Iron and Manganese Complexes of 2‑Carbonyl Pyrrolyls: Scorpionate Sandwich Anions and Extended Structures
2015-06-08T00:00:00Z (GMT) by
Attempts to synthesize complexes of Fe and Mn(II) with 2-amidopyrrolyl ligands (N–O) were unsuccessful, and only small amounts of the trivalent tris complexes M(N–O)3 were detected, although unusually in the case of Fe(III) a fac structure is observed. In contrast the 2-benzoylpyrrolyl systems give M(II) complexes, and in all instances thus far where Na+ is present, a scorpionate fac-[MII(N–O)3]− unit self-assembles into sandwich anions [MII(N–O)3Na(O–N)3MII]− in which the central metal is efficiently encapsulated by interdigitation of the aryl units. Extended structures are readily made through the use of a 2-(4-pyridinoyl)pyrrolylamide ligand. When Li+ is used, the scorpionate ligand is not assembled, and instead [M(N–O)2] units give rhombic 2D grids. The Fe system displays spin-crossover at 120 K.