Heterobimetallic {PtMn} and {PtFe} lantern complexes with exceptionally long metallophilic contacts

Abstract

A new series of heterobimetallic lantern complexes, [PtM(SAc)4(pySMe)] (M = Mn (1), Fe (2), Co (3), Ni (4), Zn (5)), as well as additions to the previously reported series, [PtM(SAc)4(pyNH2)] (M = Mn (6), Fe (7)), have been synthesized and thoroughly characterized. Notably, compounds 1 and 6 are the first crystallographically characterized, neutral Pt-Mn containing lantern complexes. Compounds 2 and 7 are the first examples of Pt-Fe containing lantern complexes with a pyridine based axial ligand. These newly synthesized complexes have been characterized by single-crystal X-ray diffraction and UV–vis (1–7), 1H and 13C NMR spectroscopies (5), and solution magnetic susceptibility (1–4 and 6–7) and analyzed in comparison to our previously reported lantern families. Compounds 2–4 are isomorphous and contain two crystallographically independent dimers with the same staggered conformations. One dimer has a typical Pt⋯Pt metallophilic interaction ranging from 3.2198(6) to 3.2913(6) Å while the other has a much longer contact ranging from 3.3212(6) to 3.4533(6) Å. These latter contacts suggest metallophilic interactions that are the longest reported to date in any system. Solid state variable-temperature magnetic susceptibility studies suggest antiferromagnetic coupling between the 3d metal centers in the two lantern complexes of the dimeric forms of 2, 3, and 4.