Olefines and Silver Ion

Complexes of Olefines and. Silver Ion.—Much work has been done on the interaction of the silver ion, Ag+, with unsaturated and aromatic hydrocarbons. (Mercuric ion and some other metal ions also react with carbon-carbon double bonde.) The structure proposed by Win-gtein and Lucas11 is probably essentially correct. Let us consider a silver ion and ethylene. The system is an electron-deficient one there are 12 valence electrons and 13 valence orbitals (including one orbital for the silver ion). We may write three structures for the complex  

If the three structures contribute equally, the C—Ag bonds have bond number and the C—C bond has bond number 1+ 

The crystal AgCKL-CeH has been studied with x-rays by Smith and Rundle.11 Each silver atom was found to be ligated to four carbon atoms Ci and C of the benzene molecule on one side of it and C and C of that on the other side. In this way chains of alternating silver atoms and benzene molecules are formed. The bond lengths Ag—Ci 

A somewhat similar structure has been found for the crystal containing silver nitrate and cyclooctatetraene.117 The silver atom is near four carbon atoms of the ring, Ci, C, Ci, and Ce. The bond lengths Ag—C and the like are 2.46,2.51,2.78, and 2.84 A, corresponding to the bond numbers 0.26, 0.22, 0.08, and 0.06, respectively. 

These two examples indicate that the Ag—C bond is essentially equivalent to half of a C=C double bond in weighting the resonance structures. 

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AN INFRARED AND NMR STUDY OF THE BONDING BETWEEN OLEFINS AND SILVER IONS. 

Ag(olefin) Tf2N-] and [AgPMBA)2 Tf2N-] ILs exhibit excellent performance for olefin/ paraffin separation. These ILs provided high permeability and good selectivity. The reversible interaction of olefins and silver ions in the [Ag (olefin)+Tf2N-] was demonstrated. 

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