Crystal structure of bis(tetramethylthiourea-κS)bis(thiocyanato-κN)cobalt(II)

Abstract

In the course of systematic investigations on the synthesis of Co(NCS)2 coordination compounds with different thiourea ligands, the title compound, [Co(NCS)2(C5H12N2S)2], was obtained. In this compound the CoII cations are coordinated by two crystallographically independent N-bonded thiocyanate anions and two tetramethylthiourea ligands into discrete complexes that are located in general positions and show a strongly distorted tetrahedral geometry. Intermolecular C—H...S hydrogen bonds of different strength can be observed between the discrete complexes, which are connected by pairs of hydrogen bonds into zigzag-like chains that elongate in the b-axis direction. These chains are additionally linked by strong C—H...S hydrogen bonds along the a-axis direction, resulting in the formation of layers that are parallel to the ab plane. There is also one weak intramolecular C—H...S hydrogen bond between two neighbouring thiourea ligands within the complexes. Comparison of the experimental PXRD pattern with that calculated from the single-crystal data prove that a pure phase has been obtained. Thermoanalytical investigations reveal that this compound melts at 364 K and decomposes upon further heating.

Synthesis, Structural Determination and Antibacterial Properties of Zinc(II) Complexes Containing 4-Aminopyridine Ligands

“…Complexes with aminopyridine ligand such as poli-[Cu(NCS) 2 (x-NH 2 py) 2 ] [2], [Cd(μ-L) 2 (NH 2 py) 2 ] (L = SCN − , dca, N 3 − ) [5][6][7], [Mn(L) 2 (3-NH 2 py) 2 ] (L = dca, SCN − ) [5][6]8] and [Co(dca) 2 (2-NH 2 py) 2 ] [3] have shown to form a polymeric structure through bidentate ligands such as dicyanamide ion (dca), nitride ion (N 3 − ) and ambidentate ligand such as SCN − . The polymeric complexes can be obtained as long as octahedral coordination of the metal center is preserved, whereas complex compounds with tetrahedral geometry such as [Zn(NCS) 2 (x-NH 2 py) 2 ] (x = 2 and 3) [9][10], [Zn(CN) 2 (x-NH 2 py) 2 ] [11], [MCl 2 (x-NH 2 py) 2 ] (M = Zn(II), Co(II) [4,12] tend to form monomeric complexes [9,[13][14]. In addition, the aminopyridine ligands prefer to act as monodentate ligands, with amino groups acting as potential H-bond donors or acceptor sites [8][9]15] Meanwhile, the bidentate anion-ligands such as thiocyanate, dicyanamide, and acetate are potential ligands to form coordination polymer.…”