Artículos de revistas
Synthesis, properties and gas phase collision-induced dissociation of the heptanuclear doubly bridged complex [Ru(bpy)(2)(BPE)(2){Ru3O(CH3COO)(6)(py)(2)}(2)](PF6)(4)
Registro en:
Polyhedron. Pergamon-elsevier Science Ltd, v. 24, n. 6, n. 731, n. 738, 2005.
0277-5387
WOS:000228779500002
10.1016/j.poly.2005.01.020
Autor
Toma, HE
Nikolaou, S
Eberlin, MN
Tomazela, DM
Institución
Resumen
The [Ru(bpy)(2)(BPE)(2){Ru3O(CH3COO)(6)(py)(2)}(2)](PF6)(4) complex, in which bpy = 2,2'-bipyridine, BPE = trans-1,2-bis(4-pyridyl)ethylene and py = pyridine, provides an interesting case of a heptanuclear mixed compound containing two triangular [Ru3O] clusters attached to a ruthenium polypyridine center. The composition and structural properties of this doubly bridged complex were investigated by means of electrospray mass (ESI-MS) and tandem mass (ESI-MS/MS) spectrometric experiments and NMR spectroscopy (H-1 and C-13). The characteristic multi-isotopic distribution, 1/4 m/z peak separation and dissociation chemistry of the isotopologue [Ru(bpy)(2)(BPE)(2){Ru3O(CH3COO)(6)(py)(2)}(2)](4+) cation provided detailed and unequivocal MS characterization of the complex. In the electronic spectra of the heptanuclear complex broad bands were observed at 427 and 696 nm, and ascribed, respectively, to [Ru(bpy)(2)(BPE)(2)] metal-to-ligand charge-transfer and to [Ru3O] internal cluster transitions. The characteristic waves associated with the [Ru3O](1-/0/1+/2+/3+) redox couples were found at -1.02, 0.16, 1.20, 2.11 V (versus SHE) in the cyclic voltammograms. Another broad wave was observed at -1.22 V, involving superimposed bpy(0/-) and BPE0/1- redox processes, and a peculiar wave at 1.48 V. exhibiting only a half of the relative intensity, was assigned to the central Ru3+/2+ redox pair. Despite the two conjugated BPE bridges, the electrochemical and spectroelectrochemical data indicated only a weak coupling through the TU-system in the heptanuclear complex. (c) 2005 Elsevier Ltd. All rights reserved. 24 6 731 738