First examples of carbacylamidophosphate pentanuclear hydroxo-complexes: Synthesis, structure, luminescence and magnetic properties

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• 作者：Nataliia S. Kariaka^a ; ^{natalia_kariaka@i.ua" class="auth_mail" title="E-mail the corresponding author} ; Julia A. Rusanova^a ; Sergii S. Smola^b ; Sergey V. Kolotilov^c ; Kateryna O. Znovjyak^a ; Marek Weselski^d ; Tatiana Yu Sliva^a ; Vladimir M. Amirkhanov^a ;
• 关键词：Lanthanides ; Carbacylamidophosphates ; Polynuclear complexes ; Luminescence ; Magnetic properties
• 刊名：Polyhedron
• 出版年：2016
• 出版时间：26 February 2016
• 年：2016
• 卷：106
• 期：Complete
• 页码：44-50
• 全文大小：1261 K

文摘

The first representatives of pentanuclear carbacylamidophosphate complexes of composition Ln₅L₆(μ-L)₄(μ₃-OH)₄(μ₄-OH) (Ln^III = Eu (1), Gd (2), Tb (3), L⁻ = dimethylbenzoylamidophosphate ion [C₆H₅C(O)–N–P(O)(OCH₃)₂]⁻) were obtained. The single crystal X-ray analysis revealed that polynuclear core of 1 contains five europium ions, connected by the μ₃- and μ₄-hydroxo groups and carbacylamidophosphate ligands. Compounds 1–3 were found to be isostructural. Temperature dependencies of magnetic susceptibility (χ_M) of the compounds 1 and 2 could be explained by spin-orbit coupling of Eu^III ions or antiferromagnetic exchange interactions of four Gd^III ions located in the base of Gd₅ pyramid, respectively. In the case of 3, the value of χ_M increases with temperature decreasing from 300 K to 50 K, and then falls down during temperature decrease till 2 K. Such behavior can be explained by comparable contribution of spin-orbit coupling and exchange interactions. No signs of single-molecule magnet behavior for 3 were found at 2 K. Phosphorescence, emission and excitation spectra at 298 K and 77 K for the complexes were measured, as well as luminescence decay times were determined. The compounds 1 and 3 showed intense luminescence with decay time at 298 K equal to 0.66 and 1.44 ms respectively. Intrinsic quantum yield for 1 determined from its emission spectrum was found to be 25%.