Preparation, crystal structure and magnetic properties of di-2-pyridylamine (dpa) copper(II) complexes [Cu(dpa)(N3)2]n and [Cu2(dpa)2(NCO)4]

✍ Scribed by José Carranza; Jorunn Sletten; Francesc Lloret; Miguel Julve

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 399 KB
• Volume: 890
• Category: Article
• ISSN: 0022-2860
• DOI: 10.1016/j.molstruc.2007.11.034

✦ Synopsis

The preparation, crystal structures and magnetic properties of two copper(II) complexes with di-2-pyridylamine (dpa) as end-cap ligand and azide (1) and cyanate (2) as bridging groups, [Cu(dpa)(N 3 ) 2 ] n (1) and [Cu 2 (dpa) 2 (NCO) 4 ] (2), are reported. Compound 1 consists of uniform chains of copper(II) ions bridged by single l-1,1-azido groups whereas that of compound 2 is made up of centrosymmetric dicopper(II) units with double l-1,1-N-cyanate bridges, the other two cyanate groups acting as terminal ligands. The copper atoms in 1 and 2 are five-coordinated with two nitrogen atoms of a bidentate dpa ligand (1 and 2), one nitrogen atom from a terminally bound azide (1)/cyanate (2) and two other nitrogens from two azide (1)/cyanate (2) bridges building intermediate square pyramidal/trigonal bipyramidal (1) and distorted square pyramidal (2) surroundings. The values of the copper-copper separation through the double end-on azido (1) and cyanato (2) bridges are 3.8556(4) and 3.5154(5) A ˚, respectively. Variable-temperature magnetic susceptibility measurements show the occurrence of weak magnetic interactions in both complexes being antiferromagnetic in 1 [J = À4.60 cm À1 , the Hamiltonian is defined as Ĥ ¼ ÀJ P i Ŝi Á Ŝiþ1 ] and ferromagnetic in 2 [J = +3.14 cm À1 with Ĥ ¼ ÀJ Ŝ1 Á Ŝ2 ]. The magnitude and nature of these magnetic interactions are discussed in the light of the respectives structures and they are compared with those reported for related systems.