Tuning a Single Ligand System to Stabilize Multiple Spin States of Manganese: A First Example of a Hydrazone-Based Manganese(III) Spin-Crossover Complex
作者:Musa S. Shongwe、Kaltham S. Al-Barhi、Masahiro Mikuriya、Harry Adams、Michael J. Morris、Eckhard Bill、Kieran C. Molloy
DOI:10.1002/chem.201402634
日期:2014.7.28
converting easily into the former complex on deprotonation. Accessibility of the higher‐valent states is achievable only when the phenolate oxygen atom is sterically hindered from participation in hydrogen bonding. The [MnIIIH(3,5‐tBu2)‐L}2]ClO4 complex is the first example of a hydrazone‐based MnIII complex to exhibit spin crossover. Formation of the tetravalent complexes [MnIV(3,5‐R1,R2)‐L}2] (R1=tBu
一系列双-螯合物伪-锰八面体单核配位络合物与发色团[MNN 4 Ò 2 ] Ñ +(Ñ = 0,1)都在环境条件下该过渡金属中心的所有三个主要氧化态被生成通过使用易于调节的通用酚醛id pyr配体系统(即H 2(3,5-R 1,R 2)-L; L =配体)。各种取代基的性质和位置的战略组合提供了锰中心多个自旋状态的选择性,自发稳定,在仔细的晶体学研究下,这似乎部分是由于氢键相互作用的出现或不存在涉及酚盐/酚氧原子。二价络合物可分离为两种形式,即分子[Mn II H(3,5-R 1,R 2)-L} 2 ]和离子型[Mn II H 2(3,5-R 1,R 2)-L} H(3,5-R 1,R 2)-L}] ClO 4,后者在去质子化时很容易转化为前者。仅当酚盐氧原子在空间上受阻于氢键结合时,才能实现较高价态的可及性。[Mn III H(3,5- t Bu 2)-L} 2 ] ClO 4配合物是a基Mn