Lescop Christophe, Luneau Dominique, Rey Paul, Bussière Guillaume, Reber Christian
Laboratoire de Chimie Inorganique et Biologique (UMR 5046), DRFMC, CEA-Grenoble, 17 Rue des Martyrs, 38054 Grenoble Cedex 09, France.
Inorg Chem. 2002 Oct 21;41(21):5566-74. doi: 10.1021/ic0257928.
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.
本文报道了一系列含有硝酰基或亚氨基氮氧化物自由基的钆（III）（1a - 4a）和铕（III）（1b - 4b）配合物的合成、结构以及磁学和光学性质。化合物1a和1b的晶体结构由[Ln(III)(自由基)(2)(NO(3))(3)]实体组成，其中钆（III）（1a）或铕（III）离子（1b）与两个硝酰基氮氧化物自由基和三个硝酸根配体形成10配位。化合物2a - 4a和2b - 4b的晶体结构由[Ln(III)(hfac)(3)(自由基)]实体组成，其中钆（III）（2a - 4a）或铕（III）离子（2b - 4b）与一个硝酰基（2a和2b）或一个亚氨基（3a、4a和3b、4b）氮氧化物自由基以及三个六氟乙酰丙酮配体形成8配位。钆（III）配合物（1a - 4a）与其铕（III）类似物（1b - 4b）具有同构结构。对钆配合物的磁学性质进行了研究。在1a - 4a系列中，只有化合物2a表现出铁磁性的Gd(III)-自由基耦合（J(Gd - rad) = +1.7 cm(-1)），而其他化合物的这种耦合是反铁磁性的（1a：J(Gd - rad1) = -4.05 cm(-1)且J(Gd - rad2) = -0.80 cm(-1)；3a：J(Gd - rad) = -2.6 cm(-1)；4a：J(Gd - rad) = -1.9 cm(-1)）。报道了镧系元素与自由基配体形成的配合物在650至1200 nm之间的首个完整发光光谱。发光和吸收光谱中丰富的振动结构表明，几个激发态决定了400至800 nm之间的吸收光谱。可以在磁基态性质与标题化合物的能量和精细结构之间建立定性趋势。
