Large Salt Effects in Non-Polar Solvents

Abstract

Surprisingly, in the course of an X-Ray study of [TiCl2(CsH6)]206 we found definite evidence of colinearity of titanium and oxygen atoms. In fact, the crystals of (I), having^t hese unit cell constants: a = 7.47 Á.; b = 9.86 A.; c = 12.58 A.; 3 = 127°56', space group P21/c, have only two molecules per unit cell, so that the molecule must be centrosymmetrical.The colinearity of titanium and oxygen atoms is further confirmed by the Patterson and Fourier syntheses on the ac and be planes. At the present stage of refinement of the structure (R = 0.20), the fractional coordinates (x, y, z) of the heavy atoms have been assumed to be: Ti: 0.454, 0.132, 0.393; CF: 0.767, 0.132, 0.403; CW 0.178,0.047, 0.187.It results that: 1, as above said, the Ti-O-Ti atoms are colinear. 2, All the carbon atoms of the cyclopentadiene ring are at the same distance (2.35 ± 0.05 A.

Solvent, salt and high pressure effects on the rate and equilibrium constants for the formation of tri‐n‐butylphosphoniumdithiocarboxylate

“…To gain further insight into the role of the medium in the studied reversible reaction, it was appropriate to study the effect of salt solution, lithium perchlorate (LP) in diethyl ether (LPDE) and acetone, on the rate and equilibrium constants of this reaction. Lithium perchlorate solutions can be considered as highly polar media 12–15. A summary of its remarkable effects was collected in several reviews 15, 16…”

Electrostatic catalysis by ionic aggregates: scope and limitations of Mg(ClO4)2 as acylation catalyst

“…Wienstein et al 20 observed that the ionisation of p-methoxyneophyl tosylate and a p-nitrobenzoate in a 0.1 M solution of LiClO 4 in ether is respectively 10 5 and 10 6 times faster than in ether itself. Pocker et al 21 showed that the ionisation of TrCl in 5.5 M LiClO 4 /ether occurs about 7.0£10 9 more rapidly than in ether.…”

Highly Selective Synthetic Transformations Catalyzed by Lithium Perchlorate in Organic Media

“…[3] Winstein recognized that the dissolution of lithium perchlorate in diethyl ether increases the polarity of the medium dramatically, a solution of lithium perchlorate in ether is more polar than acetic acid. [4] He demonstrated that the ionization of p-methoxyneophyl p-toluenesulfonate in 0.1  lithium perchlorate/diethyl ether (LPDE) is increased by a factor of 10 5 . [4] Pocker observed that the rate of ionization of trityl chloride is increased by a factor of 10 9 in a 5.0  LPDE medium compared to diethyl ether alone.…”

“…[4] He demonstrated that the ionization of p-methoxyneophyl p-toluenesulfonate in 0.1  lithium perchlorate/diethyl ether (LPDE) is increased by a factor of 10 5 . [4] Pocker observed that the rate of ionization of trityl chloride is increased by a factor of 10 9 in a 5.0  LPDE medium compared to diethyl ether alone. [5] Although the pioneering work of Winstein and others [6] on the salt effects on solvolysis reactions is of mostly mechanistic interest it was later put to use in organic synthesis.…”