engleski

Novel oxalate compounds of chromium(III) as ligands for the design of heteropolynuclear species

Oxalate anion (ox) has the ability to adopt the bis(chelating) coordination mode which makes it a suitable starting material for the preparation of oxalate-bridged complexes. Moreover, the oxalate bridge can efficiently mediate exchange interactions between paramagnetic metal ions, leading to interesting magnetic properties. On this account, stable mononuclear oxalate complexes are widely used as ligands towards other metal ions - an approach known as "complexes as ligands" or "building-blocks chemistry". We report here two new mononuclear compounds, [Cr(phen)(ox)2][phenH]·2H2O (1) with a chromium(III) complex anion, and [Cr(phen)2(ox)]NO3·H2C2O4 (2) containing a chromium(III) complex cation. To complete the coordination sphere of chromium(III) we introduced 1, 10-phenanthroline (phen) because this ligand can play a significant role on the overall structure, by means of aromatic stacking interactions. The new mononuclear compounds were obtained by self-assembling of the chromium(III) anion, the phenanthrolinium cation and water molecules in compound 1, and the chromium(III) cation, the nitrate anion and one oxalic acid molecule in compound 2. In the reactions of these chromium(III)-oxalate bricks with other transition metal ions we have managed to synthesize a number of new heterobinuclear compounds so far, and further research on the reactivity of these compounds is in progress.

chromium(III); oxalate compounds; 1; 10-phenanthroline; synthesis; characterization

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