A nickel(II) thiosemicarbazonato complex: synthesis, structure, electrochemistry, and application in catalytic coupling of terminal alkynes with arylboronic acids

作者：Prabhu Rupesh Narayana^*; Lakshmipraba Jagadeesan

来源：Transition Metal Chemistry, 2017, 42(7): 579-585.

DOI：10.1007/s11243-017-0162-8

A simple route for the synthesis of a new square-planar nickel(II) complex of 2-((3-methylthiophen-2-yl)methylene)hydrazinecarbothioamide is described. Elemental analysis, solution conductivity, and spectral measurements were used to authenticate the composition of the complex. In addition, the X-ray crystal structure of the complex was obtained. Each of the two ligands of the centrosymmetric structure is coordinated to the metal center via the azomethine N and the thioimidate S atoms, forming five-membered chelate rings. Infrared and NMR spectroscopic features of the complex are consistent with its molecular structure. The complex displays a quasi-reversible reduction with E (1/2) of -0.83 V (Delta E (p) 160 mV), indicating that the ligand system can stabilize the Ni(I) oxidation state. The complex acts as an active catalyst for the C-C coupling of aryl acetylenes with arylboronic acids containing a variety of substituents. The influence of solvent, base, reaction temperature, and catalyst loading on the C-C coupling reaction was evaluated.
A new square-planar nickel(II) complex bearing 2-((3-methylthiophen-2-yl)methylene)-hydrazinecarbothioamide was synthesized and characterized by elemental analysis, FTIR, NMR, and single-crystal X-ray crystallographic technique. Cyclic voltammetric study indicates stabilization of Ni(I) oxidation state. The complex acts as an effective catalyst for the carbon-carbon cross-coupling reaction of substituted phenylacetylenes with various arylboronic acids under optimized conditions.

• 出版日期2017-10