Synthesis of DiamidoPyrrolyl Molybdenum Complexes Relevant to Reduction of Dinitrogen to Ammonia
A potentially useful trianionic ligand for the reduction of dinitrogen catalytically by molybdenum complexes is one in which one of the arms in a [(RNCH2CH2)3N]3− ligand is replaced by a 2-mesitylpyrrolyl-α-methyl arm, that is, [(RNCH2CH2)2NCH2(2-MesitylPyrrolyl)]3− (R = C6F5, 3,5-Me2C6H3, or 3,5-t-...
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| Format: | Article |
| Language: | en_US |
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American Chemical Society
2012
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| Online Access: | http://hdl.handle.net/1721.1/69555 https://orcid.org/0000-0001-5827-3552 |
| _version_ | 1826193639381925888 |
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| author | Chin, Jia Min Schrock, Richard Royce Muller, Peter |
| author2 | Massachusetts Institute of Technology. Department of Chemistry |
| author_facet | Massachusetts Institute of Technology. Department of Chemistry Chin, Jia Min Schrock, Richard Royce Muller, Peter |
| author_sort | Chin, Jia Min |
| collection | MIT |
| description | A potentially useful trianionic ligand for the reduction of dinitrogen catalytically by molybdenum complexes is one in which one of the arms in a [(RNCH2CH2)3N]3− ligand is replaced by a 2-mesitylpyrrolyl-α-methyl arm, that is, [(RNCH2CH2)2NCH2(2-MesitylPyrrolyl)]3− (R = C6F5, 3,5-Me2C6H3, or 3,5-t-Bu2C6H3). Compounds have been prepared that contain the ligand in which R = C6F5 ([C6F5N)2Pyr]3−); they include [(C6F5N)2Pyr]Mo(NMe2), [(C6F5N)2Pyr]MoCl, [(C6F5N)2Pyr]MoOTf, and [(C6F5N)2Pyr]MoN. Compounds that contain the ligand in which R = 3,5-t-Bu2C6H3 ([Art-BuN)2Pyr]3−) include {[(Art-BuN)2Pyr]Mo(N2)}Na(15-crown-5), {[(Art-BuN)2Pyr]Mo(N2)}[NBu4], [(Art-BuN)2Pyr]Mo(N2) (νNN = 2012 cm−1 in C6D6), {[(Art-BuN)2Pyr]Mo(NH3)}BPh4, and [(Art-BuN)2Pyr]Mo(CO). X-ray studies are reported for [(C6F5N)2Pyr]Mo(NMe2), [(C6F5N)2Pyr]MoCl, and [(Art-BuN)2Pyr]MoN. The [(Art-BuN)2Pyr]Mo(N2)0/− reversible couple is found at −1.96 V (in PhF versus Cp2Fe+/0), but the [(Art-BuN)2Pyr]Mo(N2)+/0 couple is irreversible. Reduction of {[(Art-BuN)2Pyr]Mo(NH3)}BPh4 under Ar at approximately −1.68 V at a scan rate of 900 mV/s is not reversible. Ammonia in [(Art-BuN)2Pyr]Mo(NH3) can be substituted for dinitrogen in about 2 h if 10 equiv of BPh3 are present to trap the ammonia that is released. [(Art-BuN)2Pyr]Mo−N═NH is a key intermediate in the proposed catalytic reduction of dinitrogen that could not be prepared. Dinitrogen exchange studies in [(Art-BuN)2Pyr]Mo(N2) suggest that steric hindrance by the ligand may be insufficient to protect decomposition of [(Art-BuN)2Pyr]Mo−N═NH through a variety of pathways. Three attempts to reduce dinitrogen catalytically with [(Art-BuN)2Pyr]Mo(N) as a “catalyst” yielded an average of 1.02 ± 0.12 equiv of NH3. |
| first_indexed | 2024-09-23T09:42:19Z |
| format | Article |
| id | mit-1721.1/69555 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T09:42:19Z |
| publishDate | 2012 |
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| record_format | dspace |
| spelling | mit-1721.1/695552022-09-30T16:17:59Z Synthesis of DiamidoPyrrolyl Molybdenum Complexes Relevant to Reduction of Dinitrogen to Ammonia Chin, Jia Min Schrock, Richard Royce Muller, Peter Massachusetts Institute of Technology. Department of Chemistry Schrock, Richard R. Schrock, Richard Royce Chin, Jia Min Muller, Peter A potentially useful trianionic ligand for the reduction of dinitrogen catalytically by molybdenum complexes is one in which one of the arms in a [(RNCH2CH2)3N]3− ligand is replaced by a 2-mesitylpyrrolyl-α-methyl arm, that is, [(RNCH2CH2)2NCH2(2-MesitylPyrrolyl)]3− (R = C6F5, 3,5-Me2C6H3, or 3,5-t-Bu2C6H3). Compounds have been prepared that contain the ligand in which R = C6F5 ([C6F5N)2Pyr]3−); they include [(C6F5N)2Pyr]Mo(NMe2), [(C6F5N)2Pyr]MoCl, [(C6F5N)2Pyr]MoOTf, and [(C6F5N)2Pyr]MoN. Compounds that contain the ligand in which R = 3,5-t-Bu2C6H3 ([Art-BuN)2Pyr]3−) include {[(Art-BuN)2Pyr]Mo(N2)}Na(15-crown-5), {[(Art-BuN)2Pyr]Mo(N2)}[NBu4], [(Art-BuN)2Pyr]Mo(N2) (νNN = 2012 cm−1 in C6D6), {[(Art-BuN)2Pyr]Mo(NH3)}BPh4, and [(Art-BuN)2Pyr]Mo(CO). X-ray studies are reported for [(C6F5N)2Pyr]Mo(NMe2), [(C6F5N)2Pyr]MoCl, and [(Art-BuN)2Pyr]MoN. The [(Art-BuN)2Pyr]Mo(N2)0/− reversible couple is found at −1.96 V (in PhF versus Cp2Fe+/0), but the [(Art-BuN)2Pyr]Mo(N2)+/0 couple is irreversible. Reduction of {[(Art-BuN)2Pyr]Mo(NH3)}BPh4 under Ar at approximately −1.68 V at a scan rate of 900 mV/s is not reversible. Ammonia in [(Art-BuN)2Pyr]Mo(NH3) can be substituted for dinitrogen in about 2 h if 10 equiv of BPh3 are present to trap the ammonia that is released. [(Art-BuN)2Pyr]Mo−N═NH is a key intermediate in the proposed catalytic reduction of dinitrogen that could not be prepared. Dinitrogen exchange studies in [(Art-BuN)2Pyr]Mo(N2) suggest that steric hindrance by the ligand may be insufficient to protect decomposition of [(Art-BuN)2Pyr]Mo−N═NH through a variety of pathways. Three attempts to reduce dinitrogen catalytically with [(Art-BuN)2Pyr]Mo(N) as a “catalyst” yielded an average of 1.02 ± 0.12 equiv of NH3. National Institutes of Health (U.S.) (GM 31978) 2012-03-01T20:56:57Z 2012-03-01T20:56:57Z 2010-07 Article http://purl.org/eprint/type/JournalArticle 0020-1669 1520-510X http://hdl.handle.net/1721.1/69555 Chin, J. M., R. R. Schrock, and P. Müller. “Synthesis of DiamidoPyrrolyl Molybdenum Complexes Relevant to Reduction of Dinitrogen to Ammonia.” Inorganic Chemistry 49.17 (2010): 7904–7916. https://orcid.org/0000-0001-5827-3552 en_US http://dx.doi.org/10.1021/ic100856n Inorganic Chemistry Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Chemical Society Prof. Schrock via Erja Kajosalo |
| spellingShingle | Chin, Jia Min Schrock, Richard Royce Muller, Peter Synthesis of DiamidoPyrrolyl Molybdenum Complexes Relevant to Reduction of Dinitrogen to Ammonia |
| title | Synthesis of DiamidoPyrrolyl Molybdenum Complexes Relevant to Reduction of Dinitrogen to Ammonia |
| title_full | Synthesis of DiamidoPyrrolyl Molybdenum Complexes Relevant to Reduction of Dinitrogen to Ammonia |
| title_fullStr | Synthesis of DiamidoPyrrolyl Molybdenum Complexes Relevant to Reduction of Dinitrogen to Ammonia |
| title_full_unstemmed | Synthesis of DiamidoPyrrolyl Molybdenum Complexes Relevant to Reduction of Dinitrogen to Ammonia |
| title_short | Synthesis of DiamidoPyrrolyl Molybdenum Complexes Relevant to Reduction of Dinitrogen to Ammonia |
| title_sort | synthesis of diamidopyrrolyl molybdenum complexes relevant to reduction of dinitrogen to ammonia |
| url | http://hdl.handle.net/1721.1/69555 https://orcid.org/0000-0001-5827-3552 |
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