Cu(I) or Cu(I)-Cu(II) mixed-valence complexes of 2,4,6-tri(2-pyridyl)-1,3,5-triazine: Syntheses, structures, and theoretical study of the hydrolytic reaction mechanism

The reactions of 2,4,6-tri(2-pyridyl)-1,3,5-triazine (tpt) with copper( I) halides under solvothermal or traditional conditions yielded two polymeric Cu(I) complexes [Cu2I2(tpt)](n) (1) and [Cu3I3( tpt)](n) ( 2), one mixed-valence Cu(I)-Cu(II) complex [Cu4Cl2I4(tpt)(2)](3), and two Cu(II) complexes [CuBr(bpca)] (4) and [CuI(bpca)] (5) (bpca = bis(2-pyridylcarbonyl)amine). Complex 1 is a zigzag chain with tpt in a bis-bipyridine-like coordination mode, whereas complex 2 with tpt chelating three Cu(I) cations is a ladderlike coordination polymer. Complex 3 is mixed-valence, with Cu(I) in a distorted tetrahedral geometry and Cu(II) in a distorted square pyramidal geometry, forming a ladderlike supramolecular chain. Complexes 4 and 5 are the products of in situ hydrolysis of tpt involving the oxidation of Cu(I). The synthesis and characterization of complex 1, 2, and 5 indicated that Cu(I) cannot promote the hydrolysis of tpt. The theoretical study shows that the main effect for hydrolysis of tpt is the electron-withdrawing effect of metal ions.