Reaction of a bidentate ligands (4,4'-dimethyl 2,2'-bipyridine) with planar-chiral chloro-bridged ruthenium: Synthesis of cis-dicarbonyl[4,4'-dimethyl-2,2'-bipyridine- ?O1,?O2]{2-[tricarbonyl(?6-phenylene- ?C1)chromium]pyridine-?N}ruthenium hexafluorophosphate