Fluorine interactions

K. Muller, F.A. Diedrich, Fluorine interactions at the thrombin active site Protein backbone fragments H-C -C = 0 comprise a favorable C-F environment and interactions of C-F with electrophiles, ChemBioChem 5 (2004) 666-675. 

Fig. 12. The template-assisted autocatalyzed peptide replication cycle and the influence of fluorine-fluorine interactions (yellow, template red, electrophilic fragment blue, nucleophilic fragment). (See Colour Plate Section at the end of this book.)...

Being highly hydrophobic but less lipophilic than their hydrocarbon analogs, fluoroalkyl amino acid side chains tend to interact with one another by fluorine-fluorine contacts. Therefore, even one single fluorinated amino acid can direct polypeptide folding due to strong character of fluorine-fluorine interactions (Section 3.3 and 3.4). 

Even within the limitations of fixed conformation, early force fields were deficient. The predicted unit cell dimensions were too small by more than 20 percent This situation was remedied by adjusting nonbonded potentials describing the fluorine-fluorine and carbon-fluorine interactions until predicted unit cell dimensions adequately reproduced experimentally measured values. This fitting was actually carried out using structural information from several polymers and was not an ad hoc parameterization for PTFE. It should also be pointed out that reproducing PTFE cell dimensions was a process of achieving an approximately correct interchain spacing for an approximate helix since the actual crystalline structure was not known at that time. Subsequently, it has become... 

Table 6.2 SMARTS patterns for chemical features (HBA-F, hydrogen bond acceptor/electrostatic fluorine interaction HBD, hydrogen bond donor PI, positive ionizable Nl, negative ionizable)...

Fluorine. Interaction of fluorine with concentrated or very dilute HN03 results in... 

Unlike the fluorine interacting with practically any type of chemical bonds the molecular chlorine at low temperature selectively interacts with double bonds of olefin series. To overcome the high activation energy for common chlorination the UV light has been applied to dissociate molecular chlorine to atoms. 

Do Fluorine-Fluorine Interactions Interfere with Coiled Coil Association and Dissociation ... 

Al(Ci2F9)-fluorine interaction consistent with an aluminum anion-zirconium cation pair (Scheme 6.13). Polymerization using this anion-[Pg.205]

There are many unique and otherwise difficult reactions that are induced essentially by the strong interaction between fluorine and a special atom. Because of its hardness, fluorine interacts strongly with alkaline and alkaline earth metal ions, and in particular with neutral group III elements. Table 3.1 lists the strengths of chemical bonds between fluorine and other atoms, as a measure for the interaction between fluorine and other atoms [1], The theoretically calculated fluoride affinity also serves as a measure of interaction between a fluoride ion and an inorganic Lewis acid [2]. 

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