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1.
Longhua Yang Xingye Ren Hongming Wang Ning Zhang Sanguo Hong 《Research on Chemical Intermediates》2012,38(1):113-133
Density functional theory calculations have been carried out to explore the reaction mechanisms for the reactions of “frustrated
Lewis pairs” (FLPs) with small molecules. Four reactions were studied in the present investigation. A new N-heterocyclic carbene borane, boron amidinate compound HC(iPrN)2B(C6F5)2 (1), classified as FLPs, was chosen as the common reactant of these reactions. It was used to react with CO2, CO, and two terminal alkynes, methylacetylene and phenylacetylene. The reactions of 1 with CO2 and CO can both be regarded as the concerted addition mechanisms. In these reactions, the formations of the C2–N2 and B–O1
bonds take place simultaneously. For the reactions of 1 and methylacetylene or phenylacetylene, our calculations indicated that a deprotonation pathway and the connection between
B atoms and terminal alkyne C atoms occur by a concerted manner simultaneously, together with the connection between N2 and
hydrogen atoms. We also investigated the reaction mechanisms according to the frontier molecular orbital (FMO) theory and
carried out electric charge analyses, finding that the two results were consistent with each other perfectly. Electric charges
transfer from HOMO of 1_OPEN to LUMO of CO2 or CO. In contrast, electric charges transfer from HOMO of methylacetylene or phenylacetylene to LUMO of 1_OPEN. 相似文献
2.
Mieczyslaw Mαjkosza Witold Danikiewicz Krzysztof Wojciechowski 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):457-475
Abstract Carbanions stabilized with sulfur containing substituents are versatile intermedi-ates in organic synthesis. The great value and importance of such carbanions is connected with specific properties of the sulfur atom which is capable to exist in a variety of valent states and to form many functional groups. These various sulfur-containing groups exert different carbanion stabilizing effects and can also serve as leaving groups in nucleophilic substitution or elimination reactions. Taking into account numerous types of sulfur containing functional groups and a variety of reactions they can promote, it is well understandable that reactions of sulfur-containing carbanions have been thoroughly studied and widely exploited in organic synthesis. The reactions of such carbanions with aliphatic electrophilic partners: alkylating agents, carbonyl compounds and Michael acceptors consist a major section of this field and were subject of numerous studies as well as many monographs.1 Contrary to that, not very much was known about reactions of such carbanions with electrophilic aromatic compounds. Actually, there are only few reports on nitroarylation of sulfur-containing carbanions via replacement of halogen orfho- or para- to the nitro group in halonitrocornpounds.2 There are also some reports on the alkylation of nitroarenes and heterocyclic compounds in the reaction with sulfonium3 and sulfoxonium4 ylides, dimethylsulfoxide carbanion,5 and dialkyl or alkyl aryl sulfones carbanions.6 相似文献
3.
Christelle Mouveaux Fabienne Hochart Joëlle Levalois-Mitjaville Roger De Jaeger 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract Multisite receptors containing more than two macrocyclic cavities. despite of the fact that their syntheses, most often, require sophisticated pathways, arc of very high interest since they may allow new insights into ion channel transfer, ion conduction.[1] We report here a method which combine simple reactions, high yields (80%), with easily prepared starting reagents[2], of two new polymacrocyclic system, a tri-(r) and an hexamacrocyck(II). They were obtained by a condensation reaction between 4-formylbenzo-15-crown-5 (3 or 6 quiv, respectively) and phosphouihydrazide (1 equiv.) or hexahydrazide (1 equiv.) in tetrahydrofuran. 相似文献
4.
Summary. The anionic polymerization of four bis-functionalized styrene derivatives with α-alkylvinyl groups have been carried out in
THF at −78°C with the initiator prepared from oligo(α-methylstyryl)lithium and potassium tert-butoxide. The four monomers herein used are 4-isopropenylstyrene (4), 3-isopropenylstyrene (5), 2-isopropenylstyrene (6), and 4-(α-isopropylvinyl)styrene (7). It was found that under such polymerization conditions, the vinyl groups of both 4 and 7 are selectively polymerized and the isopropenyl and α-isopropylvinyl groups remain completely intact to afford stable living
anionic polymers. As expected, the resulting polymers possessed precisely controlled chain lengths and narrow molecular weight
distributions. More importantly, they also possessed the pendant isopropenyl and α-isopropylvinyl group in each monomer unit
possible for further modification. On the other hand, the anionic polymerization of either 5 or 6 proceeded more or less along with the unwanted side reactions leading to chain-branching, followed by cross-linking. The
positional effect of isopropenyl group on the polymerization and the cause of possible side reactions were discussed. 相似文献
5.
《Journal of Coordination Chemistry》2012,65(9):1497-1507
Reactions of Co(ClO4)2·6H2O with 2-pyrazinephosphonic acid (2-paPO3H2) under two different hydrothermal conditions gave two new cobalt 2-pyrazinephosphonates, Co(2-paPO3H)2 (1) and Co(2-paPO3)(H2O) (2). Compound 1 was obtained at 160 °C, while 2 was obtained at 180 °C. In 1, two Co(II) units are bridged by two O–P–O’s into a dimer and the dimers are linked by pyrazinyl groups into a 1-D double chain. In 2, the {CoO4N2} and {CPO3} polyhedra are interconnected via edge and corner-sharing into a metal phosphonate layer, and the layers are pillared by pyrazinyl groups into a 3-D network. Variable-temperature magnetic susceptibility studies reveal that both complexes have weak antiferromagnetic coupling between Co(II) ions. 相似文献
6.
N. I. Galyautdinov B. A. Arbuzov A. M. Butlerov 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract The reactions of enaminocarbonyl compounds (1) with phosphorylisocyanates have been investigated. Experiment established that the reactions with the participation of amino group and (or) C-2 atom form respectively ureas (2) and (or) their vinylogs (3) depending on the structure (1) i.e. the reactions proceed in two competitive directions. 相似文献
7.
Adriana Popa Corneliu Davidescu Carol Csunderlik Gheorghe Ilia Radu Trif 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1)
Abstract Poly(oxyethylene)s functionalized with quaternary phosphonium end groups were obtained by converting terminal hydroxyl end groups into phosphoniurn ion groups in the polymer-analogous reactions with phosphines and hydrogmu chloride. The products were characterized by: IR, UV. H NMR spectroscopy, thin-layer chromatography. 相似文献
8.
Mohammad Zakarianezhad Hamid Reza Masoodi Motahare Shool 《Phosphorus, sulfur, and silicon and the related elements》2016,191(7):1063-1068
A stepwise reaction mechanism between triphenylphosphine 1 and dialkyl acetylenedicarboxylates 2 in the presence of a SH-acid, such as 2-aminothiophenol 3, has been investigated theoretically with B3LYP method using 6-311++G(d,p) basis set. Potential energies of all structures participating along the reaction path have been evaluated. For all the reactions investigated, the first step was recognized to be the rate-determining step. Quantum mechanical calculations clarified the existence of reaction product as a mixture of two E- or Z-geometrical isomers, and indicate which one of them represents the major form. The effect of subsituated alkyl groups on the potential energy surfaces was investigated. Also, the natural bond orbital method was applied for better understanding the molecular interactions. 相似文献
9.
Ursula Diefenbach Michael Kretschmann 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract Different types of phosphazenes with (aminoalkyl)pyridyl side groups were synthesized. Mono- and cis-non-geminal disubstituted species 1 and 2 are formed when the remaining chlorine atoms of penta- or tetraphenoxy-substituted cyclotriphosphazenes are replaced by the pyridyl groups. Geminal di- and hexasubstituted compounds 3 and 4 can be obtained from reactions of hexachlorocyclotriphosphazene with the pyridine derivative. 相似文献
10.
Rachid Kitouni Pramila Selvanathan Olivier Galangau Lucie Norel Brahmia Ouarda 《合成通讯》2018,48(9):1052-1059
This work reports synthesis and characterizations of two new electron-poor “oligo(phenyleneethynylene) (OPE) type” molecular wires for fundamental studies of electron transport in molecular junctions. These OPE derivatives display three aromatic rings functionalized (i) with NO2 (OPN) or fluorine (OPF) groups on the central aryl core and (ii) with the requisite protected thiolate anchoring groups on the lateral rings at both ends. We show that the moderately effective Sonogashira couplings can give access to such rare electrodeficient molecules but are unfortunately associated with significant side reactions. We detail the choice of adequate reaction conditions to allow the recovery of suitable amounts of compounds bearing several strongly electron-withdrawing substituents on their central ring for further study of the physical properties. 相似文献
11.
AbstractSelective binding of fluoride anion and its alkali metal cation ion pairs by a fluorescent calix[4]arene (L) derivative bearing tryptophan moieties was studied in acetonitrile at 25 °C. It was found that LF? and LF22? complexes were formed and their stability constants were determined by means of UV and 1H NMR titrations. Both amide and indole NH groups were involved in the stabilisation of the fluoride complexes, i.e. L afforded two anion-binding sites. 1H NMR titrations provided evidence of simultaneous complexation of both Na+ cation and fluoride anion resulting in the formation of a ternary NaLF complex. In this ion pair complex, the Na+ cation was most probably bound primarily by the calixarene ether and amide oxygen atoms, whereas the indole NH groups interacted with the fluoride ion. A highly favourable ion pairing between Na+ and F– in acetonitrile was studied using potentiometric measurements. The results pointed out the importance of fluoride pairing with alkali metal cations in aprotic organic solvents and the necessity of taking these reactions into account in the course of speciation studies of such solutions. 相似文献
12.
John A. Mosbo 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):273-276
Abstract Equilibrium constants and reaction times were observed for six equilibria involving methanol, ethanol, dimethylamine, diethylamine and pyrrolidine with 2-R-1,3,2-dioxaphosphorinanes wherein R = MeO (1), EtO (2), Me2N (3), Et2N (4) and (CH2)4N (5), or 2-R-1,3-dimethyl-1,3,2-diazaphosphorinanes wherein R equalled the same five groups (6–10, respectively). Reaction times of amine substitutions were shorter for diaza compounds and for those reactions which contained pyrrolidine. Equilibrium constants were dependent not only upon the nucleophilicities of the exchanging groups, but also upon the steric interactions of the 2-substituents with the groups in the 1 and 3 positions. Thus, the values of K's for the equilibria 5 + Me2NH → 3 + (CH2)4NH, and 10 + Me2NH → 8 + (CH2)4NH were experimentally identical, whereas K for 9 + Me2NH → 8 + Et2NH was ca. eight times that for 4 + Me2NH → 3 + Et2NH. The reactions were acid catalyzed, and, for amine substitutions with 8–10, exchange could be rapid on the NMR time scale. Equilibrium positions of amine-containing reactions were [H+] dependent, where coordination of the less basic amine to phosphorus became increasingly favored by the addition of acid. These observations raise questions about a recent mechanistic proposal for catalyzed substitution reactions. Similar substitution reactions, such as Me2NH with the isomeric 4-methyl analogues of 3, provide a procedure for the determination of cis-trans isomer equilibrium distributions. 相似文献
13.
The synthesis and liquid crystalline properties of a new asymetrically tetrasubstituted porphyrin, namely 2,4-bis[2-(o-didodecyloxyphenoxycarbonyl)ethenyl]-6,7-bis[2-(m -didodecyloxycarbonyl)ethyl]-1,3,5,8-tetramethylporphyrin, 1 (figure 1), obtained from a commercially available porphyrin, hemin 2, are reported here. The synthetic route basically consists of two reactions: on the one hand, one esterification of the two propionic acid groups in positions 6 and 7 in the hemin 2 with the phenol 12, and on the other hand, a Heck-type reaction between the two vinyl groups in positions 2 and 4 of the hemin 2 and the iodo-aryl derivative 9. This is the first example of a porphyrin-based discotic liquid crystal which is neither symmetrically substituted nor prepared via total synthesis from monopyrrole units. It exhibits a well-defined enantiotropic discotic lamellar mesophase (DL) in a range of temperature from -2°C to the clearing point at 70°C. This interval includes room temperature, which makes this molecule suitable for a wide variety of applications. 相似文献
14.
Vladimir Yarovenko Igor Shedishev Aleksandr Dudnik Igor Zavarin Michail Kraushkin 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1558-1570
The reaction of aminothiophenes (1) with Appel's salt (2) affords 2-(1,2,3-dithiazol-5-ylidene)aminothiophenes (3). Under the action of ZnCl2, the latter compounds are transformed into 1,3-oxazin-4-one systems (4). The reactions of compounds 4 with dienophiles under atmospheric or high pressure give thienopyridines (6–11); the reactions with amines produce pyrimidinones (12) and guanidines (14–15). 相似文献
15.
Crenguta Dordea Frédéric Brisach Jaouad Haddaoui Françoise Arnaud-Neu Michael Bolte Alessandro Casnati 《Supramolecular chemistry》2013,25(6):347-357
Calix[4]arene derivatives fixed in the 1,3-alternate conformation and substituted at one side by four carbamoylmethylphosphine oxide (CMPO) residues were synthesised. Two CMPO groups are directly attached to the wide rim, while the second pair is bound to the narrow rim via a tri- or tetramethylene spacer. Similar compounds, in which two CMPO groups at the wide rim are combined with two picolinamide groups or two ionisable carboxylic groups at the narrow rim, were also prepared. Some of these calixarene derivatives were studied as extractants for lanthanides (La3+, Eu3+, Yb3+) and thorium (Th4+) from acidic solution into methylene chloride. For selected samples, stability constants in methanol were determined by spectrophotometric titrations. Three compounds (1b′, 13, 17) in the 1,3-alternate conformation and one intermediate in the cone conformation (18) were confirmed by a crystal structure. 相似文献
16.
Several new diaryl diselenides having intramolecular coordinating groups have been synthesized by ortho-lithiation/Na2Se2
routes in good yield. Bis[2-(N-phenylferrocenecarboxamide)] diselenide (10), bis[2-(N-tert-butylferrocenecarboxamide)] diselenide (11), (S)(S)-bis[2(-N-phenethylferrocene-carboxamide)] diselenide (12) were synthesized by the ortho-lithiation route. Bis[2-(N,N-dimethyl-aminomethylnaphthyl)] diselenide (13) was synthesized by lithium/bromide exchange reaction whereas bis(2,4-dinitrophenyl) diselenide (14) was prepared by the reaction of disodium diselenide with 2,4-dinitro-1-chlorobenzene. Thiol peroxidase-like activities of
the diorganodiselenides have been evaluated by using H2O2 as substrate and PhSH as cosubstrate. Diselenides (13) and (14) with dimethylami-nomethyl- or nitro-donor groups in close proximity to selenium, show much better thiol peroxidase-like
activities compared to diselenides10–12 with amide donor groups. Cyclic voltammetry study of diselenides10–12 derived from redox-active ferrocenamide has been carried out.
Dedicated to the memory of the late Professor Bhaskar G Maiya. 相似文献
17.
Tsutomu Kawai Yoichi Kodera Shigeru Oae Masahiro Ishida Takashi Takeda Shoji Wakabayashi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):139-148
Abstract Ligand coupling reactions take place not only between benzyl and 2-pyridyl groups and two 2-pyridyl groups in the treatment of benzyl, alkyl and aryl 2-pyridyl sulfoxides with Grignard reagents, but also between such groups as p-benzenesulfonylphenyl, 4-pyridyl, 2-quinolyl and 2-pyrimidyl, and the benzyl group. There are cases in which ligand exchange precedes ligand coupling, especially with 2-heteroaryl groups. In addition, even some alkyl groups were found to couple with the 2-pyridyl group. The ease of coupling seems to be associated with the electronegativity of the coupling carbon atom of the ligand, when one compares the 13C NMR chemical shifts. 相似文献
18.
G. S. Bratash M. K. Grachev G. I. Kurochkina L. K. Vasyanina E. E. Nifantiev 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2593-2599
The interaction of 1,4:3,6-dianhydro-D-sorbitol with phosphorous and phenylphosphonous acid amidochlorides leads to oligophosphites and -phosphonites with free hydroxyl groups on the periphery of their molecules. The obtained compounds were introduced into reactions via the transformation of trivalent phosphorus and hydroxyl groups. 相似文献
19.
AbstractA series of “drug-like” compounds based on quinoxaline scaffold with arylsulfonyl hydrazinyl, arylformyl hydrazinyl or arylsulfonyl groups at C-2 and aryloxy groups at C-3, were synthesized in 4 or 5 steps involving cyclization, chlorination and coupling reactions. Cellular anti-proliferative activities of these quinoxaline derivatives in vitro were determined, which revealed that the inhibitory potency and selectivity of 6f was comparable to that of the positive control. 相似文献
20.
《Journal of Coordination Chemistry》2012,65(1-3):65-78
Abstract Metal carbonyl anions exhibit one- and two-electron reactions. The two-electron processes involving transfer of groups (hydrogen, alkyl, and halogen) between metal centers are related to the nucleophilicity. The one-electron processes are primarily outer-sphere electron transfer for the metal carbonyl anions. These reactions are observed in the presence of oxidants such as coordination complexes, pyridinium salts, metal carbonyl dimers and metal carbonyl clusters. However, in contrast to organic reactions, the metal carbonyl anions may undergo inner-sphere electron transfer. Reactions of metal carbonyl anions of low nucleophilicity with metal carbonyl cations or halides are best interpreted as inner-sphere, one-electron transfer. 相似文献