Cuevas Alicia, Chiozzone Raúl, Kremer Carlos, Suescun Leopoldo, Mombrú Alvaro, Armentano Donatella, De Munno Giovanni, Lloret Francesc, Cano Juan, Faus Juan
Cátedra de Química Inorgánica y Laboratorio de Cristalografía, Facultad de Química de la Universidad de la República, Avenida General Flores 2124, CC 1157 Montevideo, Uruguay.
Inorg Chem. 2004 Nov 29;43(24):7823-31. doi: 10.1021/ic0493853.
The Re(IV) complex [ReCl4(mal)]2-, in the form of two slightly different salts, (AsPh4)1.5(HNEt3)0.5[ReCl4(mal)] (1a) and (AsPh4)(HNEt3)[ReCl4(mal)] (1b), and the Re(IV)-Cu(II) bimetallic complexes [ReCl4(mu-mal)Cu(phen)2].CH3CN (2), [ReCl4(mu-mal)Cu(bpy)2] (3), and [ReCl4(mu-mal)Cu(terpy)] (4) (mal=malonate dianion, AsPh4=tetraphenylarsonium cation, HNEt3=triethylammonium cation, phen=1,10-phenanthroline, bpy=2,2'-bipyridine and terpy=2,2':6',2' '-terpyridine) have been synthesized and the structures of 1a, 1b, 2, and 3 determined by single-crystal X-ray diffraction. The structures of 1a and 1b are made up of discrete [ReCl4(mal)]2- anions and AsPh4+ and HNEt3+ cations, held together by electrostatic forces and hydrogen bonds. The Re(IV) atom is surrounded by four chloride anions and a bidentate malonate group, in a distorted octahedral environment. The structure of 2 consist of neutral dinuclear units [ReCl4(mu-mal)Cu(phen)2], with the metal ions united through a bridge carboxilato. The environment of Re(IV) is nearly identical to that in the mononuclear complex, and Cu(II) is five coordinate, being surrounded by four nitrogen atoms of two bidentate phen ligands and one oxygen atom of the malonato ligand. In 3, there are also dinuclear units, [ReCl4(mu-mal)Cu(bpy)2], but the Cu(II) ions complete a distorted octahedral coordination by binding with the free malonato oxygen atom of a neighbor unit, resulting in an infinite chain. The magnetic properties of 1-4 were also investigated in the temperature range 2.0-300 K. The magnetic behavior of 1a and 1b is as expected for a Re(IV) complex with a large value of the zero-field splitting (2D ca. 110 cm(-1)). For the bimetallic complexes, the magnetic coupling between Re(IV) and Cu(II) is antiferromagnetic in 2 (J=-0.39 cm(-1)), ferromagnetic in 4 (J=+1.51 cm(-1)), and nearly negligible in 3 (J=-0.09 cm(-1)).
铼（IV）配合物[ReCl4(mal)]2-以两种略有不同的盐的形式存在，即(AsPh4)1.5(HNEt3)0.5[ReCl4(mal)]（1a）和(AsPh4)(HNEt3)[ReCl4(mal)]（1b），以及铼（IV）-铜（II）双金属配合物[ReCl4(μ-mal)Cu(phen)2].CH3CN（2）、[ReCl4(μ-mal)Cu(bpy)2]（3）和[ReCl4(μ-mal)Cu(terpy)]（4）（mal = 丙二酸二价阴离子，AsPh4 = 四苯基砷阳离子，HNEt3 = 三乙铵阳离子，phen = 1,10-菲咯啉，bpy = 2,2'-联吡啶，terpy = 2,2':6',2''-三联吡啶）已被合成，并通过单晶X射线衍射确定了1a、1b、2和3的结构。1a和1b的结构由离散的[ReCl4(mal)]2-阴离子以及AsPh4+和HNEt3+阳离子组成，它们通过静电力和氢键结合在一起。铼（IV）原子被四个氯离子阴离子和一个双齿丙二酸基团包围，处于扭曲的八面体环境中。2的结构由中性双核单元[ReCl4(μ-mal)Cu(phen)2]组成，金属离子通过桥连羧基连接在一起。铼（IV）的环境与单核配合物中的环境几乎相同，而铜（II）是五配位的，被两个双齿phen配体的四个氮原子和丙二酸配体的一个氧原子包围。在3中，也存在双核单元[ReCl4(μ-mal)Cu(bpy)2]，但铜（II）离子通过与相邻单元的游离丙二酸氧原子结合完成了扭曲的八面体配位，形成了无限链。还在2.0 - 300 K的温度范围内研究了1 - 4的磁性。1a和1b的磁行为对于具有大零场分裂值（2D约为110 cm(-1)）的铼（IV）配合物来说是预期的。对于双金属配合物，铼（IV）和铜（II）之间的磁耦合在2中是反铁磁性的（J = -0.39 cm(-1)），在4中是铁磁性的（J = +1.51 cm(-1)），在3中几乎可以忽略不计（J = -0.09 cm(-1)）。
