Selective synthesis and crystal structures of manganese(I) complexes with a bi- or tridentate terpyridine ligand

The crystal structures of two manganese(I) complexes with a different coordination mode of the supporting ligand are reported: fac-bromidotricarbonyl(4′-phenyl-2,2′:6′,2′′-terpyridine-κ2 N,N′)manganese(I), [MnBr(C21H15N3)(CO)3], I, and cis-bromidodicarbonyl(4′-phenyl-2,2′:6′,2′′-terpyridine-κ3 N,N′,N′′)manganese(I), [MnBr(C21H15N3)(CO)2], II. In both complexes, the manganese(I) atom is coordinated by terminal carbonyl ligands, a bromide ion, and a 4′-phenyl-2,2′:6′,2′′-terpyridine ligand within a distorted octahedral environment. In I, the metal ion is facially coordinated by three carbonyl ligands and the terpyridine ligand binds in a bidentate fashion. The non-coordinating nitrogen atom in the terpyridine ligand is positioned on the side opposite to the bromido ligand. In II, the metal ion is coordinated by two carbonyl ligands in a cis configuration and the terpyridine ligand binds in a tridentate fashion; notably, one carbonyl and the trans bromido ligand are mutually disordered over two positions. In I, the complex molecules are linked by C—H...Br hydrogen bonds. In II, aromatic π–π contacts are present, as well as pairs of C—H...Br and C—H...O hydrogen bonds.