Pentagram-type Ln15 (Ln = Dy, Tb, Eu, Sm, Ho) clusters with different anion templates: magnetic and luminescence properties. Issue 42 (17th October 2022)

• Record Type: Journal Article
• Authors: Zou, Ying; Lv, Wei; Xue, Zhe; Pan, Jie; Li, Xiao-Yu; Wang, Guo-Ming
• Is Part Of: Dalton transactions. Volume 51:Issue 42(2022)
• Page Start: 16383
• Page End: 16388
• Publication Date: 2022-10-17
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d2dt02712g
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Five pentagram-type Ln15 clusters with different anion templates were obtained. The pentagonal skeleton is composed of five cubane-like [Ln4 (μ3 -OH)4 ] building units. The magnetic properties and the luminescence behavior were investigated. Abstract : Five 15-nuclearity lanthanide clusters were obtained under solvothermal conditions based on N -tris(hydroxymethyl)methylglycine (H5 thmmg) with molecular formulas Ln15 (OH)20 (H4 thmmg)10 (H2 O)10 · x Cl·(15 − x )NO3 (Ln = Dy, x = 15 (1 ); Ln = Tb, x = 11 (2 ); Ln = Eu, x = 13 (3 ); Ln = Sm, x = 15 (4 ); and Ln = Ho, x = 15 (5 )). They have the same pentagram-type metal cores made up of five cubane-like [Ln4 (μ3 -OH)4 ] units by sharing vertical Ln 3+ ions and their peripheries are all protected by ten H4 thmmg − ligands and ten coordinated H2 O. Such structural Sm15 and Ho15 clusters are reported for the first time. For 1, 4 and 5, these metal-hydroxide cores are further stabilized only by free Cl − ions, whereas NO3 − and Cl − ions both operate as anionic templates for 2 and 3 to balance the positive charge and to promote lanthanide metal ion aggregation. These are the first reported Ln15 clusters self-assembled by NO3 − and Cl − anion templates. The luminescence behaviors of 2 and 3 show the characteristic emissions of the corresponding Ln 3+ (Ln = Tb, Eu) ions. The temperature-dependent luminescence of 2 and 3 reveals that their emission intensities increase as the temperature drops, and good linear relationships exist in the 120–300 K range, so 2 and 3 are potential luminescent molecular thermometers. Moreover, 2 and 3 exhibit high quantum yields (QYs) (58.05% for 2 and 17.34% for 3 ) and long luminescence lifetimes ( τ = 934 μs for 2, τ = 242 μs for 3 ). In addition, 1 displays slow magnetic relaxation behavior.