Structural and Electronic Rearrangements upon the Oxidation of Binuclear (Ru2) and Trinuclear (MoRu2) Complexes with Bridging o-Phenylenediamido Ligands
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- 作者：Adela Anillo ; M. Rosario Dí ; az ; Santiago Garcí ; a-Granda ; Ricardo Obeso-Rosete ; Agustí ; n Galindo ; Andrea Ienco ; and Carlo Mealli
- 刊名：Organometallics
- 出版年：2004
- 出版时间：February 2, 2004
- 年：2004
- 卷：23
- 期：3
- 页码：471 - 481
- 全文大小：365K
- 年卷期：v.23,no.3(February 2, 2004)
- ISSN：1520-6041
文摘
The redox capabilities of some binuclear and trinuclear ruthenium complexes with bridgingo-phenylendiamido ligands, C6H4(NH)2-o, have been investigated. The known species [Ru2{
mages/entities/mgr.gif">-C6H4(NH)2-o}(mages/entities/mgr.gif">-dppm)(CO)2(PPh3)2] (1) and [Ru2Mo{mages/entities/mgr.gif">-C6H4(NH)2-o}2(CO)6(PPh3)2] (5),reacted with [Fe(Cp)2](PF6), yield the salts [Ru2{mages/entities/mgr.gif">-C6H4(NH)2-o}(mages/entities/mgr.gif">-dppm)(CO)2(PPh3)2](PF6)2(2) and [Ru2Mo{mages/entities/mgr.gif">-C6H4(NH)2-o}2(CO)6(PPh3)2](PF6)2·CH2Cl2 (6), respectively (dppm = Ph2PCH2PPh2). Binuclear compounds analogous to 2 were obtained with pairs of PPh3 or COligands in place of the diphosphine dppm. The redox properties of the compounds have beenexplored also with electrochemical methods. The structural determinations of 2 and 6 show,as an evident consequence of the oxidation, the bending of the originally upright C6H4(NH)2-obridge toward one metal that is eventually mages/gifchars/eta.gif" BORDER=0 >4-coordinated by the ligand. In the trinuclearspecies 6, such a bending is limited to only one bridge and is directed toward the centralmolybdenum atom. Another structural consequence, attributable to electronic effects, is thereciprocal reorientation of two terminal L3M fragments with modes that are different in 2and 6, respectively. These aspects have been highlighted through a theoretical analysis withDFT calculations and an extension of the perturbation theory arguments already introducedfor the precursors 1 and 5. There is evidence that, in each case, the oxidation affects mainlythe bridging chelate C6H4(NH)2-o that transforms from diamido to diimino in character. Theactivated back-donation from the mages/gifchars/eta.gif" BORDER=0 >4-coordinated metal into the diimino ligand causes alsoan evident weakening of the metal-metal bond. Complex 6 represents the first well-characterized case where one o-phenylenediamido and one o-diiminobenzene coexist asligands.