Ortho-substituent induced triradical-containing tetranuclear oxo-vanadium(iv) cluster formation via ligand C–N bond breaking and C–O bond making
作者:Samir Ghorai、Chandan Mukherjee
DOI:10.1039/c2cc35963d
日期:——
Substituent having weak-coordination character, and attached at the ortho-carbon atom to the aniline moiety of 2-anilino-4,6-di-tert-butylphenol, provided a triradical-containing tetranuclear vanadium(IV) complex via ligand CâN bond breaking and CâO bond making.
Tuning of the redox potential and catalytic activity of a new Cu(<scp>ii</scp>) complex by<i>o</i>-iminobenzosemiquinone as an electron-reservoir ligand
Ancillary ligand electro-activity effects towards phenyl acetylene homocoupling reaction by a nickel(<scp>ii</scp>) complex of a non-innocent <i>O</i>-amino phenol ligand: a mechanistic insight
surrounded by two oxygen and two nitrogen atoms of two ligands. Variable-temperature magnetic susceptibility measurement for crystalline samples of complex shows the effective magnetic moment per molecule (μeff) of near zero and the diamagnetic nature of the complex (S = 0) which emphasize that strong antiferromagnetic coupling prevailed between the two unpaired electrons of LNIS ligands and Ni(II) high spin
通过非无害的邻氨基苯酚配体和Ni(OAc) 2的反应合成了一种新的Ni( II )络合物。 Ni II L 2 NIS (其中IS代表苯酚环上带有氰化物(NIS中的N表示)取代基的亚氨基半醌自由基配体)的晶体结构呈现出Ni( II )的方形平面环境。该配合物在单斜晶系中结晶,Ni( II )被两个配体的两个氧原子和两个氮原子包围。对复合物晶体样品的变温磁化率测量显示每个分子的有效磁矩 ( μ eff ) 接近于零以及复合物的抗磁性质 (S = 0),这强调了复合物的两个不成对电子之间存在强反铁磁耦合。 L NIS配体和 Ni( II ) 高自旋电子。该配合物是 EPR 沉默的,这证实了 Ni( II ) 配合物的抗磁性特征。电化学测量(CV)表明配体和金属的氧化还原活性特征。 Ni II L 2 NIS络合物被证明对于室温下苯乙炔的游离金属或碱对应物自偶联是有效的。 据我们所知,这是第
Biradical <i>o</i>-iminobenzosemiquinonato(1−) complexes of nickel(<scp>ii</scp>): catalytic activity in three-component coupling of aldehydes, amines and alkynes
and alkynes (A3-coupling) was studied in the presence of the NiL2BIS complex, and the previously reported four-coordinated bis-o-iminosemiquinone NiL2NIS. Furthermore, among these two o-iminobenzosemiquinonato(1−) complexes of Ni(II) (NiL2NIS and NiL2BIS), NiL2NIS was found to be an efficientcatalyst in A3-coupling at 85 °C under solvent-free conditions and can be recovered and reused for several cycles
合成并表征了六配位双邻亚氨基半醌配合物NiL 2 BIS ,其中L BIS是三齿邻氨基苯酚苯并恶唑基配体H 2 L BAP的邻亚氨基半醌1-电子氧化形式。该配合物的晶体结构显示出具有NiN 4 O 2配位球的八面体几何形状,其中Ni( II )被两个三齿L BIS配体包围。该化合物表现出 ( S Ni = 1) 自旋和轨道对磁矩的贡献以及两个L BIS配体上两个电子之间的反铁磁耦合,从而产生三重态自旋基态 ( S = 1)。基于实验观察和理论计算,本文介绍了这种开壳层分子的电子跃迁和电化学行为。通过循环伏安法研究了NiL 2 BIS的电化学行为,并表明了以配体为中心的氧化还原过程。 在NiL 2 BIS配合物和先前报道的四配位双邻亚氨基半醌NiL 2 NIS存在下研究了醛、胺和炔的三组分偶联(A 3 -偶联)。此外,在Ni( II )的这两种邻亚氨基苯并半醌(1−)络合物( NiL 2 NIS和NiL
Synthesis, characterization and study on the dissimilar reactivity of a Ni(II)-bis(iminosemiquinone) complex core to ligand-appended hemilabile –CH2OH and –CH2NH2 units
Noninnocent ligand H3L2CHOH reacted with NiCl2 center dot 6H(2)O under aerial atmosphere and provided corresponding complexes 1 [Ni-II(HL2CHOH)(2)](0)} and 1a [Ni-II(L-CHO)(2)](0)} in the presence of Et3N and NaOH, respectively. Ligand H 4 Ln H provided complex 2 [Ni-II(HL3](0)} in the presence of NiCl2 center dot 6H(2)O and Et3N under air. All the complexes were characterized by various spectroscopic and spectrometric techniques, which included FT-IR, mass, UV-vis/NIR, H-1 NMR, cyclic voltammetry and single crystal X-ray diffraction methods. Molecular structural analyses on complexes 1 and 1a revealed that both four-coordinate complexes were neutral in charge and consisted of two ligand-centered iminosemiquinone radicals and a Ni(II) ion. While, the hemilabile -CH2OH group remained unaffected and did not make any coordination with the central Ni(II) ion in complex 1, twoelectron oxidation of each -CH2OH group to -CHO group was realized in complex la. In complex 2, the ligand backbone was an innocent tetradentate salen unit, which was formed by a complete modification of the initial noninnocent ligand H4L2 (CHNH)(2). To find out the mechanistic path for the formation of complex 2, ligand H(3)L1 and H(4)L2 were also introduced and it was presumed that transimination took place in the ligand backbone during complex 2 formation.