Trinuclear Nickel(II) Complex through a 2,3,5,6-Tetrakis(2-pyridyl)pyrazine Ligand with a Linear Exchange Pathway

The compound [Ni3(tppz)2(NCS)2(H2O)4](NO3)4·4H2O [tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine and NCS = thiocyanate ligand] consists of trimeric units, where the three NiII cations are linked by two bis-tridentate tppz ligands. This compound crystallizes in the monoclinic space group C2/c, with Z = 4, a = 25.1116(12) A, b = 10.8127(5) A, c = 25.2294(13) A, and β = 116.856(5)°. The crystal structure is in good agreement with the antiferromagnetic interactions because of unidirectional coupling through the tppz ligands.