Mohanta Sasankasekhar, Nanda Kausik K., Werner Rüdiger, Haase Wolfgang, Mukherjee Alok K., Dutta Sujit K., Nag Kamalaksha
Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Calcutta 700 032, India, Institut für Physikalische Chemie der Technischen Hochschule Darmstadt, D-64287 Darmstadt, Germany, and Department of Physics, Jadavpur University, Calcutta 700 032, India.
Inorg Chem. 1997 Oct 8;36(21):4656-4664. doi: 10.1021/ic9611103.
A binuclear tetraprotonated macrocyclic complex Mg(2)(L(2)-H(4))(NO(3))(2)(2).6H(2)O (1) has been obtained by template condensation of 4-methyl-2,6-diformylphenol and 1,2-diaminoethane in the presence of magnesium acetate and nitrate. Complex 1 on reduction with NaBH(4), followed by the removal of magnesium, yields the 36-membered octaaminotetraphenol macrocyclic ligand H(4)L(1). The replacement of magnesium in 1 with copper(II) leads to the formation of the binuclear complex [Cu(2)L(3)(ClO(4))(2)] (2) derived from the [2+2] cyclization product of 4-methyl-2,6-diformylphenol and 1,2-diaminoethane. From H(4)L(1) a series of tetranuclear nickel(II) complexes 5-8 with the core cation Ni(4)L(1)(&mgr;(2)-X)(2)(&mgr;(2)-H(2)O)(2) (X = NCS, N(3), OAc, or Cl) have been synthesized and characterized. The trinuclear complex [Ni(3)L(1)(acac)(2)(H(2)O)(2).2H(2)O (9), obtained by reacting nickel(II) acetylacetonate with H(4)L(1), on treatment with nickel(II) perchlorate produces the tetranuclear compound Ni(4)L(1)(acac)(2)(H(2)O)(4)(2) (10). Variable-temperature (4-300 K) magnetic susceptibility measurements have been carried out for the tetracopper(II) complex Cu(4)L(1)(H(2)O)(4)(4) (3) and the tetranickel(II) complexes Ni(4)L(1)(&mgr;(3)-OH)(&mgr;(2)-H(2)O)(2)(ClO(4))(2).2CH(3)COCH(3).H(2)O (4), Ni(4)L(1)(&mgr;(2)-NCS)(2)(&mgr;(2)-H(2)O)(2)(2).2CH(3)CN (5), Ni(4)L(1)(&mgr;(2)-N(3))(2)(&mgr;(2)-H(2)O)(2)(2).2CH(3)OH (6), Ni(4)L(1)(&mgr;(2)-OAc)(2)(&mgr;(2)-H(2)O)(2)(2).2H(2)O (7), and [Ni(4)L(1)(&mgr;(2)-Cl)(2)(&mgr;(2)-H(2)O)(2)]Cl(2).4H(2)O (8). The X-ray structure of 5 has been determined. The complex (C(50)H(70)N(12)O(14)Cl(2)S(2)Ni(4)) crystallizes in the triclinic space group P&onemacr; with a = 11.794(6) Å, b = 12.523(4) Å, c = 12.794(5) Å, alpha = 117.28(5) degrees, beta = 96.38(4) degrees, gamma = 109.65(3) degrees, and Z = 1. In the asymmetric unit each of the nickel(II) centers with distorted octahedral geometry is triply-bridged by a phenoxide group, a water molecule, and a N-bonded thiocyanate and these metal centers are further bridged to their symmetry-related counterparts by another phenoxide group. The experimental susceptibility data have been analyzed using appropriate Heisenberg spin coupling models (H = -2J(ij)()S(i)().S(j)()) and the best-fit spin exchange parameters obtained are as follows: J = -288(3) cm(-)(1) (3); J(1) = -8.1(2) cm(-)(1), J(2) = -10.2(2) cm(-)(1) (4); J(1) = -34.5(1.0) cm(-)(1), J(2) = -9.5(2.0) cm(-)(1) (5); J(1) = -34(1) cm(-)(1), J(2) = 11(2) cm(-)(1) (6); J(1) = -30(1) cm(-)(1), J(2) = -7.0(1.5) cm(-)(1) (7); J(1) = -32(1) cm(-)(1), J(2) = -4(1) cm(-)(1) (8).
通过在乙酸镁和硝酸盐存在下使4-甲基-2,6-二甲醛苯酚与1,2-二氨基乙烷进行模板缩合反应，得到了双核四质子化大环配合物Mg₂(L₂-H₄)(NO₃)₂₂·6H₂O (1)。配合物1用NaBH₄还原，随后除去镁，得到36元八氨基四苯酚大环配体H₄L₁。用铜(II)取代1中的镁，导致形成源自4-甲基-2,6-二甲醛苯酚与1,2-二氨基乙烷的[2+2]环化产物的双核配合物[Cu₂L₃(ClO₄)₂] (2)。由H₄L₁合成并表征了一系列具有核心阳离子[Ni₄L₁(μ₂-X)₂(μ₂-H₂O)₂]²⁺ (X = NCS、N₃、OAc或Cl)的四核镍(II)配合物5-8。通过使乙酰丙酮镍与H₄L₁反应得到的三核配合物[Ni₃L₁(acac)₂(H₂O)₂·2H₂O (9)，用高氯酸镍处理后生成四核化合物Ni₄L₁(acac)₂(H₂O)₄₂ (10)。对四铜(II)配合物Cu₄L₁(H₂O)₄₄ (3)以及四核镍(II)配合物Ni₄L₁(μ₃-OH)(μ₂-H₂O)₂(ClO₄)₂·2CH₃COCH₃·H₂O (4)、Ni₄L₁(μ₂-NCS)₂(μ₂-H₂O)₂₂·2CH₃CN (5)、Ni₄L₁(μ₂-N₃)₂(μ₂-H₂O)₂₂·2CH₃OH (6)、Ni₄L₁(μ₂-OAc)₂(μ₂-H₂O)₂₂·2H₂O (7)和[Ni₄L₁(μ₂-Cl)₂(μ₂-H₂O)₂]Cl₂·4H₂O (8)进行了变温(4-300 K)磁化率测量。测定了5的X射线结构。配合物(C₅₀H₇₀N₁₂O₁₄Cl₂S₂Ni₄)以三斜空间群Pī结晶，a = 11.794(6) Å，b = 12.⁵²³(4) Å，c = 12.⁷⁹⁴(5) Å，α = 117.²⁸(5)°，β =⁹⁶.³⁸(4)°，γ = 109.⁶⁵(3)°，Z = 1。在不对称单元中，每个具有扭曲八面体几何构型的镍(II)中心通过一个酚氧基、一个水分子和一个N键合的硫氰酸盐三重桥连，并且这些金属中心通过另一个酚氧基进一步桥连到它们的对称相关对应物上。使用适当的海森堡自旋耦合模型(H = -2JijSiSj)对实验磁化率数据进行了分析，得到的最佳拟合自旋交换参数如下：J = -288(3) cm⁻¹ (3)；J₁ = -8.¹(2) cm⁻¹，J₂ = -10.²(2) cm⁻¹ (4)；J₁ = -³⁴.⁵(1.0) cm⁻¹，J₂ = -⁹.⁵(2.0) cm⁻¹ (5)；J₁ = -³⁴(1) cm⁻¹，J₂ = ¹¹(2) cm⁻¹ (6)；J₁ = -³⁰(1) cm⁻¹，J₂ = -⁷.⁰(1.5) cm⁻¹ (7)；J₁ = -³²(1) cm⁻¹，J₂ = -⁴(1) cm⁻¹ (8)。
