N-{2-(4-methoxyphenyltelluro)ethyl}morpholine (L-1) and bis {2-(N-morpholino)ethyl}telluride (L-2): Synthesis and complexation with palladium(II) andmercury(II). Crystal structures of trans-[PdCl2(L-1)(2)] and trans-[PdCl2(L-2)(2)]

The reactions of 4-(2-chloroethyl)morpholine hydrochloride with ArTe- and T e2-, generated in situ (under N-2 atmosphere) have resulted in N-{2-(4-meth oxyphenyltelluro)ethyl}morpholine (L-1) and bis{2-(N-morpholino)ethyl}tellu ride (L-2), respectively, which are first tellurated derivatives of morphol ine. H-1- and C-13{H-1}-NMR spectra of L-1 are as expected but HETCOR exper iments are used to assign the overlapping signals of CH2Te and CH2N in H-1- NMR spectrum of L-2. The complexes of stoichiometries [PdCl2(L-t/L-2)(2)] ( 1/3) and [HgBr2(L-1/L-2)](2) (2/4) are synthesized. The NMR (H-1 and C-13{H -t}) spectra of all the four complexes have CH2Te and ArC-Te signals deshie lded with respect to those of free L-1/L-2, indicating that the two ligands coordinate through Te only. The trans Pd-complexes 1 and 3 are characteriz ed structurally and their Pd-Te bond lengths (average) are 2.596 and 2.600 Angstrom, respectively. The Pd-CI bonds in 1 are marginally shorter (averag e 2.312 Angstrom) in comparison to those of 3 (average 2.325 Angstrom). The geometry of palladium is square planar. The Te-C(aryl) is shorter than Te- C(alkyl). The dimeric mercury complexes 2 and 4 appear to be formed through the formation two bromo bridges between Hg atoms. (C) 2000 Elsevier Scienc e B.V. All rights reserved.