Insight into anion effects on catechol oxidation catalysis: cyclodimeric Cu(II) complexes containing 1,3,5-tris(nicotinoyloxy-methyl)benzene

Self-assembly of CuX2 with C3-symmetric tridentate ligand, 1,3,5-tris(nicotinoyloxy-methyl)benzene (L), affords thermodynamically stable C2-symmetric metallacyclodimers, [Cu2X2L2(H2O)2]X2(H2O)2 (X− = NO3−, BF4−, and ClO4−) in high yields. These cyclodimeric species show the significant anion effects on the catechol oxidation catalysis in chloroform in the order [Cu2(NO3)2L2(H2O)2](NO3)2(H2O)2 > [Cu2(BF4)2L2(H2O)2](BF4)2(H2O)2 > [Cu2(ClO4)2L2(H2O)2](ClO4)2(H2O)2.