Pendant-bridging-chelating-cleavage: A series of bonding modes in ruthenium(II)-BINAPO complexes

Reaction of 1,1'-bis(diphenylphosphino)binaphthol (BINAPO, 1) with [RuCl<sub>2</sub>(η<sup>6</sup>-arene)]<sub>2</sub> in methanol leads to dinuclear BINAPO-bridged Ru compounds [{RuCl<sub>2</sub>(η<sup>6</sup>-p-cymene)}<sub>2</sub>-(μ-BINAPO)], 2a, in near quantitative yield. In dichloromethane or acetonitrile, 1 preferably affords mononuclear species in which one of the phosphine centers remains uncoordinated. These complexes can be further stabilized by reaction with BH<sub>3</sub> to afford, for example, [RuCl<sub>2</sub>(η<sup>6</sup>-p-cymene)(η<sup>1</sup>-BINAPO-BH<sub>3</sub>)], 4a. Upon heating a mixture of 1 and [RuCl<sub>2</sub>(η<sup>6</sup>-p-cymene)](2) in DMF, P-O bond cleavage occurs to afford [RuCl(η<sup>2</sup>-PPh<sub>2</sub>-BINOL)(η<sup>6</sup>-p-cymene)], 5a, bearing an anionic PO-chelating ligand. Ligand 1 acts as an intact chelate when reacted with [Ru<sub>2</sub>(μ-Cl)<sub>3</sub>(η<sup>6</sup>-p-cymene)<sub>2</sub>][PF<sub>6</sub>] to yield [RuCl(η<sup>6</sup>-p-cymene)(η<sup>2</sup>-BINAPO)][PF<sub>6</sub>], 7. Reaction of 1 with [RuCp(CH<sub>3</sub>CN)<sub>3</sub>] [PF<sub>6</sub>] in acetonitrile or chloroform affords [{RuCp(CH<sub>3</sub>CN)<sub>2</sub>}<sub>2</sub>(μ-BINAPO)][PF<sub>6</sub>]<sub>2</sub>, 8, and [RuCp(CH<sub>3</sub>CN)(η<sup>2</sup> -BINAPO)][PF<sub>6</sub>], 9, respectively. The solid-state structures of 1, 2a, 4a, and 7 are reported, that of 2a representing a rare structural example of a molecule with a bridging binaphthyl-type ligand.

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Organometallics, 24, 21, 4974-4980

 Record created 2006-02-13, last modified 2019-05-27

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