A Terminal Osmium(IV) Nitride: Ammonia Formation and Ambiphilic Reactivity

Abstract

AbstractLow‐valent osmium nitrides are discussed as intermediates in nitrogen fixation schemes. However, rational synthetic routes that lead to isolable examples are currently unknown. Here, the synthesis of the square‐planar osmium(IV) nitride [OsN(PNP)] (PNP=N(CH2CH2P(tBu)2)2) is reported upon reversible deprotonation of osmium(VI) hydride [Os(N)H(PNP)]+. The OsIV complex shows ambiphilic nitride reactivity with SiMe3Br and PMe3, respectively. Importantly, the hydrogenolysis with H2 gives ammonia and the polyhydride complex [OsH4(HPNP)] in 80 % yield. Hence, our results directly demonstrate the role of low‐valent osmium nitrides and of heterolytic H2 activation for ammonia synthesis with H2 under basic conditions.