Coordination Chemistry Reviews 219–221 (2001) 187–234 Monomeric and extended oxo-centered triruthenium clusters Henrique E. Toma *, Koiti Araki, Anamaria D.P. Alexiou, Sofia Nikolaou, Sergio Dovidauskas Instituto de Quı ´mica, Uniersidade de Sa ˜o Paulo, C. Postal 26077 CEP 05513 -970, Sa ˜o Paulo, SP, Brazil Received 20 September 2000; accepted 19 December 2000 Dedicated to Professor Alfred B. Lever on the occasion of his 65th birthday Contents Abstract .................................................... 188 1. Introduction ............................................... 188 2. Monomeric trinuclear clusters ..................................... 189 2.1 Synthetic aspects .......................................... 189 2.2 Structural aspects ......................................... 190 2.3 Kinetic behavior .......................................... 193 2.4 Electrochemical and spectroelectrochemical behavior ..................... 194 2.5 Properties and catalytic activity ................................. 202 3. Ligand-bridged dimers ......................................... 202 4. Ligand-bridged trimeric clusters .................................... 206 5. Ligand-bridged tetrameric clusters ................................... 207 6. Ligand-bridged cyclic polymeric clusters ............................... 211 7. Mixed polynuclear clusters ....................................... 214 8. Polynuclear porphyrin – ruthenium clusters .............................. 219 8.1 Tetraelectronic dioxygen reduction by CoTCP films ..................... 226 8.2 Cytochrome P-450 catalytic activity of MnTCP ........................ 229 9. Final remarks .............................................. 230 Acknowledgements ............................................. 231 References .................................................. 231 www.elsevier.com/locate/ccr * Corresponding author. Tel.: +55-11-3818-3887; fax: +55-11-3815-5579. E-mail address: henetoma@iq.usp.br (H.E. Toma). 0010-8545/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved. PII:S0010-8545(01)00326-5