PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-6 (6)
 

Clipboard (0)
None

Select a Filter Below

Journals
Authors
more »
Year of Publication
Document Types
1.  Crystal structure of 1,3-bis­(2,6-diiso­propyl­phen­yl)-4,5-dimethyl-1H-imid­azol-3-ium bromide di­chloro­methane disolvate 
The title solvated salt, C29H41N2 +·Br−·2CH2Cl2 was obtained from the reaction of the Arduengo-type carbene 1,3-bis­(2,6-diiso­propyl­phen­yl)-1,3-dihydro-4,5-dimethyl-2H-imidazol-2-ylidene with Si2Br6 in di­chloro­methane. The complete cation is generated by a crystallographic mirror plane and the dihedral angle between the five-membered ring and the benzene ring is 89.8 (6)°; the dihedral angle between the benzene rings is 40.7 (2)°. The anion also lies on the mirror plane and both di­chloro­methane mol­ecules are disordered across the mirror plane over two equally occupied orientations. In the crystal, the cations are linked to the anions via C—H⋯Br hydrogen bonds.
doi:10.1107/S1600536814023150
PMCID: PMC4257239  PMID: 25484824
Arduengo-type carbene; C—H⋯Br hydrogen bond; crystal structure
2.  Synthesis and electrical characterization of intrinsic and in situ doped Si nanowires using a novel precursor 
Summary
Perchlorinated polysilanes were synthesized by polymerization of tetrachlorosilane under cold plasma conditions with hydrogen as a reducing agent. Subsequent selective cleavage of the resulting polymer yielded oligochlorosilanes SinCl2 n +2 (n = 2, 3) from which the octachlorotrisilane (n = 3, Cl8Si3, OCTS) was used as a novel precursor for the synthesis of single-crystalline Si nanowires (NW) by the well-established vapor–liquid–solid (VLS) mechanism. By adding doping agents, specifically BBr3 and PCl3, we achieved highly p- and n-type doped Si-NWs by means of atmospheric-pressure chemical vapor deposition (APCVD). These as grown NWs were investigated by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM), as well as electrical measurements of the NWs integrated in four-terminal and back-gated MOSFET modules. The intrinsic NWs appeared to be highly crystalline, with a preferred growth direction of [111] and a specific resistivity of ρ = 6 kΩ·cm. The doped NWs appeared to be [112] oriented with a specific resistivity of ρ = 198 mΩ·cm for p-type Si-NWs and ρ = 2.7 mΩ·cm for n-doped Si-NWs, revealing excellent dopant activation.
doi:10.3762/bjnano.3.65
PMCID: PMC3458602  PMID: 23019552
chemical vapour deposition; field-effect transistor; oligosilanes; radiation-induced nanostructures; silicon nanowires; vapor–liquid–solid mechanism
3.  Directed deposition of silicon nanowires using neopentasilane as precursor and gold as catalyst 
Summary
In this work the applicability of neopentasilane (Si(SiH3)4) as a precursor for the formation of silicon nanowires by using gold nanoparticles as a catalyst has been explored. The growth proceeds via the formation of liquid gold/silicon alloy droplets, which excrete the silicon nanowires upon continued decomposition of the precursor. This mechanism determines the diameter of the Si nanowires. Different sources for the gold nanoparticles have been tested: the spontaneous dewetting of gold films, thermally annealed gold films, deposition of preformed gold nanoparticles, and the use of “liquid bright gold”, a material historically used for the gilding of porcelain and glass. The latter does not only form gold nanoparticles when deposited as a thin film and thermally annealed, but can also be patterned by using UV irradiation, providing access to laterally structured layers of silicon nanowires.
doi:10.3762/bjnano.3.62
PMCID: PMC3458599  PMID: 23019549
chemical vapor deposition; gold; nanoparticle; patterning; radiation-induced nanostructures; vapor-liquid-solid mechanism
4.  1,3-Bis(2,6-diisopropyl­phen­yl)-1H-imidazol-3-ium chloride dichloro­methane disolvate 
In the title compound, C27H37N2 +·Cl−·2CH2Cl2, the cation and the anion are each located on a crystallographic mirror plane. Both of the dichloro­methane solvent mol­ecules show a disorder across a mirror plane over two equally occupied positions. Additionally, one isopropyl group is also disordered. In the crystal, the cations are connected to the chloride ions via C—H⋯Cl hydrogen bonds.
doi:10.1107/S1600536812022234
PMCID: PMC3379413  PMID: 22719611
5.  1,3-Bis(2,6-diisopropyl­phen­yl)-1H-imidazol-3-ium bromide dichloro­methane disolvate 
In the title compound, C27H37N2 +·Br−·2CH2Cl2, both the cation and the anion are located on a crystallographic mirror plane. Both of the dichloro­methane solvent mol­ecules show a disorder across a mirror plane over two equally occupied positions. In the crystal, the cations are connnected to the bromide ions via C—H⋯Br hydrogen bonds.
doi:10.1107/S1600536812022246
PMCID: PMC3379414  PMID: 22719612
6.  N-(2,6-Diisopropyl­phen­yl)formamide toluene 0.33-solvate 
The crystal packing of the title compound, C13H19NO·0.33C7H8, shows a channel at [001], which contains grossly disordered toluene solvent mol­ecules. The angle between the benzene ring and the mean plane of the formamide group is 71.1 (1)°. The amide groups of neighbouring mol­ecules are connected by N—H⋯O hydrogen bonds, forming 21 helical chains propagating along [001]. Mol­ecules are also connected by weak inter­molecular C—H⋯O hydrogen bonds, forming 61 helices.
doi:10.1107/S1600536812017527
PMCID: PMC3344661  PMID: 22590423

Results 1-6 (6)