Investigation of the Cu-II/NCS-/dpk reaction system in CH3OH [dpk = Di(2-pyridyl) ketone]: Isolation, structural analysis and magnetic properties of a dimer and a 1D polymer with the same empirical formula [Cu(NCS)(2)(dpk center dot CH3OH)]

Two polymorphous compounds with the general formula [Cu(NCS)(2)(dpk . CH3OH )](n) (dpk = di-2-pyridyl-ketone) have been synthesised and have been chara cterised both structurally and magnetically. The dpk . CH3OH ligand is the result of the metal-promoted solvolysis of dpk in methanol and acts as a ne utral donor. X-ray analysis carried out on single crystals for both compoun ds revealed that compound 1 is dimeric exhibiting double (N,S)-thiocyanate bridges, while compound 2 is 1D consisting of chains in which the metallic centres are connected through single end-to-end NCS- groups. Magnetic susce ptibility data showed that both compounds are antiferromagnetic, the values for the exchange constant J are -0.9 (1) and -0.3 cm(-1) (2). The low valu es of J are consistent with the (N-eq,S-ax)-disposition of the thiocyanate bridges in the octahedral coordination sphere.