Anionic dihalotetraacetatodiruthenium(II,III) compounds

摘要

The synthesis and characterization of Q[Ru2Cl2(mu-O2CMe)(4)] [Q = NEt4 (1), PPh4 (2)], Q[Ru2Br2(mu-O2CMe)(4)] [Q = NEt4 (3), PPh4 (4), K (5)] and Q[Ru2I2(mu-O2CMe)(4)] [Q = NEt4 (6), PPh4 (7)] are described. All compounds have been characterized by elemental analysis. spectroscopic, mass and magnetic data. The structures of 1-3, 5 and 7 are determined by the single crystal X-ray diffraction method. The RU-Ru bond distances vary from 2.2956(5) to 2.312(3) Angstrom, slightly longer than those observed in the corresponding discrete dinuclear complexes Ru2X(mu-O2CR)(4)(S) (S = solvent molecule) with Ru-X terminal and in the polymeric arrangement [Ru2X(mu-O2CR)(4)](n) with Ru-X-Ru bonds. The anionic complexes have two axially coordinated halide ligands. The Ru-X bond distance is in accordance with the size of the axial ligand. Thus, the Ru-Cl bond lengths are 2.5396(15) and 2.5627(10) Angstrom, respectively for 1 and 2; the Ru-Br distances are 2.6763(14) (3) and 2.6779(4) Angstrom (5), and the Ru-I length are 2.897(2) and 2.893(2) Angstrom in 7. The crystal structure determination of complexes 3 and 5 constitutes the first examples of dibromotetracarboxylatodiruthenium(II, III) compounds. The electronic properties of all the compounds are also explored. Their solvatochromism is less accentuated than the corresponding monohalo derivatives. (C) 2004 Elsevier Ltd. All rights reserved.