Syntheses, Crystal Structures, and Magnetic Properties of Novel Manganese(II) Complexes with Flexible Tripodal Ligand 1,3,5-Tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene

Two novel metal-organic frameworks (MOFs)[Mn(titmb)(N3)2]·1.5H2O (1) and [Mn3(titmb)2(C2O4)3(H2O)]·10H2O
(2)were obtained by reactions of the flexible tripodal ligand 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene
(titmb) with Mn(OAc)2·4H2O, together with NaN3 and K2C2O4, respectively. The structures of these MOFs were
established by single-crystal X-ray diffraction analysis. The crystal data for 1 were as follows:  monoclinic, C2/c, a
= 20.956(13) Å, b = 9.884(6) Å, c = 24.318(14) Å, β = 95.87(5)°, Z = 8. The crystal data for 2 were as follows: 
triclinic, P1̄, a = 12.400(9) Å, b = 16.827(12) Å, c = 17.196(11) Å, α = 66.35(5), β = 95.87(5)°, γ = 71.03(6),
Z = 2. Complex 1 is a novel noninterpenetrating three-dimensional (3D) framework, in which the azide ligand
connects MnII atoms in an end-to-end (EE) mode to give [Mn−N−N−N−]n infinite one-dimensional (1D) chains, and
complex 2 has a two-dimensional (2D) network structure in which the MnII ions are linked by the oxalate anions
to form 1D [Mn(C2O4)]n chains. Each titmb in these two complexes connects three metal atoms and serves as a
three-connecting ligand. The magnetic properties of 1 and 2 were investigated. The results showed that the
antiferromagnetic interactions occurred between the MnII ions linked by the azide ligands in complex 1, and those
linked by the oxalate anions and the carboxylate in syn−anti coordination mode in complex 2. The entirely different
structures of complexes 1 and 2, on one hand, indicate that the azide and the oxalate ligands affected the structures
of MOFs greatly, and on the other hand, reveals the potential applications of MOFs with the azide and oxalate
ligands, which are efficient magnetic couplers.