Date of Award

1983

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Abstract

The synthesis of palladocycles containing trans and cis C-metal anionic sigma bonds has been accomplished. The trans ligands were prepared from 2,6-bis(chloromethyl)pyridine and alkyl malonates by a base catalyzed S(,N)2 reaction. This cis-ligands were formed by a similar reaction but using 6,6'-bis(chloromethyl)-2,2'-dipyridine as starting halide. The synthesis of the latter chloro compound is discussed in detail. The trans complexes were prepared by base mediated cyclometallation on PdCl(,2)(PhCN)(,2) in aqueous ethanol with added pyridine. This cis metallocycles were formed by a similar displacement reaction on PdCl(,2) in acetonitrile but using a heterogeneous base (K(,2)CO(,3)) and a stoichiometric amount of AgNO(,3). Full experimental detail is presented including ('1)H and ('13)C NMR, IR, MS, and X-ray analysis of the trans and cis-complexes. The ('1)H NMR revealed a stereochemical dissymmetry about a metal-containing prochiral center demonstrating the non-equivalence of the ri and si faces. ('13)C chemical shifts were found to correlate with bond angles about the metallocyclic ring. X-ray analysis revealed some interesting modes of distortion for both the core metal and the carbon framework in trans and especially in the highly strained 5(.)5(.)5 cis systems. A new and unique six-membered palladocycle has been prepared and shown to have favorable geometries about the metallocyclic ring in sharp contrast to the expectations of most researchers.

Pages

233

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