Alternating ferromagnetic and antiferromagnetic interactions in the azido-bridged copper(II) chain compound [Cu(phen)(N3)2]n

Single crystals of a copper(II) chain compound**, [Cu(phen)(N-3)(2)](n) (phen = 1,10-phenanthroline), were obtained and its crystal structure was determined by X-ray diffraction methods. The complex crystallizes in the space group P (1) over bar and is made up of neutral chains of copper(II) ions bridged by two azide groups exhibiting an asymmetrical tri-dentate mu(1,1,3) coordination mode. The copper atoms have a distorted CuN6 octahedral environment: the basal plane is built of two nitrogen atoms from a chelating phen molecule and two azide nitrogens from one bridging and one terminal azide, whereas two nitrogens from two bridging azides fill the axial positions. The intrachain copper(II)-copper(II) separation is 3.396(1) and 5.700(1) Angstrom. The magnetic behavior was investigated in the 5-300 K range. Weak intrachain alternating antiferromagnetic (J = -6.56 cm(-1)) and ferromagnetic (alpha J = 12.76 cm(-1)) interactions were observed.