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Vincent J. Chebny and Rajendra Rathore*

Convergent Synthesis of Alternating Fluorene- p -xylene Oligomers and Delineation of the (Silver) Cation-Induced Folding. Vincent J. Chebny and Rajendra Rathore*. J . Am . Chem . Soc. 2007 , 129 , 8458-8465. The Biopolymers Permit Structure Modulation by Difference Interaction.

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Vincent J. Chebny and Rajendra Rathore*

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  1. Convergent Synthesis of Alternating Fluorene-p-xylene Oligomers and Delineation of the (Silver) Cation-Induced Folding Vincent J. Chebny and Rajendra Rathore* J. Am. Chem. Soc. 2007, 129, 8458-8465

  2. The Biopolymers Permit Structure Modulation by Difference Interaction 1. Hydrogen bonding 2. -stacking 3. Columbic interactions 4. Metal-ion binding

  3. The Biopolymers Permit Structure Modulation by -Stacking NDI :1,4,5,8-naphthalenetetracarboxylic diimide acceptor DAN: 1,5-dialkoxynaphthalene Donor Zych, A. J.; Iverson, B. L. J. Am. Chem. Soc. 2000, 122, 8898

  4. Artificial Polymeric Materials can be Modulated by Light Irradiation at 365 nm Khan, A.; Kaiser, C.; Hecht, S. Angew. Chem., Int. Ed. 2006, 45, 1878.

  5. Artificial Polymeric Materials can be Modulated by Metal-ion Binding Suzuki, Y. J. Phys. Chem. B 1998, 102, 7910

  6. Selective Zinc Sensor Molecules Kikuchi.K. J. Am. Chem. Soc. 2005, 127, 10197

  7. b a Synthesis of Receptor (a) and Its Model Compound (b) Rathore, R. et. al J. Am. Chem. Soc. 2005, 127, 8012

  8. Optimized Structures of the Isoenergetic Conformers of 1 density functional theory (DFT) calculations at the B3LYP/6-31G* level Rathore, R. et. al J. Am. Chem. Soc. 2005, 127, 8012

  9. X-ray Structure of 1 Showing the Extended Conformer

  10. An Extended Conformer to an Delta Conformer by Binding a Single Silver Cation

  11. A Hitherto Unknown Polymeric Structure A

  12. A Similar Mixture of Cyclic Oligomers

  13. 1H/13C NMR Spectra of the Mixture of Cyclic Oligomers 4 3 6 5 a c 7,8 2 10 a 9 1 b e d e b d c 7,8 4 5 10 3 6 2 1 9

  14. The Syntheses of Acyclic Oligomers (a) n-BuLi/THF/-78 °C. (b) n-BuLi/-78 °C/ethyl-4-(bromomethyl)benzote. (c) LiAIH4/THF/reflux. (d) SOCI2/CHCI3/0 °C F: fluorenes group, H: hydrogens group, M: methylsgroup, E: ester group, A: alcohol group, C: chloro group, X:xylylgroup

  15. The Syntheses of Acyclic Oligomers (a) n-BuLi/THF/-78 °C. (b) n-BuLi/-78 °C/ethyl-4-(bromomethyl)benzote. (c) LiAIH4/THF/reflux. (d) SOCI2/CHCI3/0 °C. (e) Fluorene/n-BuLi/THF/-78 °C. F: fluorenes group, H: hydrogens group, M: methylsgroup, E: ester group, A: alcohol group, C: chloro group, X:xylylgroup

  16. The Syntheses of Acyclic Oligomers Z2-Z8

  17. The Syntheses of Acyclic Oligomers Z2-Z8

  18. A Comparison of the 1H NMR Spectra of Z1-Z9 Oligomers. a:b:c= 6:4n+4:4n+4

  19. 1H NMR Spectra of Z1 and Plot of Changes in the Chemical Shifts of the Xylenic Protons

  20. The Maximum Number of Ag+ Cations Captured by Zn

  21. The Maximum Number of Ag+ Cations Captured by Z1 Joe’s plot

  22. The Binding of multiple Silver Cations to Representative Zn Receptors

  23. It is important to note that the simplicity of the 1H NMR spectra, obtained in the presence of varying equivalents of Ag+, suggests the dynamic nature of the binding of Ag+ to the multiple receptor sites of Z2-Z9

  24. The Formation of Multiple -prismand-like Cavities for Binding of Ag+ Cations.

  25. Benesi, H. A.; Hildebrand, J. J. J. Am. Chem. Soc. 1949, 71, 2703

  26. Four Isoenergetic Conformers of the Oligomer Z3 density functional theory (DFT) calculations at the B3LYP/6-31G* level

  27. 1H NMR Spectra of Z3 and Plot of Changes in the Chemical Shifts

  28. Conclusions 1. They developed convergent syntheses of hitherto unknown fluorene-p-xylene oligomers Z1-Z9 in excellent yields with the aid of four repetitive sequences of reactions. 2. The binding of multiple silver cations to Z3-Z9 was possible due to the folding of these oligomers, by simple C-C bond rotations. 3. We are actively exploring the syntheses of the Zn analogues containing different substituents to further modulate the binding and selectivity of various metal cations.

  29. Possible Structures of Z3 upon Exposure to 1 and 2 Equiv of Silver Cations

  30. Four Isoenergetic Conformers of the Oligomer Z3

  31. A313 : molar absorbance ε313: extinction coefficient of the new absorption band K : association constant

  32. 462 nm, typical of pyrene excimer fluorescence J.Am. Chem. Soc. 2003, 125, 2884.

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