Shape-Persistent and Shape-Adaptable Macrocycles Based on Restricted Rotation: Studies Building Toward ‘Macromolecular Playdough’

Abstract

A rigid 48-membered macrocycle 1 was synthesized and studied that comprises two atropisomeric N,N′-diarylnaphthalenediimide building blocks that adopt stable syn and anti conformations due to restricted rotation about two C_aryl-N_imide bonds. The resulting macrocycle maintains three distinct conformations: anti/anti, syn/anti and syn/syn conformers that are stable and separable at room temperatures, and each with distinct shapes and sizes as measured by GPC. At elevated temperatures, macrocycle 1 was conformationally flexible and showed interconversion of the respective isomers. Conformational preferences established at higher temperatures were preserved on cooling to room temperature as the restricted rotation was reestablished and the macrocycle becomes conformationally rigid.

restricted rotation - atropisomerism - foldamers - macrocycles - cyclizations - conformation

References

<A NAME="RC11902SS-1">1</A> Bunz UHF. Chem. Rev.  2000,  100:  1605 

<A NAME="RC11902SS-2">2</A> Rebek J. Angew. Chem., Int. Ed. Engl.  1990,  29:  245 

<A NAME="RC11902SS-3">3</A> Hoger S. J. Polym. Sci. Pol. Chem.  1999,  37:  2685 

<A NAME="RC11902SS-4">4</A> Lehn JM. Chem.-Eur. J.  1999,  5:  2455 

<A NAME="RC11902SS-5">5</A> Lehn JM. Eliseev AV. Science   2001,  291:  2331 

<A NAME="RC11902SS-6">6</A> Gellman SH. Acc. Chem. Res.  1998,  31:  173 

<A NAME="RC11902SS-7">7</A> Nelson JC. Saven JG. Moore JS. Wolynes PG. Science  1997,  277:  1793 

<A NAME="RC11902SS-8">8</A> Degenhardt CF. Shortell DB. Adams RD. Shimizu KD. J. Chem. Soc., Chem. Commun.  2000,  929 

<A NAME="RC11902SS-9">9</A> Choi D.-S. Chong YS. Whitehead D. Shimizu KD. Org. Lett.  2001,  3:  3757 

<A NAME="RC11902SS-10">10</A> Chong YS. Smith MD. Shimizu KD. J. Am. Chem. Soc.  2001,  123:  7463 

<A NAME="RC11902SS-11">11</A> Degenhardt CF. Smith MD. Shimizu KD. Org. Lett.  2002,  4:  723 

<A NAME="RC11902SS-12">12</A> Bauer M. Vogtle F. Chem. Ber.  1992,  125:  1675 

<A NAME="RC11902SS-13">13</A> Losensky HW. Spelthann H. Ehlen A. Vogtle F. Bargon J. Angew. Chem., Int. Ed. Engl.  1988,  27:  1189 

<A NAME="RC11902SS-14">14</A> Junge DM. McGrath DV. J. Am. Chem. Soc.  1999,  121:  4912 

<A NAME="RC11902SS-15">15</A> Beattie MS. Jackson C. Jaycox GD. Polymer  1998,  39:  2597 

<A NAME="RC11902SS-16">16</A> Ikeda T. Macromolecules  1998,  31:  1104 

<A NAME="RC11902SS-17">17</A>

In this system, there are fewer than 2n conformations due to the symmetry of the molecules.

<A NAME="RC11902SS-18">18</A> Bampos N. Marvaud V. Sanders JKM. Chem.-Eur. J.  1998,  4:  335 

<A NAME="RC11902SS-19">19</A>

Calculated from the Arrhenius equation assuming an ideal value of A = 2.08·10¹⁰s^-1deg^-1.

<A NAME="RC11902SS-20">20</A> Sanders GM. Van Dijk M. Machiels BM. van Veldhuizen A. J. Org. Chem.  1991,  56; 1301 

<A NAME="RC11902SS-21">21</A> Shimizu KD. Dewey TM. Rebek J. J. Am. Chem. Soc.  1994,  116:  5145 

<A NAME="RC11902SS-22">22</A> Li S. McGrath DV. J. Am. Chem. Soc.  2000,  122:  6795 

<A NAME="RC11902SS-23">23</A>

Molecular weight estimates were made based on polystyrene standard. GPC conditions were Waters Styragel HR 4E in CHCl₃ at 1 mL min^-1.