Syntheses, Crystal Structures, and Properties of Two Novel Trinuclear Copper Complexes Constructed by a Tripodal Heptadentate Ligand Containing Three Imidazolate Groups

Two Cu II complexes, {Cu 3 [(mim) 3 htren] 2 }(ClO 4 ) 6 · 2H 2 O ( 1 ) and {Cu 3 [(mim) 3 htren] 2 }(PF 6 ) 6 · 2(CH 3 CN) · 2H 2 O ( 2 ) with the tripodal heptadentate ligand (mim) 3 htren (= tris{2‐[2‐(1‐methyl)imidazolyl]methylaminoethyl}amine) were synthesized and characterized. In complex 1 and 2 , the tripodal ligand (mim) 3 htren coordinates in a very unusual configuration to the copper atoms, which resulted in trinuclear complexes. In the trinuclear cation, {Cu 3 [(mim) 3 htren] 2 } 6+ , the middle atom located on a crystallographic inversion center is coordinated in an elongated octahedral arrangement for 1 and coordinated in square‐planar arrangement for 2 , respectively, and the other two Cu II atoms are coordinated in a distorted square‐pyramid. The results from magnetic data, measured in the temperature range 2.0–300 K, showed that 1 and 2 obeyed the Curie–Weiss law with Weiss constants θ = 0.10 and 0.14 K, respectively, and the same Curie constant C = 1.14 K · mo1 –1 , indicating weak ferromagnetic interactions in the two trinuclearentities.