Preparation, Optical, and Heat Resistance Properties of Phenyl-Modified Silicone Gel.

A series of Si-H- or Si-Vi-terminated, branched and linear oligomers containing MeSiO segments were prepared by equilibrium polymerization or non-equilibrium polymerization initiated by living anions, respectively. These oligomers were used to improve the defects of concentrated crosslinking points and the high hardness of crosslinked products when using phenyltris(dimethylsiloxy)silane or 1,1,5,5-tetramethyl-3,3-diphenyl trisiloxane as crosslinking agents in the preparation of silicone gel. NMR, FT-IR, and GPC characterized the structure and molecular weight information of the prepared oligomers.

The Preparation of Acryloxyl Group Functionalized Siloxane Polymers and the Study of Their Ultra Violet Curing Properties.

Polysiloxane with multiple acryloxyl groups at the terminal site of the polymer chain was synthesized by the condensation reaction between hydroxyl-terminated polysiloxane and acryloyl chloride and used to improve the cross-linking density of UV-curable silicone materials initiated from dual acryloxy-terminated symmetric polysiloxane or single acryloxy-terminated asymmetric polysiloxane with the mixture of Irgacure 1173 and Irgacure 184 at a mass ratio of 1:1 as the photoinitiator. The effects of factors such as initiator composition, UV irradiation time, structure, and molecular weight of linear dual acryloxy-terminated or single acryloxy-terminated asymmetric siloxane oligomers on the gelation yield, thermal properties, water absorption, and water contact angle of UV-cured film were investigated. The synthesized cross-linking density modifier can be copolymerized with acryloxy-functionalized linear polysiloxanes under the action of a photoinitiator to increase the cross-link density of UV-cured products effectively.

Preparation of Monotrimethoxylsilylethyl-Terminated Polysiloxane Fluids and Their Application in Thermal Interface Materials.

In this study, -Trimethylsilylmethyl--dimethylsilyl-terminated polydimethylsiloxane, polydiethylsiloxane and poly[2,2,2-trifluoropropyl(methyl)siloxane] are synthesized using an anion catalyzed nonequilibrium polymerization reaction with trimethylsilylmethyl lithium as the initiator; hexamethylcyclotrisiloxane, hexaethylcyclotrisiloxane or 1,3,5-trimethyl-1,3,5-trifluoropropylcyclotrisiloxane as the monomer; and dimethylchlorosilane as an end-capping agent. Three kinds of -trimethylsilylmethyl--trimethoxylsilylethyl-terminated polysiloxanes are further prepared by hydrosilylation reaction of -trimethylsilylmethyl--dimethylsilyl-terminated polysiloxanes with vinyltrimethoxysilane using Karstedt's catalyst. These -trimethylsilylmethyl--trimethoxylsilylethyl-terminated polysiloxanes are functionalized as in situ surface treatment agents for AlN particles.

Si-Bridged annulated BODIPYs: synthesis, unique structure and photophysical properties.

Two novel Si-bridged -annulated BODIPY dyes have been prepared through intermolecular C-I silylation and subsequent intramolecular C-H silylation in a one-pot reaction. A marked redshift of the main spectral bands was observed since the efficient σ*-π* conjugation results in a notable stabilization of the LUMOs. Si-annulation blocks the non-radiative decay and contributes to higher fluorescence quantum yields.

Oligosilanyl-Bridged Biscarbazoles: Structure, Synthesis, and Spectroscopic Properties.

Oligosilanyl-bridged systems are expected to give rise to unique optoelectronic properties because of σ-π conjugation between the Si-Si σ orbital and the aryl π orbital. Herein, we synthesized a small series of novel biscarbazoles bridged with permethylated oligosilanyl units (-[Si(CH)]-, = 1-4) and examined their spectroscopic properties in detail. In the target molecules , = 2-4, the efficient σ-π conjugation elevated the highest occupied molecular orbital energy level with no influence on the lowest unoccupied molecular orbital.

Thieno[3,2-b]thiophene fused BODIPYs: synthesis, near-infrared luminescence and photosensitive properties.

The fusion of π-sufficient heteroaryl moieties has proven to be an effective strategy for achieving the red shift of the main spectral bands of BODIPY. In this paper, thieno[3,2-b]thiophene-fused BODIPY derivatives 1 and 2 have been designed and characterized by various spectroscopic methods, and their photosensitive properties have also been explored. Both dyes absorb in the near-infrared region with extremely high molar extinction coefficients, due to the extension of π-conjugation by fusion of the thieno[3,2-b]thiophene moiety.

Two competing ionization processes in ESI-MS analysis of N-(1,3-diphenylallyl)benzenamines: formation of the unusual [M-H] ion versus the regular [M+H] ion.

A series of N-(1,3-diphenylallyl)benzenamine derivatives (M) were investigated by electrospray ionization mass spectrometry in the positive-ion mode. Both the anomalous [M-H] and the regular [M+H] were observed in the ESI mass spectra. The occurrence of [M-H] has been supported by accurate mass spectrometry, liquid chromatography mass spectrometry, and tandem mass spectrometry analysis.

Crystal structure of bis-[2-(1H-benzimid-azol-2-yl)-4-bromo-phenolato-κ(2) N (3),O]cobalt(II).

The asymmetric unit of the title Co(II) complex, [Co(C13H8BrN2O)2], contains two independent mol-ecules (A and B). In both mol-ecules, the Co(II) cation is N,O-chelated by two 2-(1H-benzimidazol-2-yl)-4-bromo-phenolate anions in a distorted tetra-hedral geometry. In mol-ecule A, both chelating rings display an envelope conformation, with the flap Co atom lying 0.

1-(4-Bromo-benz-yl)-2-(4-bromo-phen-yl)-1H-benzimidazole.

There are two mol-ecules in the asymmetric unit of the title compound, C20H14Br2N2. In the first, the dihedral angles between the mean plane of the benzimidazole group and those of the 4-bromo-benzyl and 4-chloro-phenyl groups are 50.72 (17) and 71.

Expanding the coordination cage: a ruthenium(II)-polypyridine complex exhibiting high quantum yields under ambient conditions.

A mononuclear ruthenium(II) polypyridyl complex with an enlarged terpyridyl coordination cage was synthesized by the formal introduction of a carbon bridge between the coordinating pyridine rings. Structurally, the ruthenium(II) complex shows an almost perfect octahedral N6 coordination around the central Ru(II) metal ion. The investigation of the photophysical properties reveals a triplet metal-to-ligand charge transfer emission with an unprecedented quantum yield of 13% and a lifetime of 1.

2-(Chloro-meth-yl)benzimidazolium chloride.

The structure of title compound, C(8)H(8)ClN(2) (+)·Cl(-), comprises discrete ions which are inter-connected by N-H⋯Cl hydrogen bonds, leading to a neutral one-dimensional network in [001]. This hydrogen bonding appears to complement π-π stacking inter-actions [centroid-centroid distances 3.768 (2) and 3.

Redetermination of 3-(ammonio-meth-yl)pyridinium dichloride.

The crystal structure of the title compound, C(6)H(10)N(2) (2+)·2Cl(-), has been reported previously in the non-standard setting P2(1)/a [Genet (1965 ▶). Bull. Soc.

Oxonium 2-carb-oxy-3-(2-fur-yl)acrylate.

In the title compound, H(3)O(+)·C(8)H(5)O(5) (-), neighbouring cations and anions are linked by O-H⋯O hydrogen bonds, forming a one-dimensional chain framework along [001]. The crystal structure is further stabilized by π-π inter-actions, with centroid-centroid distances of 3.734 (3) Å.

3-(2-Pyrid-yl)-5-(4-pyrid-yl)-4-(p-tol-yl)-1H-1,2,4-triazole.

In the mol-ecule of the title compound, C(19)H(15)N(5), the dihedral angles formed by the plane of the triazole ring with those of the 2-pyridyl, 4-pyridyl and p-tolyl rings are 28.12 (10), 34.62 (10) and 71.

2-Carb-oxy-1-phenyl-ethanaminium perchlorate.

In the title compound, C(9)H(12)NO(2) (+)·ClO(4) (-), an intra-molecular N-H⋯O inter-action results in the formation of a six-membered ring having a twisted chair conformation. In the crystal structure, inter-molecular O-H⋯O, N-H⋯O and C-H⋯O inter-actions link the mol-ecules into a network. A weak C-H⋯π inter-action is also found.

Dimethyl 1-cyano-methyl-1H-pyrazole-3,5-dicarboxyl-ate.

The title mol-ecule, C(9)H(9)N(3)O(4), syhthesized from 1H-pyrazole-3,5-dicarboxylic acid and 2-bromo-acetonitrile, is approximately planar; the inter-planar angles between the pyrazole ring and the mean planes of the two carboxylate units and the cyanomethyl unit are 4.49 (10), 5.56 (9) and 5.

2-Carb-oxy-1-(3-nitro-phen-yl)ethanaminium perchlorate.

In the cation of the title compound, C(9)H(11)N(2)O(4) (+)·ClO(4) (-), the conformation is stabilized by an intra-molecular N-H⋯O hydrogen bond. In the crystal packing, centrosymmetrically related cations inter-act through inter-molecular O-H⋯O hydrogen bonds involving the carb-oxy groups, forming dimers. The dimers and the perchlorate anions are further linked into layers parallel to the ab plane by C-H⋯O and N-H⋯O hydrogen-bonding inter-actions.

2-Carb-oxy-1-phenyl-ethanaminium nitrate.

In the title salt, C(9)H(12)NO(2) (+)·NO(3) (-), the cation and anion are linked by a bifurcated N-H⋯(O,O) hydrogen bond. The crystal packing is stabilized by inter-molecular N-H⋯O, O-H⋯O and C-H⋯O hydrogen bonds, which connect neighbouring cations and anions, resulting in a two-dimensional network.

5-p-Tolyl-1H-tetra-zole.

The title compound, C(8)H(8)N(4), possesses crystallographic mirror symmetry, with four C atoms lying on the reflecting plane, which bis-ects the phenyl and tetra-zole rings. It is composed of a planar r.m.

Does the surface matter? Hydrogen-bonded chain formation of an oxalic amide derivative in a two- and three-dimensional environment.

We report on a multi-technique investigation of the supramolecular organisation of N,N-diphenyl oxalic amide under differently dimensioned environments, namely three-dimensional (3D) in the bulk crystal, and in two dimensions on the Ag(111) surface as well as on the reconstructed Au(111) surface. With the help of X-ray structure analysis and scanning tunneling microscopy (STM) we find that the molecules organize in hydrogen-bonded chains with the bonding motif qualitatively changed by the surface confinement. In two dimensions, the chains exhibit enantiomorphic order even though they consist of a racemic mixture of chiral entities.

Homochiral laminar europium metal-organic framework with unprecedented giant dielectric anisotropy.

Hydrothermal (deuteratothermal) reaction of L-ethyl lactate (Lig-Et) with Eu(ClO(4))(3)6 H(2)O gives colorless block crystals of [Eu(Lig)(2)(X(2)O)(2)][ClO(4)] (1, X=H; 2, X=D) both of which possess a two-dimensional laminar homochiral framework. Single-crystal dielectric measurements reveal that 1 and 2 display a giant dielectric anisotropy approximately exceeding 100 and large isotopic effect with about 54 % enhancement along the a axis. Their ferroelectric features further confirm this respect.

In situ hydrothermal synthesis of tetrazole coordination polymers with interesting physical properties.

Tetrazole compounds have been studied for more than one hundred years and applied in various areas. Several years ago Sharpless and his co-workers reported an environmentally friendly process for the preparation of 5-substituted 1H-tetrazoles in water with zinc salt as catalysts. To reveal the exact role of the zinc salt in this reaction, a series of hydrothermal reactions aimed at trapping and characterizing the solid intermediates were investigated.