02.03.2013 Views

198 Topics in Current Chemistry Editorial Board: A. de Meijere KN ...

198 Topics in Current Chemistry Editorial Board: A. de Meijere KN ...

198 Topics in Current Chemistry Editorial Board: A. de Meijere KN ...

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

126 R.E. Melén<strong>de</strong>z · A.D. Hamilton<br />

Fig. 32. The crystal structure of 48 forms a sheet through Cl◊◊◊N <strong>in</strong>teractions<br />

Fig. 33. The iodo◊◊◊nitro synthon has been used <strong>in</strong> the <strong>de</strong>sign of tapes 49–52<br />

49<br />

50<br />

51<br />

52<br />

based on the iodo◊◊◊nitro polarization <strong>in</strong>duced <strong>in</strong>teraction. The iodo◊◊◊nitro<br />

synthon has been separated by different spacers; <strong>in</strong> this case the carboxylic acid<br />

dimer has also been <strong>in</strong>clu<strong>de</strong>d. In or<strong>de</strong>r to <strong>de</strong>sign a non-centrosymmetric crystal,<br />

4-iodo-4¢-nitrobiphenyl (52) was prepared. The molecular chirality of the<br />

twisted biphenyl units and the parallel orientation of the ribbons lead to crystal<br />

chirality.This crystall<strong>in</strong>e compound is second harmonic generation active.It has<br />

also been shown that this polarized <strong>in</strong>teraction prevails <strong>in</strong> the structure of 52,<br />

due to the twisted biphenyl, which gives chirality to the structure [83] (Fig. 33).<br />

48

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!