Résumé
Btzn (1), an amine-functionalized bi(1,3,5-triazine) 4,4'-(NH2)(2)-6,6'-(NHC6H5)(2)-2,2'-(1,3,5-C3N3)(2), is reported, and its coordination with Co, Ni and Cu is explored. Reactions of metal salts (2 equiv) with Btzn (1 equiv) result in dimeric species [(Btzn)Co-2(NCS)(4)(EtOH) (2)(DMF)(2)], (2), [(Btzn)Ni-2(eta(1)-ONO2)(2)(MeOH)(4)(DMF)(2)]center dot 2[NO3], (3), [(Btzn)Cu2Cl4(DMF)(2)], (4), and [(Btzn)Cu-2(eta(2)-O2NO)(2)(OH2)(2)(DMF)(2)]center dot 2[NO3], (5). These complexes are the first examples of the coordination of transition metals with bi(1,3,5-triazine) ligands. Their structures display a bridging bis-bidentate coordination mode for Btzn. Variable-temperature magnetic susceptibility of the complexes reveals antiferromagnetic exchange between the spin carriers, with calculated exchange coupling values (J) of -4.7 cm(-1) for 3, -18.2 cm(-1) for 4, and -5.5 cm(-1) for 5. An in-depth evaluation of the metal geometry highlights the inefficient overlap of the magnetic d-orbitals through the bridging ligand, most likely leading to reduced delocalization and coupling.