A Family of Three-Dimensional Molecular Framework Materials Containing the Three-Connecting Ligands 2,4,6-Tris(n'-pyridyl)-1,3,5-triazine: 3-tpt and 4-tpt

Abstract

Three-dimensional (3D) framework materials containing the ligands 2,4,6-tris(4′-pyridyl)-1,3,5-triazine (4-tpt) and 2,4,6-tris(3′-pyridyl)-1,3,5-triazine (3-tpt) have been prepared and their structure and magnetic properties investigated. The [MII(NCS)2(py)4] (MII = Fe, Co, py = 3-tpt, and 4-tpt) coordination environments in these materials have been targeted in an effort to prepare high-dimensional coordination polymers which contain spin crossover (SCO) centres. Using FeII, two isotopological cubic 3D materials [Fe(NCS)2(4-tpt)4/3]·n(BzOH,ac) (1a(Bz,ac)) and [Fe(NCS)2(3-tpt)4/3]·n(BzOH,ac) (1b(Bz,ac)) were formed. However, with CoII a different 3D framework topology results, [Co(NCS)2(3-tpt)4/3]·(BzOH,ac) (2(Bz,ac)). Further synthetic variation leads to the isostructural 3D materials trans-[MII(NCS)2(4-tpt)4/3]cis-[MII(NCS)2(4-tpt)2]·n(tce, EtOH) (Fe: 3a(Tce,Et) and Co: 3b(Tce,Et)) which form 3D networks outside Wellsian classification – and for which uniquely both two- and three-connecting modes of 4-tpt are present in the one complex. Despite having the metal coordination environments for which SCO has previously been observed, magnetic susceptibilities of this family of materials reveal a high spin nature.