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

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) over bar space group with Z = 1 and C52H84N28O12Co3W2, a = 11.690(3) Angstrom, b = 12.703(3) Angstrom, c = 13.712(3) Angstrom, alpha = 86.889(4)degrees, beta = 73.256(4)degrees, and gamma = 77.033(4)degrees for 1 and C60H72N28O8Mn3W2, a = 10.672(2) Angstrom, b = 13.024(3) Angstrom, c = 16.000(3) Angstrom, 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 M2W2(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 Co2+ for 1 and Mn2+ 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.