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61.
62.
Ishihara S Hill JP Shundo A Richards GJ Labuta J Ohkubo K Fukuzumi S Sato A Elsegood MR Teat SJ Ariga K 《Journal of the American Chemical Society》2011,133(40):16119-16126
Porphyrin derivatives bearing 2,6-di-tert-butylphenol substituents at their 5,15-positions undergo reversible photoredox switching between porphyrin and porphodimethene states as revealed by UV-vis spectroscopy, fluorescence spectroscopy, and X-ray single-crystal analyses. Photoredox interconversion is accompanied by substantial variations in electronic absorption and fluorescence emission spectra and a change of conformation of the tetrapyrrole macrocycle from planar to roof-shaped. Oxidation proceeds only under photoillumination of a dianionic state prepared through deprotonation using fluoride anions. Conversely, photoreduction occurs in the presence of a sacrificial electron donor. Transient absorption spectroscopy and electron spin resonance spectroscopy were applied to investigate the processes in photochemical reaction, and radical intermediates were characterized. That is, photooxidation initially results in a phenol-substituent-centered radical, while the reduction process occurs via a delocalized radical state involving both the macrocycle and 5,15-substituents. Forward and reverse photochemical processes are governed by different chemical mechanisms, giving the important benefit that conversion reactions are completely isolated, leading to better separation of the end states. Furthermore, energy diagrams based on electrochemical analyses (cyclic voltammetry) were used to account for the processes occurring during the photochemical reactions. Our molecular design indicates a simple and versatile method for producing photoredox macrocyclic compounds, which should lead to a new class of advanced functional materials suitable for application in molecular devices and machines. 相似文献
63.
A novel addition reaction of an aromatic hydrazine to the diketone derivative of C60 occurs highly regioselectively with an unusual migration of two hydrogen atoms from the hydrazine to the fullerene and affords a fluorescent product having a methylene carbon along the orifice. 相似文献
64.
65.
It is shown that NiN(2) and noble gas atoms, Ar, Ne, and He, combine with the binding energy of 11.52, 4.06, and 7.37 kcal/mol, respectively, by the multireference perturbational (CASPT2) method. By the density functional theory calculations using MPWPW91 functionals, the Ni-N-N bending frequency in NiN(2) and Ar-NiN(2) is estimated as 310.7 and 358.7 cm(-1), respectively, the latter of which is in good agreement with the corresponding experimental frequency, 357.0 cm(-1), determined for NiN(2) isolated in solid argon. 相似文献
66.
An aroma chemical emitted from Gerris paludum insularis was analyzed by means of GC and GC-MS. The main constituent was identified as iso amyl alcohol (3-methyl-1-butanol). The chemical showed a characteristic aroma of Gerris paludum insularis. 相似文献
67.
Kazuyuki Kubo Hiroshi Nakazawa Hiroyasu Inagaki Tomoyuki Miyake Tsutomu Mizuta Katsuhiko Miyoshi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8-9):2159-2160
Treatment of [Cp*(CO) 2 M{P(NHPh)(OMe) 2 }]PF 6 (M = Fe and Ru) with NaNH 2 gives metallaiminophosphoranes, Cp*(CO) 2 M{P(NPh)(OMe) 2 }. The x-ray structures and reactivity of the complexes are reported. 相似文献
68.
Tsuzuki S Wakisaka A Ono T Sonoda T 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(3):951-960
The geometries and interaction energies of complexes of pyridine with C6F5X, C6H5X (X=I, Br, Cl, F and H) and RFI (RF=CF3, C2F5 and C3F7) have been studied by ab initio molecular orbital calculations. The CCSD(T) interaction energies (Eint) for the C6F5X–pyridine (X=I, Br, Cl, F and H) complexes at the basis set limit were estimated to be ?5.59, ?4.06, ?2.78, ?0.19 and ?4.37 kcal mol?1, respectively, whereas the Eint values for the C6H5X–pyridine (X=I, Br, Cl and H) complexes were estimated to be ?3.27, ?2.17, ?1.23 and ?1.78 kcal mol?1, respectively. Electrostatic interactions are the cause of the halogen dependence of the interaction energies and the enhancement of the attraction by the fluorine atoms in C6F5X. The values of Eint estimated for the RFI–pyridine (RF=CF3, C2F5 and C3F7) complexes (?5.14, ?5.38 and ?5.44 kcal mol?1, respectively) are close to that for the C6F5I–pyridine complex. Electrostatic interactions are the major source of the attraction in the strong halogen bond although induction and dispersion interactions also contribute to the attraction. Short‐range (charge‐transfer) interactions do not contribute significantly to the attraction. The magnitude of the directionality of the halogen bond correlates with the magnitude of the attraction. Electrostatic interactions are mainly responsible for the directionality of the halogen bond. The directionality of halogen bonds involving iodine and bromine is high, whereas that of chlorine is low and that of fluorine is negligible. The directionality of the halogen bonds in the C6F5I– and C2F5I–pyridine complexes is higher than that in the hydrogen bonds in the water dimer and water–formaldehyde complex. The calculations suggest that the C? I and C? Br halogen bonds play an important role in controlling the structures of molecular assemblies, that the C? Cl bonds play a less important role and that C? F bonds have a negligible impact. 相似文献
69.
Hill JP Subbaiyan NK D'Souza F Xie Y Sahu S Sanchez-Ballester NM Richards GJ Mori T Ariga K 《Chemical communications (Cambridge, England)》2012,48(33):3951-3953
Tetrapyrazinoporphyrazine substituted at its periphery with eight antioxidant 3,5-di-t-butyl-4-hydroxyphenyl groups behaves as a turn-on fluorescent sensor for fluoride anions. Conversely, the precursor antioxidant-substituted 1,2-phthalonitrile was found to act in turn-off mode suggesting that the origin of the phenomenon lies at the phenolate-substituted 1,4-pyrazinyl moiety. 相似文献
70.
Novel chiral bisformamides have been prepared from (R,R)-1,2-cyclohexanediamine and utilized as Lewis bases in the asymmetric allylation of benzaldehyde with allyltrichlorosilane. The reaction in the presence of Lewis base 1i gave an 83:17 enantiomeric ratio (R/S) of the products in 90% isolated yield. 相似文献