The 9-decalyl and related cations. I. Generation of the 9-decalyl cation by solvolysis

1972 ◽  
Vol 25 (5) ◽  
pp. 1051 ◽  
Author(s):  
GE Gream
Keyword(s):  
Ion Pairs ◽  
Product Formation ◽  
Counter Ion ◽  
Quantitative Analyses ◽  
Cis And Trans

Kinetic and product studies have established that π-bond participation occurs in the acetolysis of 4-(cyclohex-1-enyl)but-1-yl derivatives to give a 9-decalyl cation. Quantitative analyses of the mixtures of products formed by the x-route (from 4-(cyclohex-1-enyl)but-1-yl derivatives), π-route (from spiro[4,5]dec-6-yl derivatives), and direct routes (from cis- and trans-9-decalyl derivatives) show that the intermediate 9-decalyl cations generated in each case must be different. Reasons for the differences are discussed; it is suggested that the counter-ion in ion-pairs involving cis-like and trans-like conformers of the 9-decalyl cation probably plays an important role in product formation.

The 9-decalyl and related cations. III. Generation of the 8-hydrindyl cation by solvolysis

1974 ◽  
Vol 27 (8) ◽  
pp. 1711 ◽  
Author(s):  
GE Gream ◽  
AK Serelis ◽  
TI Stoneman
Keyword(s):  
Ion Pairs ◽  
Cationic Species ◽  
Direct Route ◽  
Counter Ion ◽  
Product Composition ◽  
Cis And Trans

Acetolysis of 4-(cyclopent-1'-enyl)butyl and 3-(2'-methylenecyclopentyl)propyl derivatives, but not 3-(cyclohex-1'-enyl)propyl and 2-(2'-methylenecyclohexyl)ethyl derivatives, occurs with π-bond participation (95 and 92%, respectively) to give similar, including maybe identical, cationic species involving the 8-hydrindyl cation. On the basis of product composition, the 8-hydrindyl cations when generated from spiro[4,4]non-1-yl (σ-route) and cis- and trans-8-hydrindyl derivatives (direct route) are each different and are in turn different to those generated by the above π-routes. Reasons for the differences are discussed and the possible role of the counter-ion in ion-pairs is examined.

The 9-decalyl and related cations. V. Generation of cis- and trans-2-t-Butyl-9-decalyl cations through π-routes by acetolysis

1978 ◽  
Vol 31 (4) ◽  
pp. 863 ◽  
Author(s):  
GE Gream ◽  
AK Serelis
Keyword(s):  
Acetic Acid ◽  
Significant Role ◽  
Ion Pairs ◽  
Side Chain ◽  
Rate Enhancement ◽  
Cationic Species ◽  
Hydride Shift ◽  
Butyl Group ◽  
Counter Ion ◽  
Cis And Trans

The synthesis and solvolytic behaviour (in buffered acetic acid) of 4- (5?-t-butylcyclohex-1'-enyl)but-1-yl p-nitrobenzenesulfonate (6) and 3- (cyclohex-1'-enylmethyl)-4,4-dimethylpentyl p-nitrobenzene-sulfonate (7) are described. Kinetic and product studies have shown that π-bond participation occurs in the acetolysis of both compounds. The rate enhancements, compared with saturated analogues, are c. 46 and 8290 for (6) and (7). The considerably greater rate enhancement observed for (7) is a manifestation of the 'gem-dialkyl' effect and is explained in terms of the effect of the t-butyl group on the conformations that the side chain might adopt. ��� The acetolyses of (6) and (7) give rise to cyclized products (c. 97 and 100%) arising from both cis- and trans-2-t-butyl-9-decalyl cations (2) and (3). The compositions of the products, which also include compounds formed from the cis-cation (55) obtained by a 1,2-hydride shift in (2), show that (6) and (7) do not react via the same cationic species. ��� Ion-pairs of an undefined nature are implicated in the reactions. Entirely consistent evidence was not obtained for the hypothesis that the counter-ion, behaving as a base, probably plays a significant role in olefin formation from the cis- and trans-cations (2) and (3) in ion- pairs that might be formed initially from (6) and (7).

Octahedral cobalt(III) complexes in dipolar aprotic solvents. II. Association between cis- and trans-dichlorobisethylenediamine cobalt(III) cations,[Co en2 Cl2]+, and chloride and bromide ions in the solvents NN-dimethylformamide, dimethyl sulphoxide, and LVN-dimethylacetamide

1966 ◽  
Vol 19 (1) ◽  
pp. 43 ◽  
Author(s):  
WA Millen ◽  
DW Watts
Keyword(s):  
Spectrophotometric Method ◽  
Ion Pairs ◽  
Ion Association ◽  
Ion Pair ◽  
Association Constants ◽  
Dimethyl Sulphoxide ◽  
Aprotic Solvents ◽  
Ion Association Constants ◽  
Cis And Trans ◽  
Dipolar Aprotic Solvents

Ion association constants at 30� have been determined for the cis-[Co en, Cl2]+Cl- ion pair in NN-dimethylformamide (DMF), NN-dimethylacetamide (DMA), and at 20.0�, 25.0�, and 30.0� in dimethyl sulphoxide (DMSO), by a spectrophotometric method. Association constants for the cis-[Co en2 Cl2]+Br- and the trans- [Co en2 Cl2]+Cl- ion pairs have also been determined in DMF at 30�.

The thermal and photochemical decompositions of succinic anhydride and 2,3-dimethyl succinic anhydride in the gas phase

1983 ◽  
Vol 61 (12) ◽  
pp. 2790-2794 ◽  
Author(s):  
S. Yamamoto ◽  
R. A. Back
Keyword(s):  
Thermal Decomposition ◽  
Succinic Anhydride ◽  
Product Formation ◽  
Radical Mechanism ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Free Radical Mechanism ◽  
Trans Butene ◽  
Cis And Trans ◽  
Short Times

The absorption spectrum of succinic anhydride shows a broad maximum near 220 nm, attributed to the lowest π*–n− transition. Photolysis in this region (220–270 nm) gives CO2, CO, and C2H4, but not in the equimolar quantities expected from a simple molecular dissociation. Production of CO also shows a time dependence, increasing with time, and a free-radical mechanism is tentatively suggested to account for this. The thermal decomposition of succinic anhydride at 625–775 K yields the same products, but is more complex, with larger deviations from the simple stoichiometry, and product formation non-linear with time and pressure. At short times, production of CO, the most abundant product, is described by first-order Arrhenius parameters of log A (s−1) = 11.6 and E = 53 kcal/mol, apparently independent of surface.The photolysis of the cis and trans isomers of 2,3-dimethylsuccinic anhydride at 250 and 230 nm is simpler than that of succinic anhydride, giving equimolar CO and CO2, but with butene-2 still falling short of a stoichiometric yield by from 10 to 40%. Both cis- and trans-butene-2 were produced, with the latter always in excess and with no retention of the configuration of the original anhydride. The thermal decomposition of 2,3-dimethylsuccinic anhydride is more complex than the photolysis, with much less butene-2 produced (again with no retention of cis–trans configuration) and methane an important product. Activation energies for CO formation were about 48 and 45 kcal/mol and log A (s−1) was 10.4 and 9.5 for the cis and trans isomers, respectively.

Laser flash photolysis studies of the formation and reactivities of phenyl(naphthyl)methyl carbocations generated from phosphonium salt precursors

1992 ◽  
Vol 70 (6) ◽  
pp. 1784-1794 ◽  
Author(s):  
E. O. Alonso ◽  
L. J. Johnston ◽  
J. C. Scaiano ◽  
V. G. Toscano
Keyword(s):  
Rate Constants ◽  
Phosphonium Salt ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Ion Pairs ◽  
Laser Flash ◽  
Product Formation ◽  
Quantum Yields ◽  
Back Reaction ◽  
Transient Experiments

The photolysis of several substituted phenyl(naphthyl)methyl triphenylphosphonium chlorides has been examined using a combination of laser flash photolysis experiments and product studies. Both carbocation and radical intermediates have been characterized in the transient experiments, with the relative yields depending strongly on the solvent. For example, in alcohols, acetonitrile, or aqueous solvents cation formation predominates while acetonitrile/dioxane mixtures (5–10%) are required for the observation of radicals. Quantum yields for cation formation vary from 0.79 in methanol to 0.093 in 1:4 acetonitrile/dioxane, as measured by product studies and transient experiments, respectively. The addition of perchlorate salts leads to dramatic enhancements in the cation lifetimes; the effects are particularly pronounced for acetonitrile/dioxane mixtures where the cation yields also increase by factors of 3–4. In this case the effects are attributed primarily to replacement of chloride by perchlorate in the initial ion pairs. The combined data from both solvent and perchlorate salt effects on the cation lifetimes and yields suggest that the excited state of the phosphonium salt cleaves homolytically, followed by electron transfer within the initial radical/triphenylphosphine radical cation pair to generate carbocation, as opposed to direct heterolytic cleavage. The cation yields also indicate that back reaction to regenerate starting material, as well as product formation within the initial geminate cage, occur in some solvents. The effects of solvent and added perchlorate salts on the rate constants for reaction with nucleophiles have been examined. For example, rate constants that vary by an order of magnitude have been measured for quenching by azide ion in various aqueous acetonitrile and trifluoroethanol mixtures.

scholarly journals Imaging-Guided Delivery of a Hydrophilic Drug to Eukaryotic Cells Based on Its Hydrophobic Ion Pairing with Poly(hexamethylene guanidine) in a Maleated Chitosan Carrier

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7426
Author(s):  
Sofia A. Zakharenkova ◽  
Marina I. Lebedeva ◽  
Alexandra N. Lebedeva ◽  
Irina A. Doroshenko ◽  
Ksenya Yu Vlasova ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Near Infrared ◽  
Ion Pairs ◽  
Laser Scanning Microscopy ◽  
Breast Adenocarcinoma ◽  
Confocal Laser ◽  
Counter Ion ◽  
Hydrophilic Drug ◽  
Model Drug ◽  
Novel Strategy

Imaging-guided delivery is developed for hydrophobic drugs, and to a much lesser extent, hydrophilic ones. In this work we have designed a novel strategy for real-time monitoring of hydrophilic drug delivery. Traditionally, the drug and the dye are covalently attached to a nanocarrier or are electrostatically adsorbed. Recently, we found an efficient way to bind the drug by ion-paring with an appropriate counter-ion to form the aggregate that embeds a hydrophobic dye with a considerable fluorescence enhancement. We synthesized a series of carbocyanine dyes of hydrophobicity sufficient for solubilization in hydrophobic ion pairs, which restores their emission in the near-infrared (NIR) region upon the formation of the ternary aggregates. To avoid using toxic surfactants, we applied an amphiphilic polymer-oligomer poly(hexamethylene guanidine) (PHMG) as a counter-ion. Сeftriaxone was used as a model hydrophilic drug ensuring the highest fluorescent signal. The so-formed drug–counter-ion–dye aggregates were encapsulated into a cross-linked maleated chitosan carrier. Confocal laser scanning microscopy (CLSM) studies have demonstrated internalization of the encapsulated model drug by breast adenocarcinoma cells at 40 min after treatment. These results suggest the potential application of hydrophobic ion pairs containing an NIR dye in imaging-guided delivery of hydrophilic compounds.

Effect of counter-ion in the anionic polymerization of styrene in cyclohexane

1968 ◽  
Vol 46 (16) ◽  
pp. 2711-2713 ◽  
Author(s):  
J. E. L. Roovers ◽  
S. Bywater
Keyword(s):  
Anionic Polymerization ◽  
Rate Constants ◽  
Ion Pairs ◽  
Propagation Rate ◽  
Counter Ion ◽  
Counter Ions

The propagation reaction in the anionic polymerization of styrene has been studied in cyclohexane with the counter-ions: K, Rb, and Cs. Some association of the ion-pairs was found with K. Absolute propagation rate constants were determined in the three cases. Some experiments were carried out in benzene–cyclohexane mixtures to check that the results were consistent with those previously observed in benzene.

Fluorescent organic ion pairs based on berberine: counter-ion effect on the formation of particles and on the uptake by colon cancer cells

RSC Advances ◽  
2015 ◽  
Vol 5 (2) ◽  
pp. 1181-1190 ◽  
Author(s):  
Marine Soulié ◽  
Céline Frongia ◽  
Valérie Lobjois ◽  
Suzanne Fery-Forgues
Keyword(s):  
Colon Cancer ◽  
Cancer Cells ◽  
Ion Pairs ◽  
Colon Cancer Cells ◽  
Counter Ion ◽  
Counter Ions ◽  
In Cells

Counter-ions modulate the fluorescence of berberine ion pairs in cells, this process being possibly linked to the formation of nanoparticles.

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