A Mixed Porphyrin–Schiff Base Dysprosium(III) Single‐Molecule Magnet

Abstract

The mixed porphyrin–Schiff base potassium dysprosium(III) complex [K(TBPP)Dy(L)(CH3CN)2] [H2TBPP = 5,10,15,20‐tetrakis(4‐tert‐butylphenyl)porphyrin; H2L = N,N′‐bis(3‐methoxysalicylidene)benzene‐1,2‐diamine; 1] was isolated from the reaction between the metal‐free Schiff base ligand H2L and the half‐sandwich porphyrinato dysprosium compound [Dy(TBPP)(acac)] (Hacac = acetylacetone) in the presence of KOH. A sandwich‐type double‐decker structure has been unambiguously revealed by single‐crystal X‐ray diffraction analysis. Static and dynamic magnetic measurements disclosed the slow relaxation behavior of this new double‐decker compound and indicated its single‐molecule magnet (SMM) nature. Comparative studies on the magnetic properties of 1, the homoleptic bis[5,10,15,20‐tetrakis(4‐tert‐butylphenyl)porphyrinato]dysprosium double‐decker [DyH(TBPP)2] (2), and the bis(Schiff base)dysprosium double‐decker {[Dy[Zn(L)Cl]2(DMF)2]·Cl} (3, DMF = N,N‐dimethylformamide) indicate the effect of the ligand field (LF), through the deviation of the dysprosium coordination geometry from the ideal D4d form, on the SMM properties of 1–3 in addition to the effect of the charge distribution over the DyIII ion.

Dysprosium Heteroleptic Corrole-Phthalocyanine Triple-Decker Complexes: Synthesis, Crystal Structure, and Electrochemical and Magnetic Properties

“…The χ m T values of 31.68 and 26.04 cm 3 K mol −1 for 1 and 2 at 300 K are consistent with the value of 28.72 cm 3 K mol −1 for two dysprosium(III) ions ( 6 H 15/2 , S = 5/2, L = 5, g = 4/3) and one radical. 4,11,23,[28][29][30]76 When the temperature is lowered, the χ m T values of both compounds decrease slowly until about 50 K and then decrease to minimum values of 19.56 and 20.75 cm 3 K mol −1 for 1 and 2 at 2 K, respectively, owing to the crystal field effect for both compounds and possible intramolecular antiferromagnetic dipole−dipole interactions. 11,12 In addition, as shown in Figure S7 in the Supporting Information, the M versus H curves for both compounds 1 and 2 display a rapid increase at low field and eventually achieve the maximum values of 9.14 and 8.13 μ B for 1 and 2, respectively, which is far from the theoretical magnetization saturation value 0.4371 GOF on F 2 1.214 of 20.00 μ B for two dysprosium ions (10 μ B for each Dy(III) ion).…”

A new co-crystal dinuclear/trinuclear ZnII–ZnII/ZnII–SmIII–ZnII complex with a salen-type Schiff base ligand

“…A survey of the Cambridge Structural Database (CSD) (Version 5.39, last update November 2017; Groom et al, 2016) shows that dinuclear complexes of the ligand bis(2-hydroxy-3methoxybenzylidene)-1,2-diaminobenzene where the smaller N 2 O 2 cage is occupied by a 3d metal and the larger, open O 2 O 2 cage is occupied by one s-, p-, d-or f-block metal are well documented. Trinuclear complexes formed by two 3d metals with the above organic ligand in which the 3d metal atom is situated in the smaller N 2 O 2 cage and one s-, d-or f-block metal atom is coordinated to the two larger O 2 O 2 cages have also been reported: five entries corresponding to d-s [BIZBAO (Bian et al, 2008), KAZQEK (Andrez et al, 2017), KESYOY and KESZAL (Biswas et al, 2013b), LARPIG (Feng et al, 2017)], four entries correspond d-d [DEDPIM (Yang et al, 2006), OKECIS (Zhang et al, 2016), UGAMOF (Wang et al, 2008b), WOGQAL (Wang et al, 2008a)], seven correspond to s-f [FEVDUH (Wang et al, 2013), ITOVIY (Ma et al, 2016), YIMLUD, YIMMAK, YIMMEO, YIMMIS and YIMMOY (Ma et al, 2013)], twenty entries correspond to d-f [AYOKIJ (Yang et al, 2011), DEJLEK and DEJLAG (Wong et al, 2006), EBIZUM, EBOBAA and EBOBEE (Chen et al, 2011), GICBUR and GICCAY (Yang et al, 2013), KEBGUW (Pushkarev et al, 2017), MEPXEL, MEPXIP and MEPXOV (Lo et al, 2006), NOGPIJ (Bi et al, 2008a), NOMQIQ, NOMQOW and NOMQUC (Bi et al, 2008b), PALZUA (Fu et al, 2017), POXMIZ (Bi et al, 2009), VAYBEF (Liu et al, 2017) (Wang et al, 2009)]. In all, there are thirteen entries for hetero trinuclear 3d-4f-3d complexes in which the 3d metal ion is Zn 2+ [DEJKUZ and DEJLIO (Wong et al, 2006), DUCKAO, DUCKOC, DUCKUI, DUCLAP and DUCLET (Wang et al, 2009), EJAGIG (Liao et al, 2010), GICCEC and GICCIG (Yang et al, 2013), QUQKUK, QUQLAR and QUQLEV (Sun et al, 2016)].…”

Experimental and theoretical insights into Co–Ln magnetic exchange and the rare slow-magnetic relaxation behavior of [CoII2Pr]2+ in a series of linear [CoII2Ln]2+ complexes

“…Due to the strong contribution of unquenched orbital angular momentum, anisotropic lanthanides show very high intrinsic magnetic anisotropy and have been found to be comparatively better candidates for SMM construction. 4,14–19 However, in the majority of 4f based SMMs reported, the energy barrier and blocking temperature ( T B ) were found to be low. This is mainly due to under barrier magnetic relaxation processes such as quantum tunneling of magnetization (QTM) among others.…”