Synthesis, Crystal Structures, and Properties of Mn(NCS)2 Coordination Compounds with 4‐Picoline as Coligand and Crystal Structure of Mn(NCS)2

Abstract

Reaction of Mn(NCS)2 with 4‐picoline (4‐methylpyridine) leads to the formation of [Mn(NCS)2(4‐picoline)4]·0.67·4‐picoline·0.33·H2O (1‐Mn) reported in literature, Mn(NCS)2(4‐picoline)2(H2O)2 (2‐Mn/H2O), and of [Mn(NCS)2(4‐picoline)2]n (2‐Mn/I). 1‐Mn and 2‐Mn/H2O consist of discrete complexes, in which the metal cations are octahedrally coordinated, whereas in 2‐Mn/I the metal cations are linked by pairs of μ‐1,3‐bridging thiocyanate anions into corrugated chains. Measurements using thermogravimetry and differential scanning calorimetry as well as temperature dependent X‐ray powder diffraction on 1‐Mn and 2‐Mn/H2O reveal that upon heating both compounds transform into [Mn(NCS)2(4‐picoline)]n (3‐Mn) via 2‐Mn/I as intermediate. 3‐Mn shows a very rare chain topology in which the metal cations are linked by μ‐1,3,3 (N,S,S) coordinating anionic ligands which was never observed before with MnII. From these investigations there is no hint that a further modification of 2‐Mn can be prepared as recently observed for [M(NCS)2(4‐picoline)2]n (M = Fe, Cd) and such a form is also not available if the metastable forms of the FeII or CdII compounds were used as template during thermal decomposition. Magnetic investigations on 2‐Mn/H2O show only paramagnetic behavior, whereas for 2‐Mn/I antiferromagnetic ordering is observed. Finally, the crystal structure of Mn(NCS)2 was determined from XRPD data, which shows that it is strongly related to that of 3‐Mn.