University of Lyon, Laboratoire de Chimie, UMR 5182 CNRS - Ecole Normale Superieure de Lyon, 46 allee d'Italie, 69007 Lyon, France.
J Am Chem Soc. 2010 Mar 31;132(12):4328-35. doi: 10.1021/ja9100886.
The association of heptamethine cyanine cation 1(+) with various counterions A (A = Br(-), I(-), PF(6)(-), SbF(6)(-), B(C(6)F(5))(4)(-), TRISPHAT) was realized. The six different ion pairs have been characterized by X-ray diffraction, and their absorption properties were studied in polar (DCM) and apolar (toluene) solvents. A small, hard anion (Br(-)) is able to strongly polarize the polymethine chain, resulting in the stabilization of an asymmetric dipolar-like structure in the crystal and in nondissociating solvents. On the contrary, in more polar solvents or when it is associated with a bulky soft anion (TRISPHAT or B(C(6)F(5))(4)(-)), the same cyanine dye adopts preferentially the ideal polymethine state. The solid-state and solution absorption properties of heptamethine dyes are therefore strongly correlated to the nature of the counterion.
七甲川花菁阳离子 1(+)与各种抗衡离子 A（A = Br(-)、I(-)、PF(6)(-)、SbF(6)(-)、B(C(6)F(5))(4)(-)、TRISPHAT）的缔合已经实现。这六种不同的离子对已通过 X 射线衍射进行了表征，并在极性（DCM）和非极性（甲苯）溶剂中研究了它们的吸收性质。一个小的硬阴离子（Br(-)）能够强烈极化聚甲川链，导致在晶体中和在不分解溶剂中稳定非对称偶极子样结构。相反，在更极性的溶剂中或与大体积软阴离子（TRISPHAT 或 B(C(6)F(5))(4)(-)）缔合时，相同的花菁染料优先采用理想的聚甲川状态。因此，七甲川花菁染料的固态和溶液吸收性质与抗衡离子的性质密切相关。
