SYNTHESIS AND X-RAY CHARACTERIZATION OF SOME HETEROMETALLIC HG-M COMPLEXES WITH 2-OXAZOLIDONE

Mercury(II) acetate reacts with 2-oxazolidone (1,3-oxazolidin-2-one, C3H5NO2) in methanol to produce [HgL2] (L = C3H4NO2, the anion of 2-oxazolidone). An X-ray diffraction study has shown that the Hg atom binds to the ring nitrogen atom with a near linear N-Hg-N geometry. There are two HgL2 groups in the asymmetric unit which are orthogonal to one another and linked via pairs of Hg ... 0 interactions to form dimers. These bind to neighbouring units via weaker Hg-0 interactions to form a one-dimensional chain polymer. When yttrium or lanthanide(III) nitrates are added to the reaction an isostructural series of compounds of formula [{Hg2L4M(NO3)3}n], where M = La-Yb or Y, is obtained. A representative member of this group, [{Hg2L4Gd(NO3)3}n], was studied by single-crystal X-ray diffraction methods. This forms a two-dimensional polymeric array comprising two sizes of metallamacrocyclic rings (16- and 48-membered) fused together, with the gadolinium(III) ion surrounded by nine oxygen atoms in a trigonal tricapped-prismatic arrangement. The IR, UV/VIS reflectance, EPR and solid-state NMR spectroscopic properties of these complexes and, where appropriate, those of [Hg3L6Co(NO3)2] and [Hg2L4Zn-(NO3O1.33(OMe)0.67] are reported.