双核双吡唑桥联配合物的高受限双齿配体：[Fe(II)2(PMAP)2][SbF6]2.2.25(C3H8O)（PMAP=3,5-双{[N-(2-吡啶基甲基)氨基]-甲基}-1H-吡唑）的[高自旋-低自旋]态的观察。

Doubly pyrazolate-bridged dinuclear complexes of a highly constrained bis-terdentate ligand: observation of a [high spin-low spin] state for [Fe(II)2(PMAP)2][SbF6]2.2.25(C3H8O) (PMAP = 3,5-bis{[N-(2-pyridylmethyl)amino]-methyl}-1H-pyrazolate).

机构信息

Department of Chemistry and The MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Otago, PO Box 56, Dunedin, New Zealand.

出版信息

Inorg Chem. 2010 May 17;49(10):4560-9. doi: 10.1021/ic1001013.

DOI:10.1021/ic1001013

PMID:20394410

Abstract

The bis-terdentate pyrazole-based ligand 3,5-bis{[N-(2-pyridylmethyl)amino]methyl}-1H-pyrazole (PMAPH) was synthesized from 3,5-(1H)-pyrazoledicarbaldehyde and 2 equiv of 2-(aminomethyl)pyridine, using sodium borohydride to reduce the imine intermediate. A family of dinuclear complexes M(II/III)(2)(PMAP)(2)(2/4) was prepared by 2:2:2 reactions of MX(2)/PMAPH/base, where M = Zn(II) and X = BF(4)(-); M = Cu(II) and X = ClO(4)(-), BF(4)(-), OAc(-), NO(3)(-); M = Ni(II), Fe(III) and X = ClO(4)(-), BF(4)(-); M = Fe(II) and X = SbF(6)(-). Single crystal X-ray structure determinations on four complexes: Fe(III)(2)(PMAP)(2)(4).2MeCN, Ni(II)(2)(PMAP)(2)(2).2MeCN, Cu(II)(2)(PMAP)(2)(2).2MeCN, and Zn(II)(2)(PMAP)(2)(2).2MeCN confirmed a dinuclear doubly pyrazolate-bridged structure for each. The two metal centers in these complexes have similar N(6) distorted octahedral coordination spheres, with all donors provided by the two deprotonated PMAP(-) ligands. Magnetic measurements reveal intra-dinuclear antiferromagnetic interactions for both the M = Cu(II) and Ni(II) M(2)(PMAP)(2)(4) complexes, with J/k(B) = -252(2) K and J/k(B) = -24.7(2) K (H = -2JS(M)S(M)), respectively. Interestingly magnetic measurements show that the complex Fe(2)(II)(PMAP)(2)(2).2.25(C(3)H(8)O) is in a mixed high spin (HS)-low spin (LS) spin state, [HS-LS], from 300 to 1.8 K, with no sign of spin crossover to a fully low spin form [LS-LS] even at 1.8 K.

摘要

合成了一种双齿吡唑基配体 3,5-双{[N-(2-吡啶甲基)氨基]甲基}-1H-吡唑（PMAPH），由 3,5-（1H）-吡唑二醛和 2 当量的 2-（氨甲基）吡啶通过硼氢化钠还原亚胺中间体得到。通过 MX(2)/PMAPH/碱的 2:2:2 反应制备了一系列双核配合物M(II/III)(2)(PMAP)(2)(2/4)，其中 M = Zn(II)和 X = BF(4)(-)；M = Cu(II)和 X = ClO(4)(-), BF(4)(-), OAc(-), NO(3)(-)；M = Ni(II), Fe(III)和 X = ClO(4)(-), BF(4)(-)；M = Fe(II)和 X = SbF(6)(-)。通过对四个配合物的单晶 X 射线结构测定：Fe(III)(2)(PMAP)(2)(4).2MeCN、Ni(II)(2)(PMAP)(2)(2).2MeCN、Cu(II)(2)(PMAP)(2)(2).2MeCN 和Zn(II)(2)(PMAP)(2)(2).2MeCN，证实了每个配合物都是双核双吡唑桥联结构。这些配合物中的两个金属中心具有相似的 N(6)扭曲八面体配位球，所有供体均由两个去质子化的 PMAP(-)配体提供。磁测量结果表明，对于 M = Cu(II)和 Ni(II)M(2)(PMAP)(2)(4)配合物，均存在双金属核间反铁磁相互作用，J/k(B) = -252(2) K 和 J/k(B) = -24.7(2) K（H = -2JS(M)S(M)）。有趣的是，磁测量表明，配合物Fe(2)(II)(PMAP)(2)(2).2.25(C(3)H(8)O)在 300 至 1.8 K 范围内处于混合高自旋（HS）-低自旋（LS）状态[HS-LS]，甚至在 1.8 K 时也没有完全转化为低自旋形式[LS-LS]的迹象。