Structure and Properties of Binuclear and Tetranuclear Cobalt and Nickel Compounds Containing Macrocyclic Ligands
Two new macrocyclic compounds were studied: [Co2L(O2CCHPh2)(py)2]+BF4– 1 , and [Ni4L(O2CCHPh2)2]2+(BF4–)2 2. In addition, previously synthesized [Co2L(OAc)2]·H2O 3 was structurally characterized. Each of these compounds contains the Robson macrocyclic ligand L, as well as a bridging carboxylate ligand (diphenylacetate in 1 and 2, and acetate in 3). The compounds 1 and 2 were formed by reacting [M2L(py)4](BF4)2 with O2CCHPh2 and NEt3. The compound 3 was formed by a reaction of CoCHH3COO·6H2O, 1,3-dialdehyde-2-hydroxy-5-methylbenzene (dialH), and1-3-diaminopropane. The structures of these compounds were revealed by X–ray crystallography and characterized further by infrared and electronic absorption spectroscopy. Each metal atom has a six-coordinate, octahedral geometry. Compounds 1 and 2 were compared to the compounds [Co4L2(O2CCHPh2)2]2+(BF4–)2 and Ni2L(O2CCHPh)]+BF4–, which were previously characterized by X–ray crystallography. A fourth compound, 4, was synthesized by the reaction of Co(NO3)2•6H2O, O2CCHPh2, and NEt3. It was characterized by infrared and electronic spectroscopy in order to provide a non-macrocyclic example of a compound containing cobalt and diphenylacetate.