Heterobimetallic Lantern Complexes That Couple Antiferromagnetically through Noncovalent Pt···Pt Interactions

A series of Pt-based heterobimetallic
lantern complexes of the form [PtM­(SAc)4(OH2)] (M = Co, 1; Ni, 2; Zn, 3) were prepared using a facile, single-step procedure. These hydrated
species were reacted with 3-nitropyridine (3-NO2py) to
prepare three additional lantern complexes, [PtM­(SAc)4(3-NO2py)] (M = Co, 4; Ni, 5; Zn, 6), or alternatively dried in vacuo to the dehydrated species
[PtM­(SAc)4] (M = Co, 7; Ni, 8; Zn, 9). The Co- and Ni-containing species exhibit
PtM bonding in solution and the solid state. In the structurally
characterized compounds 1–6, the
lantern units form dimers in the solid state via a short Pt···Pt
metallophilic interaction. Antiferromagnetic coupling between 3d metal
ions in the solid state through noncovalent metallophilic interactions
was observed for all the paramagnetic lantern complexes prepared,
with J-coupling values of −12.7 cm–1 (1), −50.8 cm–1 (2), −6.0 cm–1 (4), and −12.6
cm–1 (5). The Zn complexes 3 and 6 also form solid-state dimers, indicating that
the formation of short Pt···Pt interactions in these
complexes is not predicated on the presence of a paramagnetic 3d metal
ion. These contacts and the resultant antiferromagnetic coupling are
also not unique to heterobimetallic lantern complexes with axially
coordinated H2O or the previously reported thiobenzoate
supporting ligand.