TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Composition: The semiconductor layer in the optoelectric transducer contains titanium oxide or tin oxide.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation: No general preparation is given. Preferred Compounds: The metal complex is preferably expressed with formula (III).R1-R4,R',m1-m4=as defined above;X1,X2=NCS;andM=ruthenium. Preferred Definitions:    M=element chosen from iron, ruthenium, osmium, copper, tungsten, chromium, molybdenum, nickel, palladium, platinum, cobalt, iridium, rhodium, rhenium, manganese or zinc;and    X1,X2=NCS.    SPECIFIC COMPOUNDS - The metal complex is chosen from 3 disclosed compounds such as compound of formula (A).    EXAMPLE - Hexane solution (72.6 ml) of n-butyl lithium (1.6 M), anhydrous tetrahydrofuran solution (200 ml) of 2-bromo picoline (in g) (20), and tributyl tin chloride (31.6 ml) were reacted to form 2-tributyl stannyl-4-picoline with yield of 83%. The 2-tributyl stannyl-4-picoline (6.23), 2,6-dibromo pyridine (9.08) and tetrakis(triphenyl phosphine)palladium(0) (0.613), were reacted to form 6-bromo-4'-methyl-2,2'-bipyridine (A). The compound (A) (13.5), potassium dichromate (41.6), were reacted at 70-80degreesC for 4 hours to form 6-bromo-4'-carboxy-2,2'-bipyridine (B). The compound (B) (8.8) was added with concentrated sulfuric acid (20 ml) in absolute ethanol solution and refluxed for 4 hours. Then, aqueous ammonia was added to adjust the pH, and 6-bromo-4'-ethoxy carbonyl-2,2'-bipyridine (C) was obtained. The compound (C) (70 mg), nickel bromo triphenyl phosphine complex of formula: NiBr2(PPh3)2 (100 mg), tetrahydrofuran (20 ml), zinc (120 mg) and nitrogen-containing compound of formula: n-Bu4NI (86 mg) were, reacted at 50degreesC for 16 hours. The formed colorless solution was added with ammonia aqueous solution (60 ml). The obtained organic phase was washed, dried and concentrated. The residue was dissolved in concentrated in hydrochloric acid, and the unreacted raw material was removed by extracting with methylene chloride. The water phase was neutralized by sodium carbonate and extracted with methylene chloride. The generated organic phase was dried, concentrated and purified to form to form 4,4'''-diethoxy carbonyl-2,2':6',2":6",2'''-tetra pyridine (D) with yield 38.6%.