Highly reduced organometallics 52. Synthesis and chemistry of tricarbonylnitrosylmanganate(2−), [Mn(CO)3(NO)]2−

Treatment of Mn(CO)3(NO)(PPh3) in THF at 20°C with excess sodium amalgam, followed by treatment with cryptand 2.2.2, or with two equiv. of potassium tri-sec-butylborohydride afforded high isolated yields (≥80%) of air sensitive yellow solids identified as [Na(crypt.2.2.2)]2[Mn(CO)3(NO)] and K2[Mn(CO)3(NO)], respectively. These products contain the only known mixed carbonylnitrosylmetallate dianion, isoelectronic with [Fe(CO)4]2− and [Mn(CO)4]3−. Reactions of [Mn(CO)3(NO)]2− with Ph3SnCl, Mn(CO)4(NO) and Fe(CO)5, followed by metathesis, provided the new derivatives [Et4N][Mn(CO)3(NO)(SnPh3)], [PPN]2[Mn2(CO)6(NO)2], and [PPN]2[MnFe(CO)7(NO)]. On the basis of IR spectral data the latter two have been formulated to contain non-bridged structures analogous to that previously established for the isoelectronic salt [PPN]2[Fe2(CO)8].