Azido and thiocyanato bridged dinuclear Ni(II) complexes involving 8-aminoquinoline based Schiff base as blocking ligands: Crystal structures, ferromagnetic properties and magneto-structural correlations

摘要

The use of two 8-aminoquinoline-based tridentate N-3-donor rigid Schiff base ligands (L1 and L2) with Ni (II) in the presence of the pseudohalides, NaN3 and NaSCN results in the crystallization of the two novel Ni(II) dimers: [Ni2(()L1)(2)(mu(1,1')-N-3)(2)(N-3)(2)] (1) and [Ni-2(L-2)(2)(mu(1,3)-NCS)(2)(NCS)(2)] (2). Both complexes are centrosymmetric Ni(II) dimers where the Schiff base ligands coordinate the octahedral Ni(II) centres in a mer configuration with one terminal and two bridging pseudohalide ligands in the remaining positions. Complex 1 shows Ni(II) ions connected by a double mu(1,1')-N-3 bridge whereas in complex 2 the Ni(II) ions are connected by a double mu(1,3)-NCS bridge. The magnetic properties show the presence of a weak ferromagnetic coupling in both compounds that can be fit with g = 2.290(6), J = 6.1(2) cm(-1), zJ' = -0.32 (1) cm(-1) and vertical bar D vertical bar = 4.34(5) cm(-1) for 1 and g = 2.096(2), J = 4.71(5) cm(-1), zJ' = -0.054(2) cm(-1) and vertical bar D vertical bar = 1.52(2) cm(-1) for 2 (the Hamiltonian is written as 2JS(1)S(2)). Both J values have been rationalized in terms of previous magneto structural correlations based on the Ni-N-Ni bridging angle in 1 and on the asymmetry of the Ni-S-C-N-Ni bridges in 2. (C) 2020 Elsevier Ltd. All rights reserved.