The tetranuclear cubane-like complex, [NiL(EtOH)]4·0.5EtOH (1) with tridentate Schiff base ligand (H2L= 2-Hydroxymethyl-N-salicylideneaniline) has been synthesized and its crystal structure and spectroscopi...The tetranuclear cubane-like complex, [NiL(EtOH)]4·0.5EtOH (1) with tridentate Schiff base ligand (H2L= 2-Hydroxymethyl-N-salicylideneaniline) has been synthesized and its crystal structure and spectroscopic properties have been studied. The complex consists of a tetranuclear (NiO)4 cubane core, of which four nickel(Ⅱ) ions are bridged by μ3-alkoxide group and each nickel(Ⅱ) ion is coordinated to three μ3-alkoxide oxygen atoms, one imino nitrogen atom and one phenoxide oxygen atom from Schiff base ligand, and further ligated by one EtOH molecule, completing a distorted octahedral geometry.展开更多
In this work, novel oxidative coupling complexes, [(Pip)<sub>4n</sub>Cu<sub>4</sub>X<sub>4</sub>(CO<sub>3</sub>)<sub>2</sub>] (n = 1 or 2, X = Cl or Br, Pip ...In this work, novel oxidative coupling complexes, [(Pip)<sub>4n</sub>Cu<sub>4</sub>X<sub>4</sub>(CO<sub>3</sub>)<sub>2</sub>] (n = 1 or 2, X = Cl or Br, Pip = piperidine), are synthesized from the reaction of well characterized Lewis base [(Pip)<sub>4n</sub>Cu<sub>4</sub>X<sub>4</sub>O<sub>2</sub>] with carbon dioxide as a Lewis acid in CH<sub>2</sub>Cl<sub>2</sub>. These carbonato-derivatives are isolated as stable solids. They are easily soluble in aprotic solvents as CH<sub>2</sub>Cl<sub>2</sub>or phNO<sub>2</sub>. Cryoscopic measurements support tetranuclear structure for all of them. Electronic spectra in the near infrared with high molecular absorptivity may be explained for tetranuclear cuban structure to fulfil 3 halo-ligands for each copper centre in [(Pip)<sub>4n</sub>Cu<sub>4</sub>X<sub>4</sub>(CO<sub>3</sub>)<sub>2</sub>]. The EPR spectra for [(Pip)<sub>4n</sub>Cu<sub>4</sub>X<sub>4</sub>(CO<sub>3</sub>)<sub>2</sub>] complexes are axial type of spectra (d<sub>x2-y2</sub> G.S) suggesting elongated tetragonal distortion for all of them. Cyclic voltammograms for [(Pip)<sub>4n</sub>Cu<sub>4</sub>X<sub>4</sub>(CO<sub>3</sub>)<sub>2</sub>] are irreversible in character. These tetranuclear carbonato complexes show catalytical activity. They initiate the oxidation of 2,6-dimethylphenol (DMP) to 3,3’,5,5’-tetramethyl-4,4’-diphenoquinone (DPQ).展开更多
文摘The tetranuclear cubane-like complex, [NiL(EtOH)]4·0.5EtOH (1) with tridentate Schiff base ligand (H2L= 2-Hydroxymethyl-N-salicylideneaniline) has been synthesized and its crystal structure and spectroscopic properties have been studied. The complex consists of a tetranuclear (NiO)4 cubane core, of which four nickel(Ⅱ) ions are bridged by μ3-alkoxide group and each nickel(Ⅱ) ion is coordinated to three μ3-alkoxide oxygen atoms, one imino nitrogen atom and one phenoxide oxygen atom from Schiff base ligand, and further ligated by one EtOH molecule, completing a distorted octahedral geometry.
文摘In this work, novel oxidative coupling complexes, [(Pip)<sub>4n</sub>Cu<sub>4</sub>X<sub>4</sub>(CO<sub>3</sub>)<sub>2</sub>] (n = 1 or 2, X = Cl or Br, Pip = piperidine), are synthesized from the reaction of well characterized Lewis base [(Pip)<sub>4n</sub>Cu<sub>4</sub>X<sub>4</sub>O<sub>2</sub>] with carbon dioxide as a Lewis acid in CH<sub>2</sub>Cl<sub>2</sub>. These carbonato-derivatives are isolated as stable solids. They are easily soluble in aprotic solvents as CH<sub>2</sub>Cl<sub>2</sub>or phNO<sub>2</sub>. Cryoscopic measurements support tetranuclear structure for all of them. Electronic spectra in the near infrared with high molecular absorptivity may be explained for tetranuclear cuban structure to fulfil 3 halo-ligands for each copper centre in [(Pip)<sub>4n</sub>Cu<sub>4</sub>X<sub>4</sub>(CO<sub>3</sub>)<sub>2</sub>]. The EPR spectra for [(Pip)<sub>4n</sub>Cu<sub>4</sub>X<sub>4</sub>(CO<sub>3</sub>)<sub>2</sub>] complexes are axial type of spectra (d<sub>x2-y2</sub> G.S) suggesting elongated tetragonal distortion for all of them. Cyclic voltammograms for [(Pip)<sub>4n</sub>Cu<sub>4</sub>X<sub>4</sub>(CO<sub>3</sub>)<sub>2</sub>] are irreversible in character. These tetranuclear carbonato complexes show catalytical activity. They initiate the oxidation of 2,6-dimethylphenol (DMP) to 3,3’,5,5’-tetramethyl-4,4’-diphenoquinone (DPQ).