Cobalt(Ill) Complexes with Cyanide and the Tetraamines l ,9-Diamino-3,7-diazanonane and l , l O-Diamino-4,7-diazadecane
Inorganica Chimica Acta
The reaction of trans-(dichloro)(1,9-diamino-3,7-diazanonane)cobalt(III) chloride and trans-(dichloro)(1,10-diamino-4,7-diazadecane)cobalt(III) chloride with sodium cyanide in aqueous solution is found to yield products with either trans or uns-cis stereochemistry depending on the reaction conditions. The stereochemistry of the products was determined by proton and carbon-13 NMR, electronic and vibrational spectroscopy. This is the first case where uns-cis diacido complexes with cobalt(III) and the tetraamines 1,9-diamino-3,7-diazanonane and 1,10-diamino-4,7-diazadecane have been prepared directly. Previous preparations of uns-cis complexes with these tetraamines have required an uns-cis complex with a chelating ligand as an intermediate. The stability of the uns-cis complexes is attributed to a greater degree of π bonding in the uns-cis complex compared with the corresponding trans complex. The difference in π bond energy must be greater than the 6 Kcal mol−1 difference in strain energy estimated from a molecular mechanics calculation.
National Institutes of Health
Brubaker, George R. and Johnson, David W., "Cobalt(Ill) Complexes with Cyanide and the Tetraamines l ,9-Diamino-3,7-diazanonane and l , l O-Diamino-4,7-diazadecane" (1984). Chemistry Faculty Publications. 27.