Fabricating Bis(phthalocyaninato) Terbium SIM into Tetrakis(phthalocyaninato) Terbium SMM with Enhanced Performance through Sodium Coordination

• Published in: Chemistry : a European journal 2018-06, Vol.24 (32), p.8066-8070
• Main Authors: Chen, Yuxiang, Liu, Chao, Ma, Fang, Qi, Dongdong, Liu, Qingyun, Sun, Hao‐Ling, Jiang, Jianzhuang
• Format: Article
• Language: English
• Subjects: Blocking; Chemistry; double-decker; Fabrication; Field strength; Magnetic anisotropy; Magnetic properties; Molecular chains; non-peripherally; phthalocyanine; Polyhedra; pseudo-quadruple-decker; SMM; Sodium; Temperature; Terbium
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201800408

The non‐peripherally substituted 1,4,8,11,15,18,22,25‐octa(butoxy)‐phthalocyanine‐involved unsymmetrical heteroleptic bis(phthalocyaninato) terbium double‐decker, Tb(Pc){H[Pc(α‐OC4H9)8]} (Pc=unsubstituted phthalocyanine) (1), was revealed to exhibit typical single ion magnet (SIM) behavior with effective energy barrier, 180 K (125 cm−1), and blocking temperature, 2 K, due to the severe deviation of the terbium coordination polyhedron from square‐antiprismatic geometry. Fabrication of this double‐decker compound into the novel tetrakis(phthalocyaninato) terbium pseudo‐quadruple‐decker Na2{Tb(Pc)[Pc(α‐OC4H9)8]}2 (2) single molecule magnet (SMM) not only optimizes the coordination polyhedron of terbium ion towards the square‐antiprismatic geometry and intensifies the coordination field strength, but more importantly significantly enhances the molecular magnetic anisotropy in the unsymmetrical bis(phthalocyaninato) double‐decker unit, along with the change of the counter cation from H+ of 1 to Na+ of 2, leading to an significantly enhanced magnetic behavior with spin‐reversal energy barrier, 528 K (367 cm−1), and blocking temperature, 25 K. The present result is surely helpful towards developing novel tetrapyrrole lanthanide SMMs through rational design and self‐assembly from bis(tetrapyrrole) lanthanide single ion magnet (SIM) building block. Sandwich time: Sodium coordination helps to optimize the coordination geometry and intensify the coordination field strength for the terbium ion, and in particular significantly enhance the molecular magnetic anisotropy, in the unsymmetrical bis(phthalocyaninato) double‐decker unit, therefore leading to a significant enhancement over the magnetic behavior from the double‐decker SIM to the tetrakis(phthalocyaninato) pseudo‐quadruple‐decker SMM.