1. Advantages of Chemical Redox Agents 878 2. Disadvantages of Chemical Redox Agents 879 C. Potentials in Nonaqueous Solvents 879 D. Reversible vs Irreversible ET Reagents 879 E. Categorization of Reagent Strength 881 II. Oxidants 881 A. Inorganic 881 1. Metal and Metal Complex Oxidants 881 2. Main Group Oxidants 887 B. Organic 891 1. Radical Cations 891 2. Carbocations 893 3. Cyanocarbons and Related Electron-Rich Compounds 894

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Chemical Redox Agents for Organometallic Chemistry

Crystal Engineering and Organometallic Architecture.

Department of Chemistry, William Mong Institute of Nano Science and Technology, Bioengineering Graduate Program, The Hong Kong University of Science & Technology (HKUST), Clear Water Bay, Kowloon, Hong Kong, China, and Department of Polymer Science and Engineering, Key Laboratory of Macromolecular Synthesis and Functionalization of the Ministry of Education, Institute of Biomedical Macromolecules, Zhejiang University, Hangzhou 310027, China

Acetylenic polymers: syntheses, structures, and functions.

Molecular materials are characterized by being made up by discrete molecules. This structural property gives in principle many possibilities, to modulate the bulk electrical, magnetic, and optical properties of the material by choosing appropriately the constituent molecules. At the same time, however, it is a challenge to develop synthetic strategies that allow the control of the spatial distribution of the molecules in the lattice. In fact, the bulk properties are always determined by cooperative interactions between the constituent molecules, which consequently must be assembled in the lattice in such a way as to maximize the bulk response. In this Account we provide a concise resume of magnetic phenomena, report briefly on the different strategies that have been developed up to the moment for designing molecular magnetic materials, and then summarize our own approach and the main results that have been obtained in this area.

Toward molecular magnets: The metal-radical approach

The building of multidimensional magnetic materials obtained with the molecular precursor [Cu(opba)]2- is described. The reaction with other paramagnetic species (3d or 4f metal ions, organic radicals) yielded one-dimensional, two-dimensional, and interlocked networks. The magnetic properties of these systems are reviewed using polarized neutron diffraction and magnetic measurements. It is shown that the spin density maps give a precise description of the ground state of such molecular magnetic species. Moreover, different long-range magnetic orderings (antiferro-, ferri-, and ferromagnetic) have been obtained.

Chemistry and physics of supramolecular magnetic materials.

Les deux composes cristallisent dans le systeme monoclinique, groupe C2/C. Comportement magnetique

Ferromagnetic behavior of [Fe(C5Me5)2]+.bul. [TCNE]-.bul.. Structural and magnetic characterization of decamethylferrocenium tetracyanoethenide, [Fe(C5Me5)2]+.bul. [TCNE]-.bul..cntdot.MeCN and decamethylferrocenium pentacyanopropenide, [Fe(C5Me5)2]+.bul. [C3(CN)5]-

A correlated study of the structural, optical, magnetic, and transport properties of polyacetylene, doped with iodine to nearly the metallic doping levels, shows that essentially all charges go into solitonlike states. The measurements are in quantitative agreement with charge transport via variable-range hopping among solitonlike levels.

Role of Solitons in Nearly Metallic Polyacetylene

The frequency ($f$) and temperature ($T$) dependent conductivity ($\ensuremath{\sigma}$) is reported for cis-${(\mathrm{CH})}_{x}$, trans-${(\mathrm{CH})}_{x}$, and ammonia-compensated ${(\mathrm{CH})}_{x}$. A strongly $T$-dependent dc $\ensuremath{\sigma}$ together with a weakly $T$-dependent ac $\ensuremath{\sigma}$ were observed for predominantly cis-${(\mathrm{CH})}_{x}$ and for N${\mathrm{H}}_{3}$-compensated samples, similar to $\ensuremath{\sigma}(f,t)$ of many semiconductors. The trans-${(\mathrm{CH})}_{x}$ has a larger "weakly" $T$-dependent dc $\ensuremath{\sigma}$ and anomalous strongly $T$-dependent ac $\ensuremath{\sigma}$. The latter results are in good agreement with Kivelson's theory of charge transport via intersoliton electron hopping.

Anomalous Frequency-Dependent Conductivity of Polyacetylene

Polymerization of 1,6-heptadiyne on the surfaces of concentrated solutions of homogeneous Ziegler-Natta catalysts leads to insoluble, free-standing films with metallic luster. “Doping” of these films by treatment with acceptors results in conductivities up to 1 S/cm. The polymer has been characterized in terms of its molecular structure, its solid-state structure and physical properties, the nature of the doping process, and its thermal and oxidative stability. Poly( 1,6-heptadiyne) provides a number of contrasts to polyacetylene in its molecular and solid-state structure which yield some information about the requirements for conductive polymers. Electrically conductive polymers have been the subject of sporadic interest for at least the last 25 The discovery of a method of preparation of free-standing films of polyacetylene4 sparked a rebirth of interest in this conjugated polyene that had been previously studied in powder form.s The films were more amenable to study of physical properties and for many potential applications. A number of dopants were subsequently found to be effective for raising the conductivity into the metallic regime.6 At the inception of the present study, no other substituted polyenes had been formed as films in situ during polymerization. Our initial goal was to determine whether other conjugated polyenes could first be polymerized in situ to free-standing films and then doped to high electrical conductivity. If this goal could be reached, optimization of properties such as flexibility, ductility, thermal transitions, oxidative stability, etc. might be achieved by modification of substituents on the polyene chain. It was known,’ however, and subsequently confirmed by using the Shirakawa catalyst* that substituted acetylenes, e.g., methyl and ethyl derivatives, polymerize sluggishly in comparison to acetylene itself. Because cyclopolymerization was of such utility in the synthesis of substituted olefin derived polymer^,^ it was our belief that cyclopolymerization of diacetylenes might prove useful in the preparation of substituted polyacetylenes. The polymerization of 1,6-heptadiyne (1) using an insoluble

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Poly(1,6-heptadiyne), a free-standing polymer film dopable to high electrical conductivity

An RFID bridge antenna is positioned between a tag antenna associated with a tag and a reader antenna associated with a reader. The bridge includes at least two RF antenna elements spaced apart from one another and coupled together by an electrical conductor. The first RF antenna element is located proximate to the tag antenna and the second RF antenna element is located proximate to the reader antenna. An electromagnetic carrier signal transmitted by the reader antenna is received by one of the RF antenna element and retransmitted to the tag antenna by the other RF antenna element, increasing the distance over which the tag can communicate with the reader. Where the tag is attached to a packaged object, the RFID bridge antenna may be included in the package to allow wireless data communication between the tag and a reader. The reader may also be located external to the package. For example, one of the RF antenna elements may be attached to a label on the package, allowing data stored in the tag to be extracted by the external reader. The object may be a module, also known as a customer replaceable unit (CRU), and the tag may be configured as a customer replaceable unit monitor (CRUM).

Heiko Rommelmann

Papers

Ferromagnetic behavior of [Fe(C5Me5)2]+.bul. [TCNE]-.bul.. Structural and magnetic characterization of decamethylferrocenium tetracyanoethenide, [Fe(C5Me5)2]+.bul. [TCNE]-.bul..cntdot.MeCN and decamethylferrocenium pentacyanopropenide, [Fe(C5Me5)2]+.bul. [C3(CN)5]-

Role of Solitons in Nearly Metallic Polyacetylene

Anomalous Frequency-Dependent Conductivity of Polyacetylene

Poly(1,6-heptadiyne), a free-standing polymer film dopable to high electrical conductivity

RFID Bridge Antenna