Polyhedron Vol. 12, No. 21, pp. 2551-2556,1993 Printed in Great Britain zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA FLEXIDENTATE BEHAVIOUR l,ZETHANEDIAMINE(L) IN 0277~5387/93 S6.00+.00 0 1993 Pergamon Press Ltd OF N-(ZHYDROXYETHYL)- PALLADIUM(II) HALIDE COMPLEXES. THERMAL, IR AND ‘H NMR STUDIES AND SINGLE CRYSTAL X-RAY ANALYSIS OF [PdLClJ SUBRATANATH KONER, ASHUTOSH GHOSH* and NIRMALENDU RAY CHAUDHURIP Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Calcutta 700 032, India MONIKA MUKHERJEE Department of Solid State Physics, Indian Association for the Cultivation of Science, Calcutta 700 032, India ALOK K. MUKHERJEE Department of Physics, Jadavpur University, Calcutta 700 032, India (Received 10 May 1993 ; accepted 12 July 1993) Abstract-Tridentate and bidentate coordination behaviour of N-(Zhydroxyethyl)- 1,2- ethanediamine(L) with PdX2 (X = Cl or Br) and their isomerization (N,N,O + N,N coor- dination) both in the solid state and in the solution have been studied by thermal techniques (DSC and TG-DTA), IR and ‘H NMR spectroscopy. One of the isomers [PdLC12] has been characterized by single crystal X-ray analysis. The palladium(I1) ion possesses a square planar geometry with the N2C12 donor set. A number of investigations have been reported’-’ on the nature of the complex formation with N-(2- hydroxyethyl)-1,2-ethanediamine(L). The ligand has three potential donor sites (N,N,O), two nitro- gens of the diamine and one oxygen of the hydroxyl group. The hydroxy coordination to metal seems to be weaker than the nitrogen. As a result the ligand is bidentate (via two N) when the other coor- dination sites of the metal are already occupied by strongly coordinating groups (e.g. N02-, ethyl- enediamine, triethylenetetramine etc.) but is tri- dentate when those are weakly coordinating (e.g. H20, halogens etc). Moreover, it has been reported * Present address : Department of Chemistry, Jhar- gram Raj College, Jhargram 721 507, India. TAuthor to whom correspondence should lx. addressed. that there is a tendency of the bidentate form of this ligand to be transformed into the tridentate form in some complexes. ’ The above propositions were made on the basis of conductance, spectral (electronic, IR and NMR) data and supported by chemical reaction (acety- lation). However, due to lack of single crystal X- ray analysis data, the structures of these complexes as well as the flexidentate behaviour of the ligand remain more or less speculative. Moreover, the coordinating power of hydroxy group (-OH) and that of halogens are not very different. Therefore, it may be expected that interchange between these coordination sites (-OH and halogens) in solid state is possible if the potential barrier of the trans- formation is not very high. 6 In this paper we report the syntheses of both bidentate and tridentate form of the ligand (L) in 2551