Crystal structure, magnetic properties, and electronic structure of Ni(NCNH2)4Cl2 and Co(NCNH2)4Cl2

The crystal structures of Ni(NCNH2)(4)Cl-2 and Co(NCNH2)(4)Cl-2, the first complexes with cyanamide as a neutral ligand, have been determined from single crystal data (Im (3) over barm, Z=6, a=1259.3(2)pm, R-1=0.0245 for Ni(NCNH2)(4)Cl-2 and a=1266.3(2)pm, R-1=0.0241 for Co(NCNH2)(4)Cl-2; both 329 intensities and 23 parameters). Ni2+ and Co2+ are octahedrally coordinated by four equatorial H2NCN molecules and two axial chloride ions, and the 20 and 29 electron octahedral complexes are connected by a network of hydrogen bonds. The cyanamide ligands are slightly bent (166 degrees), and the two N-C distances are 112 and 133pm. Ni(NChTH(2))(4)Cl-2/Co(NCNH2)(4)Cl-2 are Curie paramagnets with two/three unpaired electrons.