Probing 1J(C-F) and nJ(F-F) Spin-Spin Coupling Constants for Fluoroazines: An Ab Initio Theoretical Investigation was written by Del Bene, Janet E.;Alkorta, Ibon;Elguero, Jose. And the article was included in Journal of Physical Chemistry A in 2010.Electric Literature of C4HF3N2 This article mentions the following:
Ab initio equation-of-motion coupled cluster singles and doubles calculations have been carried out to evaluate one-bond C-F coupling constants 1J(C-F) and three-, four-, and five-bond F-F coupling constants nJ(F-F) for a series of mono-, di-, and trifluoroazines. The computed 1J(C-F) and nJ(F-F) values for these are in good agreement with available exptl. coupling constants The values of 1J(C-F) vary as the number and positions of N atoms and the number and relative positions of C-F bonds change, but it is difficult to discern general patterns for these changes due to opposing effects of the Fermi contact and paramagnetic spin-orbit terms. The majority of 1J(C-F) values lie in a range that includes the three monosubstituted pyridines. For trifluoroazines, 1J(C-F) for a C-F bond that is ortho to two other C-F bonds is greater than 1J(C-F) for the other two bonds. F-F coupling constants arise in these mols. when the two C-F bonds are ortho, meta, or para. Values of 3J(F-F) are relatively large and neg., whereas values of 5J(F-F) are relatively large and pos. 4J(F-F) may be pos. or neg. and large or small. The value of this coupling constant depends on the nature of the atom that links the two C-F bonds and the number and positions of N atoms in the ring. The calculations carried out in this study at a reliable level of theory give values for one-bond C-F and n-bond F-F spin-spin coupling constants for the fluoroazines that are not available exptl. In addition, the patterns that describe the changes that occur in these mols. provide a basis for predicting their values in larger, related systems in the absence of exptl. data and direct calculations In the experiment, the researchers used many compounds, for example, 4,5,6-Trifluoropyrimidine (cas: 17573-78-3Electric Literature of C4HF3N2).
4,5,6-Trifluoropyrimidine (cas: 17573-78-3) belongs to pyrimidine derivatives. The pyrimidine ring system has wide occurrence in nature as substituted and ring fused compounds and derivatives. For example, the neurotoxin tetrodotoxin is a pyrimidine derivative. It is found in a number of species including the Japanese puffer fish, the blue-ringed octopus, and the orange-bellied newt. Tetrodotoxin prevents the transmission of nerve signals and can result in paralysis and death.Electric Literature of C4HF3N2
Referemce:
Pyrimidine | C4H4N2 – PubChem,
Pyrimidine – Wikipedia