Experimental and theoretical investigations of copper (I/II) complexes with triazine–pyrazole derivatives as ligands and their in situ C–N bond cleavage

•C–N bond cleavage.•In situ reaction.•The mechanism for C–N bond fracturing was explored.

Two copper complexes, Cu(SCN)(Mpz∗T-(EtO)2) (1) (Mpz∗T-(EtO)2 = L3) and CuCl(H2O)(Mpz∗T-O2) (2) (Mpz∗T-O2 = L4) were synthesized by the reaction of 2,4,6-tri(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine (L1) or 2,4,6-tri(1H-pyrazol-1-yl)-1,3,5-triazine (L2) with CuCl2·2H2O in anhydrous ethanol and methanol, respectively. The complexes were characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, single crystal X-ray diffraction and X-ray powder diffraction. The structural characterizations and quantum mechanical calculations of the two complexes were analyzed in detail. It was found that an in site reaction occurred during the synthesis process of complexes 1 and 2, likely due to catalytic property of copper ions which leads to the C–N bond cleavage to generate new organic species, namely, Mpz∗T-(EtO)2 (L3) and Mpz∗T-O2 (L4).

Graphical abstractTwo copper complexes: Cu(SCN)(Mpz∗T-(EtO)2) (1) and CuCl(H2O)(Mpz∗T-O2) (2) (Mpz∗T-(EtO)2 = 2-(3,5-dimethyl pyrazole)-4,6-diethanol-1,3,5-triazine, Mpz∗T-O2 = 2-pyrazole 4,6-dioxo-1,3,5-triazine) have been synthesized. They are characterized by elemental analysis, IR spectroscopy, single crystal X-ray diffraction, X-ray powder diffraction and quantum mechanical calculations of the two complexes are analyzed in detail.Figure optionsDownload full-size imageDownload as PowerPoint slide