Dinuclear and polynuclear Cu(II) azido-bridged compounds with 7-azaindole as a ligand. Synthesis, characterization and 3D structures

► New dinuclear Cu(II) compounds with 7-azaindole and bridging azide anions. ► A new tetranuclear Cu(II) compound with two kinds of azide bridges. ► Both end-on and end-to-end bridging azidea are reported. ► Characterisation by using spectroscopic methods and by 3D X-ray structures.