EN
The results of the investigation of magnetic susceptibility, magnetization and specific heat of Cu_3(tmen)_3(tma)_2(H_2O)_2·6.5H_2O (tmen = N,N,N',N'-tetramethylethane-1,2 diamine; H_3tma = 1,3,5-benzenetricarboxylic acid) are reported. The spatial arrangement of magnetic Cu(II) ions and network of covalent bonds suggest that the studied material might be a representative of S = 1/2 sawtooth chain with moderate exchange coupling J/k_{B}. The investigation of the temperature dependence of susceptibility and magnetic field dependence of magnetization yielding J/k_{B} ≈ - 0.63 K is consistent with the structural features. In addition, specific heat data reveal short-range correlations in milikelvin temperature range and indicate long-range ordering below 150 mK.