TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Disclosed): Ligand bis(2,2')bipyrydinyl-6-yl-amine derivative, 2,2'-bipyridine derivative and primary amine are reacted in the presence of base (metal alkoxide and the cesium carbonate) and catalyst (palladium salt), in aromatic hydrocarbon or aliphatic or cycloaliphatic hydrocarbon solvent, to obtain ruthenium complex of formula (I). SPECIFIC COMPOUNDS - 3 specific ruthenium complexes such as compound of formula (II), are disclosed.    EXAMPLE - Bis(4'-ethoxy carbonyl-(2,2') bipyrydinyl-6-yl)-octyl amine (in mg) (215) obtained from 6'-octyl amino-(2,2') bipyrydinyl-4-carboxylic acid ethyl ester and 6'-bromo-(2,2') bipyrydinyl-4-carboxylic acid ethyl ester, was dissolved in mixed solvent (40 ml) containing ethyl alcohol and water in volume ratio of 4:1, in nitrogen atmosphere. Lithium hydroxide monohydrate (34.1) was added to the resulting mixture, and refluxed. Ethyl alcohol was distilled after cooling the refluxed mixture. Ice water was added to residue (100 ml). pH of the solution was adjusted to 3 using 1N hydrochloric acid. The obtained precipitate was removed by filtration, washed with water and dried, to obtain bis-(4'-carboxy-(2,2')bipyrydinyl-6-yl)-octyl amine (172). Dichloro(p-cumene) ruthenium dimer (30.6) was dissolved in diglyme (10 ml) in argon atmosphere. Diglyme solution (5 ml) of bis-(4'-carboxy-(2,2')bipyrydinyl-6-yl)-octyl amine (52.5) was slowly added to the resulting solution. The reaction solution was stirred and refluxed for 150 minutes. The refluxed solution was cooled. The precipitated product was removed by filtration, washed using water and ether, and dried, to obtain green complex of (bis-(4'-carboxy-(2,2')bipyrydinyl-6-yl)-octyl-amine)dichloro ruthenium (57.2). The obtained (bis-(4'-carboxy-(2,2')bipyrydinyl-6-yl)-octyl-amine)dichloro ruthenium (57.7) was dissolved in dimethyl formamide (15 ml) in argon atmosphere. Aqueous solution of ammonium thiocyanate (377) was slowly added to the resulting solution. The reaction solution was stirred and refluxed for 4 hours. The refluxed solution was cooled. The resulting product was removed by filtration, washed with water and ether, dried and purified using mixed solvent containing methyl and chloroform in a ratio of 1:1, to obtain purple complex of trans-form (bis-(4'-carboxy-(2,2')bipyrydinyl-6-yl)-octyl-amine)dithio cyanate ruthenium. A solar cell obtained from the (bis-(4'-carboxy-(2,2')bipyrydinyl-6-yl)-octyl-amine)dithio cyanate ruthenium, had short circuit current of 11.8 mA/cm2, open circuit voltage of 0.58V and energy conversion efficiency of 4.3%.