Regiospecific cyclometallation: Synthesis, spectral properties and crystal structure of peri-palladate

摘要

At room temperature 1-(2'-hydroxy-5'-methylphenylazo)naphthalene (H2L) reacts with disodium tetrachloropalladate in ethanol and undergoes cyclopalladation leading to the formation of the pink monomeric compound [PdL(Pic)] (1) in the presence of 4-picoline (Pic). The structure of I has been determined by single crystal X-ray crystallography. The metal ion is in a distorted square planar CNON coordination sphere. The palladium(II)-carbon bond formation occurs exclusively at the C8 (peri-) position of the naphthyl ring of H2L. 1-(2'-hydroxy-5'-methylphenylazo)naphthalene behaves as a dianionic terdentate [U(naphthyl), N(diazo). O(phenotato)] ligand towards palladium(II). The peri-palladate 1 has also been characterized by spectral (IR, electronic. H-1 and Cf-13{H-1} NMR) data. (c) 2006 Elsevier Ltd. All rights reserved.