Liao Yi, Firestone Kimberly A, Bhattacharjee Sanchali, Luo Jingdong, Haller Marnie, Hau Steven, Anderson Cyrus A, Lao David, Eichinger Bruce E, Robinson Bruce H, Reid Philip J, Jen Alex K-Y, Dalton Larry R
Department of Chemistry, University of Washington, Seattle, Washington 98195, USA.
J Phys Chem B. 2006 Mar 23;110(11):5434-8. doi: 10.1021/jp060233y.
A macrocyclic trichromophore bundle 1 with parallel-aligned dipole moments has been synthesized to study the influence of aggregation and orientation of a nonlinear optical (NLO) chromophore on its optical properties. The linear and nonlinear optical properties of 1 and a single chromophore standard 2 have been studied by UV-vis absorption, fluorescence, solvatochromic spectrometry, and hyper-Rayleigh scattering (HRS). Reduced first-order hyperpolarizability beta, hypsochromic shift, enhanced solvatochromic shifts, and fluorescence quenching for individual chromophores were observed when 1 was compared with 2. Analysis of the data showed that the transition dipole moment changes only slightly when the chromophores are parallel aligned in the bundle architecture. However, the apparent hyperpolarizability of the individual chromophores decreased significantly by about 20%. The reduction in beta for the individual chromophores in 1 is largely due to the hypsochromic shift, i.e., excitation energy increase of the interband (charge-transfer) energy gap and the reduced difference between the ground-state and excited-state dipole moments. The hypsochromic shift and fluorescence quenching are consistent with exciton theory. Possible reasons for the enhanced solvatochromic shift are discussed.
已合成一种具有平行排列偶极矩的大环三发色团束1，以研究非线性光学（NLO）发色团的聚集和取向对其光学性质的影响。通过紫外可见吸收、荧光、溶剂化显色光谱和超瑞利散射（HRS）研究了1和单个发色团标准品2的线性和非线性光学性质。与2相比，观察到单个发色团的一阶超极化率β降低、紫移、溶剂化显色位移增强和荧光猝灭。数据分析表明，当发色团在束结构中平行排列时，跃迁偶极矩变化很小。然而，单个发色团的表观超极化率显著降低了约20%。1中单个发色团β的降低主要归因于紫移，即带间（电荷转移）能隙的激发能增加以及基态和激发态偶极矩之间差异的减小。紫移和荧光猝灭与激子理论一致。讨论了溶剂化显色位移增强的可能原因。
