Synthesis, structures, and magnetic and optical properties of a series of europium(III) and gadolinium(III) complexes with chelating nitronyl and imino nitroxide free radicals.
Synthesis, structures, and magnetic and optical properties of a series of europium(III) and gadolinium(III) complexes with chelating nitronyl and imino nitroxide free radicals.
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DOI：
10.1021/ic0257928
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发表时间：
2002-09
影响因子：
4.6
通讯作者：
C. Lescop;D. Luneau;P. Rey;G. Bussière;C. Reber
中科院分区：
文献类型：
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作者：
C. Lescop;D. Luneau;P. Rey;G. Bussière;C. Reber
本文报道了一系列钆（Ⅲ）（1a-4a）和铕（Ⅲ）（1b-4 b）与硝酰基或亚氨基氮氧自由基配合物的合成、结构、磁性和光学性质。化合物1a和1b的晶体结构由[Ln（III）（radical）（2）（NO（3））（3）]实体组成，其中钆（III）（1a）或铕（III）离子（1b）与两个硝酰基氮氧自由基和三个硝酸根配体10-配位。化合物2a-4a和2b-4 b的晶体结构由[Ln（III）（hfac）（3）（radical）]实体组成，其中钆（III）（2a-4a）或铕（III）离子（2b-4 b）与一个硝酰基（2a和2b）或一个亚氨基（3a，4a和3b，4 b）氮氧自由基和三个六氟乙酰丙酮配体8-配位。钆（III）配合物（1a-4a）与它们的铕（III）类似物（1b-4 b）是同构的。研究了钆配合物的磁性。沿着系列1a-4a，只有化合物2a表现出铁磁Gd（III）-自由基耦合（J（Gd-rad）=+1.7cm（-1）），而对于其他的这种耦合是反铁磁的（1a：J（Gd-rad 1）= -4.05 cm（-1）和J（Gd-rad 2）= -0.80 cm（-1）; 3a：J（Gd-rad）= -2.6 cm（-1）; 4a：J（Gd-rad）= -1.9 cm（-1））。报道了自由基配体镧系配合物在650 ~ 1200 nm范围内的第一个全发光光谱。发光和吸收光谱中丰富的电子振动结构表明，几个激发态定义了400和800 nm之间的吸收光谱。在基态磁性质与标题化合物的能量和精细结构之间可以建立定性的趋势。
This paper reports the synthesis, structures, and magnetic and optical properties of a series of gadolinium(III) (1a-4a) and europium(III) (1b-4b) complexes with nitronyl or imino nitroxide radicals. The crystal structures of compounds 1a and 1b consist of [Ln(III)(radical)(2)(NO(3))(3)] entities in which the gadolinium(III) (1a) or europium(III) ion (1b) is 10-coordinated to two nitronyl nitroxide radicals and three nitrato ligands. The crystal structures of compounds 2a-4a and 2b-4b consist of [Ln(III)(hfac)(3)(radical)] entities in which the gadolinium(III) (2a-4a) or europium(III) ion (2b-4b) is 8-coordinated to one nitronyl (2a and 2b) or one imino (3a, 4a and 3b, 4b) nitroxide radical and three hexafluoroacetylacetonato ligands. The gadolinium(III) complexes (1a-4a) are isostructural with their europium(III) analogues (1b-4b). The magnetic properties of the gadolinium complexes were studied. Along the series 1a-4a only compound 2a exhibits a ferromagnetic Gd(III)-radical coupling (J(Gd-rad) = +1.7 cm(-1)), while for the others this coupling is antiferromagnetic (1a: J(Gd-rad1) = -4.05 cm(-1) and J(Gd-rad2) = -0.80 cm(-1); 3a: J(Gd-rad) = -2.6 cm(-1); 4a: J(Gd-rad) = -1.9 cm(-1)). The first full luminescence spectra of lanthanide complexes with free radical ligands are reported between 650 and 1200 nm. The rich vibronic structure in luminescence and absorption spectra indicates that several excited states define the absorption spectra between 400 and 800 nm. Qualitative trends can be established between magnetic ground state properties and the energies and fine structure of the title compounds.