Sarkar Biswarup, Konar Sanjit, Gómez-García Carlos J, Ghosh Ashutosh
Department of Chemistry, University College of Science, University of Calcutta, 92, APC Road, Kolkata-700 009, India.
Inorg Chem. 2008 Dec 15;47(24):11611-9. doi: 10.1021/ic8011519.
Three new copper(II) complexes, CuL(1)(NO(2)) (1), [CuL(2)(NO(2))] (2), and [CuL(3)(NO(2))] (3), with three similar tridentate Schiff base ligands [HL(1) = 6-amino-3-methyl-1-phenyl-4-azahept-2-en-1-one, HL(2) = 6-amino-3-methyl-1-phenyl-4-azahex-2-en-1-one, and HL(3) = 6-diethylamino-3-methyl-1-phenyl-4-azahex-2-en-1-one] have been synthesized and characterized structurally and magnetically. In all three complexes, the tridentate Schiff base ligand and one oxygen atom of the nitrite ion constitute the equatorial plane around Cu(II), whereas the second oxygen atom of the nitrite ligand coordinates to one of the axial positions. In 1, this axially coordinated oxygen atom of the nitrite ligand also coordinates weakly to the other axial position of a Cu(II) ion of another unit to form a one-dimensional chain with the mu-nitrito-1kappa(2)O,O':2kappaO bridging mode. Complexes 2 and 3 are discrete monomers that are joined together by intermolecular H bonds and C-H....pi interactions in 2 and by only C-H....pi interactions in 3. A weak antiferromagnetism (J = -1.96(2) cm(-1)) is observed in complex 1 due to its asymmetric nitrite bridging. Complexes 2 and 3 show very weak antiferromagnetic interactions (J = -0.089 and -0.096 cm(-1), respectively) attributed to the presence of intermolecular H-bonding and C-H....pi interactions. The corresponding Cu(I) species produced by the electrochemical reduction of complexes 1 and 2 disproportionate to Cu(0) and Cu(2+,) whereas the reduced Cu(I) species of complex 3 seems to be stable presumably due to a higher tetrahedral distortion of the equatorial plane in 3 compared to that in 1 and 2.
合成了三种新的铜（II）配合物，即CuL(1)(NO(2))（1）、[CuL(2)(NO(2))]（2）和[CuL(3)(NO(2))]（3），它们带有三种相似的三齿席夫碱配体[HL(1)=6-氨基-3-甲基-1-苯基-4-氮杂庚-2-烯-1-酮、HL(2)=6-氨基-3-甲基-1-苯基-4-氮杂己-2-烯-1-酮、HL(3)=6-二乙氨基-3-甲基-1-苯基-4-氮杂己-2-烯-1-酮]，并对其进行了结构和磁性表征。在所有三种配合物中，三齿席夫碱配体和亚硝酸根离子的一个氧原子构成了围绕铜（II）的赤道平面，而亚硝酸根配体的第二个氧原子则与一个轴向位置配位。在1中，亚硝酸根配体的这个轴向配位氧原子也与另一个单元的铜（II）离子的另一个轴向位置弱配位，以μ-亚硝酸根-1κ(2)O,O':2κO桥连模式形成一维链。配合物2和3是离散单体，在2中通过分子间氢键和C-H…π相互作用连接在一起，在3中仅通过C-H…π相互作用连接。由于其不对称的亚硝酸根桥连，在配合物1中观察到弱反铁磁性（J = -1.96(2) cm(-1)）。配合物2和3表现出非常弱的反铁磁相互作用（J分别为-0.089和-0.096 cm(-1)），这归因于分子间氢键和C-H…π相互作用的存在。配合物1和2通过电化学还原产生的相应铜（I）物种歧化为铜（0）和铜（2+），而配合物3的还原铜（I）物种似乎是稳定的，这可能是由于与1和2相比，3中赤道平面的四面体畸变更大。
