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1.
Stereoselectivity in the intermolecular Pauson-Khand reaction of electron-deficient terminal alkynes
A family of terminal alkyne dicobalthexacarbonyl complexes bearing groups with a range of electron-withdrawing abilities has been synthesized. After submitting these complexes to the intermolecular Pauson-Khand reaction with norbornadiene, electron-deficient substrates afforded up to 26% of the unexpected endo-cyclopentenone. 相似文献
2.
This review will describe the ongoing efforts being made to incorporate organometallic fragments into the framework of dendrimers. While purely dendritic organic molecules are well known and well studied, species incorporating organometallic moieties potentially offer many benefits that are not available to only organic containing dendrimers. For example, catalytic or redox active organometallic functions can be included in the dendritic framework and impart these characteristics onto the dendrimer. This report will give an overview of the latest developments in this field by highlighting selected examples that detail novel synthetic strategies or dendrimer construction methodologies, interesting practical applications or address specific problems associated with organometallic dendrimers. 相似文献
3.
Michael R. Buchmeiser 《Monatshefte für Chemie / Chemical Monthly》2003,134(3):327-342
Summary. The metathesis polymerization, respectively cyclopolymerization, of 1-alkynes and 1,6-heptadiynes using well-defined group
VIA transition metal initiators is summarized. For purposes of comparison, selected quaternary catalytic systems used as alternatives
as well as the properties of the resulting materials will be presented. Special consideration is given to the mechanistic
advancements that have been made during the last decade, which allow the tailor-made synthesis of conjugated materials with
interesting optical and electronic properties.
E-mail: michael.r.buchmeiser@uibk.ac.at
Received November 20, 2002; accepted November 21, 2002 相似文献
4.
Chinmoy Mukherjee 《Tetrahedron letters》2006,47(4):441-445
A convenient odorless methodology has been devised for the preparation of 1,2-trans-thio- and selenoglycosides through zinc-mediated cleavage of disulfides and diselenides and reaction of the thiolate and selenides formed in situ with glycosyl bromides. The yields were excellent in all cases. 相似文献
5.
The adsorption and decomposition of monoethylgermane (GeH3Et) on the Si(100)-(2×1) surface was investigated with the intent of elucidating the surface processes leading to the deposition of germanium. The low-temperature adsorption of the molecule was explored, as well as its thermal decomposition. H2 and C2H4 are observed as the desorption products in temperature-programmed desorption experiments. The ethylene is produced by a hydride elimination reaction within the adsorbed ethyl groups. The amount of Ge which can be deposited in a reaction cycle is correlated with the number of sites occupied by the ethyl groups upon the dissociation of GeH3Et. 相似文献
6.
Huan Wang Dr. Mahbod Morshedi Dr. Mahesh S. Kodikara Dr. Yovan de Coene Prof. Koen Clays Prof. Chi Zhang Prof. Mark G. Humphrey 《Angewandte Chemie (International ed. in English)》2023,62(27):e202301754
Porphyrins are important macrocycles with applications in several areas including therapy, catalysis, and sensing. Strong nonlinear optical (NLO) responses are the key to fully exploiting the potential of these biocompatible molecules. We herein report that certain metal-alkynyl donor/nitro acceptor-functionalized porphyrins are attractive candidates for NLO applications. We show that specific examples exhibit record quadratic optical nonlinearity, exceptional two-photon absorption, and outstanding three-photon absorption, and we report the first porphyrins that exhibit four-photon absorption. The two-, three-, and four-photon absorption maxima are found at the corresponding multiples of linear absorption bands that time-dependent density functional theory assigns as admixtures of porphyrin-localized π*←π and donor-porphyrin to porphyrin-acceptor charge-transfer transitions. 相似文献
7.
A summary of the Fluorinated Ylide Chemistry, Organometallic Chemistry, Phosphonate Chemistry, Single-Electron-Transfer Chemistry and Metal Hydride Chemistry carried out at the University of Iowa is described. 相似文献
8.
The synthetic route to the dimesitylpalladium(II) complex [(bpy)PdMes2] ( 1 ) (Mes = mesityl = 2,4,6‐trimethyl phenyl) does not only give the desired compound but also the 6‐mesityl‐2,2′bipyridyldimesitylpalladium [(6‐Mes‐bpy)PdMes2] ( 2 ) complex and the free ligand 6,6′‐dimesityl‐2,2′‐bipyridine in reasonable yields. Single crystals of 2 were examined by X‐Ray diffraction. The compound reveals a sterically crowded molecular structure. An intramolecular π‐stacking interaction was found between the mesityl substituent on the bipyridine ligand and the adjacent mesityl ligand. The electrochemical behaviour of 1 and 2 together with a related compound was examined at various temperatures showing two reversible reduction reactions and reversible one‐electron oxidation steps at low temperatures. The latter are assigned to PdII/PdIII couples. 相似文献
9.
Treatment of the hydrosulfido tungsten complex CpW(CO)3SH with acid chlorides (RCOCl) or sulfonyl chlorides (RSO2Cl) affords CpW(CO)3SCOR (1) [R = Me (a), CH2Cl (b), Ph (c), 4-C6H4NO2 (d)] and CpW(CO)3SSO2R (2) [R = Me (a), Ph (b), 4-C6H4Cl (c), 4-C6H4NO2 (d)], respectively. The novel complexes, 1 and 2, were fully characterized by elemental analyses, IR and 1H NMR spectroscopy. The solid state structures of CpW(CO)3SCOPh (1c) and CpW(CO)3SSO2-4-C6H4Cl (2c) were determined by an X-ray crystal structure analysis. 相似文献
10.
Kotohiro Nomura 《中国化学会会志》2012,59(2):139-148
Recent examples for synthesis and reaction chemistry with (imido)vanadium(V)‐alkyl, ‐alkylidene complexes have been briefly summarized. (Arylimido)vanadium(V) dichloride complexes especially containing aryloxo ligands exhibited notable activities for ethylene polymerization, and the reacition pathways for the polymerization/dimerization using (imido)vanadium(V) dichloride complexes containing (2‐anilidomethyl)pyridine ligands can be tuned by modification of the steric bulk in the imido substituents; the adamantylimido analogues exhibited exceptionally high both activity and selectivity in the dimerization. These vanadium(V)‐alkyl complexes showed unique reactivity toward phenols; the reaction proceeds via coordination of phenols to the vanadium. The vanadium(V)‐alkylidene complexes were generated by α‐hydrogen elimination from the dialkyl analogues in the presence of PMe3 etc.; the subsequent 1,2‐C‐H bond activation of benzene with (arylimido)vanadium(V)‐alkylidene containing 1,3‐(2′,6′‐diiso‐propylphenyl)imidazolin‐2‐iminato (ImDIPPN) ligand took place cleanly. 相似文献