جستجوی مقالات مرتبط با کلیدواژه "single crystal" در نشریات گروه "شیمی"

Two new mercury(II) Schiff base complexes [Hg((2,6-Cl-ba)2-1,2-pn)X2] (X = Cl (1), I (2) and (2,6-Cl-ba)2-1,2-pn = N,N'-bis(2,6-dichlorobenzylidene)-1,2-diaminopropane) have been synthesized and characterized by elemental analysis (CHN), FT-IR and 1H-NMR spectroscopy. The crystal structure of complexes 1 and 2 were determined by single-crystal X-ray diffraction. X-ray results shown that the mercury(II) ions in these complexes have a distorted tetrahedral geometry with HgN2Cl2 and HgN2I2 chromophores, respectively. In these complexes, the Schiff base ligand (2,6-Cl-ba)2-1,2-pn act as chelating bidentate ligand, coordinating via the two iminic nitrogen atoms and it adopts an E,E conformation. Finally, the thermal behavior of complexes was study using thermogravimetry in order to evaluate their thermal stability and thermal decomposition pathway.

Thiosemicarbazone ligand 4Hbatsc = 4-hydroxybenzaldehyde-thiosemicarbazone and its silver(I) complex [Ag(PPh3)3(4Hbatsc)]NO3 were synthesized and characterized by elemental analysis (CHN), FT-IR spectroscopy, and single-crystal X-ray diffraction. The triclinic unit cell of 4H-ba-tsc (space group P-1) contains two independent molecules. Each of the two independent molecules is almost planar, with the sulfur atom (S1/S2) and the hydrazine nitrogen atom (N6/N4) in the E position concerning the C3-N5/C4-N4. The title complex is a triclinic P-1 mononuclear complex with the silver(I) ion coordinated in a distorted tetrahedral geometry by one S atom of 4H-ba-tsc and three P atoms of three PPh3. The complex involves the 4H-ba-tsc thiosemicarbazone ligand in an S monodentate binding mode. Besides, the thermal behavior of the complex was studied using thermogravimetry in order to evaluate its thermal stability and thermal decomposition pathway. Finally, nanoparticles of the complex were prepared in an ultrasonic bath.

Single crystals of poly(ethylene glycol) (PEG)-b-polystyrene (PS), PEG-b-poly(methyl methacrylate) (PMMA), PEG-b-polycaprolactone (PCL), and polyaniline (PANI)-b-PEG-b-PANI were developed from dilute solutions and thin molten films using self-seeding methodology. The PS and PMMA grafted chains were categorized in disordered nano-brushes; however, the PCL and PANI ones were grouped in ordered nano-brushes. The characteristics of grown single crystals such as surface morphology, growth planes, and thicknesses were investigated using Atomic Force Microscopy (AFM), Electron Diffraction (ED) in Transmission Electron Microscopy (TEM), and Small Angle X-ray Scattering (SAXS). The thickness of PEG substrates, as well as polymer nano-brushes, were in the nanoscale (2-150 nm). Furthermore, the special morphologies of polymer mixed-brushes developed through the growth of single crystals of PEG-b-PS and PEG-b-PMMA diblock copolymers were introduced and characterized. Regardless of different morphologies, the total, substrate and amorphous thicknesses, tethering density as well as ED patterns were compatible in the phase regions covered by similar nano-brushes.

Single crystals consisting various surface morphologies and epitaxial structures were applied to investigate the effect of other phase regions in the vicinity of a given tethered chains-covered area having a certain molecular weight of amorphous brushes. The designed experiments demonstrated that regardless of the type of surface morphology (patterned and especial mixed-brushes, homo and copolymer single-co-crystals or homo-brush single crystals and epitaxial structures), for a phase region covered by a certain type of brushes, the respective characteristics were similar. Detection of participating phases was possible by atomic force microscopy (AFM) on the basis of quality of employed solvent (amyl acetate) in growth systems, interaction of brushes with respective substrate, stiffness, and crystallinity of PEG-formed areas; hence, fabricated surfaces were not in need of any selective solvent to be detected. Moreover, structure of various single crystals was investigated by the help of conjunction thickness.