[Ru(bpy) 2 (bqdiBr 2 )](PF 6 ) 2 bearing a 3,6-dibromo-1,2-benzoquinone diimine ligand (bqdiBr 2 =Br-C 6 H 2 (NH) 2 -Br): Synthesis and its cross coupling reactions with organostannanes and organoboronic acids

[Ru(bpy)(2)(bqdiBr(2))](PF6)(2) ([1](PF6)(2), bpy = 2,2'-bipyridyl, bqdiBr(2) = 3,6-dibromo-1,2-benzoquinone diimine) was synthesized by the reaction of 3,6-dibromo-1,2-phenylenediamine with [RuCl2(bpy)(2)] in air, and the reactivity of [1](PF6)(2) in Pd-catalyzed cross-coupling reactions with metalated thiophene and benzene was investigated. The structure of [1](PF6)(2) was determined using X-ray crystallography. The Migita-Kosugi-Stille cross-coupling of [1](PF6)(2) with 2 equiv of Th-SnBu3 (Th = 2-thienyl; Bu = butyl) afforded a 3,6-di(2-thienyl)-1,2-benzoquinone diimine (Th-C6H2(NH)(2)-Th)-coordinated Ru(II) complex [2](PF6)(2). Similarly, the Suzuki-Miyaura cross-coupling of [1](PF6)(2) with 2 equiv of CH3OC6H4-B(OH)(2)-p proceeded smoothly to afford a p-CH3OC6H4-C6H2(NH)(2)-C6H4OCH3-p-coodinated Ru(II) complex, [3](PF6)(2). The optical and electrochemical properties of these complexes were evaluated based on the presence of the extended pi-conjugated diimine ligand in the diimine moiety. The Stille cross-coupling of [1](PF6)(2) with 1 equiv of Me3Sn-C4H2S-SnMe3 (C4H2S: thiophene-2,5-diyl) afforded a pi-conjugated polymer consisting of the [Ru(bpy)(2)(bqdi)](2+) units. (C) 2014 Elsevier B.V. All rights reserved.