Two tetranuclear Cu₂Ln₂ (Ln = Dy, Tb) heterometallic complexes: Structure, solution behavior, and magnetic properties

Abstract

Two tetranuclear 3d–4f heterometallic complexes [Cu2Ln2(NO3)4(OAc)2L4] (Ln = Dy 1, Tb 2) were obtained under solvothermal reactions of 1‐amino‐propan‐2‐ol (HL) with [Cu2(OAc)4(H2O)2] and Ln (NO3)3·5H2O. The structural analyses confirmed a centrosymmetric Z‐shaped skeleton for them with the peripheral positions occupied by two Cu (II) ions. The neighboring two lanthanide ions, as well as the neighboring ions of Ln (III) and Cu (II), are all double‐bridged through two O atoms. The detailed dynamic magnetic investigation showed slow magnetic relaxation behaviors for both complexes with an energy barrier of 1.35(2) and 2.02(4) K for 1 and 2, respectively. Furthermore, it revealed from the electrospray mass spectrometry (ESI‐MS) that complexes 1 and 2 easily undergo dimerization in solution.

Structure and assembly mechanism of a centipede-shaped high-nuclear Dy14Cu12heterometallic nanocluster

“…The χ M T value of 1 at room temperature is 201.71 cm 3 K mol −1 , close to the corresponding theoretical values for fourteen independent Dy III centers (198.38 cm 3 K mol −1 ; 6 H 15/2 , S = 5/2, L = 5, J = 15/2, and g = 4/3) 43,73,74 and twelve independent Cu II centers (4.50 cm 3 K mol −1 ; S = 1/2, g = 2 and C = 0.375 cm 3 K mol −1 ). 53,75 As the temperature is lowered, the χ M T value of 1 decreases slowly to a value of 187.72 cm 3 K mol −1 at 50 K. The further decreasing temperature of the sample led to an abrupt decrease of χ M T of 1 , reaching 126.22 cm 3 K mol −1 at 2 K. The χ M T versus T profile of 1 might be caused by the depopulation of Stark levels and possible antiferromagnetic interactions.…”

“…However, related studies on the assembly mechanisms of 3d–4f heterometallic complexes are still very limited. 47,50–53 Thus, we aimed to investigate the assembling mechanism of the targeted clusters through detecting the intermediates in their formation processes using high resolution ESI-MS.…”