板状复合型碘溴化银微晶的光物理性能与其碘含量的关系

本论文测定了碘含量对板状碘溴化银微晶的光吸收的影响,并利用Dember光电效应、低温荧光、高低照曝光等光物理方法研究所制备微晶的固体物理性质,发现微晶中碘含量的增加使光吸收增加。在低照曝光时,所有的乳剂均发生低照互易律失效,而在高照曝光时仅是碘含量为18 mol%的乳剂发生高照互易律失效。板状碘溴化银微晶乳剂的Dember效应和低温荧光的实验结果表明,微晶中的碘含量增加使Dember光生电压值下降,光电压表减时间变短,荧光强度下降,说明碘离子掺入量的增加使微晶中的缺陷数目增加,导致电子陷阱数和填隙银离子的浓度增加,造成光电子被捕获。     

Molecular design and photo-physics of quaternary hybrid terbium centered systems with novel functional di-urea linkages of strong chemical bonds through hydrogen transfer addition

Two kinds of crosslinking reagents, 3-aminopropyl-methyl-diethoxylsiliane (H₂N(CH₂)₃SiCH₃(OC₂H₅)₂, abbreviated as APMES) and N-2-aminoethyl-3-aminopropyltriethoxylsiliane (H₂N(CH₂)₂HN(CH₂)₃Si(OC₂H₅)₃, abbreviated as AEAPES) are modified by 3-(triethoxysilyl)-propyl isocyanate (TESPIC) to afford two novel crosslinking molecular derivatives as bridge ligands. Then the ternary organic-inorganic molecular-based hybrid system with these functional bridge ligands and 1,10-phenanthroline (phen) are constructed with the two components equipped with covalent bonds. The two components of APMES (or AEAPES) and TESPIC is linked through -NHC(O)NH- groups which is applied to coordinate to Tb³⁺ and further formed Si-O backbones after co-hydrolysis and co-polycondensation processes, while phen behaves as the main energy donor for the sensitization of luminescence of Tb³⁺. Luminescence spectra were utilized to characterize the photo-physical properties of the obtained hybrid system and the above spectroscopic data reveal that the phen in this favorable hybrid system behaves the main energy donor for the luminescence of Tb³⁺. In this way, the intra-molecular energy transfer process took place within these molecular-based hybrids and strong green and blue emissions of Tb³⁺ have been achieved.     

Synthesis of novel dipodal-benzimidazole,benzoxazole and benzothiazole from cyanuric chloride: Structural,photophysical and antimicrobial studies

In the present study, new benzimidazole, benzoxazole and benzothiazole derivatives were prepared and screened for antimicrobial activity. The structure of 4,4′-((6-(4-(diethylamino)phenyl)-1,3,5-triazine-2,4-diyl)bis(oxy))dibenzaldehyde (DIPOD) 5 was established from p-hydroxy benzaldehyde 4 and 4-(4,6-dichloro-1,3,5-triazin-2-yl)-N,N-diethylaniline 3. The reaction of DIPOD 5 with different o-phenylenediamine or o-amino phenol or o-amino thiophenol in ethanol gave benzimidazole, benzoxazole and benzothiazole 7. Novel heterocycles showed excellent broad-spectrum antimicrobial activity against bacterial strain (Escherichia coli, Staphylococcus aureus) and fungal strain (Candida albicans, Aspergillus niger) cultures. Activity data was compared with standard Streptomycin and Fluconazole drug. Photophysical and thermal properties of synthesized compounds were also studied.