Simple Molybdenum(IV) Olefin Complexes of the Type Mo(NR)(X)(Y)(olefin)
Exposure of heptane solutions of Mo(NAr)(CHCMe2Ph)(Me2Pyr)(OAr) (1a; Ar = 2,6-diisopropylphenyl), Mo(NAr)(CHCMe3)(Me2Pyr)[OCMe(CF3)2] (1b), and Mo(NAr)(CHCMe2Ph)(Me2Pyr)(OSiPh3) (1c) to one atmosphere of ethylene for 12 h yields the ethylene complexes, Mo(NAr)(CH2CH2)(Me2Pyr)(OAr) (2a), Mo(NAr)(CH2C...
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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/1721.1/69660 https://orcid.org/0000-0001-5827-3552 |
| _version_ | 1826199174854475776 |
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| author | Marinescu, Smaranda C. King, Annie J. Schrock, Richard Royce Singh, Rojendra Muller, Peter Takase, Michael K. |
| author2 | Massachusetts Institute of Technology. Department of Chemistry |
| author_facet | Massachusetts Institute of Technology. Department of Chemistry Marinescu, Smaranda C. King, Annie J. Schrock, Richard Royce Singh, Rojendra Muller, Peter Takase, Michael K. |
| author_sort | Marinescu, Smaranda C. |
| collection | MIT |
| description | Exposure of heptane solutions of Mo(NAr)(CHCMe2Ph)(Me2Pyr)(OAr) (1a; Ar = 2,6-diisopropylphenyl), Mo(NAr)(CHCMe3)(Me2Pyr)[OCMe(CF3)2] (1b), and Mo(NAr)(CHCMe2Ph)(Me2Pyr)(OSiPh3) (1c) to one atmosphere of ethylene for 12 h yields the ethylene complexes, Mo(NAr)(CH2CH2)(Me2Pyr)(OAr) (2a), Mo(NAr)(CH2CH2)(Me2Pyr)[OCMe(CF3)2] (2b), and Mo(NAr)(CH2CH2)(Me2Pyr)(OSiPh3) (2c). Addition of 1 equiv of triphenylsilanol to a solution of 2c gives Mo(NAr)(CH2CH2)(OSiPh3)2 (3) readily. Mo(NAr)(CHCMe2Ph)(OTf)2(dme) reacts slowly with ethylene (60 psi) in toluene at 80 °C to give cis and trans isomers of Mo(NAr)(CH2CH2)(OTf)2(dme) (4a) in the ratio of 2(cis):1. Addition of lithium 2,5-dimethylpyrrolide to 4a under 1 atm of ethylene produces Mo(NAr)(CH2CH2)(η1-Me2Pyr)(η5-Me2Pyr) (5a). Mo(NAr)(CHCMe2Ph)(η1-MesPyr)2 (MesPyr = 2-mesitylpyrrolide) reacts cleanly with ethylene in benzene at 60 °C over a period of four days to give exclusively Mo(NAr)(CH2CH2)(MesPyr)2 (5b). Treatment of 5b with 2 equiv of (CF3)2CHOH in ether yields Mo(NAr)(CH2CH2)[OCH(CF3)2]2(Et2O) (6). Neat styrene reacts with 2c and 3 to generate the styrene complexes, Mo(NAr)(CH2CHPh)(Me2Pyr)(OSiPh3) (7) and Mo(NAr)(CH2CHPh)(OSiPh3)2 (8), respectively. Similarly, the trans-3-hexene complex, Mo(NAr)(trans-3-hexene)(OSiPh3)2 (9a), can be prepared from 3 and neat trans-3-hexene. When 3 is exposed to 1 atm of ethylene, the molybdacyclopentane species, Mo(NAr)(C4H8)(OSiPh3)2 (10), is generated. X-ray structural studies were carried out on 2c, 5a, 6, 8, 9a, and 10. All evidence suggests that alkene exchange at the Mo(IV) center is facile, followed by cis,trans isomerization and isomerization via double bond migration. In addition, trace amounts of alkylidene complexes are formed that result in slow metathesis reactions of free olefins to give (e.g.) a distribution of all possible linear olefins from an initial olefin and its double bond isomers. |
| first_indexed | 2024-09-23T11:15:32Z |
| format | Article |
| id | mit-1721.1/69660 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T11:15:32Z |
| publishDate | 2012 |
| publisher | American Chemical Society |
| record_format | dspace |
| spelling | mit-1721.1/696602022-09-27T18:14:41Z Simple Molybdenum(IV) Olefin Complexes of the Type Mo(NR)(X)(Y)(olefin) Marinescu, Smaranda C. King, Annie J. Schrock, Richard Royce Singh, Rojendra Muller, Peter Takase, Michael K. Massachusetts Institute of Technology. Department of Chemistry Schrock, Richard Royce Marinescu, Smaranda C. King, Annie J. Schrock, Richard Royce Singh, Rojendra Muller, Peter Takase, Michael K. Exposure of heptane solutions of Mo(NAr)(CHCMe2Ph)(Me2Pyr)(OAr) (1a; Ar = 2,6-diisopropylphenyl), Mo(NAr)(CHCMe3)(Me2Pyr)[OCMe(CF3)2] (1b), and Mo(NAr)(CHCMe2Ph)(Me2Pyr)(OSiPh3) (1c) to one atmosphere of ethylene for 12 h yields the ethylene complexes, Mo(NAr)(CH2CH2)(Me2Pyr)(OAr) (2a), Mo(NAr)(CH2CH2)(Me2Pyr)[OCMe(CF3)2] (2b), and Mo(NAr)(CH2CH2)(Me2Pyr)(OSiPh3) (2c). Addition of 1 equiv of triphenylsilanol to a solution of 2c gives Mo(NAr)(CH2CH2)(OSiPh3)2 (3) readily. Mo(NAr)(CHCMe2Ph)(OTf)2(dme) reacts slowly with ethylene (60 psi) in toluene at 80 °C to give cis and trans isomers of Mo(NAr)(CH2CH2)(OTf)2(dme) (4a) in the ratio of 2(cis):1. Addition of lithium 2,5-dimethylpyrrolide to 4a under 1 atm of ethylene produces Mo(NAr)(CH2CH2)(η1-Me2Pyr)(η5-Me2Pyr) (5a). Mo(NAr)(CHCMe2Ph)(η1-MesPyr)2 (MesPyr = 2-mesitylpyrrolide) reacts cleanly with ethylene in benzene at 60 °C over a period of four days to give exclusively Mo(NAr)(CH2CH2)(MesPyr)2 (5b). Treatment of 5b with 2 equiv of (CF3)2CHOH in ether yields Mo(NAr)(CH2CH2)[OCH(CF3)2]2(Et2O) (6). Neat styrene reacts with 2c and 3 to generate the styrene complexes, Mo(NAr)(CH2CHPh)(Me2Pyr)(OSiPh3) (7) and Mo(NAr)(CH2CHPh)(OSiPh3)2 (8), respectively. Similarly, the trans-3-hexene complex, Mo(NAr)(trans-3-hexene)(OSiPh3)2 (9a), can be prepared from 3 and neat trans-3-hexene. When 3 is exposed to 1 atm of ethylene, the molybdacyclopentane species, Mo(NAr)(C4H8)(OSiPh3)2 (10), is generated. X-ray structural studies were carried out on 2c, 5a, 6, 8, 9a, and 10. All evidence suggests that alkene exchange at the Mo(IV) center is facile, followed by cis,trans isomerization and isomerization via double bond migration. In addition, trace amounts of alkylidene complexes are formed that result in slow metathesis reactions of free olefins to give (e.g.) a distribution of all possible linear olefins from an initial olefin and its double bond isomers. National Science Foundation (U.S.) (CHE-0841187 to R.R.S.) National Science Foundation (U.S.) (CHE-0841187) 2012-03-14T21:03:18Z 2012-03-14T21:03:18Z 2010-12 2010-10 Article http://purl.org/eprint/type/JournalArticle 0276-7333 1520-6041 http://hdl.handle.net/1721.1/69660 Marinescu, Smaranda C. et al. “Simple Molybdenum(IV) Olefin Complexes of the Type Mo(NR)(X)(Y)(olefin).” Organometallics 29.24 (2010): 6816–6828. https://orcid.org/0000-0001-5827-3552 en_US http://dx.doi.org/10.1021/om101003v Organometallics 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 | Marinescu, Smaranda C. King, Annie J. Schrock, Richard Royce Singh, Rojendra Muller, Peter Takase, Michael K. Simple Molybdenum(IV) Olefin Complexes of the Type Mo(NR)(X)(Y)(olefin) |
| title | Simple Molybdenum(IV) Olefin Complexes of the Type Mo(NR)(X)(Y)(olefin) |
| title_full | Simple Molybdenum(IV) Olefin Complexes of the Type Mo(NR)(X)(Y)(olefin) |
| title_fullStr | Simple Molybdenum(IV) Olefin Complexes of the Type Mo(NR)(X)(Y)(olefin) |
| title_full_unstemmed | Simple Molybdenum(IV) Olefin Complexes of the Type Mo(NR)(X)(Y)(olefin) |
| title_short | Simple Molybdenum(IV) Olefin Complexes of the Type Mo(NR)(X)(Y)(olefin) |
| title_sort | simple molybdenum iv olefin complexes of the type mo nr x y olefin |
| url | http://hdl.handle.net/1721.1/69660 https://orcid.org/0000-0001-5827-3552 |
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