Frustrated Zig-Zag Spin Chains Formed by Hydrogen Bonds in [cu(h2o)(oh)(tmen)](2)[pd(cn)(4)]center Dot 2H(2)o

The magnetic properties of the novel dimeric compound [Cu(H2O)(OH)(tmen)](2)[Pd(CN)(4)]center dot 2H(2)O (tmen-N,N,N',N'-tetramethylethylenediamine) with modulated crystal structure were studied in the temperature range from 95 mK to 300 K. Magnetic measurements revealed a presence of weak antiferromagnetic exchange coupling in the compound. The temperature dependence of specific heat is characterized by the presence of a Schottky-like maximum at 0.47 K and a lambda-anomaly at 0.28 K, indicating the formation of long-range order in the system. The comparison of the experimental data with theoretical predictions revealed the presence of antiferromagnetic intradimer exchange coupling J/k(B) = -1.2 K and interdimer coupling of a similar strength mediated via hydrogen bonds between dimeric units forming a frustrated magnetic zig-zag chain structure.