Isolation of a Nitromethane Anion in the Calix-Shaped Inorganic Cage

A calix-shaped polyoxometalate, [V12O32]4− (V12), stabilizes an anion moiety in its central cavity. This molecule-sized container has the potential to control the reactivity of an anion. The highly-reactive cyanate is smoothly trapped by V12 to form [V12O32(CN)]5−. In the CH3NO2 solution, cyanate abstracts protons from CH3NO2, and the resultant CH2NO2− is stabilized in V12 to form [V12O32(CH2NO2)]5− (V12(CH2NO2)). A crystallographic analysis revealed the double-bond characteristic short bond distance of 1.248 Å between the carbon and nitrogen atoms in the nitromethane anion in V12. 1H and 13C NMR studies showed that the nitromethane anion in V12 must not be exchanged with the nitromethane solvent. Thus, the V12 container restrains the reactivity of anionic species.

Download Full-text

Some Considerations Regarding the 1H and 13C Spectra of 4-(1-azulenyl)-2,6-bis(2-heteroaryl-vinyl)- pyrylium and Pyridinium and their Corresponding Pyridines

Revista de Chimie ◽

10.37358/rc.18.1.6045 ◽

2018 ◽

Vol 69 (1) ◽

pp. 64-69

Author(s):

Liviu Birzan ◽

Mihaela Cristea ◽

Constantin C. Draghici ◽

Alexandru C. Razus

Keyword(s):

Double Bond ◽

13C Nmr ◽

Nmr Spectra ◽

Chemical Shifts ◽

Pyridinium Salts ◽

13C Nmr Spectra ◽

1H And 13C Nmr ◽

Pyrylium Salts

The 1H and 13C NMR spectra of several 2,6-diheteroarylvinyl heterocycles containing 4-azulenyl moiety were recorded and their proton and carbon chemical shifts were compared with those of the compounds without double bond between the heterocycles. The influence of the nature of central and side heterocycles, molecule polarization and anisotropic effects were revealed. The highest chemical shifts were recorded for the pyrylium salts and the lowest at pyridines, but in the case of the pyridinium salts, the protons chemical shifts at the central heterocycle are more shielded due to a peculiar anisotropy of the attached vinyl groups.

Download Full-text

8-Acyl-7-phenylbicyclo[2.2.2]-2,6-diones by rearrangement of 3-acyloxy-5-(2-phenylethenyl)-2-cyclohexen-1-ones. 1H and 13C NMR spectral evidence of their structure

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19901208 ◽

1990 ◽

Vol 55 (5) ◽

pp. 1208-1215 ◽

Cited By ~ 1

Author(s):

Pavel Hrnčiar ◽

Tibor Liptay ◽

Ján Šraga

Keyword(s):

Double Bond ◽

Spectral Data ◽

13C Nmr ◽

1H And 13C Nmr ◽

Spectral Evidence ◽

C Nmr

3-Acyloxy-5-(2-phenylethenyl)-2-cyclohexen-1-ones II were prepared by O-acylation of 5-(2-phenylethenyl)-1,3-cycloxanedione (I). Treatment of II with AlCl3 resulted in rearrangement of the acyl group to the double bond of the phenylethenyl grouping followed by cyclization to 8-acyl-7-phenylbicyclo[2.2.2]octane-2,6-diones III. Their structure was evidenced by analysis of the 1H and 13C NMR spectral data.

Download Full-text