Role of ligand conformation in the structural diversity of divalent complexes containing phosphinic amide ligand

Reactions of the phosphinic amide ligand N-(4-methyl-2-pyrimidinyl)-P,P-diphenyl-phosphinic amide, L, with the corresponding metal salts afforded the complexes [Zn(L)Cl2]∞, 1, and Co3(L)4Br6, 2, which have been structurally characterized by X-ray crystallography. The molecules of the free L ligands are interlinked through N–H―N and C–H―O hydrogen bonds to form a linear chain, whereas complex 1 shows the 1D helical chain structure, which is the first coordination polymer containing phosphinic amide ligands, and 2 is a linear Co(II) trimer with a rare mixed Td–Oh–Td geometry. While the free L ligand adopts the aligned conformation, those in 1 and 2 adopts the cis and both the cis and trans conformations, respectively.