Nitrogenous chelate complexes of transition metals. VII. Complexes of silver(I) and silver(II) with tridentate chelating ligands

Abstract

Silver(1) complexes of 2,2',2"-terpyridine and a related Schiff base chelate 8-(or-pyridylmethyleneamino)quinoline have been prepared. They are of the type Ag(chelate)X, where X = NO₃, ClO₄, and PF₆. Both Ag(terpy)⁺ and Ag(pmq)⁺ are stable in solution and conductance measurements have been obtained. Ag(terpy)PF₆ is monomeric in nitrobenzene. Reaction of the above complex ions with pyridine or triphenylphosphine affords stable species of the form [Ag(chelate)(py)]⁺ and [Ag(chelate)(Ph₃P)]⁺ which have been isolated as their perchlorate salts. Both Ag(chelate)⁺ and [Ag(ohelate)L]⁺ involve unusual stereochemistry for Ag^I. The known paramagnetic Ag^II complexes Ag(terpy)X₂ (X = NO₃, ClO₄, ½S₂O₈) have been reprepared. They are unstable in solution and reduce readily to Ag^I. They all show magnetic moments in the range 1.7-1.9 B.M. Ag(terpy)²⁺ in an aqueous solution of Ce^Iv shows a strong absorption band at 470 mμ (880).