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Volumn 72, Issue 25, 2007, Pages 9407-9417

Donor-acceptor triazenes: Synthesis, characterization, and study of their electronic and thermal properties

Author keywords

[No Author keywords available]

Indexed keywords

ELECTRONIC PROPERTIES; FUNCTIONAL GROUPS; NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; SYNTHESIS (CHEMICAL); THERMODYNAMIC PROPERTIES; X RAY CRYSTALLOGRAPHY;

EID: 36849071933     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo070789x     Document Type: Article
Times cited : (85)

References (108)
  • 34
    • 0001735985 scopus 로고
    • Previously, Winberg and Coffman reported that peraminoethylenes react with azides to afford triazenes similar in structure to the compounds reported herein, see
    • Previously, Winberg and Coffman reported that peraminoethylenes react with azides to afford triazenes similar in structure to the compounds reported herein, see: Winberg, H. E.; Coffman, D. D. J. Am. Chem. Soc. 1965, 87, 2776.
    • (1965) J. Am. Chem. Soc , vol.87 , pp. 2776
    • Winberg, H.E.1    Coffman, D.D.2
  • 78
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    • 2).
    • 2).
  • 83
    • 36849079262 scopus 로고    scopus 로고
    • 30 these reactions must be conducted with the rigorous exclusion of oxygen.
    • 30 these reactions must be conducted with the rigorous exclusion of oxygen.
  • 84
    • 36849062566 scopus 로고    scopus 로고
    • 3CN, etc.) and decomposed slowly over several days in solution or in the solid-state (see main text for a more detailed discussion of this phenomenon). These characteristics are partially responsible for the relatively low yields of the reactions summarized in Table 3.
    • 3CN, etc.) and decomposed slowly over several days in solution or in the solid-state (see main text for a more detailed discussion of this phenomenon). These characteristics are partially responsible for the relatively low yields of the reactions summarized in Table 3.
  • 85
    • 36849054433 scopus 로고    scopus 로고
    • Dipole moments were calculated at the B3LYP (6-31G*) level of density functional theory, as implemented in the Spartan 2004 software package (Wavefunction, Irvine, CA 92612).
    • Dipole moments were calculated at the B3LYP (6-31G*) level of density functional theory, as implemented in the Spartan 2004 software package (Wavefunction, Irvine, CA 92612).
  • 86
    • 36849034844 scopus 로고    scopus 로고
    • Similarly, heating toluene solutions of triazenes 6-H-H and 6-H-NO2 (see Table 6) to > 150°C afforded their respective guanidines (11 and 12, not shown) in ≥95% yields. This process was conveniently monitored using 1H NMR spectroscopy. For example, the methylene groups (NCH2) in triazenes 6 exhibit diagnostic chemical shifts at 4.0-4.5 ppm in their 1H NMR spectra; chemical shifts corresponding to the same group in their respective guanidine products were found at 3.5-3.8 ppm. Note that while the thermally-induced triazene decomposition reactions generally afforded high yields >95, of guanidine products, a side-reaction was evident. The residual mass was composed of a mixture of products that eluded NMR spectroscopic identification and could not be purified via column chromatography
    • 1H NMR spectra; chemical shifts corresponding to the same group in their respective guanidine products were found at 3.5-3.8 ppm. Note that while the thermally-induced triazene decomposition reactions generally afforded high yields (>95%) of guanidine products, a side-reaction was evident. The residual mass was composed of a mixture of products that eluded NMR spectroscopic identification and could not be purified via column chromatography.
  • 94
    • 36849092814 scopus 로고    scopus 로고
    • Although the spectroscopic signatures of the resulting triazenes were in accord with the aforementioned triazenes, one notable exception was found. Signals attributable to the methylene groups of the N-iso-butyl substituents (NCH2) in triazene 6-H-H appeared as two doublets at 3.97 ppm and 4.16 ppm in its 1H NMR spectrum (solvent, CDCl3) and were tentatively assigned to cis and trans diazo (N=N) isomers, respectively. While geometric isomers often absorb radiation to differing degrees see: Hartley, G. S. J. Chem. Soc. 1938, 633
    • 3) and were tentatively assigned to cis and trans diazo (N=N) isomers, respectively. While geometric isomers often absorb radiation to differing degrees (see: Hartley, G. S. J. Chem. Soc. 1938, 633
  • 95
    • 4644324133 scopus 로고    scopus 로고
    • max = 367 nm that was similar in shape to the triazenes discussed above (i.e., 1). This result suggested that the absorption of radiation was concomitant with geometric isomerization (i.e., cis → trans).
    • max = 367 nm that was similar in shape to the triazenes discussed above (i.e., 1). This result suggested that the absorption of radiation was concomitant with geometric isomerization (i.e., cis → trans).
  • 96
    • 36849043031 scopus 로고    scopus 로고
    • A similar observation was observed in benzothiazole-based triazenes analogous to 6-H-H where it was determined that cis → trans isomerization was facilitated with λ = 405 nm radiation see: Dorsch, H.-T.; Hoffman, H.; Hansel, R.; Rasch, G.; Fanghänel, E. J. Prakt. Chem. 1976, 318, 671
    • A similar observation was observed in benzothiazole-based triazenes analogous to 6-H-H where it was determined that cis → trans isomerization was facilitated with λ = 405 nm radiation (see: Dorsch, H.-T.; Hoffman, H.; Hansel, R.; Rasch, G.; Fanghänel, E. J. Prakt. Chem. 1976, 318, 671
  • 97
    • 36849072328 scopus 로고    scopus 로고
    • 1H NMR spectroscopy. Considering density functional theory calculations at the B3LYP (6-31G**) level of theory suggested that trans 6-H-H was more stable than its eis isomer by 5.1 kcal/mol, the trans isomer was assumed to dominate in all of the triazenes prepared in this study (DFT calculations were performed using Spartan 2004, Wavefunction, Irvine, CA 92612).
    • 1H NMR spectroscopy. Considering density functional theory calculations at the B3LYP (6-31G**) level of theory suggested that trans 6-H-H was more stable than its eis isomer by 5.1 kcal/mol, the trans isomer was assumed to dominate in all of the triazenes prepared in this study (DFT calculations were performed using Spartan 2004, Wavefunction, Irvine, CA 92612).
  • 98
    • 33750044837 scopus 로고    scopus 로고
    • For a direct comparision of N-heterocyclic carbenes with phosphines in various applications, see: a
    • For a direct comparision of N-heterocyclic carbenes with phosphines in various applications, see: (a) Rogers, M. M.; Stahl, S. S. Top. Organomet. Chem. 2007, 21, 21.
    • (2007) Top. Organomet. Chem , vol.21 , pp. 21
    • Rogers, M.M.1    Stahl, S.S.2
  • 104
    • 36849093871 scopus 로고    scopus 로고
    • 15N-labeled azides see: Leseticky, L.; Barth, R.; Nemec, I.; Sticha, M.; Tislerova, I. Czech. J. Phys. 2003, 53, A777.
    • 15N-labeled azides see: Leseticky, L.; Barth, R.; Nemec, I.; Sticha, M.; Tislerova, I. Czech. J. Phys. 2003, 53, A777.
  • 106
    • 36849075654 scopus 로고    scopus 로고
    • See supporting information for the synthesis and characterization of this compound
    • See supporting information for the synthesis and characterization of this compound.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.