the structure-property relationship versus performance of polymeric materials. The important information concerning relaxation transitions occurring on a molecular scale can be derived by subjecting polymers to a small amplitude cyclic deformation. Data obtained over a broad temperature range help to understand the influence of one polymer on the properties of another polymeric component... [Pg.165]

Concerning the radii of g)nation of PDMS, determined by means of SANS, a ratio good solvent. All these experimental results are in good agreement with an early theoretical treatment of stmcture-property relationships of cyclic polymers. [Pg.21]

In this article, we illustrate the theory and practice of food polymer science by highlighting the development and technological applications of a polymer characterization method, based on low temperature DSC, to analyze the structure-physicochemical property relationships of linear, branched, and cyclic mono-, oligo-, and polysaccharides. These studies have demonstrated the major opportunity offered by this food polymer science approach to expand not only our quantitative knowledge but also, of broader practical value, our qualitative understanding of the structure-function relationships of such carbohydrates in a wide variety of food products and processes. [Pg.221]

The first full study on the strueture-property relationships of 2,2 -bis-(benzo[b]phosphole), (9), and 2,2 -benzo[b]phosphole-benzo[b]heterole hybrid Tt-systems (10), (11), (12), (13), and (14) has been reported. The structure-property relationships of all the benzo[b]phosphole derivatives were investigated by using X-ray crystallography, UV-visible absorption and fluorescence spectroscopy, cyclic voltammetry, fluorescence lifetime measurements, and DFT/B3LYP/6-31G calculations. The steady-state UV-visible absorption and fluorescence spectroscopy, fluorescence lifetime measurements, and DFT theoretical calculations of the non-fused and acetylene-fused benzo[b]phosphole-benzo[b]heterole 7t-systems showed that their emissive excited states consist of two different conformers in rapid equilibrium. A novel 6/s(azidophenyl)phosphole sulfide (15) was developed to yield phosphole-containing 7t-conjugated systems by a... [Pg.418]

Derive the tc-MO patterns for these three molecules by treating them as derivatives of the three-, five-, and seven-membered cyclic conjugated systems. Explain the relationship between the derived MO pattern and the observed properties and stabilities of the molecules. [Pg.548]

Quinoxalin-2-ones are in tautomeric equilibrium with 2-hydroxy-quinoxalines, but physical measurements indicate that both in solution and in the solid state they exist as cyclic amides rather than as hydroxy compounds. Thus quinoxalin-2-one and its A -methyl derivative show practically identical ultraviolet absorption and are bases of similar strength. In contrast, the ultraviolet spectra of quinoxalin-2-one and its 0-methyl derivative (2-methoxyquinoxaIine) are dissimilar. The methoxy compound is also a significantly stronger base (Table II). Similar relationships also exist between the ultraviolet absorption and ionization properties of 3-methylquinoxalin-2-one and its N- and 0-methyl derivatives. The infrared spectrum of 3- (p-methoxy-benzyl)quinoxalin-2-one (77) in methylene chloride shows bands at 3375 and 1565 cm" which are absent in the spectrum of the deuterated... [Pg.229]

Basic Properties of Sulfosuccinate Diesters It is very difficult to establish general structure-function relationships for the sulfosuccinate diesters, although they are very similar in structure and functionalities. Looking at the variety known for these compounds, only different hydrocarbon chains—branched, linear, or cyclic—are in use. In the following chapter, basic properties of these compounds depending on the substituents used are described. [Pg.523]

In this chapter, the voltammetric study of local anesthetics (procaine and related compounds) [14—16], antihistamines (doxylamine and related compounds) [17,22], and uncouplers (2,4-dinitrophenol and related compounds) [18] at nitrobenzene (NB]Uwater (W) and 1,2-dichloroethane (DCE)-water (W) interfaces is discussed. Potential step voltammetry (chronoamperometry) or normal pulse voltammetry (NPV) and potential sweep voltammetry or cyclic voltammetry (CV) have been employed. Theoretical equations of the half-wave potential vs. pH diagram are derived and applied to interpret the midpoint potential or half-wave potential vs. pH plots to evaluate physicochemical properties, including the partition coefficients and dissociation constants of the drugs. Voltammetric study of the kinetics of protonation of base (procaine) in aqueous solution is also discussed. Finally, application to structure-activity relationship and mode of action study will be discussed briefly. [Pg.682]

The pros and cons of oxidative dehydrogenation for alkene synthesis using doped cerianites as solid oxygen carriers are studied. The hydrogen oxidation properties of a set of ten doped cerianite catalysts (Ce0.9X0.1Oy, where X = Bi, In, La, Mo, Pb, Sn, V, W, Y, and Zr) are examined under cyclic redox conditions. X-ray diffraction, X-ray photoelectron spectroscopy, adsorption measurements, and temperature programmed reduction are used to try and clarify structure-activity relationships and the different dopant effects. [Pg.201]

More than 600 different carotenoids from natural sources have been isolated and characterized. Physical properties and natural functions and actions of carotenoids are determined by their chemical properties, and these properties are defined by their molecular structures. Carotenoids consist of 40 carbon atoms (tetraterpenes) with conjugated double bonds. They consist of eight isoprenoid units j oined in such a manner that the arrangement of isoprenoid units is reversed at the center of the molecule so that the two central methyl groups are in a 1,6-position and the remaining nonterminal methyl groups are in a 1,5-position relationship. They can be acyclic or cyclic (mono- or bi-, alicyclic or aryl). Whereas green leaves contain unesterified hydroxy carotenoids, most carotenoids in ripe fruit are esterified with fatty acids. However, those of a few... [Pg.178]

The molecular characterization of a polymeric material is a crucial step in elucidating the relationship between its properties (e.g., mechanical, thermal), its chemical structure, and its morphology. As a matter of fact, the development of a new product stems invariably from a good knowledge of the above relationships. Characterization of polymers is often a difficult task because polymers display a variety of architectures, including linear, cyclic, and branched chains, dendrimers, and star polymers with different numbers of arms. [Pg.299]


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See also in sourсe #XX -- [ Pg.272 ]




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