TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preparation (Claimed): Preparation of (I) comprises: dissolving the transition metal with coordinated solvent in other solvents; adding terpyridine compounds of formula (II); (c) heating the mixture at 45-140 degrees C for 60-1440 minutes; cooling the mixture and/or removing the solvent, purifying the reaction product, and renewing lots of the solid with solvent; mixing the solution from the above step with aqueous salt solution; and (f) filtering and optionally processing the precipitated precipitation. Preferred Process: The process comprises: dissolving dichlorotetrakis(dimethyl sulfoxide) ruthenium complex (Ru(DMSO)4Cl2) or trichlorotetrakis(dimethyl sulfoxide) iridium complex (Ir(DMSO)4Cl3) in dimethylformamide; adding 2',6'-di-(2:2''-pyridylcarbonyl)pyridine; heating the mixture at 90-110 degrees C for 240-480 minutes; cooling the mixture and removing the solvent, purifying the reaction product, by chromatography, with acetonitrile/water/saturated potassium nitrate solution in a volume ratio of 80:20:2 as eluent, renewing lots of the solid with methanol; mixing the above solution with aqueous ammonium hexafluorophosphate solution; and filtering and processing the precipitated precipitation. Preferred Definitions:    A = benzyl-, phenyl-, ethynyl-, -F, -OH, -NH2 or -H (preferred);    X = O (preferred), S or NH;    M = Cr3+, Mn2+, Re+, Re3+, Fe3+, Fe2+, Ru2+, Ru3+, Co2+, Co3+, Rh+, Rh3+, Ir3+, Ni2+, Ni3+, Pd2+, Pt2+ or Pt3+; and    Z = BF4-, ClO4-, SO42-, PO43-, F-, Cl-, Br-, I-, NO3-, PF6-, O2-, OH-, CO32-, CN-, CF3SO3-, (iso)cyanate, (iso)thiocyanate, tetraphenylborate or acetate.    SPECIFIC COMPOUNDS - 2 Complexes (I) are specifically claimed i.e. bis(2',6'-di-(2:2''-pyridylcarbonyl)pyridine)ruthenium(II)-hexafluorophosphate of formula (Ia) and bis(2',6'-di-(2:2''-pyridylcarbonyl)pyridine)iridium(III)-hexafluorophosphate.    EXAMPLE - Dichlorotetrakis(dimethyl sulfoxide) ruthenium complex (Ru(DMSO)4Cl2) (206 mu mole) was completely dissolved in dimethylformamide (30 ml). Then 2,6-bis(2-picolinyl)pyridine (515 mu mole) was added and heated at 100 degrees C for 10 hours. Then the mixture was cooled to room temperature and the solvent was removed. The obtained mixture was worked up to give bis(2',6'-di-(2:2''-pyridylcarbonyl)pyridine)ruthenium(II)-hexafluorophosphate.