Preparation and stereochemistry of cobalt(III) complexes containing 1,1,10,10-tetraphenyl-4,7-diaza-1,10-diphosphadecane or 2,11-dimethyl-5,8-diaza-2,11-diphosphadodecane, R2PCH2CH2NHCH2CH2NHCH2CH2PR2(R=C6H5 or CH3).