• Bulletin of the Korean Chemical Society
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• 제30권3호
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• pp.729-730
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• 2009

• Bulletin of the Korean Chemical Society
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• 제26권9호
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• pp.1335-1338
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• 2005

Thianthrene cation radical perchlorate ($Th^{+{{\cdot}}}{ClO_4}^-$) reacted readily with two isomeric thiols, benzylthiol (1) and 4-methylbenzenethiol (7) in an acetonitrile solution at room temperature. From the reaction of 1, the major products, N-benzylacetamide (4) and benzyl sulfide (5), are characteristic of benzyl carbocations while the minor one, benzyl disulfide (6) implies free radical component of the reaction. It is unprecedented that the formation of a benzyl carbocation was caused by the extrusion of sulfur atoms from benzyl sulfur cations (3). In contrast, from the reaction of 7, only p-tolyl disulfide (10) was obtained from both sulfur radicals and cations. In the reaction of 7 the thio-extrusion was not observed from the p-tolyl sulfur cation (9). A thianthrene cation radical ($Th^{+{{\cdot}}}$) was reduced quantitatively to thianthrene (Th) in both reactions.

• Bulletin of the Korean Chemical Society
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• 제31권6호
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• pp.1467-1468
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• 2010

• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.337-345
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• 2002

The equilibrium structures for the ground and transition states of $C_7H_7^+$ isomers have been investigated using sophisticated ab initio quantum mechanical techniques with various basis sets. The structures of tropyrium and benzyl cations have been fully optimized at the DZP CCSD(T) levels of theory. And the structures of o-, m-and p-tolyl cations are optimized fully up to the DZ CCSD(T) levels of theory. The geometries for the transition states between three isomers of tolyl cations have been optimized up to DZP CISD level of theory. The SCF harmonic vibrational frequencies for tropylium, benzyl, and three isomers of tolyl cations are all real numbers, which confirm the potential minima and each unique imaginary vibrational frequencies for TS1 and TS2 confirm the true transition states. The relative energy of the benzyl cation with respect to the tropyrium cation is predicted to be 28.5 kJ/mol and is in good agreement with the previous theoretical predictions. The 0 K heats of formation, ${\Delta}H^{\circ}_{f0}$, have been predicted to be 890, 1095, 1101, and 1110 kJ/mol for tropylium, ortho-, meta-, and para-tolyl cations by taking the experimental value of 919 kJ/mol for the benzyl cation as the base level. The relative stability between tolyl cations is in the order of ortho

• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.267-270
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• 2002

Photodissociations of o-, m-, and p-iodotoluene radical cations were investigated by using Fourier-transform ion cyclotron resonance (FT-ICR) spectrometry. Iodotoluene radical cations were prepared in an ICR cell by a photoionization charge-transfer method. The time-resolved one-photon dissociation spectra were obtained at 532 nm and the identities of $C_7H_7^+$ products were determined by examining their bimolecular reactivities toward toluene-$d_8$. The two-photon dissociation spectra were also recorded in the wavelength range 615-670 nm. The laser power dependence, the temporal variation, and the identities of $C_7H_7^+$ were examined at 640 nm. The mechanism of unimolecular dissociation of iodotoluene radical cations is elucidated: the lowest barrier rearrangement channel leads exclusively to the formation of the benzyl cation, whereas the direct C-I cleavage channel yields the tolyl cations that rearrange to both benzyl and tropylium cations with dissimilar branching ratios among o-, m-, and p-isomers. With a two-photon energy of 3.87 eV at 640 nm, the direct C-I cleavage channel results in the product branching ratio, [tropylium cation]/[benzyl cation], in descending order, 0.16 for meta >0.09 for ortho >0.05 for para.

• Bulletin of the Korean Chemical Society
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• 제26권3호
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• pp.393-398
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• 2005

The stability constants for the diaza-18-crown-6 ethers 2-6 and alkali metal cations ($Na^+,\;K^+,\;Rb^+\;and\;Cs^+$) were determined using potentiometry in 95% methanol. For each metal ion the stability constants of the partiallyfluorinated ligands 3-6 were larger than that of the non-fluorinated ligand 2, which might reflect an interaction between fluorine atoms and alkali metal cations. The stability constant of the ligand 4 was larger than that of the ligand 5 for each metal cation tested. This finding was also supported by the results of cation-induced chemical shifts in $^1H-,\;^{19}F$-NMR and extraction experiment. The potentiometry and NMR results as well as the X-ray crystal structures revealed that the position and number of fluorine atoms in the benzyl side arms was crucial for the enhanced interaction between a ligand and an alkali metal.

• Bulletin of the Korean Chemical Society
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• 제29권6호
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• pp.1269-1272
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• 2008

• Bulletin of the Korean Chemical Society
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• 제12권2호
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• pp.182-188
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• 1991

The reactions of aniline with benzyl and phenacyl compounds are studied by the AM1 method. Two types of modeling were adopted: Cation-neutral, in which a proton is attached to the leaving group F and anion-neutral model, in which aniline was replaced by phenoxide with Cl as the leaving group. The cation-neutral model represented the reactvery well, reproducing the various solution-phase experimental results. In the benzyl system, the ${\pi}$-electrons of the two rings (X-ring in the nucleophile and Y-ring in the substrate) interact conjugatively in the transition state (TS) resulting in a bond contraction of the $C_{\alpha}-C_{Y1}$ bond (benzylic effect), whereas in the phenacyl system the ${\pi}$ electrons of the X-ring delocalizes more efficiently into the carbonyl group than into the Y-ring (resonance shunt effect) with a bond contraction of the $C_{\alpha}-C_{\beta}$ bond. The bond contraction in the benzylic effect was substantially greater than that in the resonance shunt effect. The TS was rather loose for benzyl while it was tighter for phenacyl system. Various bond length changes with substituents in the TS were, however, found to be irregular.

• Bulletin of the Korean Chemical Society
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• 제25권2호
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• pp.249-252
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• 2004

Cytochrome P450 (P450)/$O_2$/NADPH engender electron transfer reaction of N-benzyl-N-substituted benzylamines to yield corresponding radical cation 1 that is simultaneously converted into 2 and 3. Subsequently, expulsion of proton and hydroxylation yielding a-hydroxylamines are followed by formation of benzaldehydes and benzylamines.

• 공업화학
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• 제32권3호
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• pp.277-282
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• 2021

본 연구에서는 PF₆를 음이온으로 하며, 이미다졸리움 계열의 양이온을 변화시키면서 2종의 소수성을 띠는 이온성 액체 전해질을 합성하였다. 합성한 이온성 액체는 1-benzyl-3-butylimidazolium hexafluorophosphate [BzBIM]PF₆와 1-pentyl-3-butylimidazolium hexafluorophosphate [PBIM]PF₆이며 이들 각각의 구조는 푸에리에 변환 적외선 분광기와 핵자기공명 분광기를 이용하여 분석하였다. 이와 함께, 합성한 이온성 액체 전해질의 물리적(점도, 이온전도도, 열적 안정성) 및 전기화학적 특성을 조사하고 비교 분석하였다. 그 결과, [BzBIM]PF₆의 경우 [PBIM]PF₆와 다르게 이미다졸리움 양이온에 π-π 분자 간 결합이 강하게 존재하는 벤질링 기능기를 가지고 있어서 열적 및 전기화학적 특성에서 더 우세한 안정성을 보여주었다.