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The cubyl onium ions such as cubylcarboxonium, cubylacylium, and cubylhalonium ions have a typical structure with the strained cubane C-C bonds interacting with the electron deficient centers. The reactions between FSO3H and cubanecarboxylic acids give the respective cubylcarboxonium ions. Mono- or dicubanecarbonyl chlorides react with SbF5 to produce mono- or diacylium ions, respectively. Superacidic methylating conditions lead to the stable acylic tertiary halonium ions and dimethyl cubyl-1,4-dihalonium ions.

The synthesis of a series of substituted adamantane-1,3-dimethyl dications is presented. The method involves the ionization of alpha,alpha,alpha1',alpha'-tetrasubstituted-1,3-adamantanedimethyl diols in superacidic media. The results of 13C NMRA spectroscopic study showed that the positive charges in the dications are more delocalized into the substituents because of close proximity of the cationic centers through the adamantyl cage.

Ab initio/IGLO 29Si, 13C and 1H NMR chemical shift calculations are undertaken to investigate the supposed existence of the trimethylsilyl cation. However, comparison of these data with experimental values shows that no such cation is present in solution. Attempts to synthesize cyclic aromatic and antiaromatic organosilicenium ions and halogen-bridged organosilyl cations have failed. Likewise, the NMR spectroscopic observation of trivalent trialkyl(aryl)organosilyl cations also have failed.

The presence of a 3-spirocyclopropyl group in the structure of 2-norbornyl cations provides an exceptional stabilizing effect over the C1-C6 delta-bond participation. However, the examination of tertiary 2'-methylspiro-, 2-phenylspiro- and 2'-cyclopropylspiro(cyclopropane-3'-norbornan)-2'-yl cations shows that the nonclassical delta-participation has slightly influenced the progress of the rearrangement reactions. Additionally, individual gauge for localized orbitals 13C NMR spectroscopy has been used to determine the structural behavior of the cations.

The structural analyses of different species of cyclopropylcarbinyl cations under stable ion conditions were discussed. The cationic structures were characterized by nuclear magnetic resonance spectroscopy. In addition, the equilibriated states and structural changes as a result of the substituent were also discussed. Both the degenerate and the static arrangements of cyclopropycarbinyl cations were elucidated.

Electrochemical reductive tert-butyldimethylsilylation of tetrachlorocyclopropene to 1,2,3-tris(tertbutyldimethylsilyl)cyclopropene, a potential strained precursor for Diels-Alder and related cycloaddition reactions, is described. By hydride ion with nitrosonium tetrafluoroborate, 1,2,3-tris(tert-butyldimethylsilyl)cyclopropene is ionized quantitatively to Huckeloid 2[Pi] aromatic tris(tertbutyldimethylsilyl)cyclopropenium tetrafluoroborate.

The compound 2,6-dimethylmesitylene-2,6-diyl dication (2) has been prepared, characterized by nuclear magnetic resonance (NMR) spectroscopy and analyzed by DFT/IGLO. Basing on NMR data, a dienylic allylic dication system (2a) seems to be the major contributor to structure 2. DFT/IGLO theoretical NMR chemical shift computations provided excellent correlation with the experimental data. The combined experimental and theoretical procedure support structure 2a wherein the dienyl and allylic cation units are insulated from each other not unlike what is theoretically computed for the related benzene dication 3.

Electrochemical methods enable the conversion of the commercially available tetrachlorocyclopropene into hexakis(trimethylsilyl)-3, 3'-bicyclopropenyl. Analysis of the electrochemical reaction between tetrachlorocyclopropene and chlorotrimethylsilane reveals the occurrence of first two trimethylsilylations at the vinylic positions. The tris(trimethylsilyl)cyclopropenyl radical undergoes a radical coupling reaction after the incorporation of the third trimethylsilyl group, producing the bicyclic product.

Ionization of the associated 1,3'-spirocyclopropylbicyclo(2.2.2)octan-2'-ol facilitated the synthesis of the stabilized 1,3'-spirocyclopropylbicyclo(2.2.2)oct-2'-yl cation which was not noticeable. Generation of the allylic 2-methylbicyclo(3.2. 2)non-3-en-2-yl cation resulted from smooth alignment.

The synthesis of the 1-ferrocenyl-1-cyclopropyl cation under superacidic conditions and with the carbocationic center stabilized by the adjoining ferroncenyl moiety is presented. A dark green solution results from the dissolution of 1-ferrocenyl-1-cyclopropyl trimethylsilyl ether in FSO3H/SO2ClF at -78 degrees C. Increasing the temperature to -40 degrees C in the NMR probe for 8 min then recooling to -60 degrees C results in the desired complex.