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Various kinds of Michael acceptors could be introduced at the C13²-position in an epimeric mixture of methyl pheophorbides-$a$/$a$’ under basic conditions. The isolated yields and C13²-epimeric ratios ($R$/$S$ > 1) of the adducts depended on the electron-withdrawing group in the Michael acceptors. Some Michael acceptors possessing a less electron-withdrawing group could not react with methyl pheophorbides-$a$/$a$’. Neither α- nor β-substituted Michael acceptors gave the desired products. On the other hand, a Michael acceptor possessing a terminal alkyne was introduced as the C13²-alkenyl moiety. We here report the scope and limitations of the Michael addition reactions for chlorophyll-$a$ derivatives.

This paper explores the factors that lead to increased carbon dioxide emissions in the 18 countries of the APEC. We apply the LMDI multiplicative decomposing method to 18 countries between 1971 and 2012. We summarize these factors that are as follows: (1) population increase and economic growth play a key role in increased carbon dioxide emissions. (2) All the 18 countries of the APEC have improved their energy efficiency as manifested in the change of energy intensity ($\mathrm{\Delta }I$), which is less than 1 in the 42 years; (3) In terms of energy substitution effect ($\mathrm{\Delta }M$) and fuel coefficient effect ($\mathrm{\Delta }CE$), the decomposition results point out that Hong Kong, Indonesia, and Malaysia witnessed growth in $\mathrm{\Delta }M$ and $\mathrm{\Delta }CE$, indicating the only factor to reduce the emissions for these three countries is intensity effect, which gives rise to relatively higher emission for these three countries during the period. In the case of Peru, the Philippines, Singapore, Thailand, and Vietnam, we witnessed increases in $\mathrm{\Delta }M$, but decreases in $\mathrm{\Delta }CE$; In the case of Australia, Canada, Chile, China, Japan, South Korea, Mexico, New Zealand, Taiwan, and the US, there seem to decrease in $\mathrm{\Delta }M$, but increases in $\mathrm{\Delta }CE$ during the 42-year period.

By developing an industrial structure change model, this paper investigates the role of the information technology in explaining the process of industrial structure optimization and upgrading in China from 2001 to 2019. Then, we put forward and discuss the substitution effect and the pervasiveness effect of information technology, and deduce the theoretical propositions from the model. We use the Malmquist index method to estimate the rate of information technology progress, and then choose the genetic algorithm to calibrate the parameters of the model. The research conclusions innovatively explain how the information technology can promote the industrial structure optimization and upgrading in China based on the substitution effect and the pervasiveness effect of information technology in detail. The results point out that when the contribution of information technology to total factor productivity of the tertiary industry is higher than that of the secondary industry, the pervasiveness effect of information technology can promote the upgrading of the industrial structure. Under the comprehensive effect of the pervasiveness effect and substitution effect of information technology, the industrial structure tends to be more optimized. The further heterogeneity analysis shows that the driving effect of information technology on the optimization and upgrading of industrial structure in regions with “servitization” characteristics is more significant. It highlights policy suggestions designed to adopt innovation-driven and technology development strategy, regional industrial structure transformation and economy development strategy.

In this study, substitution effects of group 4 elements in Fe₂TiSn thermoelectric material are studied by using density functional theory (DFT) and semi-classical Boltzmann transport theory. All of the substitution elements showed the most thermodynamic preference for the Sn site, and these substitutions for Fe₂TiSn did not give much influence in the stability and mechanical property of Fe₂TiSn. e₂TiSn${}_{0.75}$Pb${}_{0.25}$, and thermoelectric calculations showed the prominence of $n$-type on $p$-type dopingin these materials. The highest Seebeck coefficients of these compounds were −148, −228, −165 and −120 $\mu$V/K for $n$-type of Fe₂TiSn, Fe₂TiSn${}_{0.75}$Si${}_{0.25}$, Fe₂TiSn${}_{0.75}$Ge${}_{0.25}$ and Fe₂TiSn${}_{0.75}$Pb${}_{0.25}$, respectively. The results showed that Si and Ge partial substitutions for Fe₂TiSn could be the effective methods to enhance the thermoelectric property, and the maximum dimensionless figure of merit (ZT) at room temperature reached about 0.7 ($6.09\times 10^{20}$cm${}^{-3}$$n$-type doping concentration) in Fe₂TiSn${}_{0.75}$Si${}_{0.25}$ and 0.6 ($8.99\times 10^{20}$cm${}^{-3}$$n$-type doping concentration) in Fe₂TiSn${}_{0.75}$Ge${}_{0.25}$.

The Box–Cox transformation indicates that the log-linear form for M2 demand cannot be rejected while the Fair (1987) specification and the linear form can be rejected at the 5% level in favor of general functional form. M2 demand is positively influenced by real GDP, the deposit rate, and the real stock price and negatively affected by the nominal exchange rate, the foreign interest rate, and the expected inflation rate. Hence, the wealth effect of an increased real stock price is greater than the substitution effect. The substitution effect of the deprecation of the New Taiwan dollar dominates the wealth effect. The capital mobility effect of an increased foreign interest rate is greater than the cost of borrowing effect. The general functional form for M2 demand performs better in forecasting than the Fair specification and the linear form.

Density functional theory (DFT) calculations were carried out to investigate the semiconductor performance of a series of phthalocyaninato zinc complexes, namely Zn[Pc(β-OCH₃)₈] (1), ZnPc (2), and Zn[Pc(β-COOCH₃)₈] (3) {[Pc(β-OCH₃)₈]^2- = dianion of 2,3,9,10,16,17,23,24-octamethoxyphthalocyanine; Pc^2- = dianion of phthalocyanine; [Pc(β-COOCH₃)₈]^2- = dianion of 2,3,9,10,16,17,23,24-octamethoxycarbonylphthalocyanine} for organic field effect transistor (OFET). The effect of peripheral substituents on tuning the nature of phthalocyaninato zinc semiconductor has been clearly revealed. Introduction of eight weak electron-donating methoxy groups onto the peripheral positions of ZnPc (2) leads to a decrease in the hole injection barrier relative to Au electrode and an increase in the electron injection barrier, making compound 1 a better p-type semiconductor material in comparison with 2. In contrast, peripheral methoxycarbonyl substitution depresses the energy level of LUMO and thus induces an increase for the electron affinity (EA) value of ZnPc (2), resulting in the change of semiconductor nature from p-type for ZnPc (2) to n-type for Zn[Pc(β-COOCH₃)₈] (3) due to the improved electron injection ability. The calculated charge transfer mobility for hole is 1.05 cm².V^-1.s^-1 for 1 and 5.33 cm².V^-1.s^-1 for 2, while that for electron is 0.16 cm².V^-1.s^-1 for 3. The present work should be helpful for designing and preparing novel phthalocyanine semiconductors in particular with good n-type OFET performance.

Octa-(meta-methoxyphenyl) substituted tetraazaporphyrin (TAP, 1) and corrolazine (Cor, 4) phosphorus(V) complexes have been synthesized and characterized. 1 has a blue-shifted, small charge transfer (CT) band while para-methoxyphenyl substituted PTAP 2 has a red-shifted, intense CT band. The difference could be interpreted as an inductive effect of the meta-methoxy groups. The position and intensity of the absorption bands of 1 are well matched to the trend of para-substituted PTAPs. The synthesis of PCor from free-base TAP was also investigated. The PCor was not generated directly but from a PTAP intermediate

As naturally occurring bacteriochlorophyll-$d$ models, zinc methyl (3¹R)-bacteriopheophorbides-$d$ possessing ethyl, vinyl, and ethynyl groups at the 3²-position were prepared by chemically modifying chlorophyll-$a$. The synthetic molecules self-aggregated in an aqueous Triton X-100 micelle solution similarly as in the major light-harvesting antenna of photosynthetic green bacteria to give supramolecularly ordered large oligomers with red-shifted and broadened visible absorption bands, compared with the monomeric bands. The sequential hydrogenation of the 3²-ethynyl to ethyl group via the vinyl group gradually suppressed the chlorosomal self-aggregation ability. The successive elongation of the 3¹-alkyl chain from a methyl to propyl group via an ethyl group also diminished the $J$-aggregation ability. These decreases in the self-aggregation were ascribable to the steric enhancement of the 3²-substituents near the 3¹-hydroxy group requisite for the $J$-aggregation.

Oxidative reactions of isomeric amino-, methylamino-, and dimethylamino-pyridines with the 3-vinyl group of methyl pyropheophorbide-$a$, a chlorophyll-$a$ derivative, afforded 3-{1-[$o$/$m$/$p$-(non/mono/di-methyl-amino)pyridinio]ethenyl}chlorins bearing the C3¹–N⁺ bond. Although all the $m$/$p$-substituents gave almost the same visible absorption spectra in acetonitrile, the $N$-methylation effect on the Qy maxima was observed in the $o$-substituted analogs with blue-shifted absorption bands. The substitution with most of the amino moieties suppressed the intramolecular electron transfer from the photoexcited chlorin core to the relatively electron-rich pyridinio periphery to enhance the fluorescence emission in acetonitrile, compared with the unsubstituted pyridinio analog. By contrast, the $o$-NH₂ substituted pyridine–chlorin conjugate was less fluorescent than any other aminated analogs as well as the unsubstituted counterpart. The electron-donating ability of the $o$-NH₂ group was recovered by the addition of alcohols to give highly fluorescent species.

In this chapter, we show how the t-statistics is used in testing whether systematic corporate financial events, such as dividend payout, bonus issue, earnings announcements, and so on, affect the market prices of the corresponding stocks.