Ionothermal synthesis of octahedral lanthanoid coordination networks exhibiting slow magnetization relaxation and efficient photoluminescence. Issue 4 (4th January 2021)

• Record Type: Journal Article
• Authors: Yang, Ting-Hai; Wang, Shu-Fan; Lin, Chen-Lan; Wang, Xin; Zhu, Binglong; Wu, Dayu
• Is Part Of: Dalton transactions. Volume 50:Issue 4(2020)
• Page Start: 1293
• Page End: 1299
• Publication Date: 2021-01-04
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d0dt03353g
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : An ionothermal reaction of lanthanoid salts with tetraethyl- p -xylenediphosphonate (tepxdp) in ionic liquids, such as choline chloride and malonic acid, resulted in the formation of three novel lanthanoid–organic coordination networks with the formula [Ln(H2 pxdp)1.5 ] n . Abstract : An ionothermal reaction of lanthanoid salts with tetraethyl- p -xylenediphosphonate (tepxdp) in ionic liquids, such as choline chloride and malonic acid, resulted in the formation of three novel lanthanoid–organic coordination networks with the formula [Ln(H2 pxdp)1.5 ] n {Ln = Tb (1 ), Dy (2 ) and Ho(3 ) and H4 pxdp = p -xylenediphosphonic acid}. The structures, photoluminescence and magnetic properties of the three compounds were investigated in detail. Single crystal X-ray diffraction analysis revealed that the three compounds are isostructural and the Ln 3+ ions show an unusual six-coordinate environment with the {LnO6 } octahedron. In these compounds, each {PO3 C} tetrahedron is corner-shared with two {LnO6 } octahedra and each {LnO6 } octahedron is corner-shared with six {PO3 C} tetrahedra, thus forming an inorganic layer in the crystallographic ab plane. The inorganic layers are further connected by a phenyl group, leading to a three-dimensional framework. Compound 1 exhibits the strong and characteristic emission of Tb III with an impressive quantum yield of 46.2%. Detailed magnetic analysis demonstrated that compound 2 displays a slow magnetic relaxation of magnetization with multiple relaxation mechanisms. The anisotropic energy barrier and the pre-exponential factor τ 0 are 51.2 K and 3.9 × 10 −7 s, respectively, in the presence of a direct-current field of 500 Oe. This work demonstrates a successful strategy to isolate octahedrally coordinated lanthanoid complexes through ionothermal synthesis to exhibit the single-ion-magnet-like behaviour and photoluminescence properties.