Synthesis, crystal structure and magnetic properties of two alternating double μ1,1 and μ1,3 azido bridged Cu(ii) and Ni(ii) chains†
Two new alternating μ1,1- and μ1,3-azido bridged chains, [Cu(N3)2(mtn)]n (1) and [Ni(N3)2(mtn)]n (2) where mtn = N-methyl-1,3-propanediamine, have been synthesized and characterized by single crystal X-ray diffraction. In both complexes, each metal atom is coordinated to six nitrogen atoms from four azide anions and one N-methyl-1,3-propanediamine molecule in a distorted octahedral geometry. In 1, the basal-apical double μ1,1-azido bridged Cu(II)-dimers are connected through two asymmetric μ1,3-N3 bridges to form a 1D chain in which one of the azide acts as a μ1,1,3 bridge while the other one is terminal. The structure of 2 is very similar but one of the azide ions acts as μ1,1 and the other as μ1,3 to form an alternating chain. Magnetic data of both compounds were fitted to an alternating ferro/antiferromagnetic chain model (g = 2.120, JF = +15.6 cm−1, JAF = −2.6 cm−1 and a paramagnetic impurity of ca. 0.4% for 1 and g = 2.180, JF = +23 cm−1 and JAF = −33 cm−1 for 2).