Photoinduced Etherification of Ru(II)‐Coordinated Chloromethyl‐Modified 2,2′‐Bipyridine Complex and Structural Characterization of Its Photoproducts

The introduction of alkyl chains into Ru(II) polypyridyl complexes is important for synthesizing functional Ru‐based materials. Generally, alkyl chains are introduced by organic synthesis. Herein, a synthesis method, involving photodisplacement of the chlorides to produce ether‐substituted Ru(II) polypyridyl complexes, is developed. The starting complex, [Ru(phen) 2 {(ClCH 2 ) 2 bpy}](OTf) 2 (phen = 1,10‐phenanthroline, bpy = 2,2′‐bipyridine, OTf −  = CF 3 SO 3 − ), is selectively synthesized in sufficient yield (87%) by reacting cis ‐[Ru(OH 2 ) 2 (phen) 2 ](OTf) 2 with 4,4′‐bis(chloromethyl)‐2,2′‐bipyridine ((ClCH 2 ) 2 bpy) in ethanol (EtOH) under reflux in the dark. Photodisplacement of the chlorides in [Ru(phen) 2 {(ClCH 2 ) 2 bpy}](OTf) 2 in water, an alcohol, or acetic acid [ROH; R  = H, methyl (Me), Et, 1‐propyl (1‐Pr), 2‐propyl (2‐Pr), or acetyl (Ac)] afforded [Ru(phen) 2 {(ROCH 2 ) 2 bpy}](OTf) 2 and two moles of HCl per Ru(II) complex. These photoproducts are characterized by elemental analysis and 1 H NMR spectroscopy. Crystallographic analyses of [Ru(phen) 2 {(ClCH 2 ) 2 bpy}](PF 6 ) 2 ·Et 2 O, [Ru(phen) 2 {(HOCH 2 ) 2 bpy}](OTf) 2 , [Ru(phen) 2 {(MeOCH 2 ) 2 bpy}](OTf) 2 , and [Ru(phen) 2 {(1‐PrOCH 2 ) 2 bpy}](PF 6 ) 2 revealed that substituent RO groups are introduced through ether bonds and did not affect the structure of the [Ru(bpy)(phen) 2 ] 2+ core. The facile method for introducing alkyl chains into Ru(II) complexes via a photoreaction is expected to advance the development of photofunctional materials, photodynamic therapy drugs, and photoacid generators.