科研之友
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摘要
The trans-dicyanide-containing precursor K[Fe(bpdBrb)(CN)(2)]center dot 2H(2)O (1) (bpdBrb(2-) = 1,2-bis(pyridine-2-carboxamido)-4,5-dibromobenzenate) and four transition metal compounds containing Fe-III, Mn-III or Cu-II have been employed as building blocks to assemble cyanide-bridged systems, resulting in a series of new cyanide-bridged single chain complexes [Fe(bpdBrb)(CN)](n)center dot nCH(3)OH (2), {[Mn(L-1)][Fe(bpdBrb)(CN)(2)]}(n)center dot nCH(3)CN (3), {[Mn(L-2)][Fe(bpdBrb)(CN)(2)]}(n)center dot 2nH(2)O (4) and {[Cu(cyclam)][Fe(bpdBrb)(CN)(2)]ClO4}(n)center dot nCH(3)OH (5) (L-1 = 5-Brsalpn and L-2 = 5-Clsaltn). Single crystal X-ray diffraction analysis reveals the rare one-dimensional "shish-kebab" neutral structure of complex 2 with bpdBrb(2-) as the equatorial ligand and single cyanide ligands as axial bridges. The other three cyanide-bridged complexes can be structurally characterized as the neutral one-dimensional chains (2 and 3) consisting of alternating units of [Mn(L)](+) (L = L-1 or L-2) and [Fe(bpdBrb)(CN)(2)](-) and a cationic one-dimensional single chain (4) consisting of the repeating units {NC-[Fe(bpdBrb)]-CN-Cu(cyclam)(+)} with free ClO4- as the counter-anion. Investigation of the magnetic properties of the four 1D chain complexes reveals the antiferromagnetic coupling between neighbouring low spin Fe(III) ions in complex 2 and the ferromagnetic interaction between the cyanide-bridged Fe(III)-Mn(III)/Cu(II) ions in complexes 3-5. By employing infinite chain models or a MAGPACK program, the magnetic susceptibilities of these complexes were simulated, leading to the magnetic coupling constants J = -1.98(2) cm(-1) for 2, J(1) = 0.56(1), J(2) = 0.45(2) cm(-1) for 3, J(1) = 0.59(3), J(2) = 0.43(8) cm(-1) for 4, and J = 1.77(5) cm(-1) for 5.
