Review of gold(I) N-heterocyclic carbenes

2005 ◽  
Vol 83 (6-7) ◽  
pp. 812-825 ◽  
Author(s):  
Ivan JB Lin ◽  
Chandra Sekhar Vasam
Keyword(s):  
Liquid Crystal ◽  
Heterocyclic Carbenes ◽  
Supramolecular Assemblies ◽  
Easy Method ◽  
Carbene Transfer

This review presents an overview of the work on Au(I)–NHC chemistry. The efficiency of different synthetic strategies of Au(I)–NHCs is discussed. Transmetallation of Ag(I)–NHCs appears to be an easy method as compared with the others. The influence of aurophilicity "a traditional property of a Au(I) center" in making the supramolecular assemblies is also covered. The combination of the Au(I) center with NHCs has great potential in the fields of medicine, catalysis, liquid crystal, and optoelectronic.Key words: gold–carbenes, silver–carbenes, carbene transfer, aurophilicity.

Building new discrete supramolecular assemblies through the interaction of iso-tellurazole N-oxides with Lewis acids and bases

2017 ◽  
Vol 203 ◽  
pp. 187-199 ◽  
Author(s):  
Peter C. Ho ◽  
Hilary A. Jenkins ◽  
James F. Britten ◽  
Ignacio Vargas-Baca
Keyword(s):  
Electron Acceptor ◽  
Lewis Acids ◽  
Heterocyclic Carbenes ◽  
Supramolecular Assemblies ◽  
Triphenyl Phosphine ◽  
Tellurium Atom ◽  
Lewis Bases ◽  
Acids And Bases ◽  
Lewis Acids And Bases

The supramolecular macrocycles spontaneously assembled by iso-tellurazole N-oxides are stable towards Lewis bases as strong as N-heterocyclic carbenes (NHC) but readily react with Lewis acids such as BR3 (R = Ph, F). The electron acceptor ability of the tellurium atom is greatly enhanced in the resulting O-bonded adducts, which consequently enables binding to a variety of Lewis bases that includes acetonitrile, 4-dimethylaminopyridine, 4,4′-bipyridine, triphenyl phosphine, a N-heterocyclic carbene and a second molecule of iso-tellurazole N-oxide.

3D and 2D supramolecular assemblies and thermotropic behaviour of a carbo-benzenic mesogen

2017 ◽  
Vol 53 (43) ◽  
pp. 5902-5905 ◽  
Author(s):  
Chongwei Zhu ◽  
Tsai-Hui Wang ◽  
Chien-Jhang Su ◽  
Shern-Long Lee ◽  
Arnaud Rives ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Supramolecular Assemblies ◽  
Discotic Liquid Crystal ◽  
Stm Images

A carbo-benzenic mesogen gives rise to a tubular-columnar discotic liquid crystal at 115 °C, the rectangular arrangement of which is identical in STM images on an HOPG surface.

Self-Organization of a Dinuclear Metal Complex in Lyotropic Liquid Crystal:  Ribbonlike Supramolecular Assemblies

Langmuir ◽  
1998 ◽  
Vol 14 (19) ◽  
pp. 5631-5635 ◽  
Author(s):  
Toyoko Imae ◽  
Yoshiteru Ikeda ◽  
Masayasu Iida ◽  
Norio Koine ◽  
Sumio Kaizaki
Keyword(s):  
Liquid Crystal ◽  
Metal Complex ◽  
Supramolecular Assemblies ◽  
Lyotropic Liquid Crystal ◽  
Self Organization

Enhancement of N-heterocyclic carbenes on rhodium catalyzed olefination of triazoles

2016 ◽  
Vol 14 (8) ◽  
pp. 2550-2555 ◽  
Author(s):  
Shixian Zhao ◽  
Feifei Wu ◽  
Yuyu Ma ◽  
Wanzhi Chen ◽  
Miaochang Liu ◽  
...  
Keyword(s):  
Diffraction Analysis ◽  
Heterocyclic Carbenes ◽  
Transfer Reactions ◽  
Rhodium Complexes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbene Transfer

A few rhodium complexes of N-heterocyclic carbenes were prepared through carbene transfer reactions and their structures were characterized by X-ray diffraction analysis.

Combination of an Aromatic Core and Aromatic Side Chains Which Constitutes Discotic Liquid Crystal and Organogel Supramolecular Assemblies

Langmuir ◽  
2005 ◽  
Vol 21 (4) ◽  
pp. 1261-1268 ◽  
Author(s):  
Tsutomu Ishi-i ◽  
Tomoyuki Hirayama ◽  
Ko-ichi Murakami ◽  
Hiroshi Tashiro ◽  
Thies Thiemann ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Supramolecular Assemblies ◽  
Side Chains ◽  
Discotic Liquid Crystal ◽  
Aromatic Side Chains

A New Technique for the Light and Electron Microscopic Study of Individual Cerebro-Spinal Fluid Cells in a Mona Plane Layer

1976 ◽  
Vol 34 ◽  
pp. 362-363
Author(s):  
L.A. Dell
Keyword(s):  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Plane Layer ◽  
Ultrastructural Level ◽  
Spinal Fluid ◽  
Electron Microscopic Level ◽  
Electron Microscopic ◽  
Easy Method ◽  
Cell Pellet ◽  
A New Technique

A new method has been developed which readily offers the microscopist a possibility for both light and electron microscopic study of selected cells from the cerebrospinal fluid. Previous attempts to examine these cells in the spinal fluid at the ultrastructural level were based on modifications of cell pellet techniques developed for peripheral blood. These earlier methods were limited in application by the number of cells in spinal fluid required to obtain a sufficient size pellet and by the lack of an easy method of cellular identification between the light and electron microscopic level. The newly developed method routinely employs microscope slides coated with Siliclad and tungsten oxide for duplicate cytocentrifuge preparations of diagnostic spinal fluid specimens. Work done by Kushida and Suzuki provided a basis for our use of the metal oxide.

Freeze-fracture TEM of the helical smectic A* phase

1992 ◽  
Vol 50 (1) ◽  
pp. 278-279
Author(s):  
K.J. Ihn ◽  
R. Pindak ◽  
J. A. N. Zasadzinski
Keyword(s):  
Liquid Crystal ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Freeze Fracture ◽  
Smectic Phase ◽  
Layer Spacing ◽  
Screw Dislocations ◽  
Smectic A ◽  
Smectic Phases ◽  
Discrete Amount

A new liquid crystal (called the smectic-A* phase) that combines cholesteric twist and smectic layering was a surprise as smectic phases preclude twist distortions. However, the twist grain boundary (TGB) model of Renn and Lubensky predicted a defect-mediated smectic phase that incorporates cholesteric twist by a lattice of screw dislocations. The TGB model for the liquid crystal analog of the Abrikosov phase of superconductors consists of regularly spaced grain boundaries of screw dislocations, parallel to each other within the grain boundary, but rotated by a fixed angle with respect to adjacent grain boundaries. The dislocations divide the layers into blocks which rotate by a discrete amount, Δθ, given by the ratio of the layer spacing, d, to the distance between grain boundaries, lb; Δθ ≈ d/lb (Fig. 1).

Attractive mode force microscopy of chiral liquid crystal surfaces

1992 ◽  
Vol 50 (1) ◽  
pp. 268-269
Author(s):  
B.D. Terris ◽  
R. J. Twieg ◽  
C. Nguyen ◽  
G. Sigaud ◽  
H. T. Nguyen
Keyword(s):  
Liquid Crystal ◽  
Crystal Surfaces ◽  
Free Surfaces ◽  
Control Range ◽  
Force Microscopy ◽  
Liquid Crystal Films ◽  
Chiral Liquid Crystal ◽  
Crystal Films ◽  
Electrostatic Charging ◽  
And Shifts

We have used a force microscope in the attractive, or noncontact, mode to image a variety of surfaces. In this mode, the microscope tip is oscillated near its resonant frequency and shifts in this frequency due to changes in the surface-tip force gradient are detected. We have used this technique in a variety of applications to polymers, including electrostatic charging, phase separation of ionomer surfaces, and crazing of glassy films.Most recently, we have applied the force microscope to imaging the free surfaces of chiral liquid crystal films. The compounds used (Table 1) have been chosen for their polymorphic variety of fluid mesophases, all of which exist within the temperature control range of our force microscope.

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