Substituted phenanthrolines and their metal chelates

Abstract

Substituents at and adjacent to the nitrogen atoms in 2,2?-bipyridyl and 1,10-phenanthroline are most likely to cause drastic changes in the magnetic properties of complexes with these ligands. Complexes of the N-oxides (2,2?-bipyridine 1,1?-dioxide, and 1,10-phenanthroline 1- oxide) with copper, and of 2-substituted phen (substituent = Cl, CONH₂) with iron(II) are investigated, and a new one-step reaction to convert phno into cphn is reported. The copper complex Cu(bpyo)Br₂ shows antiferromagnetic interactions, but other complexes Cu(bpyo)X₂ (X = Cl, NO₃) with this ligand are magnetically normal, as are Cu(phno)Cl₂ and Cu(phno)Br₂. The complex [Fe(cphn)₃] (ClO₄)₂ lies near the high spin-low spin crossover for iron(II), and its magnetic moment is normal at room temperature but falls with decreasing temperature. The dioxide of phen appears not to be formed by the literature method and no successful synthesis can be reported here.