1,721,191 research outputs found
Weak Interactions Involving Aryl -Systems and Halogen Atoms in the Crystal Structures of Phosphorus Derivatives of Betti Bases.
No full text
Organometallic strategies for the synthesis of conjugated oligomers
No full text: In this account we report our contribution to the synthesis of conjugated oligomers with defined structure. The targets of our work are oligoenes, oligophenylenevinylenes, also with fluorinated vinylene units, oligophenylenes and oligomers with thiophene-arylene or thiophene-anthraquinone units. The synthetic strategies developed in our research group are based on transition-metal catalyzed coupling reactions
Organometallic chemistry directed towards the synthesis of electroactive materials: stereoselective routes to extended polyconjugated systems
No full textVarious synthetic methodologies involving organometallic reagents and leading to conjugated oligomers and polymers are presented. Polyenes and oligomers of poly(paraphenylenevinylene) with well-defined length of the conjugated system were prepared by straightforward synthetic procedures based upon organometallic derivatives of silicon or boron. Fluorinated oligo(para-phenylenes) containing up to five aromatic rings were easily obtained by homocoupling reaction promoted by copper(I) thiophenecarboxylate. The Stille cross-coupling reaction was applied to the synthesis of poly(para-phenylenevinylene) polymers with various substituents on the aromatic rings. Some relevant electro-optical properties of these materials are also discussed
C-Alkylation and Michael Addition Involving the Polymer - Supported Carbanion from Methyl Nitroacetate
No full textCONJUGATED POLYENE SYNTHESIS VIA DISILYL DERIVATIVES - A DIRECT ACCESS TO OSTOPANIC ACID, A PLANT ANTICANCER AGENT, AND TO (6E)-LTB3 LEUKOTRIENE
No full textSynthesis of conjugated oligomers and polymers: the organometallic way
No full textResults of special interest in the field of organometallic
chemistry directed towards the synthesis of conjugated
oligomers and polymers are reviewed. Methodologies
widely employed in the synthesis of well-defined molecules
and based on the transition metal catalyzed coupling
reactions of various organometallic (B, Sn, Si, Mg and Zn)
reagents have been more recently extended to build up polyor
oligo-meric conjugated molecular architectures.
Although the focus of the present work is on transition
metal cross-coupling or homo-coupling processes, other
useful organometallic routes, such as metathesis reactions
and acetylene polymerization, have also been dealt with.
Owing to their higher versatility with respect to the nonorganometallic
processes commonly used for the synthesis
of these materials, the approaches presented allow the
realization of more complex molecular structures, which are
nowadays required in many electronic and optoelectronic
applications. The use of organometallic strategies has been
discussed from a synthetic organic chemist’s point of view,
and advantages and limitations of the different
methodologies reviewed have been highlighted. Some
attention has also been paid to the properties of the resulting
materials and to their dependence on the procedure
followed and the framework obtained
Il vasellame bronzeo nell'Italia preromana (VI-IV sec. a.C.). Forme, associazioni, servizi,
No full textEdizione di contributi dedicati al vasellame bronzeo da banchetto in alcune regioni nella penisola italiana risalente al VI-IV sec. a.C
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