STUDIES ON THE INTERRELATIONSHIP AMONG THE INTENSITY OF A RAMAN MARKER BAND OF CAROTENOIDS, POLYENE CHAIN STRUCTURE, AND EFFICIENCY OF THE ENERGY TRANSFER FROM CAROTENOIDS TO BACTERIOCHLOROPHYLL IN PHOTOSYNTHETIC BACTERIA

Abstract Resonance Raman spectroscopy was used to study the polyene-chain structure of carotenoids in light-harvesting pigment-protein complexes from purple photosynthetic bacteria. When major carotenoids of Rhodobacter sphaeroides were incorporated into the light-harvesting complexes of Chromatium vinosum , they showed a relatively intense Raman band at 965 cm^-1 arising from the CH out-of-plane wagging modes of the polyene chain. This result was almost the same as that for the intrinsic carotenoids in Chromatium vinosum , but completely different from that for the intrinsic carotenoids in Rhodobacter sphaeroides . On the other hand, the intrinsic carotenoids of Chromatium vinosum lost the intensity of the 965 cm^-1 Raman band upon protein denaturation. These results support the view that the intensity of the 965 cm^-1 Raman band reflects distortion of the polyene chain, independent of its chemical structure. The polyene-chain distortion is affected by the apoprotein to which carotenoids are bound. The distortion of the polyene chain is correlated with a decrease in the efficiency of the energy transfer from carotenoids to bacteriochlorophyll.     

Theoretical Study of the Rate Coefficients for CH3NHNH2 + NO2 and Related Reactions

The kinetics and mechanisms of H atom abstraction reactions from CH₃NHNH₂ by NO₂ (R1) and related reactions have been investigated theoretically by using ωB97X‐D and CCSD(T)‐F12 quantum chemical calculations and the steady‐state unimolecular master equation analysis based on Rice–Ramsperger–Kassel–Marcus (RRKM) theory. For reaction (R1), both dissociation and isomerization steps between intermediate complexes were found to be important for the distribution of the dissociated bimolecular products. The dominant products of (R1) were found to be cis‐CH₃NHNH and HONO at lower temperature. The branching ratios for CH₃NNH₂ formation paths increased with increasing temperature. On the same reaction potential energy surface, six reactions including isomerization reactions between CH₃NNH₂ and cis‐/trans‐CH₃NHNH catalyzed by HONO were suggested to compete with the reverse reaction of (R1). The temperature‐ and pressure‐dependent rate expressions are proposed for kinetic modeling.     

Role of initial complexes in 1,2-addition reactions of disilene derivatives

Mechanisms of four 1,2-addition reactions, H₂Si=SiHMe + H₂O, H₂Si=SiHF + H₂O, H₂Si=SiH(C≡CH) + H₂O, H₂Si=SiH(NH₂) + HF, were investigated in detail by the ab initio MO method using a recent approach combined with frontier MO theory. Twelve reaction pathways were found. The initial step of each reaction is the formation of a weakly bonded complex. According to the structure and the charge distribution of the complexes, the reactions are categorized into two types. Reactions starting from electrophilic interaction between the LUMO of water (or hydrogen fluoride) and the HOMO of disilene always result in syn-adducts. On the other hand, nucleophilic interaction between the HOMO of the water and the LUMO of disilene leads both syn and anti adducts. Depending on the acidity of the reagent and the charge on the silicon to be attacked, the reactions proceed in simple one-step mechanisms or in two-step ones via a Lewis-type complex. The paired interacting orbitals of the initial complexes were examined in order to predict the reaction pathways.     

1,2-二乙炔基四苯基乙硅烷与1,2-二乙炔基四甲基乙硅烷的共聚及其光解

１，２－二乙炔基四苯基乙硅烷与１，２－二乙炔基四甲基乙硅烷在催化剂铑（Ⅰ）络合物［氯化三－（三苯基膦）铑］的作用下得到一种新的含硅共聚物。实验证明此共聚物的主链是有规交替结构。研究了固体薄膜及其溶液的光解作用，并测定了ＳｂＦ５蒸气处理后的共聚物薄膜的导电性。     

利用链式反应同步氧化烟气中NO和SO2的研究

燃煤烟气中NO和SO2的氧化对于提高其脱除效率和改良脱除产物有重要意义。基于大气化学的研究成果,本文提出了利用链式反应同步氧化烟气中NO和SO2的设想。阐述了该方法的反应机理,数值实验研究了在烟气条件下该链式反应发生的可能性以及反应温度对NO和SO2氧化率的影响,提出了利用低成本的添加剂引发链式反应的方法,并分析了选择添加剂的原则。