This paper describes the synthetic organic phase of a project directed toward the construction of molecular scale electronic devices. Outlined is a convergent synthetic route to orthogonally fused conjugated organic oligomers. The final systems are to have a potentially conducting chain fused perpendicularly to a second potentially conducting chain via a σ bonded network. One of the core segments synthesized is based on a spirobithiophene moiety with a central silicon atom. It is formed by a zirconium-promoted bis(bicyclization) of a tetrapropargylsilane. The second core is a 9,9‘-spirobifluorene system. Terminal halide groups provide the linkage points for further extension of the chains via Pd-catalyzed or Pd/Cu-catalyzed cross coupling methods. All four branching arms are affixed to the core in a single operation, thus making the syntheses highly convergent. In the cases of the larger functionalized systems, alkyl substituents on the thiophenes afford soluble materials. In order to prepare the molecule...

Convergent Synthetic Routes to Orthogonally Fused Conjugated Oligomers Directed toward Molecular Scale Electronic Device Applications

Photoactivation of the nematicidal compound alpha-terthienyl from roots of marigolds (Tagetes species). A possible singlet oxygen role.

A well-defined triblock copolymer is synthesized by using a strategy in which the α-coupling of 11 thiophene rings of the middle block and the monodispersity (DP = 30 and Mw/Mn = 1.1) of the two polystyrene outer blocks is ensured. Monofunctional polystyrene 1 is first modified with an α-terthiophene unit 2 to form 3, and two of these units are coupled in a double Stetter reaction of 4 with a difunctional α-terthiophene 5 to yield a tetraketone 6 as the precursor of the triblock copolymer, which was formed with excess Lawesson's reagent. The polymer 7 is fully characterized with IR and NMR spectroscopy and MALDI-TOF mass spectrometry. Size exclusion chromatography, transmission electron microscopy, and scanning force microscopy show that 7 is self-assembled into spherical, micellar structures with average diameters of 12 nm, which corresponds to about 60 block copolymer molecules per aggregate. The optical properties of 7 are in full agreement with an associated unsubstituted oligothiophene. Electrochem...

A polystyrene-oligothiophene-polystyrene triblock copolymer

Human organ alkaline phosphatases: discrimination by several means including starch gel electrophoresis of axtienzysie‐enzyme supernatant fluids*

Publisher Summary This chapter discusses the molecular structure and physical properties of thiophenes. The whole arsenal of spectroscopic and other physical methods are utilized to study the aromatic character of thiophene and the substituent effects in thiophenes. Metalation and halogen-metal interconversion reactions are shown to be of great utility in the preparation of substituted thiophenes. The chapter also discusses the spectroscopy of thiophenes and thermodynamic properties of thiophene 2-methylthiophene, and 3-methylthiophene. Different methods discussed for the preparation of thiophenes are ring-closure reactions, heterocyclic systems, 2-substituted compounds, and 3-substituted compounds. Comparison of the 2- and 3-positions of thiophene with benzene is provided. In the reactions of 2, 5-disubstituted thiophenes elimination of α-substituent occurs to a much greater extent than in the benzene series. Side-chain reactivity of thiophenes is also provided in the chapter. The reactions leading to the destruction of the thiophene aromaticity is discussed.

Recent advances in the chemistry of thiophenes.

Investigations on nematicides: III. Polythienyls and related compounds

An improved synthesis of 4,6-dichloro-2-phenoxy-1,3,5,-triazine from cyanuric chloride and phenol in the presence of collidine (2,4,6-trimethyl-pyridine) induced us to investigate the scope and limitation of the substitution of one chlorine atom in cyanuric chloride and the influence of the base used as an acid acceptor. Phenols, thiophenols, alcohols, thiols and oximes generally reacted with cyanuric chloride in the presence of collidine giving good yields of the corresponding substitution derivatives. The herbicidal and fungicidal properties of the compounds are dealt with and are briefly discussed. The influence of the alkyl or aryl side chain on the biological activity was determined. For this reason some derivatives mentioned in the literature were included for comparison in our biological tests.

Investigations on herbicides II: 2-Alkyloxy- and 2-aryloxy -4,6-dichloro-1,3,5-triazines 2-Alkylthio- and 2-arylthio-4,6-dichloro-1,3,5-triazines

A new and simple method is described for the preparation of symmetrically and asymmetrically substituted diaryl sulphides from sodium thiophenolates and halogenated aromatics by heating in a suitable solvent, preferably dimethylformamide. Formation of poly-substituted products may be suppressed by using an excess of the halogenated aromatic hydrocarbon.

Preparation of diaryl sulphides

Method of combating insects comprising contacting with a dichloro-1, 3, 5-triazine

IN the course of investigations on s-triazines, we have discovered a new synthesis of 2-alkoxy- and 2-alkylthio-4,6-dichloro-s-triazines. These substances can be obtained by the reaction of an alcohol or a thiol with cyanuric chloride and 2,6 x collidine as the acid acceptor. The yield was approximately 80–90 per cent. In a further systematic investigation, we found that in these compounds the chlorine atom can be specifically substituted in good yield by an alkylamino, alkyloxy or alkylthio group.

New s -Triazine Herbicides

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