Palladium(II) halide complexes with dithioesters derived from sarcosine

The compounds EtO2CCH2(Me)NCS2R (R = Me, ESDTM; R = Et, ESDTE) were prepared from sarcosine ethyl ester hydrochloride, CS2 and alkyl iodide in EtOH-H2O. These ligands react with palladium halides in benzene to yield the benzene solvates [Pd(ESDTR)X2]·nC6H6 (R = Me or Et; X = Cl or Br; n < 1), in which the dithioester molecule coordinates through both sulphur atoms. Ligands and complexes have been characterized by i.r. and 1H n.m.r. spectroscopy and by thermal analysis (t.g., d.t.g. and d.t.a.). The low stability of the adducts in both solution and solid phase is discussed on the basis of proton n.m.r. spectra. Thermal degradation of the 1∶1 complexes has been examined up to 1000° C. The first decomposition step involves release of alkyl halide to form the [Pd(ESDT)X] n (X = Cl or Br) intermediates, which successively decompose, finally giving palladium.