One-Dimensional Coordination Polymers of Cobalt with 4,4‘-Bipyridine: Syntheses and Structures

Several new one-dimensional coordination polymers were obtained by reactions of different simple cobalt salts
with 4,4‘-bipyridine. Co(SO4)(H2O)3(4,4‘-bipy)·2H2O (1) was obtained by reacting CoSO4 with 4,4‘-bipy in a
water/ethanol solvent system:  hexagonal, P65, a = 11.435(2) Å, c = 20.886(4) Å, Z = 6. CoCl2(DMSO)2(4,4‘-bipy) (2) was crystallized from the reaction of an aqueous solution of CoCl2 with a DMSO solution of 4,4‘-bipy: 
orthorhombic, Pbcn, a = 11.470(2) Å, b = 11.390(2) Å, c = 14.753(1) Å, Z = 4. Reaction of Co(CH3COO)2
with 4,4‘-bipy in water/acetonitrile under hydrothermal conditions yielded Co(CH3COO)2(4,4‘-bipy) (3):  triclinic,
P1̄, a = 7.996(1) Å, b = 9.128(1) Å, c = 10.676(1) Å, α = 109.79(1)°, β = 99.90(1)°, γ = 100.98(1)°, Z = 2.
1 and 2 have structures containing linear Co−bipy−Co chains. In 1, the chains are connected by a network of
hydrogen bonds. The structure of 3 contains linear double Co−bipy−Co chains bridged by CH3COO- groups.
The reaction chemistry observed in different solvent systems and under hydrothermal conditions is discussed.