Design of Novel Inorganic−Organic Hybrid Materials Based on Iron-Chloranilate Mononuclear Complexes: Characteristics of Hydrogen-Bond-Supported Layers toward the Intercalation of Guests

Novel intercalation compounds constructed from the common two-dimensional hydrogen-bond-supported layers and functional guests {(H0.5phz)2[Fe(CA)2(H2O)2]·2H2O}n (1), {[Fe(Cp)2][Fe(CA)2(H2O)2]}n
(2), {[Fe(Cp*)2][Fe(CA)2(H2O)2]}n (3), and {(TTF)2[Fe(CA)2(H2O)2]}n (4) (H2CA = chloranilic acid, phz =
phenazine, [Fe(Cp)2] = ferrocene, [Fe(Cp*)2] = decamethylferrocene, TTF = tetrathiafulvalene) are described. The guest cations are introduced between the {[Fe(CA)2(H2O)2]m-}l layers by electrostatic (1−4)
and π−π stacking (3, 4) interactions. [Fe(Cp*)2]+ cations in 3 are stacked on each other making tilted
columns which are included in the channel created by the chlorine atoms of CA2- dianions. TTF cations in
4 are stacked face to face with two types of S···S distances (type A; 3.579(3) Å, and type B; 3.618(3) Å)
making a columnar structure. The TTF cations in the stacked column have a head-to-tail arrangement with
respect to the iron-chloranilate layer. Mössbauer spectroscopy suggests that [Fe(CA)2(H2O)2]m- anion in 3
is consistent with high-spin (S = 5/2) iron(III) ions and [Fe(Cp*)2]+ in the low-spin (S = 1/2) iron(III) ions.
In 4, Mössbauer spectroscopy shows high-spin iron(II) ions (IS = 1.10 mm·s-1 and QS = 1.66 mm·s-1 at
297 K) and high-spin iron(III) ions (IS = 0.42 mm·s-1 and QS = 1.27 mm·s-1 at 297 K), suggesting that
the anionic layer of iron-chloranilate has a valence-trapped mixed-valence state. At the temperature range
of 77−300 K, the compounds 1, 2, and 3 are EPR silent, whereas the EPR spectrum of 4 shows two types
of signals with g = 2.008 indicating the radical form of TTF.

本文报道了由常见二维氢键支撑层与功能性客体构筑的新型插层化合物{(H₀.₅phz)₂[Fe(CA)₂(H₂O)₂]·2H₂O}ₙ (1)、{[Fe(Cp)₂][Fe(CA)₂(H₂O)₂]}ₙ (2)、{[Fe(Cp*)₂][Fe(CA)₂(H₂O)₂]}ₙ (3)以及{(TTF)₂[Fe(CA)₂(H₂O)₂]}ₙ (4)，其中H₂CA = 氯冉酸（chloranilic acid），phz = 吩嗪（phenazine），[Fe(Cp)₂] = 二茂铁（ferrocene），[Fe(Cp*)₂] = 十甲基二茂铁（decamethylferrocene），TTF = 四硫富瓦烯（tetrathiafulvalene）。客体阳离子通过静电相互作用（对应化合物1~4）与π-π堆积相互作用（对应化合物3、4），被引入至{[Fe(CA)₂(H₂O)₂]^m⁻}层之间。化合物3中的[Fe(Cp*)₂]⁺阳离子相互堆叠形成倾斜柱结构，该柱被包埋在由CA²⁻二阴离子的氯原子构筑的通道中。化合物4中的TTF阳离子面对面堆叠，存在两种类型的S···S距离（A型：3.579(3) Å，B型：3.618(3) Å），从而形成柱形结构。堆叠柱中的TTF阳离子相对于铁-氯冉酸层呈头对尾排列。穆斯堡尔（Mössbauer）光谱研究表明，化合物3中的[Fe(CA)₂(H₂O)₂]^m⁻阴离子对应高自旋（S = 5/2）铁(III)离子，而[Fe(Cp*)₂]⁺则为低自旋（S = 1/2）铁(III)离子。在化合物4中，穆斯堡尔光谱显示存在高自旋铁(II)离子（297 K下，同质异能位移IS=1.10 mm·s⁻¹，四极分裂QS=1.66 mm·s⁻¹）与高自旋铁(III)离子（297 K下，IS=0.42 mm·s⁻¹，QS=1.27 mm·s⁻¹），这表明铁-氯冉酸阴离子层存在价态捕获的混合价态。在77~300 K的温度范围内，化合物1、2和3均无电子顺磁共振（EPR，electron paramagnetic resonance）信号，而化合物4的电子顺磁共振光谱则呈现两种g=2.008的信号峰，对应TTF的自由基形式。