Metal Complex Systems of Novel Spectroscopic Significance with Applications to Biochemical Probing

化学探针（报告分子）能够检测生物系统中的自组装介质，如脂质双分子层、细胞表面糖链和核酸，已经在这种微环境存在下的敏化光谱响应方面进行了研究。适合这一功能的光物理过程是在金属络合系统中发现的；(1)近红外（NIR）光吸收（低能电子跃迁）和(2)室温磷光。（I-a）疏水环境，如表面活性剂胶束、人工脂质双分子层和脂质体，强烈增强了平面1,2 -二氨基苯螯合物对Ni、Pd和Pt离子的MR吸收（730 nm - 850 nm, ε =(5-13) × 10^4 M^<-1> cm^<-1>）。（I-b）从结构促进剂、结构破断剂、More剂和疏水水化破断剂等几种添加剂对水溶液结构的影响因素方面，对这种疏水环境识别的机理进行了研究。尿素是一种强疏水性水化剂，它的加入使MIR的吸收和脂质体一样得到了极大的增强。这表明，识别取决于这些螯合探针附近的水结构，而不是对感兴趣的介质的亲脂性负责。（II-a） Pt(II) - 7-碘-5-亚砜-8-喹啉醇螯合物（径475 nm，径630 nm）的室温磷光在正十二烷基- β -d -麦芽糖糖苷胶束溶液中被强烈促进。这种糖基表面活性剂胶束的增强与生物学研究中必要的糖链识别的应用有关。合成了具有较大pi电子体系的（II-b） 4-羟基吖啶，具有较高的发光灵敏度。Pt（II）螯合物在上述糖基胶束中也是磷光的（ex. 396nm, em. 448rim）。小牛胸腺DNA对螯合物的发光也有类似的增强作用，表明螯合物可以与DNA分子发生插层相互作用。少

Chemical probes (reporter molecules) which are capable of detecting self-assembly media in biological systems such as lipid bilayers, cell-surface sugar-chains, and nucleic acids have been investigated in terms of the sensitized spectroscopic response in the presence of such microenvironment. The photophysical processes amenable to this function are found in metal-complex systems ; (I) near-infrared (NIR) light absorption(low energy electronic transition) and (II) room-temperature phosphorescence.(I-a) It has been found that the hydrophobic environment, such as surfactant micelles, artificial lipid bilayers, and liposomes strongly enhances the MR absorption (730 nm - 850 nm, epsilon=(5-13)x10^4 M^<-1> cm^<-1>) of planar1 , 2-diaminobenzene chelates of Ni, Pd, and Pt ions.(I-b) The mechanistic investigation of this hydrophobic environment recognition has been made in terms of factors affecting solution structure of water with several additives of structure-promoters, structure-breakers, … More and hydrophobic hydration breakers. The addition of urea, a strong hydrophobic hydration breaker, gives rise to the great enhancement of the MIR absorption as the liposome medium does. This suggests that the recognition depends upon the water-structure in the close vicinity of these chelate probes, rather than being responsible for the lipophilicity of the media of interest.(II-a) The room-temperature phosphorescence from Pt(II) - 7-iodo-5-sulfo-8-quinolinol chelate (ex. 475 nm, em. 630 rim) is strongly facilitated in particular in n-dodecyl-beta-D-maltoside micellar solutions. This enhancement in such sugar-based surfactant micelles is interesting in relation with the applications tosugar-chain recognition necessary in biological studies.(II-b) 4-Hydroxyacridine possessing larger pi-electron system has been synthesized for the benefit of the greater luminescence sensitivity. The Pt(II) chelate is also phosphorescent (ex. 396 nm, em. 448rim) in the above sugar-based micelles. Calf thymus DNA gives the similar enhancement effect on the luminescence of the chelate, which indicates that the chelate can afford to report the intercalation interaction with DNA molecules. Less