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

Synthetic organic chemists enjoy the luxury of having a large collection of reliable reactions at their disposal for preparing small molecules, mesoscopic structures, and polymers. Coordination chemists, on the other hand, are faced with the fact that transition metal chemistry, when normalized for the number of transition metals, has relatively few high-yielding reactions, when compared to the chemistry of carbon, for preparing even small molecule structures. This lack of control is manifested, in large part, in the weak metal-ligand interactions found in coordination complexes as compared with the strong covalent bonds in organic compounds. Weak bonding often translates into many reaction pathways that are not substantially different from an energetic point of view, and therefore, results in poor selectivity. As a result, many coordination chemists in recent years have come to the realization that it may be easier and more productive to develop straightforward and reliable routes to mesoscopic supramolecular structures by capitalizing on the modest collection of high-yielding reactions in coordination chemistry, the directional bonding afforded by metal centers, and strategies aimed at taking advantage of the weak metal bonds found in coordination complexes. Three emerging synthetic strategies, the symmetry-interaction, directional-bonding, and weak-link synthetic approaches, all use metal centers as structural building blocks to rationally assemble molecular components into supramolecular metallocyclophanes. These three approaches are discussed herein, and the fundamental principles underlying each as well as their capabilities are compared and contrasted.

Strategies for the Construction of Supramolecular Compounds through Coordination Chemistry

Crown ethers: sensors for ions and molecular scaffolds for materials and biological models.

Iron-catalyzed hydroxyl radical formation. Stringent requirement for free iron coordination site.

The literature has shown numerous contributions on the synthesis and physicochemical properties of persistent organic radicals but there are a lesser number of reports about their use as building blocks for obtaining molecular magnetic materials exhibiting an additional and useful physical property or function. These materials show promise for applications in spintronics as well as bistable memory devices and sensing materials. This critical review provides an up-to-date survey to this new generation of multifunctional magnetic materials. For this, a detailed revision of the most common families of persistent organic radicals—nitroxide, triphenylmethyl, verdazyl, phenalenyl, and dithiadiazolyl—so far reported will be presented, classified into three different sections: materials with magnetic, conducting and optical properties. An additional section reporting switchable materials based on these radicals is presented (257 references).

Playing with organic radicals as building blocks for functional molecular materials

The mean P C bond lengths for the sulphide and selenide are almost exactly the same (~1.812 A) but are noticeably longer in the phosphine (1.835/k). The lengths do not vary significantly from those observed in the o-tolyl derivatives and it would seem, therefore, that the position of substitution of the methyl group has no direct effect upon them. The length of the P C bonds seems to be influenced by two factors only: the valence state of the P atom and, for individual bond lengths, the degre~ of intermolecular steric hindrance.

Structures of polyfluoroaromatic compounds. II. Crystal structure of 2,3,5,6‐tetrafluorobiphenyl

http://journals.iucr.org/b/issues/1978/03/00/a15881/a15881.pdf

The crystal and molecular structure of 2H-nonafluorobiphenyl

http://journals.iucr.org/b/issues/1976/08/00/a28741/a28741.pdf

The crystal and molecular structure of 3-methoxypentafluorotropone at − 50°C

The reactions of (diethyldithiocarbamato)halogenotellurium(II) with thiourea, benzimidazole-2-thiol, halides (Cl–, Br–, I–) and 1,10-phenanthroline (phen) have been studied. The products were principally characterized by elemental analyses, IR and 1H NMR spectroscopies. Novel anionic (diethyldithiocarbamato)dihalogenotellurate(II) complexes resulted from the reactions of Te(S2CNEt2)X (X = Br or I) with NEt4X (X = Br or I) and phen. The crystal structures of the complexes [NEt4][Te(S2CNEt2)I2], [H(phen)2][Te(S2CNEt2)I2] and [H(phen)2][Te(S2CNEt2)Br2] have been determined. In the anions tellurium is co-ordinated to two sulfur atoms of the dithiocarbamate in an almost isobidentate manner and to two halides in an overall planar trapezoidal geometry. In [NEt4][Te(S2CNEt2)I2] the two iodides are almost equidistant to tellurium with distances of 3.079(1) and 3.072(1)A, whereas in [H(phen)2][Te(S2CNEt2)I2] the two Te–I distances are 3.151(1) and 3.038(1)A and in [H(phen)2][Te(S2CNEt2)Br2] the two Te–Br distances are 2.911(1) and 2.986(1)A. In [H(phen)2]+ the proton is bound to one of the nitrogen atoms of a phenanthroline group and the two phen groups are held together by three hydrogen bonds, of which two are of the interesting type C–H ⋯ N.

Reactions of (diethyldithiocarbamato)halogenotellurium(II); crystal structures of R[Te{S2CNEt2}X2][R = NEt4, X = I; R = H(phen)2(phen = 1,10-phenanthroline), X = I or Br]

Thomas A. Hamor

Papers

Structures of polyfluoroaromatic compounds. II. Crystal structure of 2,3,5,6‐tetrafluorobiphenyl

The crystal and molecular structure of 2H-nonafluorobiphenyl

The crystal and molecular structure of 3-methoxypentafluorotropone at − 50°C

Reactions of (diethyldithiocarbamato)halogenotellurium(II); crystal structures of R[Te{S2CNEt2}X2][R = NEt4, X = I; R = H(phen)2(phen = 1,10-phenanthroline), X = I or Br]

Bis-(8-oxo quinoline)diorgano tellurium(IV) compounds; structural and spectroscopic studies