Two different coordination geometries in polynuclear manganese(II) complexes with bis(mu-phosphinato)bridges

Four new polynuclear phosphinato-bridged manganese(II) complexes, three dinuclear compounds [Mn(μ-dpp)(5-dmbpy)(NO3)]2 (1), [Mn(μ-dpp)(Me-phen)(NO3)]2 (2), [Mn(μ-bmp)(neocuproine)(NO3)]2 (3) and a 1D compound [Mn(μ-bmp)2]n (4) where Hdpp is diphenylphosphinic acid, Hbmp is bis(4-methoxyphenyl)phosphinic acid, 5-dmbpy = 5,5′-dimethyl-2,2′-dipyridyl, Me-phen = methyl-1,10-phenanthroline and neocuproine = 2,9-dimethyl-1,10-phenanthroline, have been synthesized and structurally characterized by X-ray crystallography. In this series, the dinuclear structures consist in a bis(diphenylphosphinato) (dpp) or a bis(4-methoxyphenyl)phosphinato (bmp) anion bridging the two Mn(II) centers in a syn–syn coordination mode for 1–3. The monodimensional compound 4 is built from double bridging syn–syn bis(4-methoxyphenyl)phosphinato anions. The coordination geometry around the Mn(II) ions in 1–3 is six-coordinate with distorted octahedral environment. Moreover, the coordination geometry around the Mn(II) ions in 4 is tetrahedral. The magnetic behavior of these complexes is reported. The complexes show weak antiferromagnetic coupling with J in the range 0.05–0.43 cm−1 for 1–3 and 0.88 cm−1 for 4. The magnetic properties are discussed in relation to the structural data.