We report the synthesis and characterization of novel bistetracenes, an unconventional, linearly extended conjugated core with eight fused rings. Also described are bisoligoacenes. In general, the properties and stability of large polycyclic aromatic hydrocarbons (PAHs) strongly depend on the mode of ring annellation and the topology of their it-electron systems, which are usually associated with the resonance stabilization energy in large PAHs.

There is provided herein a polyalkylene-oxide-free surfactant composition comprising an ester-modified organosilicon having the general formula (I)
AO.sub.aR.sup.4.sub.b(BO.sub.cR.sup.11.sub.d).sub.e(C).sub.fD.sub.g.
There is also provided methods for making the ester-modified organosilicon (I) and agricultural, coating, personal care and home care applications containing the polyalkylene-oxide-free surfactant composition.

Articles and methods comprising persistent carbenes are provided, as well as related compositions. In some embodiments, a persistent carbene may be associated with a portion of a substrate (e.g., at least a portion of a surface on the substrate). In certain embodiments, the association of persistent carbene with the substrate may be used to affect certain properties of substrate (e.g., surface chemistry, stability). In some cases, a persistent carbene may be functionalized after association with a portion of a substrate. In some embodiments, a persistent carbene and at least one secondary compound may be associated with a portion of a substrate. Articles and methods of the present invention may be useful for applications involving electronics, sensing, microfabrication, nanotechnology, biomimetic, and drug delivery, amongst others.

The present invention describes chemical systems and methods for silylating aromatic organic substrates, said system or method comprising or consisting essentially of a mixture of (a) at least one organosilane and (b) at least one strong base, the definition of strong base now also including hydroxide, especially KOH, said system being preferably, but not necessarily substantially free of a transition-metal compound, and said methods comprising contacting a quantity of the organic substrate with a mixture of (a) at least one organosilane and (b) at least one strong base, under conditions sufficient to silylate the aromatic substrate.

The disclosure relates to methods for forming at least partially saturated cyclic and heterocyclic borylated hydrocarbons, as well as related compounds, which can be precursor compounds in the synthesis of any of a variety of pharmaceutical or medicinal compounds with a desired structure and/or stereochemistry for drug synthesis or drug candidate evaluation. The methods generally include reduction of an unsaturated cyclic or heterocyclic borylated hydrocarbon having a boron-containing substituent at an sp.sup.2-carbon, where such reduction converts the sp.sup.2-carbon to an sp.sup.3-carbon at the point of attachment of the boron-containing substituent. The methods can exhibit a selectivity for syn-addition during reduction, which can provide stereospecific products, such as when the unsaturated cyclic or heterocyclic reactant is multiply substituted with boron groups and/or other functional groups.

The present invention describes chemical systems and methods for silylating heteroaromatic organic substrates using at least alkoxide base, preferably a potassium alkoxide base and at least one organodisilane and (b) at least one alkoxide base. Both methods and compositions for affecting these transformations are disclosed.

In one embodiment, provided are a new class of diarylethene-containing photochromic compounds with the incorporation of silicon- or phosphorus-containing heterocycles into the ethene part of the diarylethene backbone that has been shown to be capable of displaying tunable, robust and thermally stable photochromic properties. Also provided are methods for synthesizing these compounds, as well as uses of these compounds as these compounds may be used as the photochromic layer in an optical recording material and other optical functioning devices.

Group 4 transition metal complexes of bidentate iminonaphthol pro-ligands can be used as catalysts to polymerize olefins, such as ethylene. Group 4 transition metal complexes of bidentate iminonaphthol pro-ligands can have a single-site nature, allowing the catalysts to be used to prepare ultra high molecular weight polyethylene having a narrow molecular weight distribution.

The present invention describes chemical systems and methods for silylating heteroaromatic organic substrates using at least alkoxide base, preferably a potassium alkoxide base and at least one organodisilane and (b) at least one alkoxide base. Both methods and compositions for affecting these transformations are disclosed.

The present invention is directed to a mild, efficient, and general direct C(sp)-H bond silylation. Various embodiments includes methods, each method comprising or consisting essentially of contacting at least one organic substrate comprising a terminal alkynyl CH bond, with a mixture of at least one organosilane and an alkali metal hydroxide, alkali metal alkoxide, or alkali metal hydride under conditions sufficient to form a silylated terminal alkynyl moiety. The methods are operable in the presence or substantially absence of transition-metal compounds. The systems associated with these methods are also disclosed.