Synthesis and characterization of dinuclear complexes containing the FeIII–F· · ·(H2O)MII motif
Synthesis and characterization of dinuclear complexes containing the FeIII–F· · ·(H2O)MII motif
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含有 FeIII–F···(H2O)MII 基序的双核配合物的合成和表征
DOI：
10.1039/a902678i
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
J. Ulstrup
中科院分区：
文献类型：
--
作者：
M. Ghiladi;K. B. Jensen;J. Jiang;C. McKenzie;S. Mørup;I. Søtofte;J. Ulstrup
双核酚酸酯铰链配体4-叔丁基-2，6-双[双（2-吡啶甲基）氨甲基]酚（bpbp-）已被用于制备一系列在外源结合位点含有独立物种的FeIIIMII配合物。这些位置被氟化物和水配体占据，并且显示通式[（bpbp）Fe（F）2 M（H2O）n][BF 4]2，M = Zn或Cu，n = 1; M = Co或Fe，n = 2。两个末端氟离子与铁（III）离子结合，一个或两个水配体与相邻的二价金属离子结合。氟化物配体衍生自四氟硼酸盐的水解。在[（bpbp）Fe（F）2Cu（H2O）][BF 4]2·4 H2O的晶体结构中。铜（Ⅱ）和铁（Ⅲ）原子通过bpbp-酚氧原子铰链不对称连接，Cu-O-phenolato为2.270（2），Fe-O-phenolato为2.041（2），Cu· · ·Fe距离为3.828（1）。两个末端氟离子与Fe原子结合（Fe-F 1.818（2），1.902（2）A），其中一个与相邻Cu原子上的水分子形成强氢键（F-H· · ·O 2.653（4）A）。[（bpbp）Fe（F）_2M（H_2O）_2][BF_4]_2（M = Fe或Co）中的金属离子为弱反铁磁耦合（J = -8和-10 cm ~（-1）），[（bpbp）Fe（F）_2Cu（H_2O）][BF_4]_2中的金属离子为弱铁磁耦合（J = 2 cm ~（-1））。这些配合物的光谱，电化学和磁性进行比较，在外源性网站含有两个乙酸桥连基团的一系列类似的配合物。电化学结果表明，与双-µ-乙酸盐络合物相比，双氟化物络合物中的铁（III）离子在还原时稳定约300 mV。一种双-µ-乙酸根配合物[Fe 2（bpbp）（CH 3CO 2）2][BF 4]2的晶体结构显示了预期的排列;铁-（II）和-（III）原子通过bpbp-和两个µ-乙酸根基团的酚氧原子三重桥接，FeII-O酚合2.088（4）和FeIII-O酚合1.951（5）A，Fe·· ·Fe距离为3.380（2）A。在120 K的晶体结构表明，铁原子的价态被捕获，并根据该穆斯堡尔测量80和200 K之间的显示清楚地区分铁-（II）和-（III）的组件。[（bpbp）Fe（F）2Cu（H2O）][BF 4]2·4 H2O的穆斯堡尔谱受顺磁弛豫效应的影响，弛豫时间为1 ns量级。当施加磁场时，弛豫时间增加。这种效应可以用交叉弛豫模型和化合物的晶体对称性来解释。
The dinucleating phenolate-hinged ligand 4-tert-butyl-2,6-bis[bis(2-pyridylmethyl)aminomethyl]phenolate (bpbp–) has been used to prepare a series of FeIIIMII complexes containing independent species at the exogenous binding sites. These sites are occupied by fluoride and water ligands and show the general formulation [(bpbp)Fe(F)2M(H2O)n][BF4]2, M = Zn or Cu, n = 1; M = Co or Fe, n = 2. Two terminal fluoride ions are bound to the iron(III) ion and one or two water ligands to the adjacent divalent metal ion. The fluoride ligands are derived from the hydrolysis of tetrafluoroborate. In the crystal structure of [(bpbp)Fe(F)2Cu(H2O)][BF4]2·4H2O. The copper(II) and iron(III) atoms are linked asymmetrically by the phenolic oxygen atom hinge of bpbp– with Cu–Ophenolato 2.270(2) and Fe–Ophenolato 2.041(2) A with a Cu· · ·Fe distance of 3.828(1) A. The two terminal fluoride ions are bound to the Fe atom (Fe–F 1.818(2), 1.902(2) A) and one of them is strongly hydrogen bonded to the water molecule on the adjacent Cu atom (F–H· · ·O 2.653(4) A). The metal ions in the aquafluoride complexes [(bpbp)Fe(F)2M(H2O)2][BF4]2, M = Fe or Co, are weakly antiferromagnetically coupled (J = –8 and –10 cm–1 respectively) and in [(bpbp)Fe(F)2Cu(H2O)][BF4]2 are weakly ferromagnetically coupled (J = 2 cm–1). The spectroscopic, electrochemical and magnetic properties of these complexes are compared to those of an analogous series of complexes containing two acetate bridging groups in the exogenous site. Electrochemical results indicate that the iron(III) ions in the bis-fluoride complexes are stabilized by about 300 mV towards reduction compared to the bis-µ-acetate complexes. The crystal structure of one bis-µ-acetate complex, [Fe2(bpbp)(CH3CO2)2][BF4]2, shows the expected arrangement; the iron-(II) and -(III) atoms are triply bridged by the phenolic oxygen atom of bpbp– and two µ-acetate groups with FeII–Ophenolato 2.088(4) and FeIII–Ophenolato 1.951(5) A and an Fe· · ·Fe distance of 3.380(2) A. The crystal structure at 120 K indicates that the iron atoms are valence trapped and in accordance with this Mossbauer measurements between 80 and 200 K show clearly distinguishable iron-(II) and -(III) components. The Mossbauer spectra of [(bpbp)Fe(F)2Cu(H2O)][BF4]2·4H2O are influenced by paramagnetic relaxation effects with relaxation times of the order of 1 ns. The relaxation time increases when a magnetic field is applied. This effect can be explained by a model for cross-relaxation in conjunction with the crystal symmetry of the compound.
影响因子：
2.9
作者：
VINCENT, JB;CROWDER, MW;AVERILL, BA
通讯作者：
AVERILL, BA
高盐型牛脾紫色酸性磷酸酶的电子顺磁共振研究。
影响因子：
2.9
作者：
Crowder,MW;Vincent,JB;Averill,BA
通讯作者：
Averill,BA