Strong antiferromagnetic interaction in µ-Oxo-bridged diiron(III) complex and paramagnetic nickel(II) complex of pyridoxal Schiff base ligands

IF 2.8 4区化学 Q3 CHEMISTRY, INORGANIC & NUCLEAR

Transition Metal Chemistry Pub Date : 2026-02-18 DOI:10.1007/s11243-025-00713-y

Viera Murašková, Václav Eigner, David Sedmidubský

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Abstract

Dinuclear and mononuclear pyridoxal Schiff base complexes, specifically [{FeL}₂(µ-O)]·2.2H₂O (1) and [NiL’(H₂O)]·2H₂O (2) (where L^2– is the dianion of tetradentate pyridoxal Schiff base generated in situ by the iron-catalyzed oxidative C − N bond cleavage of the initial pentadentate Schiff base, and L’^2– is the dianion of pentadentate Schiff base ligand formed from pyridoxal and N-(2-aminoethyl)propane-1,3-diamine) have been synthesized and characterized by elemental analysis, Fourier transform infrared spectroscopy, and mass spectrometry. The crystal structures of these complexes were determined using single-crystal X-ray diffraction. The Fe atoms in complex 1 exhibit a distorted square pyramidal coordination geometry, while Ni atom in complex 2 displays a distorted octahedral geometry. The most significant finding is the strong antiferromagnetic exchange coupling observed in the diiron complex 1. Magnetic susceptibility data revealed an exchange coupling constant of J = − 173 cm^–1, confirming its potential role as a model for non-heme diiron metalloenzymes. In contrast, complex 2 exhibits typical paramagnetic behavior of an octahedral Ni(II) complex with two unpaired electrons. Calculations based on density functional theory confirmed the high-spin state of the Fe(III) centers in the diiron complex and verified the magnitude of the strong antiferromagnetic exchange coupling. For the nickel complex, these calculations also revealed a significant degree of bond covalency, providing a comprehensive understanding of the structural and magnetic properties of these pyridoxal-based coordination compounds.

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吡哆醛席夫碱配体微氧桥接双铁（III）配合物与顺磁性镍（II）配合物的强反铁磁相互作用

合成了双核和单核吡哆醛席夫碱配合物，特别是[{FeL}2（µ- o）]·2.2H2O(1)和[NiL ' (H2O)]·2H2O(2)（其中L2 -是由初始五齿席夫碱的铁催化氧化C - N键裂解原位生成的四齿吡哆醛席夫碱的癸离子，L ' 2-是由吡哆醛和N-（2-氨基乙基）丙烷-1,3-二胺形成的五齿席夫碱配体的癸离子），并通过元素分析对其进行了表征。傅里叶变换红外光谱和质谱。用单晶x射线衍射测定了这些配合物的晶体结构。配合物1中的Fe原子呈现畸变的方锥体配位几何，而配合物2中的Ni原子呈现畸变的八面体配位几何。最重要的发现是在二铁配合物1中观察到的强反铁磁交换耦合。磁化率数据显示其交换偶联常数为J =−173 cm-1，证实了其作为非血红素二铁金属酶模型的潜在作用。相反，配合物2表现出典型的八面体Ni（II）配合物的顺磁性，具有两个不成对的电子。基于密度泛函理论的计算证实了双铁配合物中Fe（III）中心的高自旋态，并验证了强反铁磁交换耦合的强度。对于镍配合物，这些计算还揭示了相当程度的键共价，为这些吡哆基配位化合物的结构和磁性提供了全面的了解。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Transition Metal Chemistry 化学-无机化学与核化学

CiteScore

3.60

自引率

0.00%

发文量

审稿时长

1.3 months

期刊介绍： Transition Metal Chemistry is an international journal designed to deal with all aspects of the subject embodied in the title: the preparation of transition metal-based molecular compounds of all kinds (including complexes of the Group 12 elements), their structural, physical, kinetic, catalytic and biological properties, their use in chemical synthesis as well as their application in the widest context, their role in naturally occurring systems etc. Manuscripts submitted to the journal should be of broad appeal to the readership and for this reason, papers which are confined to more specialised studies such as the measurement of solution phase equilibria or thermal decomposition studies, or papers which include extensive material on f-block elements, or papers dealing with non-molecular materials, will not normally be considered for publication. Work describing new ligands or coordination geometries must provide sufficient evidence for the confident assignment of structural formulae; this will usually take the form of one or more X-ray crystal structures.