2.2]Paracyclophane as a bridging unit in the design of organic dyes for sensitized solar cells

Organic dyes consisting of a [2.2]paracyclophane unit along the main chromophore are examined for their application in sensitized solar cells. These materials exhibit considerably high values of open-circuit voltage (V(oc)) ranging 0.69-0.72 V, and an overall efficiency up to 3.8%.     

Synthesis and Solvatochromatic properties of 9-(4-Aminophenylethynyl)-10-(4-nitrophenylethynyl)anthracene

9-(4-Aminophenylethynyl)-10-(4-nitrophenylethynyl)anthracene (2) was synthesized in high yield by using a route involving sequential Sonogashira cross coupling reactions of 9-bromo-10-iodoanthracene with 4-nitrophenylacetylene and 4-aminophenylacetylene. Solvatochromism was observed in the absorption and fluorescence spectra of 2 in a variety of solvents. In less polar solvents, such as hexane and benzene, the fluorescence emission band of 2 appears in the green to orange region while this substance does not fluoresce in polar solvents, such as acetonitrile and DMF.     

地基多轴DOAS仪器的NO2斜柱浓度对比研究

介绍了两台地基多轴DOAS仪器测量的NO2斜柱浓度的对比研究。利用日本海洋研究开发机构的一套多轴DOAS设备在2009年11月—12月31日期间16d的观测数据,与安光所自主研发的一套多轴DOAS设备测量的NO2差分斜柱浓度进行了对比。通过对比发现,采用自动调整积分时间的方法,与固定积分时间的设置相比仪器具有更高的信噪比;两套仪器的反演结果在小角度下具有比较好的一致性,相关系数高达0.995,但随着角度的增大相关性逐渐变差。在9点至16点时段内相对偏差较小,其中20°方向的结果最为接近,最小偏差仅有12%,但在9点前和16点后二者偏差增大。日方仪器在可见波段的反演结果明显好于紫外波段,反演中的剩余噪声减小了60%以上,同时在可见波段的差分斜柱浓度的计算结果与我们的多轴DOAS在紫外波段的计算结果在全天都具有非常好的一致性。     

Dynamical quark effects on light quark masses

Light quark masses are calculated in lattice QCD with two degenerate flavors of dynamical quarks. The calculations are made with improved actions with lattice spacing a = 0.22-0.11 fm. In the continuum limit we find m(M&Smacr;)(ud)(2 GeV) = 3.44(+0.14)(-0.22) MeV using the pi and rho meson masses as physical input, and m(M&Smacr;)(s)(2 GeV) = 88(+4)(-6) MeV or 90(+5)(-11) MeV with the K or straight phi meson mass as additional input. The quoted errors represent statistical and systematic combined, the latter including those from continuum and chiral extrapolations, and from renormalization factors. Compared to quenched results, two flavors of dynamical quarks reduce quark masses by about 25%.     

Most stable conformation of the cyclopropane ring attached at a carbon atom in a 1,2-dicarba-closo-dodecaborane(12) system

We obtained two crystal structures of electronically interesting dicarba-closo-dodecaborane(12)s (hereafter, "carboranes") substituted with a cyclopropyl group at a caged carbon atom, i.e., C-cyclopropyl-o-carborane (4) and C-cyclopropyl-o-carboranylphenylmethanol (9), at 123 K. In these C-cyclopropyl-o-carboranes, the cyclopropyl group adopted a slightly twisted perpendicular conformation with respect to the electron-deficient carbon-carbon (C-C) bond axis in the o-carborane cage. In contrast, it has previously been shown that a phenyl group substituted at the caged carbon atom, i.e., C-phenyl-o-carborane (3), is almost parallel to this axis at both 150 and 199 K. In other words, the pi system of the phenyl ring adopted an almost bisected conformation in 3. The preferred conformation of the cyclopropane ring in these C-cyclopropyl-o-carboranes was compared among the solid, the solution, and the gaseous states and was retained under the present conditions. Moreover, we found that the C-C bond length in the o-carborane cage not only varied along the rotation of the cyclopropyl group in 4 but also was longer than that in 3, which bears a phenyl group at the dominant conformation. These phenomena may be related to homoconjugations between the caged o-carborane system that serves as an electron acceptor and the homoconjugative substituent that serves as an electron donor. In these C-cyclopropyl-o-carboranes, two types of homoconjugations would result in a slightly twisted perpendicular conformation and 4 would be more strongly stabilized than would the phenyl derivative 3. On the basis of these studies, we propose the existence of a third type of strongly stabilizing interactive geometry for a cyclopropane ring in an o-carborane system.