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121.
Temperature dependences of the relative reactivity of potassium aryloxides XC6H4O?K+ toward 2,4‐dinitrophenyl benzoate in 50 mol% dimethylformamide (DMF)–50 mol% H2O mixture have been studied using the competitive reactions technique. Correlation analyses of the relative rate constants kX/kH and differences in the activation parameters (ΔΔН and ΔΔS) of the competitive reactions have revealed the existence of two isokinetic series of the reactions of 2,4‐dinitrophenyl benzoate with potassium aryloxides with electron‐donating substituent (EDS) and electron‐withdrawing substituent (EWS), respectively. We have investigated the effect of the substituent X on the activation parameters for each isokinetic series and concluded that the mechanism of the reactions of 2,4‐dinitrophenyl benzoate with potassium aryloxides XC6H4O?K+ in 50 mol% DMF–50 mol% H2O mixture is the same as in DMF. Analysis of the obtained data with using the method of two‐dimensional reaction coordinate diagram leads to the conclusion that the variation of the solvent from DMF to 50 mol% DMF–50 mol% H2O mixture affects the reaction pathway. The rate constant kX for the reaction of 3‐nitrophenyl benzoate with potassium 4‐methoxyphenoxide and the relative rate constants kX/kH for the reaction of 3‐nitrophenyl benzoate with potassium aryloxides XC6H4O?K+ with EDS were measured in 50 mol% DMF–50 mol% H2O mixtures at 25°C, and it has been shown that the addition of water to DMF does not change the mechanism but slows down these reactions.  相似文献   
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By tuning the length and rigidity of the spacer of bis(biurea) ligands L, three structural motifs of the A2L3 complexes (A represents anion, here orthophosphate PO43?), namely helicate, mesocate, and mono‐bridged motif, have been assembled by coordination of the ligand to phosphate anion. Crystal structure analysis indicated that in the three complexes, each of the phosphate ions is coordinated by twelve hydrogen bonds from six surrounding urea groups. The anion coordination properties in solution have also been studied. The results further demonstrate the coordination behavior of phosphate ion, which shows strong tendency for coordination saturation and geometrical preference, thus allowing for the assembly of novel anion coordination‐based structures as in transition‐metal complexes.  相似文献   
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A new amino‐functionalized strontium–carboxylate‐based metal–organic framework (MOF) has been synthesized that undergoes single crystal to single crystal (SC‐to‐SC) transformation upon desolvation. Both structures have been characterized by single‐crystal X‐ray analysis. The desolvated structure shows an interesting 3D porous structure with pendent ?NH2 groups inside the pore wall, whereas the solvated compound possesses a nonporous structure with DMF molecules on the metal centers. The amino group was postmodified through Schiff base condensation by pyridine‐2‐carboxaldehyde and palladium was anchored on that site. The modified framework has been utilized for the Suzuki cross‐coupling reaction. The compound shows high activity towards the C?C cross‐coupling reaction with good yields and turnover frequencies. Gas adsorption studies showed that the desolvated compound had permanent porosity and was microporous in nature with a BET surface area of 2052 m2 g?1. The material also possesses good CO2 (8 wt %) and H2 (1.87 wt %) adsorption capabilities.  相似文献   
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In many organic electronic devices functionality is achieved by blending two or more materials, typically polymers or molecules, with distinctly different optical or electrical properties in a single film. The local scale morphology of such blends is vital for the device performance. Here, a simple approach to study the full 3D morphology of phase‐separated blends, taking advantage of the possibility to selectively dissolve the different components is introduced. This method is applied in combination with AFM to investigate a blend of a semiconducting and ferroelectric polymer typically used as active layer in organic ferroelectric resistive switches. It is found that the blend consists of a ferroelectric matrix with three types of embedded semiconductor domains and a thin wetting layer at the bottom electrode. Statistical analysis of the obtained images excludes the presence of a fourth type of domains. The criteria for the applicability of the presented technique are discussed. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 1231–1237  相似文献   
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