Thiocyanate-Ligated Heterobimetallic {PtM} Lantern Complexes Including a Ferromagnetically Coupled 1D Coordination Polymer

A series of heterobimetallic
lantern complexes with the central unit {PtM­(SAc)4(NCS)}
have been prepared and thoroughly characterized. The {Na­(15C5)}­[PtM­(SAc)4(NCS)] series, 1 (Co), 2 (Ni), 3 (Zn), are discrete compounds in the solid state, whereas
the {Na­(12C4)2)}­[PtM­(SAc)4(NCS)] series, 4 (Co), 5 (Ni), 6 (Zn), and 7 (Mn), are ion-separated species. Compound 7 is the first {PtMn} lantern of any bridging ligand (carboxylate,
amide, etc.). Monomeric 1–7 have
M2+, necessitating counter cations that have been prepared
as {(15C5)­Na}+ and {(12C4)2Na}+ variants,
none of which form extended structures. In contrast, neutral [PtCr­(tba)4(NCS)]∞ 8 forms a coordination
polymer of {PtCr}+ units linked by (NCS)− in a zigzag chain. All eight compounds have been thoroughly characterized
and analyzed in comparison to a previously reported family of compounds.
Crystal structures are presented for compounds 1–6 and 8, and solution magnetic susceptibility
measurements are presented for compounds 1, 2, 4, 5, and 7. Further structural
analysis of dimerized {PtM} units reinforces the empirical observation
that greater charge density along the Pt-M vector leads to more Pt···Pt
interactions in the solid state. Four structural classes, one new,
of {MPt}···{PtM} units are presented. Solid state magnetic
characterization of 8 reveals a ferromagnetic interaction
in the {PtCr­(NCS)} chain between the Cr centers of J/kB = 1.7(4) K.