杂原子Pb同晶取代Si－ZSM－12中的部分Si及其鉴定

杂原子Ｐｂ同晶取代Ｓｉ－ＺＳＭ－１２中的部分Ｓｉ及其鉴定赵修松，王清遐，李宏愿（中国科学院大连化学物理研究所，大连１１６０２３）关键词Ｐｈ－ＺＳＭ－１２，合成，表征ＺＳＭ－１２属丝光沸石类，具有一维线性非交叉孔道（０．５７×０．６１ｎｍ）［１，２］，...     

Regulation of lithospermic acid B and shikonin production in Lithospermum erythrorhizon cell suspension cultures

Cell suspension cultures of Lithospermum erythrorhizon produced a large amount of lithospermic acid B, a caffeic acid tetramer, as well as shikonin derivatives (each ca. 10% of dry wt.) when cultured in shikonin production medium M-9. Various culture factors for increasing the production of lithospermic acid B were investigated. Lithospermic acid B production was inhibited by 2, 4-D or NH4+, whereas it was stimulated by Cu2+. These regulatory patterns were similar to those for the production of shikonin derivatives in these cell cultures, suggestive of close relations and similar metabolic regulation between the production of these compounds. Cultivation under light illumination, however, showed that these metabolisms were independently regulated. In particular, blue light showed a stimulatory effect on lithospermic acid B production, while shikonin production was strongly inhibited, indicative of an effective condition for lithospermic acid B production.     

Macroporous poly(methyl methacrylate) produced by phase separation during polymerisation in solution

Polymethyl methacrylate (PMMA) sponges were obtained by polymerization in a solution with monomer/ethanol ratios up to 20:80. The material obtained after the elimination of the solvent present a homogeneous distribution of dispersed pores up to a monomer/ethanol ratio lower than 40:60. For higher ethanol contents in the reacting mixture, the morphology of the sponge corresponds to a network of PMMA microparticles, leaving large empty spaces leading to highly porous structure. The monomer/ethanol ratio during polymerization has a large influence on the porosity, thermal, and mechanical properties of the material and, for large solvent contents, on the size of the polymer microparticles.     

Mixed ligand system of cysteine and thioglycolic acid assisting in the synthesis of highly luminescent water-soluble CdTe nanorods

Highly luminescent water-soluble CdTe nanorods were prepared with the assistance of the mixed ligand system of cysteine and thioglycolic acid; the aspect ratio and photoluminescence of the CdTe nanorods could be controlled by the refluxing time.     

衬钽管石墨炉中小量氢气的影响及稀土基质激光晶体中铕的测定

通过纯氩中加入小量氢气,研究了保护气体对衬鉏管石墨炉分析性能的影响,结果表明,采用5％H_2-Ar作保护气体,可以显著提离衬鉏管的成品率,明显延长衬鉏管的使用寿命,使衬钽管的测定重现性得到改善,而对测定灵敏度没有明显影响。干扰试验表明,本方法可直接用于稀土基质激光晶体中铕的测定,分析结果与计算值基本一致。     

Rh complexes of 1-(2,4,6-triisopropylphenyl-)3-methyl-1H-phosphole: preparation and use as catalysts in the hydroformylation of styrene

In the series of 1-(2,4,6-trialkylphenyl-)3-methyl-1H-phospholes (1a–c) that are to a certain extent of aromaticity, only the isopropyl substituted one (1a) entered into reaction with dimeric (pentamethylcyclopentadienyl)rhodium dichloride to afford Rh(III) complex (2a) in a reversible manner. After a careful workup, (2a) could be prepared and characterized whose stereostructure was elucidated by B3LYP/3–21G*, B3LYP/6–31G* and LANL2DZ calculations. Complex (2a) as a preformed catalyst, as well as the Rh(acac)(CO)₂ + 2(1a) in situ catalytic system were useful in the hydroformylation of styrene and gave the branched aldehyde in regioselectivities of 65–96%.     

轻稀土B-15-C-5联吡啶三元配合物

合成了稀土(Ln=La—Eu)硝酸盐与苯并-15-冠-5和2,2’-联吡啶的三元配合物,并培养出La-配合物的单晶,测定了的分子结构和晶体结构。经元素分析确定其化学组成为Ln(NO_3)_3·bipy·2H_2O·B-15-C-5。晶体属单斜晶系,空间群为P2_1/n。晶胞参数:a=11.951(6),b=18.181(7),c=14.754(5);β=96.19(3)°;V=3187.0,Z=4,D_c=1.637g/cm~3。最后偏离因子R=0.035。     

Achieving ‘Desirable and Feasible’ Change: An Application of Soft Systems Methodology

Rational intervention in human affairs, if it is to constitute not only action but also research, so that future interventions may be made more effective, needs a well-defined methodological framework. Soft systems methodology (S.S.M.) provides one such framework. S.S.M. is doubly systemic: it is itself a learning system, and within that system it uses systems models, models of human activity systems. It accepts that such models are not models of parts of the real world, only models of ways of perceiving the real world, that is to say, models relevant to debate about ‘reality’ (one man's ‘terrorism’ is another's ‘freedom fighting’).S.S.M. is here illustrated by means of an account of a systems study of change in the information function of a sophisticated science-based company. The study is described from the point of view of a professional analyst who was helping a team of three managers carry out the study. The course of the study is described, and a separate commentary relates its activity to the seven stages of S.S.M. The study involved three cycles round stages 2–3–4–5 of S.S.M., the stages in which models of relevant human activity systems are built and compared with the real world in order to construct a rich debate about changes whose introduction in the problem situation world be both (systemically) desirable and (culturally) feasible.     

Ultraviolet photolysis of CH2I2 in methanol: O-H insertion and HI elimination reactions to form a dimethoxymethane product

Ultraviolet photolysis of low concentrations of CH2I2 in methanol solution found that CH2I2 is converted into dimethoxymethane and some H+ and I- products. Picosecond time-resolved resonance Raman (ps-TR3) experiments observed that the isodiiodomethane (CH2I-I) photoproduct decayed faster as the concentration of methanol increases, suggesting that isodiiodomethane is reacting with methanol. Ab initio calculations indicate isodiiodomethane is able to react with methanol via an O-H insertion/HI elimination to form an iodoether (ICH2-O-CH3) and HI products. The iodoether can then further react via another O-H insertion/HI elimination reaction to form the dimethoxymethane (CH3-O-CH2-O-CH3) observed in the photochemistry experiments. A reaction mechanism consistent with these experimental and theoretical observations is proposed.     

The anion sequence in the phase transformation of mesostructures templated by non-ionic block copolymers

A p6m to Ia3d mesophase evolution is achieved by simply adjusting the acidity and/or anion species in the presence of block copolymers; the unusual anion sequence that affects the phase behavior of block copolymer templated mesostructured solids is revealed to be SO(4)(2-)(HSO(4)(-)) > NO(3)(-) > Br(-) > Cl(-).