Alkyne Metathesis: Catalysts and Synthetic Applications

Zhang, Wei; Moore, Jeffrey S.

doi:10.1002/adsc.200600476

Cited by 265 publications

(137 citation statements)

References 159 publications

Supporting

Mentioning

129

Contrasting

Unclassified

Order By: Relevance

“…Two different crosslinking chemistries were used to form linked monolayers from these SAMs. Mo(IV)-catalyzed, vacuum-driven alkyne metathesis (17) linked the dipropyne SAMs derived from 1. Cu-catalyzed Hay-type coupling conditions (18) created linked monolayers from SAMs of monomers 2 and 3.…”

Section: Resultsmentioning

confidence: 99%

“…Aryl alkynes are attractive monomers for this chemistry because they are a chemically diverse class of molecules that are already highly conjugated, contain primarily carbon by mass, and can be chemically linked through a variety of methods including alkyne metathesis (17), oxidative Cu coupling (18), and Pd-catalyzed cross-coupling (18). Di-functional monomers (1 and 2) and a hexa-functional monomer (3) were synthesized with triethoxysilyl groups attached by a carbamate group to the aryl core (Fig.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis of linked carbon monolayers: Films, balloons, tubes, and pleated sheets

Schultz

Zhang

Unarunotai

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Because of their potential for use in advanced electronic, nanomechanical, and other applications, large two-dimensional, carbon-rich networks have become an important target to the scientific community. Current methods for the synthesis of these materials have many limitations including lack of molecular-level control and poor diversity. Here, we present a method for the synthesis of two-dimensional carbon nanomaterials synthesized by Mo-and Cu-catalyzed cross-linking of alkyne-containing selfassembled monolayers on SiO 2 and Si3N4. When deposited and cross-linked on flat surfaces, spheres, cylinders, or textured substrates, monolayers take the form of these templates and retain their structure on template removal. These nanomaterials can also be transferred from surface to surface and suspended over cavities without tearing. This approach to the synthesis of monolayer carbon networks greatly expands the chemistry, morphology, and size of carbon films accessible for analysis and device applications.networks ͉ nanomaterials ͉ self-assembled I n contrast to carbon nanotubes, fullerenes and various derivatives (1-3), the synthesis of large 2D sheets such as graphene (4), graphyne, and graphdiyne (5, 6) extending over micrometers in lateral dimensions is either in its infancy or has significant limitations. In fact, the synthesis of 2D carbon networks has been recognized as an outstanding challenge in materials chemistry (7).Graphene, the simplest of the 2D conjugated carbon nanomaterials, is produced by micromechanical cleavage of bulk graphite (HOPG) or by thermal decomposition of silicon carbide (8, 9). However, these approaches lack the molecular-level control necessary to define the chemical makeup of these systems. Scholl coupling reactions on oligophenylene precursors (10) produce small (Ͻ15 nm) 2D graphene fragments with improved molecular diversity, and radiation induced modifications of self-assembled (11, 12) or Langmuir-Blodgett (13) monolayers create larger sheets, but with reduced control of the chemistry. Polyelectrolytes (14) represent a different class of chemistry that can form 2D (15) and 3D (16) nanomaterials. These films are formed through deposition of separately synthesized polymers, often in layer-by-layer assemblies, in the form of relatively thick (typically Ͼ5 nm) films governed by electrostatic interactions. These limitations, together with those associated with the planar, radiation-cross-linked monolayers, motivate the need for alternative approaches to these classes of materials.A potential solution to the formation of large 2D conjugated carbon nanomaterials would employ a two-step procedure involving the formation of self-assembled monolayers (SAMs) with highly functionalized monomers followed by chemical crosslinkage of the SAMs to form linked monolayers. Fig. 1 shows the overall process beginning with the formation of SAMs of suitably designed carbon precursors on solid supports, followed by chemical cross-linking to yield covalently bonded networks with monolayer thicknesses. Not...

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Synthesis of linked carbon monolayers: Films, balloons, tubes, and pleated sheets

Schultz

Zhang

Unarunotai

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…[61] The original work on this system exploited aryl alkynes as monomers due to their highly conjugated, carbon functionality, and to their ability to be chemically crosslinked by alkyne metathesis, [62] oxidative copper coupling, [63] or palladiumcatalyzed cross coupling. [63] To assemble SAMs of these molecules on oxide bearing substrates, pendant hydroxyl groups on an aryl ring can be reacted with 3-(triethoxysilyl)propyl isocyanate to yield a carbamate group linked to a siloxane tether.…”

Section: Graphene and Related Materials By Chemical Synthesismentioning

confidence: 99%

Conjugated Carbon Monolayer Membranes: Methods for Synthesis and Integration

et al. 2010

View full text Add to dashboard Cite

Monolayer membranes of conjugated carbon represent a class of nanomaterial with demonstrated uses in various areas of electronics, ranging from transparent, flexible, and stretchable thin film conductors, to semiconducting materials in moderate and high-performance field-effect transistors. Although graphene represents the most prominent example, many other more structurally and chemically diverse systems are also of interest. This article provides a review of demonstrated synthetic and integration strategies, and speculates on future directions for the field.

show abstract

“…138 We were aware that this was an ambitious endeavor as few examples of this approach applied in the context of total synthesis have been reported. 139,148,[159][160][161][162][163][164][165][166][167][168][169][170] One major issue that has likely contributed to little published work in the area of alkyne metathesis is preparation and use of catalysts and precatalysts, which typically requires rigorous exclusion of moisture and air in order to preserve activity. Furthermore, basic amines were known to be incompatible with the most common and readily accessible alkyne metathesis catalyst, Schrock's tungsten neopentylidyne (4.75), due to the Lewis acidic tungsten center ( Figure 34).…”

Section: Scheme 67 Conversion To the Ring-closing Metathesis Precursormentioning

confidence: 99%