REARRANGEMENT STUDIES WITH 14C: XIX. THE REACTION OF 2-PHENYL-1-14C-ETHANOL WITH THIONYL CHLORIDE

1964 ◽  
Vol 42 (5) ◽  
pp. 1130-1136 ◽  
Author(s):  
C. C. Lee ◽  
D. J. Kroeger ◽  
D. P. Thornhill
Keyword(s):  
Thionyl Chloride ◽  
Ion Pairs ◽  
Aqueous Sodium Hydroxide ◽  
Covalent Bonding ◽  
Ion Pair ◽  
Aqueous Sodium ◽  
Carbonium Ion ◽  
Partial Completion ◽  
The Stability ◽  
Excess Thionyl Chloride

The reaction of 2-phenyl-1-14C-ethanol with thionyl chloride in pyridine, dioxane, toluene, or excess thionyl chloride as solvent gave 2-phenylethyl chloride showing, respectively, about 0, 15, 44, and 48% rearrangement of the 14C-label from the C-1 to the C-2 positions. When reactions of 2-phenyl-1-14C-ethauol or 2-p-anisyl-1-14C-ethanol with thionyl chloride in dioxane or excess thionyl chloride were carried only to partial completion and the undecomposed chlorosulphites hydrolyzed by aqueous sodium hydroxide, the recovered alcohols showed only 0.1 to 0.5% isotope position rearrangement. This indicated a lack of return from ion-pairs to isotopically rearranged 2-arylethylchlorosulphite and suggested that the first stage of ionization may involve ion-pairs with structures that will not result in rearrangement on return to covalent bonding, or that the first ion-pair may decompose faster than it can return to reactant. The possibility that rearrangements via rigidly oriented ion-pairs and via the concerted SNi′ mechanism may represent the two extremes of a graded series is discussed. It is suggested that the relative contributions from the ion-pair and from the SNi′ mechanisms will depend on the stability of the carbonium ion as well as on the nature of the reaction solvent.

Structures of ion-pairs derived from dihydroanthracenes I. Electronic spectra

1967 ◽  
Vol 301 (1466) ◽  
pp. 223-230 ◽  
Keyword(s):  
Wide Temperature Range ◽  
Electronic Spectra ◽  
Absorption Maximum ◽  
Ion Pairs ◽  
Alkyl Substituent ◽  
Ion Pair ◽  
The Other ◽  
Lithium Salts ◽  
Sodium Salts ◽  
The Stability

The optical spectra of the 9-lithium and sodium salts of 9, 10-dihydroanthracene and its 10-alkyl substituted derivatives have been investigated in tetrahydrofuran over a wide temperature range (25°C to about −70°C). The spectra of the lithium salts indicate the coexistence of two species having a different degree of solvation, one absorbing at λ max . = 400 nm, the other at λ max . = 450 nm. Lower temperatures favour the latter. It has been found that the presence of an alkyl substituent on carbon 10 greatly increases the stability of that species which absorbs at the longer wavelength. Only one absorption peak is seen in the spectrum of the respective sodium salts. The absorption maximum of the unsubstituted ion-pair shifts with temperature, namely λ max . = 455 nm at −70°C and 425 nm at +20°C. Similar behaviour was observed for the substituted salt. These observations suggest the need for a ‘dynamic’ model of ion-pairs in preference to the ‘static’ one in which the energy of the pair is uniquely determined by the interionic distance. Such models are discussed.

REARRANGEMENT STUDIES WITH C14: XIV. THE REACTION OF 2-p-ANISYLETHANOL-1-C14 WITH THIONYL CHLORIDE

1963 ◽  
Vol 41 (3) ◽  
pp. 620-624 ◽  
Author(s):  
C. C. Lee ◽  
Donna Newman ◽  
D. P. Thornhill
Keyword(s):  
Thermal Decomposition ◽  
Thionyl Chloride ◽  
Ion Pair ◽  
Excess Thionyl Chloride

Reaction between 2-p-anisylethanol-1-C14 and thionyl chloride was carried out with pyridine, n-hexane, toluene, dioxane, or excess thionyl chloride as solvent. The 2-p-anisylethyl chloride obtained showed rearrangement of the C14 label from the C-1 to C-2 positions ranging from about 0.5% for the reaction in pyridine to about 46% for the reaction in excess thionyl chloride. The results can be explained on the basis of varying degrees of involvement of the ethylene-p-methoxyphenonium chlorosulphite ion pair, thus supporting the suggestion that thermal decomposition of alkyl chlorosulphites to give chlorides may be considerably ionic in character.

Stereospecific 1,3-H Transfer of Indenols Proceeds via Persistent Ion-Pairs Anchored By NH···Pi Interactions

2018 ◽  
Author(s):  
David Ascough ◽  
Fernanda Duarte ◽  
Robert Paton
Keyword(s):  
Computational Analysis ◽  
Ion Pairs ◽  
Ion Pair ◽  
Hydrogen Atom Transfer ◽  
Polar Solvents ◽  
Chirality Transfer ◽  
Activation Barriers ◽  
Sense And Avoid ◽  
Phase Dynamics ◽  
Pi Interactions

The base-catalyzed rearrangement of arylindenols is a rare example of a suprafacial [1,3]-hydrogen atom transfer. The mechanism has been proposed to proceed via sequential [1,5]-sigmatropic shifts, which occur in a selective sense and avoid an achiral intermediate. A computational analysis using quantum chemistry casts serious doubt on these suggestions: these pathways have enormous activation barriers and in constrast to what is observed experimentally, they overwhelmingly favor a racemic product. Instead we propose that a suprafacial [1,3]-prototopic shift occurs in a two-step deprotonation/reprotonation sequence. This mechanism is favored by 15 kcal mol<sup>-1</sup> over that previously proposed. Most importantly, this is also consistent with stereospecificity since reprotonation occurs rapidly on the same p-face. We have used explicitly-solvated molecular dynamics studies to study the persistence and condensed-phase dynamics of the intermediate ion-pair formed in this reaction. Chirality transfer is the result of a particularly resilient contact ion-pair, held together by electrostatic attraction and a critical NH···p interaction which ensures that this species has an appreciable lifetime even in polar solvents such as DMSO and MeOH.

scholarly journals Tripodal, Squaramide-Based Ion Pair Receptor for Effective Extraction of Sulfate Salt

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2751
Author(s):  
Damian Jagleniec ◽  
Marcin Wilczek ◽  
Jan Romański
Keyword(s):  
Ion Pairs ◽  
Binding Mode ◽  
Selective Extraction ◽  
Ion Pair ◽  
Hofmeister Series ◽  
Sulfate Salt ◽  
Lower Affinity ◽  
High Affinity ◽  
Binding Domains ◽  
Hydrated Sulfate

Combining three features—the high affinity of squaramides toward anions, cooperation in ion pair binding and preorganization of the binding domains in the tripodal platform—led to the effective receptor 2. The lack of at least one of these key elements in the structures of reference receptors 3 and 4 caused a lower affinity towards ion pairs. Receptor 2 was found to form an intramolecular network in wet chloroform, which changed into inorganic–organic associates after contact with ions and allowed salts to be extracted from an aqueous to an organic phase. The disparity in the binding mode of 2 with sulfates and with other monovalent anions led to the selective extraction of extremely hydrated sulfate anions in the presence of more lipophilic salts, thus overcoming the Hofmeister series.

Ion pair binding by an l-tyrosine-based polymerizable molecular receptor

2015 ◽  
Vol 39 (8) ◽  
pp. 6216-6222 ◽  
Author(s):  
Szymon Zdanowski ◽  
Jan Romański
Keyword(s):  
Ion Pairs ◽  
Functional Polymers ◽  
Ion Pair

A polymerizable molecular receptor able to bind ion pairs and new functional polymers containing the receptor units were synthesized and characterized.

scholarly journals Triple Helix of Scleroglucan in Dilute Aqueous Sodium Hydroxide

1981 ◽  
Vol 13 (12) ◽  
pp. 1135-1143 ◽  
Author(s):  
Toshio Yanaki ◽  
Takemasa Kojima ◽  
Takashi Norisuye
Keyword(s):  
Sodium Hydroxide ◽  
Triple Helix ◽  
Aqueous Sodium Hydroxide ◽  
Aqueous Sodium
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