Robert Metzger

University of Alabama | UA · Department of Chemistry

Five years ago, rectification of electrical current was found in 4'-bromo-3,4-dicyano-2',5'-dimethoxy-[1,1'-biphenyl]-2,5-dione (1), a hemibiquinone (which we will call either 1 or HBQ) that has a very small working length (1.1 nm). Monolayers of HBQ on AuTS were detected by "nanodozing" atomic force microscopy (AFM) and were contacted with two typ...

Ferrocene is a good electron donor, and as such has been used to test asymmetric conduction (rectification) in molecules that contain ferrocene. Of the five ferrocene-containing molecules that rectify (structures 11, 15, 19, 20, and 22), the last (22) exhibits a record rectification ratio, which should be a dramatic incentive for searching for more...

This paper reviews the present status of unimolecular electronics (UME). The field started in the 1970s with a hope that some day organic molecules (~2 nm in size), when used as electronic components, would challenge Si-based inorganic electronics in ultimate-high-density integrated circuits. The technological push to ever smaller inorganic device...

In this paper we expand on the search for molecular rectifiers of electrical current and report on a hexacoordinate metallosurfactant [FeIII (LN3O)(OMe)2], where (LN3O)- is the deprotonated form of the new asymmetric ligand 2-((E)-((4,5-bis (2-methoxyethoxy)-2-(((E)–pyridin-2-ylmethylene)amino)phenyl)imino)methyl)-4,6-di-tert-butyl-phenol. This spe...

To shrink electrical circuits beyond the looming practical limits of Moore's Law, it has been a common goal to create carbon-based components. Here is the first example of a new class of donor-σ-acceptor rectifiers: the hemibiquinones (HBQs).HBQs possess donor and acceptor moieties that are electronically isolated by inter-ring torsion. A HBQ-dinit...

The sandwiches “EGaIn | Ga2O3 | LB monolayer of 2 | Au” and “EGaIn | Ga2O3 | LB monolayer of 3 | Au” rectify. They are formed from a Langmuir-Blodgett (LB) monolayer of 2 or 3 transferred onto thermally evaporated gold. Molecules 2 and 3 are of the donor-sigma-acceptor (D-σ-A) type and have the same perylenebisimide (PBI) acceptor as a previously s...

Examples of coordination compounds that act as molecular rectifiers are rare. Recently a pentacoordinate [N2O2] Fe(III) surfactant, namely [FeIII(LN2O2)Cl] (1), was studied as a Langmuir–Blodgett (LB) monolayer between two Au electrodes, “Au | LB1 | Au”. Rectification was observed, but only at low currents. In order to verify the current rectificat...

In the title compound, C14H10Br2O4, the dihedral angle between the aromatic rings is 67.29 (19)°. Both meth­oxy-group C atoms lie close to the plane of their attached ring [deviations = −0.130 (4) and 0.005 (5) Å]. In the crystal, mol­ecules pack in a centrosymmetric fashion and inter­act via a mixture of weak π–π stacking inter­actions [centroid–c...

A molecule containing the electron donor (pyrene, Py), an insulating tetramethylene bridge, an electron acceptor (perylene bisimide, PBI) and a bis-decyl swallowtail with two terminal thioesters was studied for its electrical rectification as a Langmuir-Blodgett (LB) monolayer between two Au electrodes at room temperature (over a 9-month period, th...

This is a brief update on our experimental work towards better one-molecule-thick monolayer rectifiers of electrical current, and on theoretical progress towards a one-molecule amplifier of electrical current. This program aims to provide electronic devices at the 2 to 3 nm level, as a dramatic advance towards practical integrated circuits of the f...

A single molecule composed of three linked moieties can function as an amplifier of electrical current, when certain conditions are met by the molecular orbitals of the three component parts. This device should exhibit power gain at appropriate voltages. In this work, we will explain a plausible mechanism by which this device should work, and prese...

The working tools of the physical sciences, expertly organized into one volume Covering the basic concepts and working tools in the physical sciences, this reference is a unique, indispensable guide for students and researchers in chemistry, physics, and related disciplines. Everyone from novices to experienced researchers can turn to this book to...

Electronic devices at the single-molecule level (<3 nm in all directions) may provide the fastest possible electronic components, whose excited states would decay by photons, while comparably sized Si-based components must decay by phonons, and require enormous heat dissipation methods. Progress in unimolecular rectification is reviewed, with parti...

The current-voltage characteristics in Langmuir-Blodgett monolayers of \gamma-hexadecylquinolinium tricyanoquinodimethanide (C16H33Q-3CNQ) sandwiched between Al or Au electrodes is calculated, combining ab initio and self-consistent tight binding techniques. The rectification current depends on the position of the LUMO and HOMO relative to the Ferm...

The first active electronic components used vacuum tubes with appropriately-shaped electrodes, then junctions of appropriately-doped Ge, Si, or GaAs semiconductors. Electronic components can now be made with appropriately-designed organic molecules. As the commercial drive to make ever-smaller and faster circuits approaches the 3-nm limit, these un...

The reaction of the lithium salt of 7,7,8,8-tetracyanoquinodimethan (TCNQ) with 1.2-dimethylpyridinium iodide in ethanol leads to a conventional charge-transfer salt. However, the same reagents dissolved in acetonitrile yield crystals which belong to space group P21/c, with unit cell constants a = 1493.5(2), b = 720.9(2) (stack axis), C = 1380.2(3)...

The progress of the Organic Rectifier Project (ORP) is reviewed. Several molecules of the type D-σ-A (D=organic one-electron donor, σ = covalent saturated bridge, A = organic one-electron acceptor) have been synthesized, to test the Aviram-Ratner Ansatz that they could be one-molecule thick rectifiers of electrical current. Many of these molecules...

We report nanometer-scale ordered arrays of cylindrical magnetic nanoparticles with low aspect ratio and ultra-high uniformity. Protracted anodization provides hexagonally ordered nanopores in amorphous Al2O3. For instance, pulsed electrochemical deposition grows Co particles of uniform length from the bottoms of these pores: These particles are po...

The Madelung energies of 18 cuprates and 1 nickelate with sheets or chains of Cu and O have been computed, along with the relevant Madelung site potentials for O and Cu. The difference between these site potentials has been shown to correlate extremely well with the conductivity of these cuprates: only if the site potential difference is intermedia...

The asymmetrical forward versus reverse - bias DC electrical conductivity (macroscopic and also nanoscopic) through Langmuir-Blodgett multilayers and monolayers of γ-(nhexadecyl) quinolinum tricyanoquinodimethanide, C16H33Q-3CNQ (1) is attributable to rectification of electrical current by a single molecule.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

For Abstract see ChemInform Abstract in Full Text.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Unimolecular or molecular-scale electronics has made huge progress towards unimolecular resistors, switches, rectifiers, negative differential resistance devices, and gain-less single-electron transistors. Twelve unimolecular rectifiers have been found in Tuscaloosa, and many others elsewhere. The challenges are to understand the “metal|molecule” i...

Appropriately chosen molecules (electron donors or acceptors) could replace doped inorganic semiconductors to form active electronic components. Ultimately, small electronic devices (<3 nm in all directions) may be the fastest possible electronic components, whose excited states would decay by photons, while comparably sized Si-based components mus...

From the nanoscale to the macroscopic scale, intelligent materials are triggering a response across both dimensions and scientific disciplines... World class, leading experts in the fields of chemistry, physics and engineering have contributed to Intelligent Materials, highlighting the importance of smart material science in the 21st century. In th...

The advantage of "self-assembly" (strong covalent binding to substrates) was combined with the advantage of Langmuir-Blodgett (LB) or Langmuir-Schaefer (LS) transfer to a solid substrate (quantitative transfer of monolayers to the substrate). The electrical rectification (asymmetric conduction) by a monolayer of thioacetylalkylquinolinium tricyanoq...

Rectification of electrical current was observed in a Langmuir-Schaefer monolayer of fullerene-bis[ethylthio-tetrakis(3,4-dibutyl-2-thiophene-5-ethenyl)-5-bromo-3,4-dibutyl-2-thiophene] malonate, Au electrodes at room temperature (there are two regimes of asymmetry, at lower bias, i.e., between 0 and +/-2 V, and at higher bias), and also between Pb...

A Langmuir-Schaefer monolayer of Fullerene-bis-[ethylthio-tetrakis(3,4- dibutyl-2-thiophene-5-ethenyl)-5-bromo-3,4-dibutyl-2-thiophene] malonate is a unimolecular rectifier. This has been measured using not only Au electrodes at room temperature, but also between Pb and Al electrodes at 4.2 K. At liquid helium temperature, the rectification was als...

A Langmuir-Blodgett (LB) multilayer film of the unimolecular rectifier hexadecyl-gamma-quinolinium-7,7,8-tricyanoquinodimethanide (C(16)H(33)gammaQ-3CNQ) has two distinct polarized charge-transfer bands, one at lower film pressures (28 mN m(-1)) with a peak at 530 nm, due to an intramolecular charge transfer or intervalence transfer (IVT); past the...

We report spectroscopic characterization and unimolecular rectification (asymmetric electrical conduction) measurements of three donor-sigma-acceptor (D-sigma-A) compounds N-(10-nonadecyl)-N-(1-pyrenylmethyl)perylene-3,4,9,10-bis(dicarboximide) (1), N-(10-nonadecyl)-N-(4-[1-pyrenyl]butyl)perylene-3,4,9,10-bis(dicarboximide) (2), and N-(10-nonadecyl...

Six unimolecular rectifiers have been studied at the University of Alabama: Langmuir-Blodgett (LB) or Langmuir-Schaefer (LS), or self-assembled monolayers of these molecules show asymmetric electrical conductivity between Au or Al electrodes. These molecules are gamma-hexadecylquinolinium tricyanoquinodimethanide (Fig. 1, 2), 2,6-di[dibutylamino-ph...

Asymmetries in the macroscopic and the nanoscopic direct-current electrical conductivity through Langmuir-Blodgett multilayers and monolayers of γ-(n-hexadecyl)quinolinum tricyanoquinodimethanide, HDQ-3CNQ (1) can be ascribed to a transition from the ground-state zwitterionic state (shown) to a presumably neutral excited-state conformer, thus confi...

New electron-donor (D)-electron-acceptor (A) TTF architectures are presented in which two electron-donating 1,3-dithiole moieties are connected by a pi bridge to the weak electron-accepting quinoxaline moiety (D-pi-A compounds 9a and 9b and also two 1,3-dithiole-2-ylidene moieties are connected by a pi bridge to the electron-accepting thieno[3,4-b]...

Langmuir-Schaefer (LS) monolayer films of fullerene-bis-[4-diphenylamino-4' '-(N-ethyl-N-2' ''-ethyl)amino-1,4-diphenyl-1,3-butadiene] malonate, 1, sandwiched between two Au electrodes, exhibit pronounced current asymmetries (rectification) between positive and negative bias at room temperature, with no decay of the rectification after several cycl...

The goal of electronic functionality within an individual organic molecule was set many decades ago, but achieving it has not been straightforward. The simple combining rules of chemistry allow an unlimited variety of structures, and it has not been clear which are worth pursuing. It has also not been clear how it might be possible to assemble well...

We discuss three unimolecular rectifiers: gamma-hexadecylquinolinium tricyanoquinodimethanide, 2,6-di[dibutylamino-phenylvinyl]-1-butylpyridinium iodide and dimethylanilino-aza[C60]fullerene, and discuss the progress towards useful one-molecule electronic devices for the ultimate reduction in integrated circuit sizes.

Rectification, i.e. asymmetrical electrical conduction by a Langmuir-Blodgett monolayer of dicyano{4-[1-cyano-2-(1-hexadecylquinolin-1-ium-4-yl)vinyl]phenyl} methanide (1), occurs between both Al and Au electrodes: this rectification arises from the asymmetry of the molecule, and the interplay between the zwitterionic ground state D+-π-A− and the l...

The unimolecular electronics (UE) aims to produce molecular electronic devices at 1-2 nm scale to meet the needs of integrated circuits. The UE is advanced by measuring electrical conductivity of single molecules or Langmuir-Blodgett (LB) monolayers. A single molecule is touched by scanning tunneling microscopy (STM) tip, conducting-tip atomic forc...

The electrostatic interaction at a distance between two molecules or other neutral aggregates of matter can be called the London dispersion interaction, and pictured as resulting from zero-point fluctuations of the electrons in the aggregates. It can also be called the Casimir effect, and pictured as resulting from zero-point fluctuations of the ph...

“Molecular electronics”, molecular-scale electronics, or unimolecular electronics (UE), studies electronic processes measured or controlled on a nanoscopic or molecular scale [1]. (In the 1980’s, when results on single molecules were still scarce, molecular electronics, also known as molecule-based electronics, was defined more boadly to also inclu...

Since the first proposals of using organic molecules to perform electronic operations [1], [2], there have been many efforts to synthesize molecules and construct devices. The types of devices proposed have ranged from simple wires to diodes and switches and the quest to make them has been driven by the promise of an entire new set of capabilities...

The rectification by three molecules that form Langmuir-Blodgett monolayers between gold electrodes is reviewed, along with a proposal for the means to obtain gain in a unimolecular amplifier, the molecular analog of a bipolar junction transistor.

We briefly review the progress towards useful one-molecule electronic devices, toward the ultimate reduction in integrated circuit sizes, and then describe five unimolecular rectifiers, or one-way conductors of electrical current: γ-hexadecylquinolinium tricyanoquinodimethanide, an acetyl sulfoxide derivative of this compound, 2,6-di[dibutylamino-p...

For Abstract see ChemInform Abstract in Full Text.

Rectification by a monolayer of (acetylthioundecyl)quinolinium tricyanoquinodimethanide, 6, sandwiched or physisorbed or chemisorbed on gold electrodes, was studied by scanning tunneling microscopy and scanning tunneling spectroscopy, and also by macroscopic “gold | monolayer | gold” pads, using either physisorption (Langmuir−Blodgett deposition, f...

This is the report of a DOE-sponsored workshop organized to discuss the status of our understanding of charge-transfer processes on the nanoscale and to identify research and other needs for progress in nanoscience and nanotechnology. The current status of basic electron-transfer research, both theoretical and experimental, is addressed, with empha...

Electrical rectification by a Langinuir-Blodgett rnonolayer of gamma-hexadecylquinolinium tricyanoquinodimethanide, C(16)H(33)Q-3CNQ, 1 has been verified first between Al electrodes, then between Au electrodes: this rectification arises from the asymmetry of the molecule, and the interplay between the zwitterionic ground state D+-pi-A(-) and the le...

Asymmetries were observed across a monolayer of dimethylanilinoaza[C60]fullerene, (DMA-NC60, 1) sandwiched between gold electrodes of relatively large size (0.265 mm2). Two modes of behavior are observed:  (1) a sigmoidal and slightly asymmetric behavior, bespeaking of a moderate unimolecular rectifier (rectification ratio of about 2), and (2) abov...

Rectification was observed across a monolayer of 2,6-di[dibutylamino-phenylvinyl]-1-butylpyridinium iodide, (Bu2NφV)2BuPy+I-, 1 sandwiched between gold electrodes. The current is enhanced at a forward bias above 0.5 to 1.0 V, as electrons flow preferentially from the iodide ions to the pyridinium ring, and is as high as 100 000 electrons molecule-1...

Molecular-scale electronics has now been enriched by the discovery that molecules, studied singly by scanning tunneling spectroscopy, or a large array of those molecules, studied in parallel as a Langmuir-Blodgett monolayer between metal electrodes, exhibit rectification, i.e., an asymmetric current as a function of applied voltage. This asymmetry...

Didecylammonium tricyanoquinodimethanide, a zwitterionic molecule of the type D+––A–(where D+= ammonium, = ethylene bridge, and A–= tricyanoquinodimethanide), forms a Pockels–Langmuir monolayer film at the air–water interface. The molecules can be transferred quantitatively as a Langmuir–Blodgett (LB) monolayer onto a gold surface. Using the cold-g...

We have prepared Langmuir−Blodgett monolayers of hexadecylquinolinium tricyanoquinodimethanide (C16H33Q+-3CNQ-) on gold surfaces and characterized the structure by surface plasmon resonance (SPR), X-ray photoelectron spectroscopy (XPS), reflection−absorption infrared spectroscopy (RAIRS), Raman spectroscopy, and water contact angle measurements. We...

Single-walled carbon nanotubes (SWCNTs) and multiple-walled nanotubes (MWCNTs) were used as contact masks to create nanoditches within a thin layer of oxide-covered Ti. The nanotubes buried in the Ti film can be removed by ultrasonication, leaving the Ti layer with well-formed uniform ditches up to several μm in length and as narrow as 10 nm in wid...

3,4-Cyanomethyl substituted thiophenes reacted with thionyl chloride in the presence of base to give dicyano substituted thieno(3,4-c)thiophenes. The use of selenium oxychloride furnished the corresponding cyano substituted seleno(3,4-c)thiophene. 1,2-Phenylenediacetonitriles gave the corresponding cyano substituted benzo(c)thiophenes and benzo(c)s...

2,6-Bis-[2-(4-dibutylamino-phenyl)-vinyl]-1-butylpyridinium iodide, originally synthesized and studied for second harmonic generation in Langmuir-Blodgett (LB) films, is a rectifier of electrical current, as measured in an Au | LB monolayer | Au junction. The technique of ¡°cold¡± gold fabrication of a gold electrode atop a delicate LB monolayer ha...

The electrical rectification by a Langmuir-Blodgett monolayer of gamma-hexadecylquinolinium tricyanoquinodimethanide, C16H33Q-3CNQ, 1 has been verified between Al electrodes, then Au electrodes: this is due to the asymmetry of the molecule, and the interplay between the zwitterionic ground state D+-pi-A- and the less dissociated first electronic ex...

The fabrication of arrays of nanometer scale particles has recently assumed enormous relevance in the study of the magnetic, optical and electronic properties of materials having dimensions comparable to the length scales where size quantization and surface phenomena determine the properties of interest. Large area arrays of identical particles in...

Long-term anodization of aluminum provides a hexagonally ordered array of nanopores with very uniform pore diameters (between 30 and 50 nm, depending on pH, acid, and potential) and pore spacings of 80 to 100 nm within a matrix of amorphous aluminum oxide. However, one often desires smaller diameters. Because the bottom of each pore is U-shaped, we...

A unimolecular electronic device should perform active electronic functions by exploiting the energy levels, or conformations, of a singlemolecule, or a very few molecules, and should be addressable electrically by macroscopic electrodes. We found unimolecular rectification in a molecule, γ-hexadecylquinolinium tricyanoquinomethanide, 4, in which t...

Hexadecylquinolinium tricyanoquinodimethanide (1) is a unimolecular rectifier of electrical current with a large hypsochromic shift in the absorption spectrum, due to an electronically allowed transition between a large ground-state dipole moment (43 ± 8 D) and a small excited-state dipole moment (3 to 8 D). Two fluorescent emissions were observed:...

Unimolecular rectification of electrical current was confirmed between 105 and 370 K in a single molecule, γ-hexadecylquinolinium tricyanoquinomethanide, 1, in which the ground state is zwitterionic (D+–π–A−) with a large dipole moment (43 Debyes) while the first excited state is undissociated: (D0–π–A0) with a smaller estimated moment (3–9 Debyes)...

Unimolecular rectification was detected between oxide-free Au electrodes for a Langmuir−Blodgett (LB) monolayer of the zwitterionic D+-π-A- molecule hexadecylquinolinium tricyanoquinodimethanide, C16H33Q−3CNQ. The top gold pad was deposited by a process that cools the metal vapor before deposition. The maximum rectification ratio is 27.5 at 2.2 V (...

We report the fabrication of nanometer scale ordered arrays of magnetic cylindrical nanoparticles with low aspect ratio (height/radius a=0.2–7) and ultrahigh uniformity. Anodization and electrochemical deposition are employed for template synthesis and metal particle growth, respectively. Particle uniformity is achieved by an electrodeposition sche...

45 000 electrons per molecule per second: such currents and a rectification ratio of 5.38 at 2.2 V were detected between oxide-free Au electrodes for a Langmuir–Blodgett monolayer of the D+–π–A− molecule 1.

We demonstrate a simple analytical model for elastic charge transport on the nanometer scale within a single molecule. It is based on the assumptions usually employed for quantum chemical calculations, except that of equilibrium between the currents flowing in opposite directions. It allows the possibility of a nonuniform potential distribution and...

45 000 electrons per molecule per second: such currents and a rectification ratio of 5.38 at 2.2 V were detected between oxide-free Au electrodes for a Langmuir–Blodgett monolayer of the D+–π–A− molecule 1.

Nanometer scale arrays of magnetic particles have been fabricated by double anodization of aluminum oxide and pulse-reverse (PR) electrodeposition (ECD) in the resulting ordered aluminum oxide porous template ("alumite"). In contrast with conventional alternate current AC-ECD, PR-ECD results in a stable and reproducible process and enables the synt...

Highly ordered ferromagnetic Co arrays were fabricated by electrodeposition into the pores of porous alumina surfaces with hexagonally ordered areas up to 100 μm². The pore diameter varied between 25-60 nm, while pore-to-pore distance was 110 nm. Various voltage and current waveforms were employed to control the nucleation, growth and co...

DMPC (dimyristoyl-L-alpha-phosphatidylcholine) liposomes are used as artificial photosynthetic media to study the behavior of carotenoids. 8'-Apo-beta-caroten-8'-al (I) and beta-carotene (II) degrade faster under irradiation in DMPC liposomes than in organic solvents, which is possibly because vibrational deactivation of carotenoid excited states i...

We found electrical rectification in a single molecule, γ-hexadecylquinolinium tricyanoquinomethanide, 1, in which the ground state is zwitterionic: D+-π-A−, while the first excited state is undissociated: D0-π-A0, between 370 K and 105 K. While the ground state has a high dipole moment (43±8 Debyes), the first excited state has a very low estimate...

Unimolecular rectification, previously reported between oxide-bearing electrodes, was detected between oxide-free Au electrodes for a Langmuir-Blodgett monolayer of the zwitterionic D+-π-A− molecule hexadecylquinolinium tricyanoquinodimethanide, C16H33Q-3CNQ. The top gold electrode was deposited from a Au vapor pre-cooled by multiple collisions wit...

Photoinduced changes in electrical rectification were measured for a 5-layer Langmuir-Blodgett multilayer of hexadecylquinolinium tricyanoquinodimethanide, sandwiched between opaque and semitransparent Al electrodes, as a function of bias and wavelength. The current increases with the light intensity, but this may be simply due to heating of the sa...

We found unimolecular rectification in a single molecule, (N-hexadecylquinolin-4-ium-1-yl)methylidenetricyanoquinomethanide, 1, in which the ground state is zwitterionic: D+–π–A−, and has a large dipole moment (43 D) while the first excited state is undissociated: D0–π–A0 (and has a smaller moment, between 3 and 9 D). The intervalence optical absor...

Unimolecular rectification, previously reported between oxide-bearing electrodes, was detected between oxide-free Au electrodes for a Langmuir-Blodgett monolayer of the zwitterionic D+∼-A- molecule hexadecylquinolinium tricyanoquinodimethanide, C16H33Q-3CNQ. The top gold electrode was deposited from a Au vapor pre-cooled by multiple collisions with...

A single molecule, γ-hexadecyl-quinolinium tricyanoquinomethanide, 1, whose ground state is zwitterionic: D+-π-A−, with dipole moment 48±8 Debyes, and whose first excited state is undissociated: D0-π-A0, with an estimated moment between 3 and 9 Debyes, is a unimolecular rectifier of electrical current between 370 and 105 K. Spectroscopy data confir...

A single molecule, gamma-hexadecyl-quinolinium tricyanoquinomethanide, 1, whose ground state is zwitterionic: D+-pi-A(-), with dipole moment 43 +/- 8 Debyes, and whose first excited state is undissociated: D-0-pi-A(0), with an estimated moment between 3 and 9 Debyes, is a unimolecular rectifier of electrical current between 370 and 105 K, Spectrosc...

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Five zwitterions based on a coupling reaction between 2-methylbenzothiazole and its selenium and tellurium analogues with the lithium salt of tetracyanoquinodimethane were designed and synthesized, bearing long alkyl tails to facilitate Pockels-Langmuir film formation at the air-water interface. Stable monolayers were formed at the air-water interf...

Unimolecular electronic devices use the energy levels, or conformations, of one molecule or a very few molecules, and are contacted electrically from the outside. When made practical, these devices, the ‘advanced guard’ of unimolecular electronics, should leapfrog below the 50 nm limit of conventional inorganic microelectronics. Aviram and Ratner p...