N-{2-(4-methoxyphenyltelluro)ethyl}morpholine (L1) and its platinum(II) and ruthenium(II) complexes. Synthesis and crystal structure of L1 and trans-[PtCl2(L1)2]

The first tellurated derivative of morpholine, N-{2-(4-methoxyphenyltelluro)ethyl}morpholine (L1) has been synthesized by reacting in situ generated ArTe− with 4-(2-chloroethyl)morpholine hydrochloride under N2 atmosphere. The compound L1 gives molecular ion peak at m/z 351 and is characterized structurally. The donor atoms N and Te in compound L1 are rightly oriented for its ligation in bidentate mode. The TeC(alkyl) is 0.02 Å longer than TeC(aryl). The complexes of ligand L1 having composition [PtCl2(L1)2] (1) and [RuCl2(p-cymene)L1] (2) have been synthesized. The compound 1 has been characterized structurally. The Pt has a square planar geometry in complex 1 and two molecules of ligand L1 bonded through Te alone are trans to each other (PtTe=2.583(2) Å). The 13C{1H} NMR spectrum of complex 1 is as expected. The 1H NMR spectrum of single crystals of complex 1 shows multiplication of signals, which is supported by HETCOR experiments. The complex 2 also has ligand L1 in a monodentate coordination mode, bonded through Te alone. This is supported by deshielded CH2Te and ArCTe signals in 1H and 13C{1H} NMR spectra of complex 2 with respect to those of free ligand L1. The HETCOR spectrum of complex 2 has been used to authenticate the assignments of CH2Te group, as its two protons appear to be magnetically non-equivalent.