Diverse Polymorphism of G-Quadruplexes as a Kinetic Phenomenon

2008 ◽  
Vol 130 (43) ◽  
pp. 14161-14169 ◽  
Author(s):  
Iztok Prislan ◽  
Jurij Lah ◽  
Gorazd Vesnaver
Keyword(s):  
Kinetic Phenomenon

scholarly journals Evidence for an unusual kinetic phenomenon in the metallation of porphyrins

1991 ◽  
pp. 731-732
Author(s):  
Francisco González-Vílchez ◽  
Rosario A. Vilaplana ◽  
Robert F. Pasternack
Keyword(s):  
Kinetic Phenomenon

scholarly journals A New Insight into the Comonomer Effect through NMR Analysis in Metallocene Catalysed Propene–co–1-Nonene Copolymers

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1266
Author(s):  
Qiong Wu ◽  
Alberto García-Peñas ◽  
Rosa Barranco-García ◽  
María Luisa Cerrada ◽  
Rosario Benavente ◽  
...  
Keyword(s):  
Active Sites ◽  
Nmr Analysis ◽  
Reaction Parameters ◽  
Transfer Processes ◽  
Detailed Explanation ◽  
Selective Interaction ◽  
End Groups ◽  
Alpha Olefin ◽  
Kinetic Phenomenon ◽  
Insight Into

The “comonomer effect” is an intriguing kinetic phenomenon in olefin copolymerization that still remains without a detailed explanation. It typically relates to the rate of enhancement undergone in ethylene and propene catalytic polymerization just by adding small fractions of an alpha-olefin. The difficulty lies in the fact that changes caused by the presence of the comonomer in reaction parameters are so conspicuous that it is really difficult to pin down which of them is the primary cause and which ones are side factors with marginal contribution to the phenomenon. Recent investigations point to the modification of the catalyst active sites as the main driving factor. In this work, the comonomer effect in the metallocene copolymerization of propene and 1-nonene is analysed and correlated to the comonomer role in the termination of the chain-growing process. The associated termination mechanisms involved furnish most of chain-free active sites, in which the selective interaction of the comonomer was proposed to trigger the insertion of monomers. A thorough characterisation of chain-end groups by means of the 1H NMR technique allows for detailing of specific transfer processes, ascribed to comonomer insertions, as well as evidencing the influence of the growing chain’s microstructure over the different termination processes available.

Modeling and Validation of an Unusual Kinetic Phenomenon During the Enzymatic Hydrolysis of Lactose to Glucose

2007 ◽  
Author(s):  
Michael Arlante Teruel ◽  
Atma Bhawuk ◽  
Daniel McKewn Jenkins ◽  
José I Reyes de Corcuera
Keyword(s):  
Enzymatic Hydrolysis ◽  
Kinetic Phenomenon ◽  
Hydrolysis Of

scholarly journals XI. On the structure of metals, its origin and changes

1896 ◽  
Vol 187 ◽  
pp. 417-432 ◽  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Fractional Power ◽  
Close Relation ◽  
Thermal Capacity ◽  
Mean Value ◽  
Atomic Volume ◽  
Kinetic Phenomenon

It has been shown by Herbert Tomlinson that the atomic volume of metals is intimately connected with their thermal capacity and with Young’s modulus. He considers in view of the work of Wertheim of Maxwell, and of Heen, and as the result of his own experiments, that the value of the product of the elasticity E, when multiplied by a fractional power of the atomic volume, A/D, is a constant for all metals. E (A/D) 7/3 = 181 X 10 4 . The divergencies shown by several metals from this mean value arise from the fact that the presence of small amounts of impurity makes a great difference in their elasticity. Sutherland finds a close relation between the atomic volume and the rigidity of metals, and considers that this rigidity is “in its essence a kinetic phenomenon almost as simple in character as the elasticity of perfect gases."

scholarly journals Photochemical Reactions of Hydrogen-bonded Coordination Polymers

2014 ◽  
Vol 70 (a1) ◽  
pp. C529-C529
Author(s):  
Jagadese Vittal
Keyword(s):  
Metal Ions ◽  
Coordination Polymers ◽  
Structural Transformations ◽  
Photochemical Reactions ◽  
Supramolecular Interactions ◽  
Network Structures ◽  
Experimental Conditions ◽  
Hydrogen Bonding Interactions ◽  
Kinetic Phenomenon ◽  
Solvent Molecules

Crystallization is a kinetic phenomenon and the experimental conditions like solvents, concentration, pH, temperature and time have greater influence on the nature of products in the synthesis of coordination network structures. During crystallization, the solvents and ligands bind to the metal ions reversibly and hence, the least soluble polymer will crystallize first, independent of the metal-ligand ratio used in the crystallization. The kinetic products quite often contain solvents bonded to the metal ions. The removal of these coordinated solvents is likely to transform the kinetically formed coordination polymers (CPs) into thermodynamically stable products. In these structural conversions, supramolecular interactions play a major role. Such structural transformations as well as [2+2] cycloaddition reactions have been demonstrated in many coordination polymeric network structures aided by the directional hydrogen bonding interactions. A number of structural transformations involving the loss of solvent molecules and use of photodimerization reactions in the solid state will be presented in this talk.

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