Novel azo octupoles with large first hyperpolarizabilitiesElectronic supplementary information (ESI) is available: molar absorptivity spectra of 1a,d,e, P1 and P2 in THF and plots of I2ω vs. number density for 1a,d,e and 2a,c,e in THF at 1064 nm. See http://www.rsc.org/suppdata/jm/b3/b300777d/
摘要:
合成了含有偶氮基团的新型二维八极子及其低聚物,并测定了它们的第一个超极化率。无论桥的性质或共轭长度如何,偶氮八极子的 λmax 和 β(0) 值几乎相同。另一方面,1,3,5-三氰基-2,4,6-三[4-(对二乙基氨基苯乙烯基)苯乙烯基]苯比相应的偶氮类似物具有更大的 β(0) 值,这可能是因为其效率更高。 CC 与 NN 键的共轭能力比较。八极子的 β(0)/MW 大于相应的偶极子,而偶氮八极子的 β(0)/MW 与偶极子相当。此外,在八极低聚物中观察到单体 β(0) 的保留。
Novel azo octupoles with large first hyperpolarizabilitiesElectronic supplementary information (ESI) is available: molar absorptivity spectra of 1a,d,e, P1 and P2 in THF and plots of I2ω vs. number density for 1a,d,e and 2a,c,e in THF at 1064 nm. See http://www.rsc.org/suppdata/jm/b3/b300777d/
摘要:
合成了含有偶氮基团的新型二维八极子及其低聚物,并测定了它们的第一个超极化率。无论桥的性质或共轭长度如何,偶氮八极子的 λmax 和 β(0) 值几乎相同。另一方面,1,3,5-三氰基-2,4,6-三[4-(对二乙基氨基苯乙烯基)苯乙烯基]苯比相应的偶氮类似物具有更大的 β(0) 值,这可能是因为其效率更高。 CC 与 NN 键的共轭能力比较。八极子的 β(0)/MW 大于相应的偶极子,而偶氮八极子的 β(0)/MW 与偶极子相当。此外,在八极低聚物中观察到单体 β(0) 的保留。
Chiral p-sulfonatocalix[n]arenes (n = 4, 6, and 8) bearing (S)-2-methylbutoxy groups (1(n)) have been synthesized. 1(n = 4) gave a simple, positive CD band, whereas 1(n = 6) and 1(n = 8) gave split CD bands characteristic of an exciton coupling at 1L(a) region. The sign (positive first Cotton effect and negative second Cotton effect) indicates that the chirality of excitons in these calixarenes is arranged in a clockwise direction. The difference between 1(n = 4) and the larger calixarenes 1(n = 6) and 1(n = 8) is accounted for by the difference in the ring rigidity: that is, 1(n = 6) nad 1(n = 8) are flexible enough to allow interactions of excitons in the excited state, whereas 1(n = 4) is too rigid to allow the interactions. On the addition of guest molecules (aliphatic alcohols) the CD band of 1(n = 4) was scarcely changed, whereas those of 1(n = 6) and 1(n = 8) were weakened. This result, together with the H-1 NMR data, suggests that the conformational fluctuation in 1(n = 6) and 1(n = 8) is considerably suppressed upon inclusion of these guest molecules. In the presence of 1(n = 6) or 1(n = 8) ICD bands were also observed for certain dye molecules (e.g., 4-cyano-4'-(diethylamino)azobenzene and 4-nitro-4'-(diethylamino)azobenzene). Careful comparison of the ICD spectra with the absorption spectra established that the calixarene complexes having 2:1 guest/calixarene stoichiometry are ICD-active whereas those having 1:1 guest/calixarene stoichiometry are ICD-silent. Interestingly, the sign of the Cotton effect showed that 4-cyano-4'-(diethylamino)azobenzene included in 1(n = 6) gives a counterclockwise exciton coupling, whereas that included in 1(n = 8) gives a clockwise exciton coupling. Thus, the present study demonstrates that the CD spectral technique is very useful to obtain insights into calixarene conformations and calixarene complexation properties.