Stabilization of Cu-II-I Bonds Using 2-Benzoylpyridine Thiosemicarbazones - Synthesis, Structure, Spectroscopy, Fluorescence, and Cyclic Voltammetry

作者：Indoria Shikha; Lobana Tarlok S^*; Singh Deep; Kumari Sangita; Kumari Parveen; Bala Tanu; Kamal Ajar; Jassal Amanpreet K; Garcia Santos Isabel; Castineiras Alfonso; Jasinski Jerry P

来源：European Journal of Inorganic Chemistry, 2015, 2015(30): 5106-5117.

DOI：10.1002/ejic.201500618

• Copper
• EPR spectroscopy
• Fluorescence
• Ligand design
• N,N,S ligands

The reactions of copper(I) iodide with N-1-substituted 2-benzoylpyridine thiosemicarbazones [(C6H5)(C5H4N)C-2=N-3-(NH)-H-2-C(=S)-(NHR)-H-1 (R = Me, HLMe; Et, HLEt; Ph, HLPh)] in acetonitrile/dichloromethane mixtures have formed the complexes [(Cu2I2)-I-II((4)-N,N,S-L-Me)(2)] (1), [(CuI)-I-II((3)-N,N,S-L-Et)] (4), and [(CuI)-I-II((3)-N,N,S-L-Ph)] (7) through proton-coupled electron transfer (PCET), and these complexes have rare Cu-II-I bonds. The above thio ligands with copper(I) bromide and copper(I) chloride also formed similar Cu-II-Br and Cu-II-Cl bonds in complexes of stoichiometry [(CuX)-X-II((3)-N,N,S-L)] (L = L-Me, L-Et, L-Ph, X = Br 2, 5, 8; X = Cl 3, 6, 9) by PCET. All of the complexes have been characterized by elemental analysis, infrared spectroscopy, electronic absorption spectroscopy, ESR spectroscopy, magnetic susceptibility measurements, molecular fluorescence, cyclic voltammetry, and single-crystal X-ray crystallography. The thio ligands coordinate as monoanionic N,N,S donors in 1-9. The ESR data support the divalent oxidation state of the metal centers in the complexes, and the ESR parameters follow the trend g(vertical bar)>g>2 with G values in the range 2-4, which suggests a dx2-y2 ground state for the copper(II) complexes with variable exchange interaction in the solid complexes. The geometry around each copper(II) center is distorted square planar (mononuclear, 2-9) or square pyramidal (dinuclear, 1). The stabilization of copper(II)-iodide bonds as well as the formation of Cu-II-Br and Cu-II-Cl bonds from thio ligands and copper(I) halides by a PCET process represents basic research of topical interest.

• 出版日期2015-10