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Updated: Sep 9, 2025

The Synthesis, Characterization and Reactivity of a Series of Ruthenium N-triphosPh Complexes
Published on: April 10, 2015
Synthesis and Photodriven Hydrogenation of Tungsten Nitride Complexes Prepared from Dinitrogen Cleavage
Matthew V Pecoraro1, Grace B Panetti1, Junho Kim1
1Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States.
Abstract:
Oxidation of the Chatt-type tungsten dinitrogen compound, trans-(depe)2W-(N2)2 (depe = Et2PCH2CH2PEt2), with [(η5-C5H5)2Fe]-[BArF 4] (BArF 4 = B-(3,5-(CF3)2C6H3)4) resulted in isolation of [(depe)2WN]-[BArF 4], a rare example of a tungsten-(IV) nitride prepared from N2 cleavage. A bimetallic μ-N2 ditungsten intermediate supported by terminal N2 ligands was identified, and irradiation with visible light promoted dinitrogen cleavage and formation of [(depe)2WN]-[BArF 4]. Performing the analogous one-electron oxidation of the related tungsten dinitrogen compound, trans-(dppe)2W-(N2)2 (dppe = Ph2PCH2CH2PPh2), furnished the corresponding cationic, 17-electron tungsten dinitrogen complex, [(dppe)2W-(N2)2]-[BArF 4], that was characterized by X-ray diffraction and vibrational and EPR spectroscopies. The generation of [(dppe)2W-(N)]-[BArF 4] was observed in low yield from the in situ formed mixed N2-bridged compound, [(N2)-(depe)2W-(μ-N2)-W-(dppe)2(N2)]-[BArF 4]2, and was confirmed by independent synthesis using 1-azidoadamantane. Addition of ammonia or water to [(depe)2WN]-[BArF 4] resulted in formation of the cationic imide and hydroxide complexes, [(depe)2W-(NH)-(X)]-[BArF 4] (X = NH2, OH). Irradiation of [(depe)2WN]-[BArF 4] with 440 nm visible light in the presence of Ir-(ppy)3 (ppy = 2-phenylpyridine) under 4 atm of dihydrogen resulted in hydrogenation of the tungsten nitride to the cationic tungsten pentahydride, [(depe)2WH5]-[BArF 4], with the release of free ammonia in 21% yield, a rare example of ammonia generation from dinitrogen and dihydrogen from a well-defined tungsten nitride.
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