Tetranuclear and Pentanuclear Compounds of the Rare-Earth Metals: Synthesis and Magnetism

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• 作者：Munendra Yadav ; Abhishake Mondal ; Valeriu Mereacre ; Salil Kumar Jana ; Annie K. Powell ; Peter W. Roesky
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：August 17, 2015
• 年：2015
• 卷：54
• 期：16
• 页码：7846-7856
• 全文大小：652K
• ISSN：1520-510X

文摘

The Schiff-base proligand 4-tert-butyl-2,6-bis-[(2-hydroxy-phenylimino)methyl]phenol (H₃L) was prepared in situ from 4-tert-butyl-2,6-diformylphenol and 2-aminophenol. The proligand (H₃L) was used with dibenzoylmethane (DBMH) or acetylacetone (acacH) with lanthanides giving compounds with varying arrangements of metal atoms and nuclearities. The tetranuclear compound {[Dy₄(L)₃(DBM)₄][Et₃NH]} (1) and pentanuclear compound {[Dy₅(渭₃-OH)₂(L)₃(DBM)₄(MeOH)₄]路4(MeOH)} (2) were obtained from the ligand (L)^{3鈥?/sup> and dibenzoylmethane. The tetranuclear compounds {[Dy₄(渭₄-OH)(L)₂(acac)₄(MeOH)₂(EtOH)(H₂O)]路(NO₃)路2(MeOH)路3(EtOH)} (3) and {[Ln₄(渭₃-OH)₂(L)(HL)(acac)₅(H₂O)] (HNEt₃)(NO₃)路2(Et₂O)} (Ln = Tb (4), Dy (5), Ho (6), and Tm (7)) resulted when the ligand (L)3鈥?/sup> was used in the presence of acetylacetone. In the solid state structures, the tetranuclear compound 1 adopts a linear arrangement of metal atoms, while tetranuclear compound 3 has a square grid arrangement of metal atoms, and tetranuclear compounds 4鈥?b>7 have a seesaw-shaped arrangement of metal atoms. The composition found from single-crystal X-ray analysis of compound 1 and 3鈥?b>7 is supported by electrospray ionization mass spectrometry (ESI-MS). The magnetic studies on compounds 1 suggest the presence of weak ferromagnetic interactions, whereas compounds 2鈥?b>6 exhibit weak antiferromagnetic interactions between neighboring metal centers. Compounds 1, 2, and 3 also show single-molecule magnet behavior under an applied dc field.}