Polynuclear Complexes of Macrocyclic Oxamide with Thiocyanate: Syntheses, Crystal Structures and Magnetic Properties

Five complexes with the formula {[(CuL) 2 Cr(μ‐SCN) 2 ]OH} n ( 1 ), [Mn(CuL) 2 (NCS) 2 ] ( 2 ), [Cu(CuL) 2 (NCS) 2 ] ( 3 ), [Ni(CuL) 2 (NCS) 2 ] ( 4 ) and [Co(CuL)(NCS) 2 (CH 3 OH) 2 ] 2 ( 5 ), (H 2 L = 2,3‐dioxo‐5,6,14,15‐dibenzo‐1,4,8,12‐tetraazacyclopentadeca‐7,13‐diene) were synthesized and structurally determined. The structure of 1 has oxamido‐bridged trinuclear [Cr III Cu II 2 ] units and consists of a 1D helical chain formed by the linking of copper(II) and chromium(III) ions through the oxamido and μ 1,3 ‐NCS bridges. The structure of 2 , 3 or 4 consists of oxamido‐bridged trinuclear [M III Cu II 2 ] molecules (for 2 – 4 , M = Mn, Cu, Ni, respectively) and arranges in a 1D zig‐zag chain. Complex 5 is a composed of a tetranuclear [Co II 2 Cu II 2 ] molecule with both the oxamido and μ 1,3 ‐NCS bridges. The variable‐temperature magnetic susceptibility measurements (2–300K) of 1 , 2 , 4 and 5 show pronounced antiferromagnetic interactions between the copper(II) atom and neighbouring metal ions.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)