Heptacopper(II) and dicopper(II)-adenine complexes: synthesis, structural characterization, and magnetic properties

• Published in: Journal of coordination chemistry 2015-08, Vol.68 (16), p.2770-2787
• Main Authors: Leite Ferreira, B.J.M., Brandão, Paula, Dos Santos, A.M., Gai, Z., Cruz, C., Reis, M.S., Santos, T.M., Félix, V.
• Format: Article
• Language: English
• Subjects: Adenine complexes; Adenines; ARENE INCLUSION COMPLEXATION; BUILDING-BLOCKS; CLUSTER; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COORDINATION POLYMERS; Copper; Copper cluster; COPPER COMPOUNDS; COPPER OXIDE; CRYSTAL STRUCTURE; Dicopper(II); DINUCLEAR COPPER(II) COMPLEX; Distortion; DNA-BINDING; Ferromagnetism; Heptacopper(II); HEPTANUCLEAR; LIGANDS; MAGNETIC PROPERTIES; Magnetism; PROPERTIES; TETRANUCLEAR
• ISSN: 0095-8972; 1029-0389
• DOI: 10.1080/00958972.2015.1061126

The syntheses, crystal structures, and magnetic properties of two new copper(II) complexes with molecular formulas [Cu 7 (μ 2 -OH 2 ) 6 (μ 3 -O) 6 (adenine) 6 ](NO 3 ) 2 ·6H 2 O (1) and [Cu 2 (μ 2 -H 2 O) 2 (adenine) 2 (H 2 O) 4 ](NO 3 ) 4 ·2H 2 O (2) are reported. The heptanuclear compound is composed of a central octahedral CuO 6 core sharing edges with six adjacent copper octahedra. In 2, the copper octahedra shares one equatorial edge. In both compounds, these basic copper cluster units are further linked by water bridges and bridging adenine ligands through N3 and N9 donors. All copper(II) centers exhibit Jahn-Teller distorted octahedral coordination characteristic of a d 9 center. The study of the magnetic properties of the heptacopper complex revealed a dominant ferromagnetic intra-cluster interaction, while the dicopper complex exhibits antiferromagnetic intra-dimer interactions with weakly ferromagnetic inter-dimer interaction.