Syntheses, structures, and properties of copper(II) and copper(I) complexes of the new binucleating ligand 1,3-bis[bis(2-pyridylmethyl)amino]benzene

Abstract

The synthesis and characterization of the new copper complexes Cu[sub 2]L[prime][sub 2](H[sub 2]O)[sub 2](ClO[sub 4])[sub 4][center dot]2H[sub 2]O (VI), Cu[sub 2]L(H[sub 2]O)[sub 2](ClO[sub 4])[sub 4][center dot]4H[sub 2]O (VII), Cu[sub 2]L(CH[sub 3]CN)(PF[sub 6])[sub 2](VIII), and Cu[sub 2]L(CO)[sub 2](PF[sub 6])[sub 2] (IX) (L = 1,3-bis[bis(2-pyridylmethyl)amino]benzene, L[prime] = 1-[bis(2-pyridylmethyl)amino]-3-[(2-pyridylmethyl)amino]benzene) are described. The crystal structures of the copper complexes were determined. The copper(II) ions in VII are bridged by a perchlorate ion in the solid state. Complex VIII of formula Cu[sub 2]P[sub 2]F[sub 12]N[sub 7]C[sub 32]H[sub 31] crystallizes in the triclinic space group. The two copper(I) ions in VIII are in different environments because acetonitrile is bound to only one copper site. Complex IX of formula Cu[sub 2]P[sub 2]F[sub 12]O[sub 2]N[sub 6]C[sub 32]H[sub 28] crystallizes in the triclinic space group. The dicarbonyl complex IX is formed from the addition of two molecules of carbon monoxide to VIII. The binding constant for this reaction, measured at 22 [plus minus] 2C in dimethylformamide by cyclic voltammetry, is 2.1 [times] 10[sup 8] M[sup [minus]2] per copper(I) dimer. Cyclic voltammetry and differential pulse voltammetry show that the redox potentials for Cu[sup II]Cu[sup II] [yields] Cu[sup I]Cu[sup II] [yields] Cu[sup I]Cu[sup I] are strongly solvent dependent. Reaction of themore » copper(I) complex with oxygen in methanol yields the same copper(II) species as is obtained independently from the reaction of Cu[sup 2+] with L. Hydroxylation of the benzene ring of the ligand is not observed.« less