Transition metal complexes having 2,2'-bipyridine ligands substituted by at least one ammonium alkyl radical

A transition metal complex having three bidentate ligands at least two of which are substituted in the 4,4' position by quaternary ammonium alkyl groups with the formula ##STR6## wherein R.sub.1, R.sub.2, and R.sub.3 may be the same or different and each represents a straight chain or branched chain alkyl group having 1 to 5 carbon atoms or taken together with the adjacent nitrogen atom represent a heterocyclic radical having 5 to 7 carbon atoms;

• alk represents a straight chain or branched alkylene radical having 1 to 5 carbon atoms;
• R.sub.4 represents the group -alk-N.sup.+ R.sub.1 R.sub.2 R.sub.3 wherein alk, R.sub.1, R.sub.2, and R.sub.3 have the meanings given above;
• R.sub.5 to R.sub.8, which may be the same or different, represent hydrogen, or a hydroxy, alkoxy, aryloxy or primary, secondary or tertiary amino group or the group -alk-N.sup.+ (R.sub.1 R.sub.2 R.sub.3) wherein alk, R.sub.1, R.sub.2, and R.sub.3 have the meanings given above;
• M represents a transition metal selected from iron, ruthenium or osmium;
• x represents an anion selected from Cl, PF.sub.6.sup.-, BR.sup.-, or BF.sub.4.sup.- and n is an integer corresponding to the number of positive charges of the ligands and of the transition metal.