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ab initio Calculation of the Cl2C=CHOMe molecule has been carried out with geometrical optimization in the split valence basis set in the RHF/6-31G*//RHF/6-31G* approximation. An analysis of the populations of the p-orbitals of the Cl atoms implies the absence of p,-conjugation between the unshared electron pairs of these atoms and the -bond. The asymmetry parameters of the electric field gradient at the35Cl nuclei, calculated from the 3p-orbital populations of the Cl atoms, practically coincide with the experimental values.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2369–2372, December, 1995.The authors are grateful to G. S. Beloglazov for assistance in accomplishingab initio calculations. 相似文献
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Ab initio calculation of the 4-ClC6H4CH2Cl molecule was performed by the restricted Hartree-Fock method in the split valence 6–31 G* basis set with complete optimization of its geometry. Populations of p-orbitals of atoms of this molecule were analyzed.35Cl NQR frequencies and asymmetry parameters of the electric field gradient on35Cl nuclei were estimated on the basis of the populations of valent p-orbitals of CI atoms and their components. Good conformity with the experimental values was obtained when only less diffuse components of p-orbitals were used in calculations of populations.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 823–826, April, 1996. 相似文献
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Based on the MNDO calculations of the electronic structure of the molecules of acrolein, glyoxal, and butadiene, possible mechanisms of the conjugation in systems containing conjugated C=C and C=O bonds have been analyzed. In the electronic ground state ofs-trans-acrolein, the , -conjugation is very small, whereas in the first excited electronic state, the conjugation is substantial, In the ground state ofs-trans-glyoxal, the ,-conjugation should manifest itself clearly but should be weaker than in butadiene, whereas in the first excited electronic state, this conjugation should be more pronounced, Alternation of double and single bonds in the classic structural formula of a molecule does not ensure that this molecule exhibits the properties of a -conjugated system even in planar conformations.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1648–1652, July, 1996. 相似文献
4.
Elisabet Öberg Sascha Ott 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-3):164-167
Abstract Bis(trimethylsilyl)-terminated C,C-diacetylenic phosphaalkene was prepared from Mes*PCl2 and a propargylic Grignard reagent that in turn was formed from 3-bromo-1,5-bis(trimethylsilyl)penta-1,4-diyne and Rieke-Mg. 相似文献
5.
Elisabet Öberg Andreas Orthaber Marie-Pierre Santoni Fredrick Howard Sascha Ott 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-3):152-158
Abstract Attempts to utilize C-ethylenic phosphaalkenes in metathesis reactions are discussed. Unprecedented reactivity is observed where the vinylphosphaalkene undergoes the first step of the catalytic cycle and cross-metathesis with the phenylmethylene moiety of Grubbs 2nd generation catalyst. However, homo-metathesis reaction to form 1,6-diphosphahexa-1,3,5-triene is not observed, presumably due to steric constraints. 相似文献
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Stable meso‐Aryl β‐Alkyl Hybrid Sapphyrin with a Warped π‐Conjugation Circuit and Neo‐Confused Sapphyrin–Silver(I) Complex
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A meso‐aryl and β‐alkyl substituted sapphyrin and its rhodium(I) and silver complexes were synthesized. This sapphyrin was so stable that the non‐inverted and warped structure could be analyzed by X‐ray crystallography even in its neutral state. Its bis‐rhodium(I) complex has a more planar structure than the sapphyrin with enhanced aromaticity over the conjugation circuit. On the other hand, silver metalation of the sapphyrin caused a marked core rearrangement into a neo‐confused sapphyrin derivative with a C(α)?N bond and a twisted macrocycle. 相似文献
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Dr. Nicolas D'Imperio Dr. Valentina Pelliccioli Dr. Sara Grecchi Dr. Alberto Bossi Prof. Francesca Vasile Prof. Silvia Cauteruccio Dr. Anna I. Arkhypchuk Dr. Arvind Kumar Gupta Prof. Dr. Andreas Orthaber Prof. Dr. Sascha Ott Prof. Emanuela Licandro 《European journal of organic chemistry》2023,26(4):e202201209
The first examples of a π-conjugated benzo[b]phosphole P-oxide in which two phosphole P-oxide units are connected by a carbon-carbon double bond are described. The molecules are synthesized as E isomers with respect to the carbon-carbon double bond and exist as stable cis and trans isomers (chiral and meso one respectively) relatively to the two stereogenic P atoms. The optical and electrochemical properties of both isomers have been investigated by experiment and computations. 相似文献
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Prof. Dr. Michio Yamada Yuta Uokawa Shino Sasaki Naohiro Iha Yoshihisa Hashimoto Yuya Nagasaki Prof. Dr. Yutaka Maeda Prof. Dr. Mitsuaki Suzuki 《European journal of organic chemistry》2023,26(35):e202300633
The physicochemical properties of fullerene-based materials typically vary depending on the type and mode of addition of functional groups; therefore, developing fullerene derivatives with novel structures is imperative for further progress in materials science. In this study, we develop an efficient one-step strategy for synthesizing cyclobutene-annulated fullerene derivatives (cyclobutenofullerenes) and characterize their electronic properties. Despite the steric strain, cyclobutenofullerenes can be easily prepared via a one-step reaction of C60 with a secondary propargylic phosphate. Structural analysis of the reaction intermediates suggests that the cascade reaction proceeds through a formal [2+2] cycloaddition of C60 with an allene, caused by the 1,3-migration of the propargylic phosphate, followed by an additional 1,3-migration and the subsequent 1,2-elimination of the phosphodiester moiety. 相似文献
10.
The rates of aqua substitution from [Pt{2-(pyrazol-1-ylmethyl)quinoline}(H2O)2](ClO4)2, [Pt(H2Qn)], [Pt{2-(3,5-dimethylpyrazol-1-ylmethyl)quinoline}(H2O)2](ClO4)2, [Pt(dCH3Qn)], [Pt{2-[(3,5-bis(trifluoromethyl)pyrazol-1-ylmethyl]quinoline}(H2O)2](ClO4)2, [Pt(dCF3Qn)], and [Pt{2-[(3,5-bis(trifluoromethyl)pyrazol-1-ylmethyl]pyridine}(H2O)2](ClO4)2, [Pt(dCF3Py)], with three sulfur donor nucleophiles were studied. The reactions were followed under pseudo-first-order conditions as a function of nucleophile concentration and temperature using a stopped-flow analyzer and UV/visible spectrophotometry. The substitution reactions proceeded sequentially. The second-order rate constants for substituting the aqua ligands in the first substitution step increased in the order Pt(dCH3Qn) < Pt(dCF3Qn) < Pt(H2Qn) < Pt(dCF3Py), while that of the second substitution step was Pt(dCH3Qn) < Pt(dCF3Qn) < Pt(dCF3Py) < Pt(H2Qn). The reactivity trends confirm that the quinoline substructure in the (pyrazolylmethyl)quinoline ligands acts as an apparent donor of electron density toward the metal center rather than being a π-acceptor. Measured pKa values from spectrophotometric acid–base titrations were Pt(H2Qn) (pKa1 = 4.56; pKa2 = 6.32), Pt(dCH3Qn) (pKa1 = 4.88; pKa2 = 6.31), Pt(dCF3Qn) (pKa1 = 4.07; pKa2 = 6.35), and Pt(dCF3Py) (pKa1 = 4.76; pKa2 = 6.27). The activation parameters from the temperature dependence of the second-order rate constants support an associative mechanism of substitution. 相似文献