[Cu-2{1,4-bis[(3-methyl-2-pyridyl)amino]-phthalazine-H}(N-3)(3)] at 40 K

The structure of the title compound, mu-azido-1:2 kappa(2)N(1)-[mu-4-(3-met hyl-2-pyridyl-2 kappa N-amino)-1-(3-methyl-2-pyridyl-1 kappa N-imino)-1,2-d ihydrophthalazin-2-yl-1:2 kappa(2)N(2):N-3]-bis[(azido-kappa N-1)copper(II) ], [Cu-2(C20H17N6)(N-3)(3)], (I), determined from data recorded at 40(1)K u sing a new open-flow He gas cryostat, is presented here as part of an exten ded study program on dicopper(II) azide-bridged compounds. Each pair of Cu- II centres in (I) is equatorially bridged by a mu(2)-1,1-azide, with a brid ge angle of 107.2(1)degrees. The dinuclear centres form tetranuclear cluste rs through two mu(2)-1,3-azide bridges, which in turn form chains along the a axis. Two C-H ... N intermolecular interactions interlink these chains a long the [110] and [1 (1) over bar 0] directions.