176977-39-2Relevant academic research and scientific papers
Metal-molecule-metal junctions in langmuir-blodgett films using a new linker: Trimethylsilane
Pera, Gorka,Martin, Santiago,Ballesteros, Luz M.,Hope, Adam J.,Low, Paul J.,Nichols, Richard J.,Cea, Pilar
, p. 13398 - 13405 (2011/03/17)
Herein trimethylsilane (TMS) is demonstrated to be an efficient binding group suitable for construction of metal-molecule-metal (M-mol-M′) junctions, in which one of the metal contacts is an atomically flat gold surface and the other a scanning tunnelling microscopy (STM) tip. The molecular component of the M-mol-M′ devices is an oligomeric phenylene ethynylene (OPE) derivative Me3Si C≡C{C6H4C≡C} 2C6H4NH2, featuring both Me 3SiC≡C and NH2 metal contacting groups. This compound can be assembled into Langmuir-Blodgett (LB) films on Au-substrates by surface binding through the amine groups. Alternatively, low coverage (sub-monolayer) films are formed by adsorption from solution. In the case of condensed monolayers top electrical contacts are formed to STM tips through the TMS end group. In low coverage films, single molecular bridges can be formed between the gold surface and a gold STM tip. The similarity in the I-V response of a one-layer LB film and the single molecule conductance experiments reveals several points of critical importance to the design of molecular components for use in the construction of M-mol-M′ junctions. Firstly, the presence of neighbouring π systems does not have a significant effect on the conductance of the M-mol-M′ junction. Secondly, in the STM configuration, intermolecular electron hopping does not significantly enhance the junction transport characteristics. Thirdly, the symmetric behaviour of the I-V curves obtained, despite the different metal-molecule contacts, indicates that the molecule is simply an amphiphilic electron-donating wire and not a molecular diode with strong rectifying characteristics. Finally, the conductance values obtained from the amine/TMS-contacted OPE described here are of the same order of magnitude as thiol anchored OPEs, making them attractive alternatives to the more conventionally used thiol-contacting chemistry for OPE molecular wires. Junction box: 4-[4-{4-(Trimethylsilylethynyl)phenylethynyl}phenylethynyl]aniline has been assembled into well-packed monolayer films by using the Langmuir-Blodgett technique. Trimethylsilane (TMS) is demonstrated to be an efficient binding group suitable for construction of metal-molecule-metal junctions, making this group an attractive alternative to the more conventionally used thiol-contacting chemistry for molecular wires (see picture). Copyright
Systematic studies on photoluminescence of oligo(arylene-ethynylene)s: Tunability of excited states and derivatization as luminescent labeling probes for proteins
Zhi, Yong-Gang,Lai, Siu-Wai,Chan, Queenie K.-W.,Law, Yuen-Chi,Tong, Glenna S.-M.,Che, Chi-Ming
, p. 3125 - 3139 (2007/10/03)
Functionalized oligo(phenylene-ethynylene)s (OPEs) with different conjugation lengths, p-X(C6H4C≡C) nSiMe3 (n = 1-4; X = NH2, NMe2, H) were synthesized by Sonogashira coupling of (phenylene-ethynylene)s and 1-iodo-4-(trimethylsilylethynyl)benzene, followed by desilylation of the p-substituted (trimethylsilylethynyl)benzenes with potassium hydroxide. The photoluminescent properties for the OPE series with different chain lengths and their solvatochromic responses were examined. The absorption maxima were red-shifted with increasing numbers of -(C6H4C≡C)- units (n), and a linear plot of the absorption energy maxima vs. 1/n was obtained for each series. The emission spectra in dichloromethane showed a broad and structureless band, the energies of which (in wavenumbers) also fit linearly with 1/n. Both the absorption and emission wavelength maxima of the NH2- and NMe2-substituted OPEs exhibited significant solvent dependence, whereas the parent OPEs (X = H) showed only minor shifts of the λmax values in different solvents. Substituent effects upon the photoluminescent characteristics of the OPEs and the tunability of the excited states were examined with the p-X(C6H4C≡C) nSiMe3 (n = 2, 3; X = NH2, NMe2, H, SMe, OMe, OH, and F) series. The H- and F-substituted counterparts exhibited high-energy vibronically structured emissions attributed to the 3(ππ*) excited states of the (arylene-ethynylene) backbone. For compounds bearing NH2 and NMe2 groups, a broad red-shifted emission with a remarkable Stokes shift from the respective absorption maximum was observed, which can be assigned to an n → π* transition. The n → π* assignment was supported by MO calculations on the model compounds p-X(C6H4C≡C) 2SiH3 (X = NH2, H). Functionalization of the oligo(arylene-ethynylene)s with the N-hydroxysuccinimidyl (NHS) moiety enabled covalent attachment of the fluorophore to HSA protein molecules. A series of fluorescent labels, namely p-X(C6H4C≡C) n-C6H4NHS, (n = 1, X = NH2, NMe 2, SMe, OMe, OH, F; n = 2, X = NH2, NMe2) and p-Me2NC6H4C≡C(C4H 2S)-C≡CC6H4NHS were synthesized, and their conjugates with HSA (human serum albumin) were characterized by MALDI-TOF mass spectrometry, UV/Vis absorption spectroscopy, and gel electrophoresis. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Fabrication of carbon nanotube-molecule-silicon junctions
Flatt, Austen K.,Chen, Bo,Tour, James M.
, p. 8918 - 8919 (2007/10/03)
A hybridization strategy for the covalent connection of single wall carbon nanotubes to silicon surfaces via oligo(phenylene ethynylene)s has been demonstrated using an orthogonal bisdiazonium functionalization protocol. Copyright
Multiple self-assembled nanostructures from an oligo(p-phenyleneethynylene) containing rod-coil-rod triblock copolymer
Li, Kun,Wang, Qing
, p. 4786 - 4788 (2008/01/27)
Induced by systematic variation of the initial polymer concentration in toluene, various morphologies of aggregates including vesicles, spheres, onion-like structures, and worm-like fibers from a rod-coil-rod triblock copolymer, oligo(p-phenyleneethynylene)-polystyrene-oligo(p-phenyleneethynylene) , were observed by transmission electron microscopy. The Royal Society of Chemistry 2005.
LIGHT EMITTING MOLECULES AND ORGANIC LIGHT EMITTING DEVICES INCLUDING LIGHT EMITTING MOLECULES
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Page/Page column 55; 57, (2008/06/13)
Light emitting molecules and organic light emitting devices comprising such light emitting molecules are described. In one embodiment, a light emitting molecule comprises an anchoring group and a charge transport group having a first end and a second end.
An approach to long and unsubstituted molecular wires: Synthesis of redox-active, cationic phenylethynyl oligomers designed for self-assembled monolayers
Hortholary, Cedric,Coudret, Christophe
, p. 2167 - 2174 (2007/10/03)
Various oligo(phenyleneethynylene)s (OPEs) have been synthesized in the past, as they are considered as prototypes of molecular wires. When the oligomers are capped by a redox site at one end and a thiol at the other end, the resulting molecules can be grafted as a self-assembled monolayer on a gold electrode and fully studied by electrochemical techniques. Unfortunately, such molecules are usually poorly soluble and require the incorporation of solubilizing pendant groups. In this paper, we show that the replacement of the classically used redox group ferrocene by a cationic organometallic ruthenium complex, namely, [Ru(bipy)2(ppH)]+ (bipy, 2,2′-bipyridine; ppH, 2-(2′-yl-phenyl)pyridine), allows a concise synthesis of an unsubstituted thioacetate-capped OPE up to four repetitive units long. The positive charge does not interfere with the conventional organic chemistry used to elongate, purify, or characterize the hexafluorophosphate salts of the molecules. To our knowledge, this represents the first family of long, poorly substituted OPEs designed for self-assembly.
Selective and efficient access to ortho, meta and para ring-substituted phenylacetylene derivatives R-[C≡C-C6H4](x)-Y (Y:H, NO2, CN, I, NH2)
Lavastre, Olivier,Cabioch, Sandrine,Dixneuf, Pierre H.,Vohlidal, Jiri
, p. 7595 - 7604 (2007/10/03)
ortho, meta and para isomers of iodo and amino ring-substituted phenylacetylene as well as rod-like arylacetylene derivatives were prepared by a simple synthetic route involving three consecutive reactions: the palladium-catalysed carbon-carbon bond forma
Sequential catalytic synthesis of rod-like conjugated poly-ynes
Lavastre, Olivier,Ollivier, Laurence,Dixneuf, Pierre H.,Sibandhit, Sourisak
, p. 5495 - 5504 (2007/10/03)
Several poly-ynes X-[C ≡ C-C6H4-](n)C ≡ C-Si(i)Pr3 (X = H, SiMe3) with controlled length (n = 1, 2, 3, 4) have been prepared from the easily accessible 4-trimethylsilylethynyl iodobenzene by using iterative and convergent methods based on both Pd/Cu catalysed C-C cross-coupling and selective desilylation reactions.
