A metamagnetic 2D copper(ii)-azide complex with 1D ferromagnetism and a hysteretic spin-flop transition

Compound [Cu(3)(N(3))(6)(DMF)(2)](n) () was initially obtained in a serendipitous way during efforts to prepare a Cu(II)/N(3)(-)/Mebta coordination polymer (Mebta = 1-methylbenzotriazole). With the identity of established by single-crystal crystallography, a rational preparative route to this complex was designed and carried out by reacting Cu(ClO(4)).6H(2)O with two equivalents of NaN(3) in DMF. Complex is a 2D coordination polymer possessing mu(1,1,1) and mu(1,1,3) azido ligands. Its structure consists of {Cu(3)(N(3))(6)(DMF(2))} repeating units, which form chains that run parallel to the a axis; their bridging is achieved through end-on azides. The chains form sheets parallel to the ab plane through end-to-end azides. The magnetic properties of have been studied in detail. The complex contains 1D ferromagnetic chains, based on a Cu(II)(3) repeating unit, which can be viewed as having an S = 3/2 ground state. The ferromagnetic chains undergo antiferromagnetic coupling, which is weak enough to be overcome by moderate magnetic fields at 2 K leading to a metamagnetic spin-flop transition at 2.7 T. The transition is first-order, leading to hysteresis of the order of 0.2 T.