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1.
Chem Asian J ; 19(9): e202400111, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38380801

RESUMO

A stable dialkylgermanone was generated by mixing a solid of the corresponding dialkylgermylene and gaseous N2O. While the dialkylgermanone is marginally persistent in solution and gradually converts to its head-to-tail dimer at room temperature, the addition of THF to the dialkylgermanone provided an isolable THF-coordinated dialkylgermanone. The THF-coordinated dialkylgermanone reacts with H2O, THF, and B(C6F5)3 similar to the corresponding base-free two-coordinate dialkylsilanone. The dialkylgermanone undergoes deoxygenation in the presence of triphenylphosphine to provide the corresponding germylene and olefination upon treatment with phosphaylide Ph3PCHPh to afford the corresponding Ge=C bond compound (germa-Wittig reaction).

2.
Molecules ; 29(2)2024 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-38257320

RESUMO

Several types of 1,4-diphenylanthracene derivatives 1-4 were prepared, and their photophysical properties were observed in the solid and solution states. Interestingly, the CN-group-substituted 1,4-diphenylanthracene derivative 2 was found to exhibit a higher fluorescence quantum yield (ϕf = 0.71) in the solid state than in the solution state, probably due to the formation of an intermolecular Ar-CN⋯H-Ar hydrogen bond and antiparallel type locked packing structure in the solid state. Furthermore, for some derivatives, an increase in the fluorescence quantum yield was observed in the PMMA film (1 wt%) over both the solid state and the solution state. More interestingly, some of the 1,4-diphenylanthracene derivatives exhibited unusual mechanofluorochromic properties with a "hypsochromic shift" in luminous color depending on the substituents of the phenyl group, and with the derivatives having CF3, OMe, CN, and two F substituents (1d-1f, 2-4) showing a significant luminous color change with a "hypsochromic shift" after grinding. However, no change in the luminous color was observed for the derivatives having H, Me, and one F substituent (1a-1c), and especially for some of the CN-substituted derivatives, a reversible luminous color change with a "hypsochromic shift" was observed, probably due to the formation of an antiparallel type packing structure. These "hypsochromic" anthracene derivatives could probably be utilized as new mechanofluorochromic materials.

3.
ACS Appl Mater Interfaces ; 13(34): 40612-40617, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34415717

RESUMO

µ-Nitrido- and µ-carbido-bridged iron phthalocyanine dimers, when used as cathode-active materials for rechargeable lithium batteries, showed four stable redox waves in cyclic voltammetry studies in solution and a stable discharge capacity of approximately 60 mAh g-1 after 200 cycles. These results indicate that µ-heteroatom-bridged iron phthalocyanine dimers are good platforms for designing novel phthalocyanine-based electrode-active materials.

4.
Chem Asian J ; 15(14): 2218-2230, 2020 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-32495490

RESUMO

A 2 : 4 mixture of tetrakis[4-(4-pyridyl)phenyl]cavitand (1) or tetrakis[4-(4-pyridyl)phenylethynyl]cavitand (2) and Pd(dppp)(OTf)2 self-assembles into a homocapsule {12 ⋅ [Pd(dppp)]4 }8+ ⋅ (TfO- )8 (C1) or {22 ⋅ [Pd(dppp)]4 }8+ ⋅ (TfO- )8 (C2), respectively, through Pd-Npy coordination bonds. A 1 : 1 : 4 mixture of 1, 2, and Pd(dppp)(OTf)2 produced a mixture of homocapsules C1, C2, and a heterocapsule {1 ⋅ 2 ⋅ [Pd(dppp)]4 }8+ ⋅ (TfO- )8 (C3) in a 1 : 1 : 0.98 mole ratio. Selective formation (self-sorting) of homocapsules C1 and C2 or heterocapsule C3 was controlled by guest-induced encapsulation under thermodynamic control. Applications of Pd-Npy coordination capsules with the use of 1 were demonstrated. Capsule C1 serves as a guard nanocontainer for trans-4,4'-diacetoxyazobenzene to protect against the trans-to-cis photoisomerization by encapsulation. A chiral capsule {12 ⋅ [Pd((R)-BINAP)]4 }8+ ⋅ (TfO- )8 (C5) was also constructed. Capsule C5 induces supramolecular chirality with respect to prochiral 2,2'-bis(alkoxycarbonyl)-4,4'-bis(1-propynyl)biphenyls by diastereomeric encapsulation through the asymmetric suppression of rotation around the axis of the prochiral biphenyl moiety.

5.
Chem Sci ; 11(31): 8145-8150, 2020 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34123086

RESUMO

Introduction of atropisomeric axes into a bent bispyridine ligand leads to the quantitative formation of a complex mixture of atropisomeric M2L4 cages upon treatment with metal ions. Whereas the isomer ratio of the obtained cage mixture, consisting of up to 42 isomers, is insensitive to temperature and solvent, the quantitative convergence from the mixture to a single isomer is accomplished upon encapsulation of a large spherical guest, namely fullerene C60. The observed isomerization with other guests depends largely on their size and shape (e.g., <10 and 82% convergence with planar triphenylene and bowl-shaped corannulene guests, respectively). Besides the unusual guest-induced convergence, the present cage mixture displays the strongest guest emission (Φ F = 68%) among previously reported M n L m cages and capsules, upon encapsulation of a BODIPY dye in water.

6.
Acta Crystallogr C Struct Chem ; 75(Pt 3): 265-270, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30833520

RESUMO

Calix[4]arene and oxacalix[4]arene derivatives have eight possible conformations in the up and down directions of their four aromatic rings from the mean plane of a bridged central ring, the conformations of which determine the functionality of the host frameworks. Despite being a known compound for five decades, oxacalix[4]arene, C24H16O4, has not been characterized previously by crystallographic methods. It crystallizes from hexane/CH2Cl2 solution to give two polymorphs, i.e. prismatic and block-shaped crystals as twisted 1,3-alternate structures with S4 and C2 symmetry, respectively. These were previously suggested as the prefered stable conformations by density functional theory (DFT) calculations.

7.
Chempluschem ; 84(11): 1647, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31943871

RESUMO

Invited for this month's cover are Takahiro Tsuchiya and Yasuhiro Mazaki, and their colleague Yuka Katsuoka, from Kitasato University, Japan, along with collaborators from Bruker Japan (Kenji Yoza) and Rigaku Corporation (Hiroyasu Sato). The cover picture shows the twisted structure of 2,2'-di(pyridin-4-yl)-1,1'-biazulenes, which form a 3:3 cyclic complex with PdCl2 . The rotation of the bonds at the 1,1'-positions of the azulene subunits was padlocked by the complexation. Read the full text of the article at 10.1002/cplu.201900262.

8.
Chempluschem ; 84(11): 1659-1667, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31943874

RESUMO

2,2'-Diaryl-1,1'-biazulenes were synthesized and electronic communication between the azulene subunits was suggested based on redox measurements. The linkage of azulene at the 1-position also appeared to increase the HOMO levels. In addition, cyclic voltammetry measurements of 2-arylazulenes showed a return peak associated with the oxidation, which was not observed for azulene. The stabilization of the single-electron oxidant may be due to the SOMO-HOMO energy inversion phenomenon. X-ray crystallography of the azulene dimers revealed that this species possessed a syn-type structure in which both aryl groups in the 2-positions formed π-stacks. The twisted structure was indicated to be in the (R)- or (S)-configuration for all molecules in the unit cell. Spontaneous resolution was also shown. Furthermore, from the solid circular dichroism (CD) spectral measurements, the relationship between the absolute configuration of the molecules and the CD spectra was determined. A racemization rotational barrier of ca. 27 kcal mol-1 was calculated. Moreover, the pyridylazulene dimer cyclized upon reaction with PdCl2 to form a 3 : 3 complex, in which the biazulene units cyclized to give ratios between the (R)- and (S)-forms of either 2 : 1 or 1 : 2.

9.
RSC Adv ; 9(22): 12365-12369, 2019 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-35515875

RESUMO

A novel asymmetric photodimerization reaction of coumarin derivatives bearing the (S)-4-benzyl-2-oxazolidinone auxiliary provides only the syn-head-to-tail (syn-HT) dimer with moderate diastereoselectivity (up to 75 : 25). The mechanism of complete syn-HT selectivity and moderate diastereoselectivity is proposed based on the result of density functional theory (DFT) calculation. The benzyl group of the (S)-4-benzyl-2-oxazolidinone auxiliary in combination with a Lewis acid exerts effective diastereofacial shielding of the reaction site.

10.
Org Lett ; 20(21): 6934-6937, 2018 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-30346183

RESUMO

The dielectric properties of powdered molecular gyrotops with a thiophenedioxide-diyl are reported. Crystals without a solvent molecule show usual dielectric relaxation spectra due to orientation polarization of the dipolar rotor, while a crystal having ethanol as the crystalline solvent molecule showed novel temperature-dependent dielectric relaxation switching by crystal-to-crystal phase transition, which is induced by hydrogen-bonding interactions between thiophene dioxide and ethanol.

11.
J Pept Sci ; 24(10): e3120, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30221432

RESUMO

Four cyclic octapeptides were designed from ascidiacyclamide [cyclo(-Ile-Oxz-D-Val- Thz-)2 ] (ASC, 1) to investigate the effects of oxazoline (Oxz) and thiazole (Thz) rings on the structures and cytotoxicities of the peptides. cyclo(-Ile-Thz-D-Val-Oxz-)2 (2) had the same number of Oxz and Thz rings as ASC, but the ring positions were switched. cyclo(-Ile-Oxz-D-Val-Thz-Ile-Thz-D-Val-Thz-) (3) and cyclo(-Ile-Thz-D-Val-Oxz-Ile-Thz-D-Val-Thz-) (4) contained one Oxz and three Thz rings within the molecule. All Oxz rings were substituted with Thz in cyclo(-Ile-Thz-D-Val-Thz-)2 (5). These analogues had new Oxz and Thz blocks forming the 24-membered ring. Based on CD spectra and X-ray diffraction analyses, the structures of all four analogues were classified as square ASC forms. But the structures of 2 and 5 differed from the original square form of 1, and they showed no cytotoxicity. The structure of 3 was very similar to that of 1, and 3 showed 10 times greater cytotoxicity than 1. Although no definite structure of 4 was obtained, it showed three times greater cytotoxicity than 1. It appears that the position and number of Oxz residues are essential determinants in the structure-cytotoxicity relationship of ASC analogues.


Assuntos
Antineoplásicos/síntese química , Peptídeos Cíclicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Dicroísmo Circular , Cristalografia por Raios X , Humanos , Conformação Molecular , Oxazolona/química , Peptídeos Cíclicos/química , Peptídeos Cíclicos/farmacologia , Relação Estrutura-Atividade , Tiazóis/química
12.
J Org Chem ; 83(17): 10655-10659, 2018 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-30066569

RESUMO

C2 v-Symmetric octaalkoxyfullerenes, C60(OR)8 (R = CH3, C2H5, CH2CF3), were synthesized by reacting octabromofullerene with the corresponding alcohols in the presence of AgBF4. The reactions occurred with no change in the addition pattern, and the compounds were unambiguously characterized by NMR spectroscopy and X-ray structure analysis. Electrochemical measurements revealed not only that these derivatives have stable redox properties but also that their LUMO levels can be tuned over a very wide range.

13.
Inorg Chem ; 57(8): 4571-4589, 2018 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-29611703

RESUMO

Herein, we report on the stereospecific synthesis of two single isomers of tris-heteroleptic tris-cyclometalated iridium(III) (Ir(III)) complexes composed of three different nonsymmetric cyclometalating ligands via heteroleptic halogen-bridged Ir dimers [Ir(tpy)(F2ppy)(µ-Br)]2 17b and [Ir(mpiq)(F2ppy)(µ-Br)]2 27b (tpyH: (2-(4'-tolyl)pyridine) and F2ppyH: (2-(4',6'-difluorophenyl)pyridine), and mpiqH: (1-(4'-methylphenyl)isoquinoline)) prepared by Zn2+-promoted degradation of Ir(tpy)2(F2ppy) 21 and Ir(mpiq)2(F2ppy) 26, as reported by us. Subsequently, 17b and 27b were converted to the tris-heteroleptic tris-cyclometalated Ir complexes Ir(tpy)(F2ppy)(mpiq) 25 consisting of tpy, F2ppy, and mpiq, as confirmed by spectroscopic data and X-ray crystal structure analysis. The first important point in this work is the selective synthesis of specific isomers among eight possible stereoisomers of Ir complexes having the same combination of three cyclometalating ligands. Namely, two meridional forms of 25 were synthesized and isolated. The second finding is that the different stereoisomers of 25 have different stability. Finally, different stereoisomers exhibit different emission spectra. Namely, one of its stereoisomers 25a exhibits a single broad emission from ca. 550 nm to ca. 650 nm (orange emission), while stereoisomer 25c emits dual emission at ca. 509 nm and ca. 600 nm (pale pink emission), as supported by time-dependent density functional theory calculation. To the best of our knowledge, this is the first report of the selective and efficient synthesis of different stereoisomers of tris-heteroleptic tris-cyclometalated Ir(III) complexes that have different stabilities and different photophysical properties.

14.
Chem Commun (Camb) ; 53(91): 12258-12261, 2017 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-29094113

RESUMO

Two novel meso-dicycloalkylporphycenes, namely meso-dicyclopentyl- (Cy5Pc) and meso-dicyclohexylporphycenes (Cy6Pc) are synthesized for the first time in porphycene chemistry. We use intermolecular oxidative coupling of 5,6-dicycloalkydipyrroethenes mediated by hypervalent iodine(iii) reagents. The solution fluorescence maxima of Cy5Pc are more than 400 times as intense as that of Cy6Pc. The results suggested that photoluminescence switching is achieved through the ring strain perturbation of the meso-substituted cycloalkyl groups on the porphycene cavity.

15.
J Am Chem Soc ; 138(38): 12564-77, 2016 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-27623394

RESUMO

The components of a 4:1 mixture of Rh(III)Cl tetrakis(4-methylphenyl)porphyrin 1 and a bowl-shaped tetra(4-pyridyl)cavitand 4 self-assemble into a 4:1 complex 14•4 via Rh-pyridyl axial coordination bonds. The single-crystal X-ray diffraction analysis and variable-temperature (VT) (1)H NMR study of 14•4 indicated that 14•4 behaves as a quadruple interlocking gear with an inner space, wherein (i) four subunits-1 are gear wheels and four p-pyridyl groups in subunit-4 are axes of gear wheels, (ii) one subunit-1 and two adjacent subunits-1 interlock with one another cooperatively, and (iii) four subunits-1 in 14•4 rotate quickly at 298 K on the NMR time scale. Together, the extremely strong porphyrin-Rh-pyridyl axial coordination bond, the rigidity of the methylene-bridge cavitand as a scaffold of the pyridyl axes, and the cruciform arrangement of the interdigitating p-tolyl groups as the teeth moiety of the gear wheels in the assembling 14-unit make 14•4 function as a quadruple interlocking gear in solution. The gear function of 14•4 was also supported by the rotation behaviors of other 4:1 complexes: 24•4 and 34•4 obtained from Rh(III)Cl tetrakis[4-(4-methylphenyl)phenyl]porphyrin 2 or Rh(III)Cl tetrakis(3,5-dialkoxyphenyl)porphyrin 3 and 4 also served as quadruple interlocking gears, whereas 14•5 obtained from 1 and tetrakis[4-(4-pyridyl)phenyl]cavitand 5 did not behave as a gear. The results of activation parameters (ΔH(⧧), ΔS(⧧), and ΔG(⧧)) obtained from Eyring plots based on line-shape analysis of the VT (1)H NMR spectra of 14•4, 24•4, and 34•4 also support the interlocking rotation (geared coupled rotation) mechanism.

16.
Chemistry ; 22(23): 7771-81, 2016 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-27136086

RESUMO

Bis[2,4-di(trifluoromethyl)quinoline-7-yl]amine (1), bis[2,4-di(trifluoromethyl)quinoline-7-yl]methylamine (2), bis[2,4-di(trifluoromethyl)quinoline-7-yl]phenylamine derivatives, Q2 NPhX; X=NO2 (3 a), I (3 b), H (3 c), OMe (3 d), and NH2 (3 e), tris[2,4-di(trifluoromethyl)quinoline-7-yl]amine (4), and bis[2,4-di(pentafluoroethyl)quinoline-7-yl]-4-nitrophenylamine (5) were prepared as functional fluorophores. On irradiating the solution samples, 1 showed no noticeable alteration, whereas 2, 3 a-d, and 4 showed emission color changes from yellowish green to blue, indicating that a photoreaction took place. Analyses of the photoproduct based on absorption and emission spectra, (1) H NMR spectra, and X-ray crystallography indicated that photocyclization reactions occurred regioselectively and quantitatively to form bent-bent dipyridocarbazoles. In 3 a-d, the reaction rates depended on the solvent polarity and the substituent on the benzene ring. The photoreactions were accelerated with decreasing solvent polarity and with increasing electron-withdrawing character of the substituents. The photocyclization of triquinolineamine 4 was faster than that of 3 a in all solvents. The results of semiempirical quantum-chemical PM6 calculations suggested that the observed regioselective photocyclization could be explained by stabilization of the excited triplet transition state for the bent-bent form because of the molecular geometry with the CH-NQ hydrogen bonds. The solution of 5 in MeOH displayed photoreaction-induced self-assembly behavior to form twisted tape-like fibers of width 200 nm, as determined by TEM imaging.

17.
Dalton Trans ; 45(16): 7067-77, 2016 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-27003316

RESUMO

3- and 4-(α-diazophenyl)pyridine-N-oxides, and , were prepared as new photoresponsive magnetic couplers in heterospin systems. Lanthanide dinuclear complexes, [Ln(III)(tta)3()]2; Ln(III) = Gd (), Tb (), and Dy () and tta = 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionate, bridged with in µ2 coordination mode were obtained. The obtained , , and were isostructures. The isomeric complex, [Tb(III)(tta)3()]2 was also prepared. In the carbene-Ln(III) complexes [Ln(III)(tta)3( and )]2 generated by photolysis, regioselectively interacted with the Ln(III) ions through pyridine-N-oxide, in which the magnetic coupling of was weakly ferromagnetic, while that of was insignificant. Before and after irradiation of , no SMM behavior was observed. In contrast, the Tb(III) and Dy(III) complexes being anisotropic functioned as heterospin SMMs. Before irradiation, showed no SMM behavior. After irradiation, two species showing slow magnetic relaxations were produced and one of them exhibited SMM behavior with the thermal activation barrier, Ueff/kB = 30 K, and τ0 = 5.8 × 10(-8) s. In , SMM behaviors were observed before and after irradiation, and the Ueff/kB value of 102 K (τ0 = 3.6 × 10(-7) s) before irradiation was reduced to 39 K (τ0 = 1.5 × 10(-8) s) after irradiation.

18.
Angew Chem Int Ed Engl ; 54(9): 2734-8, 2015 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-25641269

RESUMO

A series of thiacalix[n]dithiothiophenes (n=4-10) was prepared by a facile method and X-ray analysis was used to determine the molecular structures of square- (4-mer) and pentagonal-shaped macrocycles (5-mer). In the cyclic voltammograms, reversible multielectron redox processes, which are due to electronic delocalization, were observed at low oxidation potentials. The cyclic 4-mer acted as a "Janus-head" cavitand for two C60 molecules, whereas the 5- and 6-mer formed stable 1:1 complexes with C60 .

19.
Artigo em Inglês | MEDLINE | ID: mdl-25643722

RESUMO

The entrance and diffusion pathway of CO2 and dimethyl ether (DME) in MFI-type zeolite channels were investigated by a selective sealing method using large silicalite-1 crystals. The MFI-type zeolite has two kinds of orthogonal channels: straight channels and sinusoidal channels. The mouths of the straight channels are on (010) crystal faces, while those of the sinusoidal channels are on (100) faces. The channel mouths are directly sealed by silicone resin on the (100) and (010) faces so as to restrict the entrance and diffusion pathways to straight and sinusoidal channel pathways, respectively. The locations and loadings of the guest CO2 and DME molecules are determined by single-crystal X-ray diffraction structural analysis. The loadings show the difference of the adsorption rates between the pathways. The straight channel pathway is 4.2 times faster than the sinusoidal channel pathway for the CO2, and the sinusoidal channel pathway is 5.1 times faster than the straight channel pathway for the DME. It reveals their dominant pathways and the anisotropy of adsorption. The dominant pathway correlates to the stability of the channel as adsorption sites.

20.
Acta Crystallogr E Crystallogr Commun ; 71(Pt 12): o1003-4, 2015 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-26870465

RESUMO

In the title hemisolvate, C25H28N2O7S·0.5C4H8O2, the thio-morpholine ring adopts a chair conformation, with the exocyclic N-C bond in an equatorial orientation. The dihedral angle between the coumarin ring system (r.m.s. deviation = 0.044 Å) and the furan ring is 64.84 (6)°. An intra-molecular N-H⋯O hydrogen bond closes an S(6) ring. The ethyl acetate solvent mol-ecule is disordered about a crystallographic inversion centre. In the crystal, the components are linked by C-H⋯O and C-H⋯S hydrogen bonds, generating a three-dimensional network.

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