101 Journal of Organometallic Chemistry, 243 (1983) 101-109 Elsevier Sequoia S.A., Lausanne - Printed in The Netherlands zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQP CYCLIC ACYL COMPLEXES OF PALLADIUM(D). SYNTHESIS AND NMR SPECTROSCOPY OF ACYL COMPLEXES DERIVED FROM QUINOLINE-S-CARBALDEHYDE AND 2-(DIMETHYLAMINO)BENZALDEHYDE C.G. ANKLIN and P.S. PREGOSIN Laboratorium fur Anorganische Chemie, ETH Ziiruch, Uniuersitiitstrasse 6, CH-8092 Ziirich (Switzerland) (Received August 19th, 1982) Summary The room temperature syntheses of new chelating acyl palladium(I1) complexes, [Pd(p-Cl)(C(O)C,H,N>1, and [Pd(p-Cl)(C(O)C,H,N(CH,),)I,, derived from quinoline-Scarbaldehyde and 2-(dimethylamino)benzaldehyde are described. These chloro bridged dimers may be cleaved with neutral phosphine and nitrogen ligands, L, to give the monomeric [PdCl(C(O)C,H,N)L] and [PdCl(C(O)C,H,N(CH,),)L] compounds. ‘H-, 13C- and 31P-NMR data for the new complexes are reported. Introduction Acyl complexes of transition metals are known to be intermediates in the hydroformylation reaction [l], and an increasing number of studies have been dedicated to their reactivity [2]. As part of our interest in this area we have synthesized Pd” and Pt” complexes containing cyclic acyl ligands of the general type [mO)L,], (L = tertiary phosphine) derived from salicylaldehyde [3,4]. These can be prepared by deprotonation of the phenol oxygen, followed by oxygen coordination to the metal, and subsequent activation of the aldehyde. A similar type of aldehyde activation has been reported for the ligand 2-diphenylphosphinoben- zaldehyde [5], using Ir’ and Pt” precursors. Having noted that prior coordination of either oxygen or phosphorus leads to formation of cyclic acyl complexes, we have investigated the products of the reaction of palladium salts with organic aldehydes which contain nitrogen coordination sites, and describe below the synthetic and spectroscopic results for quinoline-%carbalde- hyde and 2-(dimethylamino) benzaldehyde. 0022-833X/83/0000-0000/$03.00 0 1983 Elsevier Sequoia S.A.