Synthesis and Reactivity of Tethered η¹:η⁶-(Phosphinoarene)ruthenium Dichlorides

The coordination properties of ortho- and meta- substituted [(2-diphenylphosphanylethyl)phenyl]methanol 4a and 4b toward ruthenium(II) have been investigated. To ensure coordination of both the arene and the tethered phosphine, the labile ruthenium arene dimer [RuCl 2 (EtO 2 CC 6 H 5 )] 2 ( 7 ) was synthesized and structurally characterized. Both the ortho and meta isomers [Ru( 4a )Cl 2 ] ( 9a ) and [Ru( 4b )Cl 2 ] ( 9b ) were characterized by X-ray crystallography. The lack of reactivity of the benzylic alcohol functionality in complexes 9a and 9b toward various P and C electrophiles is rationalized with extended Hückel calculations.