釹/鐠草酸甲基磷酸鹽之合成、結構鑑定與性質研究

Synthesis , Crystal Structures and Properties of Lanthanide Oxalatophosphonates : Na[Ln3(H2O)4(C2O4)4(CH3PO3)]·2H2O (Ln = Nd and Pr)

黃雅玲(Ya-ling Huang)

指導教授 ： 李光華

國立中央大學/理學院/化學系/碩士(2007年)

摘要

本論文研究利用中溫水熱法合成新穎鑭系金屬草酸甲基磷酸鹽 化合物：Na[Ln3(H2O)4(C2O4)4(CH3PO3)]·2H2O [Ln = Nd (A) and Pr (B)]。藉由一系列鑑定方法，包括以Ｘ光單晶繞射法決定出化合物 的結構與化學式，再搭配元素分析、紅外線光譜、粉末繞射、熱重 分析及超導量子干涉等方法進行結構組成分析、熱穩定性、熱分解 反應及磁性等研究。並利用螢光光譜法深入探討放光譜線與單晶結 構之間的相關性。 化合物A和B 為等結構，所有的Ln 都是九配位。當中的Ln(1)O9 和Ln(2)O9 以邊共用及面共用的方式形成四聚體，此四聚體與草酸 和甲基磷酸連接形成單元層。而Ln(3)O9 則是與草酸形成Z 字型無 限延伸鏈，此單元鏈與單元層再經由草酸連結形成三維結構。 在磁性方面，化合物A 和B 皆為反鐵磁性，A 的μeff = 3.663 μb； B 的μeff = 3.795 μb，皆與其理論值接近。在放光光譜中，化合物A 的放光波段在近紅外光區，螢光生命期為1.6 ± 0.1 μs；化合物B 的 放光波段則涵蓋了綠光及紅光區，螢光生命期為1.7 ± 0.1 μs 和2.6 ± 0.1 μs。兩者之螢光生命期皆遠低於理論值，這是由於化合物當中含 水分子所造成的消激效應(Quenching Effect)。

關鍵字

鑭系草酸甲基磷酸 ； 水熱合成

並列摘要

A neodymium oxalatophosphonate and the praseodymium
analogue, Na[Ln3(H2O)4(C2O4)4(CH3PO3)]·2H2O [Ln = Nd (A) and Pr
(B)], have been synthesized by hydrothermal method and characterized
by single-crystal X-ray diffraction and thermogravimetric analysis. We
studied the photoluminescence spectra as well as the magnetic
properties of the both compounds. The structure consists of layers built
of tetramers of edge- and face-sharing LnO9 polyhedra connected by
oxalate and methylphosphonate units, which are linked by zigzag
infinite chains of oxalate-bridged LnO9 polyhedra to form a 3-D
framework. They are the first examples of lanthanide
oxalate-methylphosphonate. The μeff of Nd is 3.663 μb and the μeff of Pr
is 3.795 μb; both are very close to the theoretical values. The Nd
compound displays characteristic emission bands in the near IR region
with lifetime 1.6 ± 0.1 μs. Luminescence of the Pr compound consists
of many emission bands at 480-760 nm with lifetime 1.7 ± 0.1 μs and
2.6 ± 0.1 μs, respectively. The lifetimes of both compounds are much
shorter than the expected values due to the quenching effects of water
molecules in the structure. Crystal data for the Nd compound follow:
triclinic, P`1 (No. 2), a = 9.0682(2) Å, b = 9.5114(3) Å, c = 14.0066(4)
Å, a = 74.975(2)°, b = 86.534(2)º, g = 82.725(2)°, and Z = 2. Crystal
data for the Pr compound are the same as those for the Nd compound
except a = 9.125(1) Å, b = 9.549(1) Å, c = 14.073(2) Å, a = 75.086(2)°,
b = 86.611(2)º, and g = 82.545(2)°.

並列關鍵字

hydrothermal ； Lanthanide Oxalatophosphonates

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