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)

New quadridentate phosphine ligands, 1,1,10,10-tetraphenyl-4,7-diaza-1,10-diphosphadecane (pp-PNNP) and 2,11-dimethyl-5,8-diaza-2,11-diphosphadodecane (mm-PNNP), were prepared from (ClCH2CH2NHCH2)· 2HCl and NaPR2 (R=C6H3, CH3) and purified through their Ni(II) complexes. Seven new cobalt(III) complexes containing the phosphine ligand were prepared: [CoX2(pp- or mm-PNNP)]n+(X2=(Cl)2, (NCS2), C5H7O2−(2,4-pentanedionate ion), and CO32−). Four complexes of [CoX2(pp- or mm-PNNP)]+ (X=Cl, NCS) afforded only a trans(X,X) isomer, and [Co(acac)(pp- or mm-PNNP)]2+ and [Co(CO3)(pp-PNNP)]+ complexes yielded a cisβ isomer. The geometrical structures were assigned on the basis of the NMR and visible-ultraviolet absorption spectra.