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1.
Ji X Wang C Xu J Zheng J Gattás-Asfura KM Leblanc RM 《Langmuir : the ACS journal of surfaces and colloids》2005,21(12):5377-5382
Trioctylphosphine oxide- (TOPO-) capped (CdSe)ZnS quantum dots (QDs) were prepared through a stepwise synthesis. The surface chemistry behavior of the QDs at the air-water interface was carefully examined by various physical measurements. The surface pressure-area isotherm of the Langmuir film of the QDs gave an average diameter of 4.4 nm, which matched very well with the value determined by transmission electron microscopy (TEM) measurements if the thickness of the TOPO cap was counted. The stability of the Langmuir film of the QDs was tested by two different methods, compression/decompression cycling and kinetic measurements, both of which indicated that TOPO-capped (CdSe)ZnS QDs can form stable Langmuir films at the air-water interface. Epifluorescence microscopy revealed the two-dimensional aggregation of the QDs in Langmuir films during the early stage of the compression process. However, at high surface pressures, the Langmuir film of QDs was more homogeneous and was capable of being deposited on a hydrophobic quartz slide by the Langmuir-Blodgett (LB) film technique. Photoluminescence (PL) spectroscopy was utilized to characterize the LB films. The PL intensity of the LB film of QDs at the first emission maximum was found to increase linearly with increasing number of layers deposited onto the hydrophobic quartz slide, which implied a homogeneous deposition of the Langmuir film of QDs at surface pressures greater than 20 mN.m(-1). 相似文献
2.
Serdar Karabcek Ismail Degirmencioglu Nevin Karabcek Mustafa Er Kerim Serbest 《Journal of heterocyclic chemistry》2003,40(4):639-643
The synthesis and structural properties of three novel imidates, 11,13‐bis‐(2‐amino‐ethylimino)‐1,10‐dioxa‐4,7‐dithiacyclotridecane ( 2 ), 11,13‐bis‐(3‐aminopropylimino)‐1,10‐dioxa‐4,7‐dithiacyclotridecane, ( 3 ) and 2,11‐dioxa‐5,8‐dithia‐13,16,19,22‐tetraazabicyclo[10.10.1]tricosa‐1(22),12‐diene, ( 4 ) have been described. These compounds were synthesized by treating 1,10‐dioxa‐4,7‐dithiacyclotridecane‐11,13‐diester ( 1 ) with the appropriate diamine under N2 and their structures have been characterised by elemental analyses, 1H‐ and 13C‐nmr, ir, and mass spectral studies. Elemental analyses and spectroscopic data support the proposed imidate structures. In addition, total energy and heat of formation (Figure 2) calculated for imidates 2a‐4a and 2b‐4b by the semiempirical AM1 calculations have shown that imidates 2b‐4b having intramolecular hydrogen bonds are more stable (5‐10 kcal/mol) than compounds 2a‐4a . 相似文献
3.
Nagihan Saglam Ahmet Colak Kerim Serbest Serdar Karab?cek Saadettin Güner 《Monatshefte für Chemie / Chemical Monthly》2004,15(4):1023-1031
Nucleolytic activities of novel mononuclear Cu(II), homo- and heterodinuclear Cu(II)–Ni(II) complexes with two diester-type ligands were investigated on pCYTEXP by neutral agarose gel electrophoresis. The analyses of the cleavage products obtained electrophoretically indicate that the examined complexes induce very similar conformational changes on supercoiled DNA by converting supercoiled form to nicked form. At concentrations greater than 100M, the complexes possessed effective nucleolytic activities for 10min of incubation time. However, their nucleolytic activities did not increase significantly with longer periods of incubation. The pH-nucleolytic activity profiles of the complexes differed significantly. Metal complex induced DNA cleavage was also tested for inhibition by various radical scavengers. It could be proposed from the data that diffusible intermediate oxidants are not involved in these reactions or they are not necessary for DNA cleavage since none of antioxidants inhibited DNA cleaving activities of the complexes. 相似文献
4.
The infrared absorption spectra of 12 lanthanide acetylacetonate complexes were measured in the region 400–2000 cm?1 and discussed. Assignments of the bands especially those due to metal-oxygen (M—O), C=O and C=C stretching vibration is given. It is found that the band at 530 ± 5 cm?1 is due mainly to Ln—O stretching vibration. In the carbonyl region, it is confirmed that the band at lower frequency is a C=C stretching vibration while that at higher frequency is due to C=O stretching vibration. Integral intensities for the M—O, C=O and C=C stretching vibrations were calculated in KB1 and CHCl3 solutions. The variation of the intensities of the M—O bands witn complexed cation were discussed in terms of crystal field stabilization energy (CFSE). 相似文献
5.
6.
Gly-His-Leu-Leu-Cys coated CdS quantum dots detected Cu2+ and Ag+ selectively with high sensitivity, below 0.5 microM. 相似文献
7.
为了阐明芳香性及磁性原因,用Aihara提出的TRE概念计算了 ,苯并环丁二烯和戊搭烯等烃的共振能,环共振能和环电流.计算结果表明 因有正共振能具有芳香性并产生反磁性环电流,而苯并环丁二烯和戊塔烯因有负共振能具有反芳香性并产生顺磁性环电流. 相似文献
8.
The olefinic centred Schiff base (3) was obtained from the condensation of substituted dialdehyde (1) with 2-amino-4-methylphenol (2) in a 1:2 ratio. The diphthalonitrile derivative (5) was prepared by the reaction of 4-nitrophthalonitrile (4) and compound (3) in dry dimethylformamide/potassium carbonate. The key product (5) was obtained by nucleophilic substitution of an activated nitro group into an aromatic ring. The cyclotetramerization of compound (5) with phthalonitrile (6) in 1:6.15 ratio gave the expected metal-free phthalocyanine of clamshell type (7), and with metal salts of Zn(II), Ni(II), Co(II) and Cu(II) gave metallophthalocyanines of clamshell types (8-11), respectively in dimethylaminoethanol/1,8-diazabycyclo[5.4.0]undec-7-ene system. The products were purified by several techniques such as crystallization and preparative thin layer chromatography. The newly prepared compounds were characterised by a combination of elemental analyses, IR, 1H/13C NMR, MS and UV-Vis spectroscopy. 相似文献
9.
Zusammenfassung Es wird ein zweites graphisches Verfahren dargestellt, welches gestattet, die Viskosität zäher Flüssigkeiten zu ermitteln. 相似文献
10.
Kerim Serbest Hakan Kayi Mustafa Er Kemal Sancak smail Deirmenciolu 《Heteroatom Chemistry》2008,19(7):700-712
Four new mononuclear metal complexes with a mononucleating Schiff base ligand containing two thiadiazoles units have been synthesized. The ligand and metal complexes were characterized by elemental analyses, IR, 1H, and 13C NMR, UV–vis, ESR, electrospray ionization mass spectra, and magnetic susceptibility measurements. Electronic spectra, magnetic susceptibility measurement, and molecular modeling studies support octahedral geometry around the Ni(II), Cu(II), and Zn(II) ions. The magnetic properties were investigated, and ferromagnetic coupling is observed in Cu(II) and Ni(II) complexes. In addition, total energy and heat of formation calculated for conformers of the Schiff base ligand by the semiempirical AM1 calculations have shown that E,Z‐isomer of the ligand is more stable (about 5.3 kcal/mol) than E,E‐ and Z,Z‐isomers. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:700–712, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20496 相似文献