Refernces
10.1021/jo026186x
The research focuses on the synthesis of conjugated dendrons with nonlinear optical (NLO) activity, featuring electron-withdrawing groups on the periphery and electron-donating groups at the core. The study explores the unique properties of these dendrimers, which have a π-conjugated dendritic skeleton that extends conjugation between electron donor-acceptor pairs, potentially enhancing their performance in photonic devices. The experiments involve a convergent approach to synthesize these dendrons, utilizing reactants such as para- and meta-branched phenylacetylenes, trimethylsilylacetylene, and oligo(ethylene glycol) chains. The synthesis includes steps like demethylation, nucleophilic substitution, and palladium-catalyzed coupling (Sonogashira reaction). The dendrons were characterized using 1H and 13C NMR spectroscopy, elemental analysis, and their optical properties were investigated through UV/vis and fluorescence spectroscopy. The results showed that the dendrons exhibited red-shifted absorption and fluorescence emissions as the generation increased, with the potential for further functionalization of the surface groups.
10.1016/j.jorganchem.2008.08.005
The research investigates the electrochemical behavior and properties of alkyne–dicobaltcarbonylthiophene complexes, specifically focusing on the effects of thiophene ring substitution positions. Various complexes were synthesized using reactants such as dibromothiophene, trimethylsilylacetylene (TMSA), and dicobalt octacarbonyl (Co2(CO)8), employing palladium-catalyzed cross-coupling reactions. The synthesized compounds were characterized through techniques including cyclic and square-wave voltammetry, NMR spectroscopy, infrared spectroscopy, and mass spectrometry. The study also involved controlled potential electrolysis and detailed spectroscopic analyses to evaluate the electronic interactions and redox properties of the complexes, highlighting the influence of substituent positions on their electrochemical behavior.
10.1021/om010685r
The study investigates the mechanism of formation of mer,trans-[(PMe3)3Rh(-CtC-R)2H] complexes from [(PMe3)4Rh(Me)] and terminal alkynes. The research explores the initial steps of the reaction, which involve the elimination of methane and the formation of a trigonal bipyramidal complex, followed by an oxidative addition reaction with a second equivalent of alkyne to yield the kinetic product fac-[(PMe3)3Rh(-CtC-R)2H]. This fac isomer is unstable and isomerizes to the thermodynamic product mer,trans-[(PMe3)3Rh(-CtC-R)2H]. The study also examines alkyne exchange reactions and the configurational stability of the formed complexes. Chemicals used include [(PMe3)4Rh(Me)], terminal alkynes such as ethynyltrimethylsilane (TMSA), p-methoxyphenylethyne, and p-cyanophenylethyne, which serve as reactants in the synthesis and investigation of the reaction mechanisms. The purpose of these chemicals is to understand the formation and behavior of rhodium complexes with potential applications in areas such as molecular wires, polymeric systems, catalysts, liquid crystals, and nonlinear optics. Density functional theory (DFT) studies were also conducted to support the experimental observations.
10.1016/j.tet.2008.08.054
This research describes the synthesis, characterization, and self-assembly of supramolecular oligo-phenylene-ethynylene (OPE) wires, which are bridged bis-Hamilton receptors, and their interaction with a cyanuric acid-modified tetraphenylporphyrin (TPP). The purpose of the study was to investigate the electronic, photoluminescence, and electroluminescence properties of these π-conjugated systems, which are relevant for their potential use as nanowires between electrodes. The researchers synthesized new OPE bridged bis-Hamilton receptors and characterized their linear H-bonding behavior with the modified TPP. The resulting complexes were analyzed using 1H NMR, UV/vis, and fluorescence spectroscopies, and the association constants and cooperativity of binding were determined. The study concluded that the self-assembled structures formed 1:2 complexes with strong association constants, indicating a robust supramolecular interaction. No electronic communication was detected between the OPE wires and the porphyrin, suggesting that OPEs can serve as inactive bridges in supramolecular donor-acceptor arrays. Key chemicals used in the process included 5-iodo-xylene, KMnO4, thionyl chloride, aminopyridine derivatives, trimethylsilylacetylene, TBAF, and various catalysts and solvents for the coupling and deprotection reactions.
10.1039/c2cc33740a
The research focuses on the synthesis and structural analysis of 1,4,5,8-tetraethynylnaphthalene derivatives (4a–c), which were synthesized for the first time. The study aimed to understand the steric repulsion reduction mechanisms in these overcrowded molecules with acetylene linkages. The experiments involved the use of various reactants, including lithium (trimethylsilyl)acetylide, 5,8-dibromo-1,4-naphthoquinone, SnCl2, and (trimethylsilyl)acetylene, among others, to synthesize the target compounds through a series of reactions like Sonogashira coupling. The synthesized compounds were characterized using X-ray crystallographic structure analysis, UV-Vis and fluorescence spectra, and DFT calculations to elucidate their structures and conformational behaviors. The analyses revealed three different modes of distortion—expanding of substituents, twisting of the naphthalene skeleton, and bending of acetylene units—to reduce steric repulsion, with the crystal structures being stabilized by intermolecular C–H?π interactions.
10.1055/s-2002-19298
The study focuses on the equatorial preference in the GaCl3-promoted ethenylation of cyclic ketones. The main content of the research revolves around the use of trimethylsilylethyne and GaCl3 to ethenylate silyl enol ethers derived from substituted cyclohexanones. The reaction proceeds via carbogallation of gallium enolate and alkynylgallium, generating a bisgallio-intermediate that is protodegallated under acidic conditions to form α-enones. The study investigates the stereoselectivity of this reaction, which exhibits a bias for equatorial C–C bond formation, contrasting with the axial stereochemistry observed in enolate alkylation. The chemicals used serve to explore and understand the mechanism behind this novel ethenylation reaction, which has implications for the synthesis of compounds with quaternary α-carbon atoms and enolizable products. The purpose of these chemicals is to facilitate the ethenylation process and provide insights into the stereochemical outcomes of the reactions, which are of significant interest in the field of organic synthesis.
10.1021/jo00048a038
The research focuses on the synthesis of highly substituted alkylpyrazines using a zirconium-mediated reaction. The key chemicals involved include Cp2Zr(Me)(THF)+ (1), various alkylpyrazines such as 2,5-dimethylpyrazine and 2,3-dimethylpyrazine, and different alkynes like 1-pentyne, (trimethylsilyl)acetylene, and 1-(trimethylsilyl)propyne. The process involves a sequential one-pot addition of alkylpyrazines, alkynes, and a proton source to a solution of Cp2Zr(Me)(THF)+ in CH2Cl2, yielding (E)-alkenyl-substituted alkylpyrazines in excellent yields. The regio- and stereoselectivity observed in these reactions are attributed to steric and electronic effects. The resulting alkenylpyrazines can be further manipulated using conventional synthetic techniques to produce a variety of highly substituted alkylpyrazines, including tri- and tetrasubstituted alkylpyrazines, bromoalkylpyrazines, and epoxyalkylpyrazines.
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