The isotopic scrambling during partial isomerization of l-14C-l-chloropropane (I-C1-1-14C) to 2-chloropropane (IV-C1-14C) induced by treatment with A1C13 at 0°has been investigated. When the isomerization to IV-C1-14C was 90%, the recovered I-C1-14C showed about 7 and 22% rearrangements of the label from C-l to C-2 and C-3, respectively. Since some conversion of IV-C1 to I-Cl was found to take place under the conditions employed, reversible isomerizations between I-Cl and IV-C1 would contribute to some of the isotope position rearrangements from C-l to C-3. To account for the scrambling to C-2, it is proposed that equilibrating protonated cyclopropane intermediates were involved, and these would collapse to I-Cl with the 14C-label rearranging to both C-2 and C-3. Small amounts of ,4C activity (1.4-3.0%) were found at the C-2 position of the IV-C1-14C obtained in these experiments.
believe that the azide complex has a trigonal-planar geometry.6Addition of CS2 to a chloroform solution of ((C6-H6)3P)2CuN3 in a 1:1 mole ratio results in a clear yellow solution which, upon photolysis,7 very rapidly evolves nitrogen, deposits colloidal sulfur, and leaves a colorless solution from which crystalline material was isolated. This crystalline material was shown to be ((C6H5)3P)2-CuNCS on the basis of elemental analysis and its physical properties, which are identical with those of an authentic sample of ((CeH5)3P)2CuNCS.8 Anal. Caled for ((CeH6)3P)2CuNCS:
Ion cyclotron resonance spectroscopy has been used to study the general gas-phase reaction of alkoxide ions (RBO-) with alkyl formates (HCOORb) for R = CH3, C&, and i-CbHT. These systems are shown to lead in all cases to the formation of a complex ion, (R,Rb02H)-, and to produce alkoxide displacement (RbO-) only when the electron affinity of RbO . is equal to or larger than that of R,O.. Evidence is presented that the complex ions correspond to alkoxide ions "solvated" by a single neutral molecule of alcohol and presumably held by hydrogen bonding, The "solvated" alkoxide ions can react further with alcohols to establish the intrinsic clustering ability of alcohols by the formation of a preferential "solvated" species. The order of solvating ability is shown to follow the scale of gas-phase acidity, t-C4H90H > i-CaH70H > on cyclotron resonance spectroscopy (icr) has been I successfully used in gas-phase studies of ion-molecule reactions to point out the importance of solvent effects in determining reactivity in solution. For example, the acidity order of simple alcohols in the gas phase is the reverse of the order in so1ution.'P2 Likewise, the acidities of the hydrocarbons toluene and propylene are greater than the acidity of water in the gas phase.3 The basicities of the amines follow thewhereas the solution order does not obey this simple trend. Since equilibria and kinetics are generally complex functions of intrinsic effects and solvation, these studies are particularly relevant for the separation of these factors and the understanding of the correct relationship between structure and reactivity. This paper.reports the application of icr to a new and unique method for the indirect preparation of gasphase alkoxide ions, "solvated" by a single neutral molecule of alcohol. This method is based on the general gas-phase reaction of alkoxide ions with alkyl formates in the pressure range of to 5 X 10-5 Torr, where bimolecular collisions are the only important processes. The "solvated" alkoxide ions thus formed can be further reacted with other neutral molecules to establish the order of preference of neutrals as solvating agents. In this study, the relative order of intrinsic solvating ability of the simple alcohols is determined by icr and related to hydrogen-bonding ability.The trend observed for relative stability of "solvated" species parallels closely the extensive measurements recently carried out by high-pressure mass spectrometry on gas-phase ionic equilibria of C1-solvated by different hydrogen-bonding neutral^.^ Furthermore, the relationship established in ref 5 by Kebarle between gas-phase acidity and the hydrogen-bonding capability of the "solvent" molecule is further explored for the case of the simple alcohols. Experimental SectionAll the experiments were carried out in a Varian V-5900 icr spec-(1) J. I. Brauman and L. K. Blair, J. Amer. Chem. SOC., 90, 6561 (2) J. I. Brauman and L. K. Blair, ibid., 92, 5986 (1970). (3) J. 1. Brauman and L. K. Blair, ibid., 93, 4315 (1971). (4) J. I. Brauman, J. M. Ri...
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