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Volumn 129, Issue 32, 2007, Pages 10019-10028

Tracking "invisible" alkylchlorocarbenes by their σ → p absorptions: Dynamics and solvent interactions

Author keywords

[No Author keywords available]

Indexed keywords

ALKYLCHLOROCARBENES; INTERMOLECULAR CARBENES; LASER FLASH PHOTOLYSIS;

EID: 34547899129     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja071799i     Document Type: Article
Times cited : (32)

References (51)
  • 6
    • 34250685756 scopus 로고    scopus 로고
    • Preliminary results were presented at the 18th IUPAC International Conference on Reactive Intermediates, Warsaw, Poland, August 23, 2006, and are contained in a written version of that talk: Moss, R. A.; Tian, J.; Chu, G.; Sauers, R. R.; Krogh-Jespersen, K. Pure Appl. Chem. 2007, 79, 993. Neither the spectra themselves, nor descriptions of the time-dependent dynamics of the carbene-solvent and carbene-diazirine reactions, are contained in this report.
    • Preliminary results were presented at the 18th IUPAC International Conference on Reactive Intermediates, Warsaw, Poland, August 23, 2006, and are contained in a written version of that talk: Moss, R. A.; Tian, J.; Chu, G.; Sauers, R. R.; Krogh-Jespersen, K. Pure Appl. Chem. 2007, 79, 993. Neither the spectra themselves, nor descriptions of the time-dependent dynamics of the carbene-solvent and carbene-diazirine reactions, are contained in this report.
  • 8
    • 34547866249 scopus 로고    scopus 로고
    • 1H NMR vs an internal dioxane standard.
    • 1H NMR vs an internal dioxane standard.
  • 9
    • 34547865490 scopus 로고    scopus 로고
    • Details of our LFP apparatus appear in the Supporting Information
    • Details of our LFP apparatus appear in the Supporting Information.
  • 10
    • 34547863997 scopus 로고    scopus 로고
    • See the Supporting Information for references to and details of the calculations
    • See the Supporting Information for references to and details of the calculations.
  • 16
    • 34547870286 scopus 로고    scopus 로고
    • The decay of ylide 5a should provide an azine [MeClC=N-N=CClMe, This product (in addition to vinyl chloride) was detected by GC-MS after 350 nm photolysis of diazirine 4a in pentane. We have not kinetically monitored the decay of ylide 5a
    • The decay of ylide 5a should provide an azine [MeClC=N-N=CClMe]. This product (in addition to vinyl chloride) was detected by GC-MS after 350 nm photolysis of diazirine 4a in pentane. We have not kinetically monitored the decay of ylide 5a.
  • 23
    • 34547918087 scopus 로고    scopus 로고
    • The LFP-UV spectrum of MeCCl in anisole is identical under air or nitrogen, excluding the intervention of a carbene-oxygen ylide carbonyl oxide
    • The LFP-UV spectrum of MeCCl in anisole is identical under air or nitrogen, excluding the intervention of a carbene-oxygen ylide (carbonyl oxide).
  • 24
    • 34547883630 scopus 로고    scopus 로고
    • We would expect the MP2 method to produce the more accurate interaction energies because dispersion interactions are included in this method. However, MP2 calculations scale poorly with molecular size and are cumbersome to use in exhaustive studies of potential energy surfaces for larger molecular systems. DFT, on the other hand, scales favorably with system size but does not generally include dispersion interactions in the functionals employed. That the PBEPBE functionals tend to err on the side of overbinding, whereas the B3LYP functionals underbind, particularly for weak interactions, probably works in our favor here.
    • We would expect the MP2 method to produce the more accurate interaction energies because dispersion interactions are included in this method. However, MP2 calculations scale poorly with molecular size and are cumbersome to use in exhaustive studies of potential energy surfaces for larger molecular systems. DFT, on the other hand, scales favorably with system size but does not generally include dispersion interactions in the functionals employed. That the PBEPBE functionals tend to err on the side of overbinding, whereas the B3LYP functionals underbind, particularly for weak interactions, probably works in our favor here.
  • 26
    • 34547896375 scopus 로고    scopus 로고
    • Attempts to reorient the carbene Me group of 6d toward the phenyl center resulted (upon structural reoptimization) in rotation of the carbene back to its original position or in migration to complex 6c.
    • Attempts to reorient the carbene Me group of 6d toward the phenyl center resulted (upon structural reoptimization) in rotation of the carbene back to its original position or in migration to complex 6c.
  • 27
    • 34547910771 scopus 로고    scopus 로고
    • Consideration of the gas-phase MP2/6-311+G(d) and B3LYP/6-311+G(d) energies (Supporting Information) does not alter this conclusion.
    • Consideration of the gas-phase MP2/6-311+G(d) and B3LYP/6-311+G(d) energies (Supporting Information) does not alter this conclusion.
  • 28
    • 34547911167 scopus 로고    scopus 로고
    • MP2 and B3LYP results (Supporting Information) indicate that the THF and dioxane ylides could be less favorable than anisole O-ylide 6d; however, the relative destabilization is not large.
    • MP2 and B3LYP results (Supporting Information) indicate that the THF and dioxane ylides could be less favorable than anisole O-ylide 6d; however, the relative destabilization is not large.
  • 29
    • 34547885553 scopus 로고    scopus 로고
    • The local σ → p MeCCl transition is computed at 574.3 nm (f = 0.04) in 7a and at 498.6 nm (f = 0.04)in 7b.
    • The "local" σ → p MeCCl transition is computed at 574.3 nm (f = 0.04) in 7a and at 498.6 nm (f = 0.04)in 7b.
  • 33
    • 0000241299 scopus 로고    scopus 로고
    • Brinker, U. H, Ed, JAI Press: Stamford, CT
    • (b) Platz, M. S. In Advances in Carbene Chemistry; Brinker, U. H., Ed.; JAI Press: Stamford, CT, 1998; Vol. 2, pp 133 f.
    • (1998) Advances in Carbene Chemistry , vol.2
    • Platz, M.S.1
  • 35
    • 34547894374 scopus 로고    scopus 로고
    • 1H NMR vs an internal dioxane standard.
    • 1H NMR vs an internal dioxane standard.
  • 37
    • 34547879778 scopus 로고    scopus 로고
    • H can also be determined by monitoring the decay of 2b at 310 nm (ref 27), but product β-chlorostyrene absorbs in the 290-300 nm region. Following the 576 nm σ → p absorption is simpler.
    • H can also be determined by monitoring the decay of 2b at 310 nm (ref 27), but product β-chlorostyrene absorbs in the 290-300 nm region. Following the 576 nm σ → p absorption is simpler.
  • 39
    • 34547878832 scopus 로고    scopus 로고
    • This figure shows a composite of the carbene σ → p absorbance at 50 ns after the laser pulse and the carbene-diazirine ylide at greater elapsed time (1000 ns) so that the intensities of both signals are maximized
    • This figure shows a "composite" of the carbene σ → p absorbance at 50 ns after the laser pulse and the carbene-diazirine ylide at greater elapsed time (1000 ns) so that the intensities of both signals are maximized.
  • 44
    • 84982056158 scopus 로고    scopus 로고
    • The steric substituent constants of t-butyl and 1-adamantyl are comparable: Hellmann, G.; Beckhaus, H.-D.; Rüchardt, C. Chem. Ber. 1979, 112, 1808.
    • The steric substituent constants of t-butyl and 1-adamantyl are comparable: Hellmann, G.; Beckhaus, H.-D.; Rüchardt, C. Chem. Ber. 1979, 112, 1808.
  • 45
    • 34547863996 scopus 로고    scopus 로고
    • These spectra were acquired 50 ns after the laser pulse
    • These spectra were acquired 50 ns after the laser pulse.
  • 49
    • 34547875147 scopus 로고    scopus 로고
    • 2: cf., ref 25b.
    • 2: cf., ref 25b.
  • 50
    • 37049109895 scopus 로고    scopus 로고
    • R = t-Bu: Moss, R. A.; Munjal, R. C. Chem. Commun. 1978, 775.
    • (b) R = t-Bu: Moss, R. A.; Munjal, R. C. Chem. Commun. 1978, 775.
  • 51
    • 0001716360 scopus 로고    scopus 로고
    • 5: Moss, R. A.; Shen, S.; Krogh-Jespersen, K.; Potenza, J. A.; Schugar, H. J.; Munjal, R. C. J. Am. Chem. Soc. 1986, 108, 134.
    • 5: Moss, R. A.; Shen, S.; Krogh-Jespersen, K.; Potenza, J. A.; Schugar, H. J.; Munjal, R. C. J. Am. Chem. Soc. 1986, 108, 134.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.