Delgado Fernando S, Kerbellec Nicolas, Ruiz-Pérez Catalina, Cano Joan, Lloret Francesc, Julve Miguel
Laboratorio de Rayos X y Materiales Moleculares, Departamento de Física Fundamental II, Facultad de Física, Universidad de La Laguna, Avda, Astrofísico Francisco Sánchez s/n, 38204 La Laguna, Tenerife, Spain.
Inorg Chem. 2006 Feb 6;45(3):1012-20. doi: 10.1021/ic0508526.
The novel manganese(III) complexes PPh4[Mn(mal)2(H2O)2] (1) and AsPh4[Mn(mal)2(H2O)2] (2) (PPh4+ = tetraphenylphosphonium cation, AsPh4+ = tetraphenylarsonium cation, and H2mal = malonic acid) have been prepared, and the structure of 2 was determined by X-ray diffraction analysis. 2 is a mononuclear complex whose structure is made up of trans-diaquabis(malonato)manganate(III) units and tetraphenylarsonium cations. Two crystallographically independent manganese(III) ions (Mn(1) and Mn(2)) occur in 2 that exhibit elongated octahedral surroundings with four oxygen atoms from two bidentate malonate groups in equatorial positions (Mn(1)-O = 1.923(6) and 1.9328(6) A and Mn(2)-O = 1.894(6) and 1.925(6) A) and two trans-coordinated water molecules in the axial sites (Mn(1)-Ow = 2.245(6) A and Mn(2)-Ow = 2.268(6) A). The [Mn(mal)2(H2O)2]- units are linked through hydrogen bonds involving the free malonate-oxygen atoms and the coordinated water molecules to yield a quasi-square-type anionic layer growing in the ab plane. The shortest intralayer metal-metal separations are 7.1557(7) and 7.1526(7) A (through the edges of the square). The anionic sheets are separated from each other by layers of AsPh4+ where sextuple- and double-phenyl embraces occur. The magnetic behavior of 1 and 2 in the temperature range 1.9-290 K reveals the occurrence of weak intralayer ferromagnetic interactions (J = +0.081(1) (1) and +0.072(2) cm(-1) (2)). These values are compared to those of the weak antiferromagnetic coupling [J = -0.19(1) cm(-1)], which is observed in the chain compound K2[Mn(mal)2(MeOH)2][Mn(mal)2] (3), where the exchange pathway involves the carboxyate-malonate bridge in the anti-syn conformation. The structure of 3 was reported elsewhere. Theoretical calculations on fragment models of 2 and 3 were performed to analyze and substantiate both the nature and magnitude of the magnetic couplings observed.
已制备出新型锰（III）配合物四苯基鏻[Mn(丙二酸)₂(H₂O)₂]（1）和四苯基砷[Mn(丙二酸)₂(H₂O)₂]（2）（PPh₄⁺ = 四苯基鏻阳离子，AsPh₄⁺ = 四苯基砷阳离子，H₂mal = 丙二酸），并通过X射线衍射分析确定了2的结构。2是一种单核配合物，其结构由反式二水双（丙二酸根）锰（III）单元和四苯基砷阳离子组成。2中存在两个晶体学独立的锰（III）离子（Mn(1)和Mn(2)），它们呈现出拉长的八面体环境，赤道位置有来自两个双齿丙二酸根基团的四个氧原子（Mn(1)-O = 1.923(6) Å和1.9328(6) Å，Mn(2)-O = 1.894(6) Å和1.925(6) Å），轴向位置有两个反式配位的水分子（Mn(1)-Ow = 2.245(6) Å和Mn(2)-Ow = 2.268(6) Å）。[Mn(丙二酸)₂(H₂O)₂]⁻单元通过涉及游离丙二酸根氧原子和配位水分子的氢键相连，形成在ab平面生长的准方形阴离子层。层内最短的金属 - 金属间距为7.1557(7) Å和7.1526(7) Å（通过正方形的边）。阴离子片层被AsPh₄⁺层隔开，其中存在六重和双重苯基包围。1和2在1.9 - 290 K温度范围内的磁行为表明存在弱的层内铁磁相互作用（J = +0.081(1) （1）和 +0.072(2) cm⁻¹ （2））。将这些值与在链状化合物K₂[Mn(丙二酸)₂(MeOH)₂][Mn(丙二酸)₂]（3）中观察到的弱反铁磁耦合[J = -0.19(1) cm⁻¹]的值进行了比较，在该化合物中交换途径涉及反 - 顺构象的羧酸根 - 丙二酸根桥。3的结构已在其他地方报道。对2和3的片段模型进行了理论计算，以分析和证实所观察到的磁耦合的性质和大小。
