In the subsequent discussion and in Table bond lengths and angles for only one part are considered for clarity. The Co1-N1 amide bond lengths were found to be 1.9165(113) Å and 1.9421(33) Å, respectively (Figure ). Interestingly, these bond lengths are shorter than those seen for TMS-amide bond lengths in the heteroleptic, tetrahedral complexes 5 and 6 and rather comparable to TMS-amide bond lengths found in complexes, 1 -4, which exhibit tricoordinated Co(II) ions. The Co1-N2 bonds describing the distance between the Co(II) ions and the chelating dimethyl-amines amounted to 2.1767(114) Å (10) and 2.1478(35) Å (11) which is longer than the respective distance found in 7. τ4 / τ4' 0.708 / 0.652 0.782 / 0.774 0.723 / 0.713 0.741 / 0.686 With 1.6896(37) Å, the N1-Si1 bond length in 11 was found to be surprisingly short, shorter [Co(TMSMAPY)2(TBUPY)2], in which the TMSMAPY ligands adopted the expected chelating binding mode. In a prior study Glatz and Kempe had introduced the related N 2 ,N 6bis(trimethylsilyl)pyridine-2,6-diamide ligand (BTMSAPY) for the complexation of Co(II). They obtained a binuclear, symmetrical complex, Co2(BTMSAPY)3, in which both Co(II) ions were surrounded by a slightly distorted tetrahedral coordination sphere. Hereby, one of three BTMSAPY ligands adopted a μ2-coordination utilizing both side chain amide-nitrogen and the pyridine-nitrogen atoms, while the other two were μ2-coordinating with only one side chain amide-nitrogen and pyridine-nitrogen atom. Reminiscence of these structural features is essential when considering our homoleptic and binuclear complex [Co(TMSAMAPY)2]2 (12).