High Nuclearity Complexes of Lanthanide Involving Tetrathiafulvalene Ligands: Structural, Magnetic, and PhotoPhysical Properties

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• 作者：Fabrice Pointillart ; Boris Le Guennic ; St茅phane Golhen ; Olivier Cador ; Olivier Maury ; Lahc猫ne Ouahab
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：February 4, 2013
• 年：2013
• 卷：52
• 期：3
• 页码：1610-1620
• 全文大小：880K
• 年卷期：v.52,no.3(February 4, 2013)
• ISSN：1520-510X

文摘

The reaction between the tetrakis(2-pyridyl-N-oxidemethylthio)tetrathiafulvalene ligand (L) and Ln(hfac)₃路2H₂O precursors (where hfac^{鈥?/sup> = 1,1,1,5,5,5-hexafluoroacetylacetonate anion and Ln = TbIII (1), DyIII (2), ErIII (3), and YbIII (4) and (4b)) leads to the formation of five tetranuclear complexes of formula [Ln₄(hfac)₁₂(L)₂]_n路xCHCl₃路yC₆H₁₄ (n = 1, x = 2, y = 0 for (1), (2), and (4), n = 1, x = 4 for (3), and n = 2, x = 2.5, y = 1 for (4b)). Their X-ray structures reveal that the surrounding of each LnIII center is filled by two N-oxide groups coming from two different ligands L. These tetranuclear complexes have the highest nuclearity which is reported until now for coordination compounds of lanthanide involving TTF-based ligands. Direct current (dc) measurements highlight the paramagnetic behavior of the compounds with a significant crystal field effect. The temperature dependences of static magnetic measurements for 4 have been fitted. The ground state corresponds to M_J = 卤5/2 while the first excited state (M_J = 卤3/2) was localized at +214 cm鈥? which was well correlated with the luminescence transition. UV鈥搗isible absorption properties have been experimentally measured and rationalized by time-dependent density functional theory (TD-DFT) calculations. Upon irradiation at 77 K and room temperature, in the range 24390鈥?0835 cm鈥?, both compounds 3 and 4 display a metal-centered luminescence attributed to 4I_13/2 鈫?4I_15/2 (6660 cm鈥?) and 2F_5/2 鈫?2F_7/2 (signal centered around the value of 9966 cm鈥?) transitions, respectively. The observed six transitions could be attributed to the M_J state splitting due to the existence of two Yb1 and Yb2 ions with slightly different polyhedra in 4.}