Coordination Polymers of Co(NCS)2 with Pyrazine and 4,4‘-Bipyridine:  Syntheses and Structures

Three compounds were obtained from the reactions of Co(NCS)2 with pyrazine and 4,4‘-bipyridine in different solvents: Co(NCS)2(pyz)2 (1) has a 2D sheet structure, monoclinic, C2/m, a = 10.039(2) Å, b = 10.382(2) Å, c = 7.190(1) Å, β = 118.64(1)°, Z = 2; Co(NCS)2(H2O)2(4,4‘-bipy)·4,4‘-bipy (2) has linear Co−bipy−Co chains connected by hydrogen bonds between H2O and noncoordinated 4,4‘-bipy molecules to form stair type sheets, triclinic, P1̄, a = 7.450(1) Å, b = 9.020(1) Å, c = 10.122(1) Å, α = 107.74(1)°, β = 104.02(1)°, γ = 97.16(1)°, Z = 1; Co(NCS)2(4,4‘-bipy)2·2(CH3CH2)2O (3) has ether molecules intercalated between layers formed by Co(NCS)2 and coordinated 4,4‘-bipyridine ligands, monoclinic, P2/c, a = 11.483(2) Å, b = 11.397(3) Å, c = 13.609(1) Å, β = 107.55(1)°, Z = 2. Compounds 2 and 3 thermally decompose to form the same products. The identities of the decomposition products are discussed.