کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1338657 | 979674 | 2010 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Novel photoluminescent hemi-disclike liquid crystalline Zn(II) complexes of [N2O2] donor 4-alkoxy substituted salicyldimine Schiff base with aromatic spacer Novel photoluminescent hemi-disclike liquid crystalline Zn(II) complexes of [N2O2] donor 4-alkoxy substituted salicyldimine Schiff base with aromatic spacer](/preview/png/1338657.png)
A series of novel hemi-disclike four coordinated distorted square planar Zn(II) Schiff base complexes containing 4-substituted alkoxy chains on the side aromatic ring [Zn (4−CnH2n+1O)2 salophen], n = 14, 16, 18 and salophen = N,N′-4-methyl phenylene bis (salicylideneiminato), have been prepared and their mesogenic, photophysical properties were investigated. The phase behavior of these compounds were characterized by differential scanning calorimetry, polarized optical microscopy and variable temperature PXRD study. The ligands are non-mesogenic but the complexes exhibited an unprecedented 2D-hexagonal columnar mesophase (Colh) in the temperature 175–185 °C range. In the mesophase (Colh), the molecules self assemble in a columnar stack in antiparallel fashion. All λmax of the UV–Vis absorption and photoluminescence band occurred at ca. 291–425 and 504–524 nm, respectively. The ligands are non-emissive, but on coordination with Zn(II), the complexes show intense green emission at room temperature in dichloromethane solution (∼505 nm, Φ = 20%) as well as in solid (∼522 nm, Φ = 9%) at 360 nm excitation. The DFT calculations were performed using Dmol3 program at BLYP/DNP level to obtain the stable electronic structure of the complex. A small LUMO-HOMO band gap (∼2.1 eV), presumably suggests a rather strong electronic correlation among the molecules along the column.
Green fluorescent, liquid crystalline hemi-disclike Zn(II) complexes of [N2O2] donor tetradentate salicylaldimine based Schiff base complexes, [Zn(4−CnH2n+1O)2salophen], n = 14, 16, 18 with aromatic spacer has been prepared. The molecules self assemble in a randomly piled columnar stack with rather strong intermolecular electronic correlation exhibiting 2D-hexagonal columnar mesophase (Colh).Figure optionsDownload as PowerPoint slide
Journal: Polyhedron - Volume 29, Issue 16, 29 October 2010, Pages 3089–3096