Structural and magnetic properties of dinuclear Cu(II) complexes featuring triazolyl-naphthalimide ligands

Abstract

Naphthalimide-based ligands have received significant attention for their ability to act as secondary building units for metal containing network structures. The potentially bridging 1,2,4-triazole containing N-(1,2,4-triazolyl)-1,8-naphthalimide (L1) and N-(1,2,4-triazolyl)-4-dimethylamino-1,8-naphthalimide (L2) were prepared, characterized, and complexed with Cu(II) salts. L1 resulted in crystallographically characterized dinuclear complexes, [Cu2(L1)4(NO3)4] and [Cu2(L1)2(OAc)4] when reacted with Cu(NO3)2 and Cu2(OAc)4, respectively. Packing interactions are dominated by π⋯π and anion⋯π interactions and gave rise to structure extension through weak supramolecular interactions. Solid state EPR and magnetism measurements on [Cu2(L1)4(NO3)4] revealed the expected values for a non-magnetically coupled square-based pyramidal dimer structure, while [Cu2(L1)2(OAc)4] showed strong anti-ferromagnetic coupling (JCu–Cu = −185.6 cm−1).