Supramolecular self-assembly of two Cu(II) complexes with 1,2,4-triazole derivatives: Syntheses, crystal structures and magnetic properties

Two two-dimensional coordination complexes, {[Cu₄(BTM) ₆(OPA)₄]·4DMF·3H₂O} _n (1) and {[Cu(BDTM)(OH)](ClO₄)·2H₂O} _n (2) (BTM = bis(1,2,4-triazol-1-yl)methane, BDTM = bis(3,5-dimethyl-1,2,4- triazol-1-yl)methane, OPA^2- = ortho-phthalic dianion, DMF = N,N-dimethylformamide), were synthesized and structurally characterized. Each Cu(II) ion locates in a distorted square pyramidal geometry in 1, in which OPA^2- ligands bridge Cu²⁺ ions along a axis to form a magnetic transmission chain and BTM ligands act as flexible spacers to construct the two-dimensional layer structure. In 2, each Cu²⁺ ion adopts tetra-coordination geometry to two hydroxyl groups and two triazolyl nitrogen atoms from two different BDTM ligands. Two hydroxyl groups bridge two Cu ²⁺ ions to form a rhombic diamond, and four BDTM ligands connect four diamonds to form a 36-membered macrocyclic structure with large channels along a axis. Magnetic properties revealed that both OPA^2- and OH ^- mediate anti-ferromagnetic interactions between Cu²⁺ ions with J = - 0.06(3) and -301.9(2) cm^-1 for 1 and 2, respectively.