Synthesis of organosoluble polyamides with bulky triaryl imidazole pendent group

New unsymmetrical diamine monomer containing triaryl imidazole pendent group, 4-[4-（4,5-diphenyl-1H-imidazol-2-y1）phe- noxy]-1,3-benzenediamine, was synthesized via aromatic substitution reaction of 1-chloro-2,4-dinitrobenzene with 4-（4,5- diphenyl-1H-imidazol-2-y1）pbenol, followed by palladium-catalyzed hydrazine reduction. This new monomer was further confirmed by FT-IR, IH NMR and ^13C NMR. Novel polyamides having pendant triaryl imidazole group were prepared by the phosphorylation polycondensation of four commercially aromatic dicarboxylic acids with the prepared diamine. Inherent viscosities of polyamides were in the range 0.42-0.53 dL/g indicating formation of medium molecular weight polymers. Polyamides exhibited glass-transition temperature （Tg） in the range 236-265 ℃. These polymers are essentially amorphous and were soluble in polar aprotic solvents such as DMF, NMP, DMAc. The 10% weight loss temperatures in air atmosphere, measured by TGA were in the range 350-373 ℃ indicating their good thermal stabilities. ？2009 Mousa Ghaemy. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Solar cells sensitized by porphyrin dyes containing a substituted carbazole donor with synergistically extended absorption and suppressed the dye aggregation

To achieve high power conversion efficiency(PCE),three porphyrin sensitizers have been synthesized and explored to simultaneously enhance the photocurrent(JSC)and photovoltage(VOC).On basis of the XW4,a benzothiadiazole(BTD)unit has been introduced to afford XW57 with the aim to extend the absorption wavelength and enhance the light harvesting ability.As a result,a JSC of 13.72 mA/cm^2 has been obtained for XW57,higher than that of XW4.On this basis,XW58 has been prepared by modifying the carbazole-based donor with two bulky dihexyloxyphenyl groups,and the superior anti-aggregation character raises the VOC from 781 mV(XW4)to 844 mV.When both the BTD unit and the bulky groups are introduced to the acceptor and donor units,respectively,the resulting sensitizer XW59 exhibits a highest PCE value of 7.34%with synergistically enhanced JSC of 13.19 mA/cm^2 and VOC of 793 mV.These results provide further insight into developing high performance dye-sensitized solar cells.

Use of Silicon Substituents in the Syntheses of Natural and Non-natural Molecules

Trimethylsilyl groups have been used in our research as a director as well as a bulky and lipophilic group in our quest for natural and non-natural molecules.