A mononuclear iron(II) complex has been isolated in two polymorphs. Polymorph 1b remains high-spin over all temperatures, whereas polymorph 1a undergoes a cooperative two-step spin crossover accompanied by symmetry breaking, showing an ordered 2:1 high-spin-low-spin intermediate phase.
An Fe(II) SCO complex based on an acylhydrazone ligand with an amino functional group has been prepared. The complex is able to dissociate and regather upon protonation and deprotonation, in both solid state and solution, accompanied by spin state switching, marked change of color, and distinct solubility in water. Moreover, the complex shows distinct magnetic responses toward formaldehyde and protic and nonprotic solvents, as a result of the different affinity of the amino functional site with those chemicals. Communication pubs.acs.org/IC
A series of new d−f heterometallic coordination frameworks, namely, [LnM(Hbic)2(ox)H2O]·2H2O [Ln = Nd, M = Cu (1); Ln = Eu, M = Ag (2); Ln = Tb, M = Ag (3); H2bic = 1H-benzimidazole-5-carboxylic acid; ox = oxalate] for type I, [LnCu(Hbic)3(ox)0.5]·H2O [Ln = Sm (4), Ln = Dy (5)] for type II, and [LnAg(Hbic)(ox)1.5] [Ln = Eu (6)] for type III, were successfully synthesized by using different metal salts and rationally controlling reaction temperature. Complexes 1−3 represent 1D polymeric chain architectures that are constructed from the connections between lanthanide-oxalate chains and M(Hbic)2 subunits. Complexes 4 and 5 are 2D layered structures which are assembled by lanthanide-oxalate and Cu(Hbic)3 units. Complex 6 exhibits another 2D layered coordination framework that is built up by tetranuclear Eu2Ag2 clusters and mixed ox and Hbic linkers. The polymeric coordination frameworks of complexes 1−6 are sustained by both hydrogen bonding and π−π stacking interactions, and they are self-assembled to form the 3D supramolecular frameworks.
A family of six dinuclear lanthanide complexes have been obtained via in situ hydrothermal synthesis with lanthanide ions as catalyst. These six complexes are formulated as [Ln(2)(3-Htzba)(2)(3-tzba)(2)(H(2)O)(8)]·4H(2)O [Ln = Gd, 1; Dy, 2; Eu, 3; Tb, 4; Sm, 5; Er, 6; 3-H(2)tzba = 3-(1H-tetrazol-5-yl)benzoic acid]. The magnetic investigations show that complex 2 behaves as a single-molecule magnet (SMM) with a quantum relaxation time of ~10(-2) s.
The magnetostructural coupling between structural and magnetic transitions leads to magneto-multifunctionalities of phase-transition alloys. Due to the increasing demands of multifunctional applications, to search for the new materials with tunable magnetostructural transformations in a large operating temperature range is important. In this work, we demonstrate that by chemically alloying MnNiSi with CoNiGe, the structural transformation temperature of MnNiSi (1200 K) is remarkably decreased by almost 1000 K. A tunable magnetostructural transformation between the paramagnetic hexagonal and ferromagnetic orthorhombic phase over a wide temperature window from 425 to 125 K is realized in (MnNiSi)1−x(CoNiGe)x system. The magnetic-field-induced magnetostructural transformation is accompanied by the high-performance magnetocaloric effect, proving that MnNiSi-CoNiGe system is a promising candidate for magnetic cooling refrigerant.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.