One-pot and selective synthesis of a series of [RuCl6−2nLn] (L=bidentate ligand, n=0−3) types of complexes with polypyridyl ligands; another example of the synthetic utility of ‘ruthenium-blue’ solution
摘要:
Convenient (one-pot) and selective syntheses of a series of ruthenium complexes with polypyridyl ligands, [RuL3]2+, cis-[RuCl2L2]+ and [RuCl4L]- (L=bpy, phen or Hdpa (di-2,2-dipyridylamine)), including [RuCl6]3-, have been reported as further examples of the synthetic utility of 'ruthenium-blue' solution. The methods developed here are also useful for synthesizing selectively such pair complexes as [Ru(III)Cl3(terpy)]-[Ru(II)(terpy)2]2+ and [Ru-(III)Cl4py2]--[Ru(II)Cl2py4].
Formation of optically active [Ru(bipy)<sub>2</sub>Cl<sub>2</sub>](bipy = 2,2′-bipyridyl) by photodissociation of [Ru(bipy)<sub>3</sub>]Cl<sub>2</sub>in dichloromethane
An optically active bis-chelated complex, [Ru(bipy)2Cl2] (bipy = 2,2'-bipyridyl), has been obtained when enantiomeric [Ru(bipy)3]Cl2 was illuminated by visible light in dichloromethane. From the dependence of the optical purity of the product on light intensity, it is proposed that the reaction from DELTA-[Ru(bipy)3]Cl2 to DELTA-[Ru(bipy)2Cl2] (Chirality retention) proceeds by way of the dissociation of a monodentate ligand, bipy*, from a photoactivated intermediate, DELTA-[Ru(bipy)2(bipy*)Cl]Cl in the dark, while the reaction to LAMBDA-[Ru(bipy)2Cl2] (chirality inversion) involves the further photoactivated configurational change of DELTA-[Ru(bipy)2(bipy*)Cl]Cl to LAMBDA-[Ru(bipy)2(bipy*)Cl]Cl. Racemization is avoided under the conditions of weak light and high temperature. The synthetic value of optically active [Ru(bipy)2Cl2] as a chiral intermediate has been exemplified by preparing a new chiral amphiphilic ruthenium(II) complex.