메뉴 건너뛰기




Volumn 132, Issue 2, 2010, Pages 777-790

Guest-encapsulation properties of a self-assembled capsule by dynamic boronic ester bonds

Author keywords

[No Author keywords available]

Indexed keywords

ANTHRACENE DERIVATIVES; ASSOCIATION CONSTANT; BORONIC ESTERS; CAVITANDS; GUEST MOLECULES; KINETIC STUDY; NMR STUDIES; PARTIAL DISSOCIATION; SELECTIVE RECOGNITION; SELF-ASSEMBLE; SELF-ASSEMBLED; SOLVENT EFFECTS; TETRAKIS; THERMODYNAMIC STUDIES; X-RAY CRYSTALLOGRAPHIC ANALYSIS;

EID: 74949129532     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja9084918     Document Type: Article
Times cited : (92)

References (116)
  • 26
    • 19944429121 scopus 로고    scopus 로고
    • Park, S. J.; Shin, D. M.; Sakamoto, S.; Yamaguchi, K.; Chung, Y. K.; Lah, M. S.; Hong, J.-I. Chem.sEur. J. 2005, 11, 235-241.
    • (h) Park, S. J.; Shin, D. M.; Sakamoto, S.; Yamaguchi, K.; Chung, Y. K.; Lah, M. S.; Hong, J.-I. Chem.sEur. J. 2005, 11, 235-241.
  • 34
  • 54
    • 2942746446 scopus 로고    scopus 로고
    • For self-assembled macrocycles based on boronic ester formation, see: a
    • For self-assembled macrocycles based on boronic ester formation, see: (a) Christinat, N.; Scopelliti, R.; Severin, K. Chem. Commun. 2004, 1158-1159.
    • (2004) Chem. Commun , pp. 1158-1159
    • Christinat, N.1    Scopelliti, R.2    Severin, K.3
  • 59
    • 34347243104 scopus 로고    scopus 로고
    • For, self-assembled capsules based on boronic or boronate ester formation, see: a
    • For, self-assembled capsules based on boronic or boronate ester formation, see: (a) Iwasawa, N.; Takahagi, H. J. Am. Chem. Soc. 2007, 129, 7754-7755.
    • (2007) J. Am. Chem. Soc , vol.129 , pp. 7754-7755
    • Iwasawa, N.1    Takahagi, H.2
  • 64
    • 1642365135 scopus 로고    scopus 로고
    • For catechol-based metal ion assisted self-assembly of capsules, see: a
    • For catechol-based metal ion assisted self-assembly of capsules, see: (a) Schalley, C. A.; Lützen, A.; Albrecht, M. Chem.-Eur. J. 2004, 10, 1072-1080.
    • (2004) Chem.-Eur. J , vol.10 , pp. 1072-1080
    • Schalley, C.A.1    Lützen, A.2    Albrecht, M.3
  • 68
    • 74949119692 scopus 로고    scopus 로고
    • See the Supporting Information
    • See the Supporting Information.
  • 72
    • 74949106695 scopus 로고    scopus 로고
    • Spartan '06; Wavefunction Inc.: Irvine, CA, USA, 2006.
    • Spartan '06; Wavefunction Inc.: Irvine, CA, USA, 2006.
  • 78
    • 74949096432 scopus 로고    scopus 로고
    • v. d. Bussche-Hünnefeld, C.; Bühring, D.; Knobler, C. B.; Cram, D. J. J. Chem. Soc., Chem. Commun. 1995, 108, 5-1087.
    • (a) v. d. Bussche-Hünnefeld, C.; Bühring, D.; Knobler, C. B.; Cram, D. J. J. Chem. Soc., Chem. Commun. 1995, 108, 5-1087.
  • 81
    • 74949141002 scopus 로고    scopus 로고
    • The 1H NMR chemical shifts (δ) of the acetoxy and methyl ester protons of free 8 and 8@3a were as follows: for free 8, 2.33 (acetoxy) and 3.63 ppm (methyl ester) in CDCl3 and 1.70 and 3.22 ppm in C6D6; for 8@3a,-1.66 and 3.02 ppm in CDCl3 and-1.11 and 3.05 ppm in C6D6. Thus, ΔδG (δencapsulated-guest- δfree-guest) values of 8 in C6D 6 showed less upfield shifts by ca. 0.4-1.2 ppm relative to those in CDCl3. This result can be interpreted as follows, 1) Free 8 is solvated by C6D6 and is subject to the ring current effect of C6D6-solvation, 2) Upon encapsulation of 8 in 3a, desolvation of C6D6 from 8 occurs, and the 8 encapsulated in 3a is no longer subject to the rin
    • 3.
  • 82
    • 74949086924 scopus 로고    scopus 로고
    • The exchange of 20 in and out of 3a was fast on the NMR time scale in C6D6, and the signals were observed as averaged forms. Thus, the Ka of 3a with 20 in C6D6 at 313 K was calculated from a nonlinear curve fitting, wherein [3a], 2.5 mM (constant) and [20], 2.0-10.0 mM variable
    • 6 at 313 K was calculated from a nonlinear curve fitting, wherein [3a] ) 2.5 mM (constant) and [20] ) 2.0-10.0 mM (variable).
  • 84
    • 74949086925 scopus 로고    scopus 로고
    • a could not be determined directly but just by competitive encapsulation experiments.
    • a could not be determined directly but just by competitive encapsulation experiments.
  • 86
    • 74949135070 scopus 로고    scopus 로고
    • In the 1H NMR spectra of 3a in CHCl3 even at 218 K with CDCl3 sealed in a capillary for NMR deuterium-locking or a mixture of 3a and 100 equiv of CHCl3 in C6D 6, no signal of CHCl3 encapsulated in 3a was observed. These results suggest a small Ka and very fast exchange of CHCl 3 in and out of 3a on the NMR time scale
    • 3 in and out of 3a on the NMR time scale.
  • 89
    • 74949087679 scopus 로고    scopus 로고
    • The 1H NMR spectra of 28a (17 mM) in CDCl3 and C6D6 at 298 K showed a mixture of 28a and its boroxine (trimeric anhydride of 28a) in ratios of 36.8:63.2 and 61.1:38.9, respectively, after 30 min of dissolution.17 After reaching an equilibrium in 36 h at 298 K, the ratio of 28a and its boroxine was 43.5:56.5 in CDCl3 and 60.0:40.0 in C6D 6. This result indicates that the boroxine is thermodynamically more stable in CDCl3 than in C6D6. Upon addition of 29 to this mixture, the boroxine almost disappeared to produce 30a concomitantly with 28a. In contrast, 28b (17 mM) remained intact in both CDCl3 and C6D6 and its boroxine was not detected even after heating at 323 K for 12 h.17
    • 17
  • 90
    • 74949111528 scopus 로고    scopus 로고
    • 1H NMR integration ratio with p-dimethoxybenzene as an internal standard.
    • 1H NMR integration ratio with p-dimethoxybenzene as an internal standard.
  • 94
    • 74949095785 scopus 로고    scopus 로고
    • Guests 5, 6, and 8 were chosen for the 2D EXSY analysis because the diagonal peaks of encapsulated and free guests in the 2D NOESY spectra did not overlap with each other or those of the capsule 3a. However, when excess amounts of guests were used, those faintly overlapped with each other in some cases, increasing experimental errors for k 1 and k-1. The use of excess amounts of guests or low 8@3a/free-8 would produce a large difference in integration values between the diagonal peak of the free guest and the exchange cross-peak, also increasing experimental errors for k1 and k-1. Note that the values of k1 and k-1 contain an experimental error of 10%-15
    • -1 contain an experimental error of 10%-15%.
  • 107
    • 74949136158 scopus 로고    scopus 로고
    • 17
    • 17


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.