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

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 [M-II(NCS)(2)(py)(4)] (M-II = 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 Fe-II, two isotopological cubic 3D materials [Fe(NCS)(2)(4-tpt)(4/3)]center dot n(BzOH, ac) (1a(Bz, ac)) and [Fe(NCS)(2)(3-tpt)(4/3)]center dot n(BzOH, ac) (1b(Bz, ac)) were formed. However, with Co II a different 3D framework topology results, [Co(NCS)(2)(3-tpt)(4/3)]center dot(BzOH, ac) (2(Bz, ac)). Further synthetic variation leads to the isostructural 3D materials trans-[M-II(NCS)(2)(4-tpt)(4/3)]cis-[M-II(NCS)(2)(4-tpt)(2)]center dot 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.