Coexistence of long-range ferromagnetic ordering and glassy behavior in one-dimensional bimetallic cyano-bridged...

Two new one-dimensional (1-D) 3d-5d cyano-bridged bimetallic assemblies, ([Co(3)(II)(DMF)(12)][W(V)(CN)(8)](2)])(infinity) (1) and ([Mn(3)(II)(bipy)(2)(DMF)(8)][W(V)(CN)(8)](2))(infinity) (2), have been synthesized and characterized, where bipy stands for 2,2'-bipyridine and DMF represents N,N-dimethylformamide. The X-ray analyses show that the two complexes belong to the P(-)1 space group with Z = 1 and C(52)H(84)N(28)O(12)Co(3)W(2), a = 11.690(3) A, b = 12.703(3) A, c = 13.712(3) A, alpha = 86.889(4) degrees, beta = 73.256(4) degrees, and gamma = 77.033(4) degrees for 1 and C(60)H(72)N(28)O(8)Mn(3)W(2), a = 10.672(2) A, b = 13.024(3) A, c = 16.000(3) A, alpha = 78.32(3) degrees, beta = 75.69(3) degrees, and gamma = 66.63(3) degrees for 2. The structures of the two complexes are similar and consist of 12-atom rhombic M(2)W(2)(CN)(4) (M = Co (1), Mn (2)) units, which act as a basic component to be repeatedly connected through W-C-N-M-N-C-W linkages to form a one-dimensional infinite 3,2-chain; these chains are well separated by the DMF molecules or 2,2'-bipyridines coordinated to the metal ions Co(2+) for 1 and Mn(2+) for 2. Magnetic studies, including linear and nonlinear ac susceptibility measurements, demonstrate that the long-range magnetic ordering and spin glass behavior coexist in the two 1-D compounds.