Liquid Crystalline and Luminescent Behavior of Lanthanide Complexes Composed of Terbium or Europium and Dendritic Amphiphile

Luminescent lanthanide (Tb³⁺, Eu³⁺) complexes were prepared by reaction of Tb³⁺ or Eu³⁺ with dendritic amphiphile (3,4,5-tris(dodecyloxy)benzoate), then their liquid crystalline and luminescent behavior were studied. The complexes exhibited thermotropic liquid crystalline mesophases with columnar hexagonal structure. The complexes emitted the characteristic luminescence of the core metals. Additionally, in the Eu³⁺ complex, the ratio of the intensity of 614 nm to the intensity of 585 nm (I₆₁₄/I₅₈₅) remarkably decreased around the transition temperature from crystal to mesophase, suggesting that the coordination environment of Eu³⁺ gets more symmetrical due to the phase transition.     

Rapid Detection of Infestation of Apple Fruits by the Peach Fruit Moth, Carposina sasakii Matsumura, Larvae Using a 0.2-T Dedicated Magnetic Resonance Imaging Apparatus

Infestation of harvested apple fruits by the peach fruit moth (Carposina sasakii Matsumura) was studied using a dedicated magnetic resonance imaging (MRI) apparatus equipped with a 0.2-T permanent magnet. Infested holes on the three-dimensional (3-D) images tracked ecological movements of peach fruit moth larvae within the food fruits, and thus in their natural habitat. Sensitive short solenoid coil and surface coil detectors were devised to shorten measurement times. The short solenoid coil detected infestation holes at a rate of 6.4 s per image by the single-slice 2-D measurement. The multi-slice 2-D measurement provided six slice images of a fruit within 2 min taken by the two detectors. These results indicate that the 0.2-T MRI apparatus allows one to distinguish sound fruits from infested ones, and also as a means for plant protection and the preservation of natural ecological systems in foreign trade.     

Charge-transfer complexes from decamethylferrocene and 1,4-quinone derivatives: neutral-ionic phase diagrams for metallocene complexes

Charge-transfer (CT) complexes of ferrocenes with 1,4-quinone derivatives were investigated. Deca- and octamethylferrocene complexes with 1,4-naphthoquinone derivatives were prepared and structurally characterized; these were neutral 1:2 DA complexes with mixed-stack structures. The formation of complexes with 1,4-benzoquinones was examined by applying solvent-drop grinding. CT energies and phase transitions in these neutral and other ionic complexes were investigated. Their electronic states are discussed on the basis of the phase diagrams derived for mixed-stack ferrocene-based CT complexes, taking into account their dependence on the DA ratio, dimensionality, and intermolecular interactions.     

A convergent synthesis of the C1-C16 segment of goniodomin A via palladium-catalyzed organostannane-thioester coupling

A convergent synthesis of the C1-C16 segment of goniodomin A, an actin-targeting marine polyether macrolide natural product, has been achieved via a 2-fold application of palladium-catalyzed organostannane-thioester coupling.     

Fe(z+) (z = 1-6) generation from ferrocene

Multiply charged iron atoms up to Fe(6+) with few carbon ions were produced from ferrocene under intense femtosecond laser fields. The production of Fe(4+) and Fe(5+) from ferrocene requires much less laser intensity than theoretically expected for iron atoms. The dissociation of ferrocene and the generation mechanism of multiply charged iron atoms are discussed.     

Prism-Based Spectral Imaging of Single-Molecule Fluorescence from Gold-Nanoparticle/Fluorophore Complex

A wavelength-calibration method for prism-based spectral imaging of single-molecule (SM) fluorescence was developed. With this method, a wavelength reference is provided by photoluminescence from 50-nm-diameter gold nanoparticles (AuNPs) binding with fluorophores. The AuNPs each bound with a SM fluorophore, either Alexa488 or Cy3, to form AuNP/fluorophore complexes in tris-HCl buffer. Each complex was immobilized on a silica slide and then excited by total-internal-reflection illumination to make it emit SM fluorescence and AuNP photoluminescence. The portion of the AuNP photoluminescence transmitted by a band-pass filter gives the wavelength reference. A spectral-imaging system composed of a prism-based spectroscope (with a reciprocal dispersion of about 4 nm/μm) and a charge-coupled device with 6.45-μm-square pixels was used to obtain an SM-fluorescence spectrum and a wavelength-reference spectrum. Through smoothed differentiation of these two spectra, the peak location of the former in relation to the latter was determined with subpixel precision. After that, the SM fluorophore was classified as either Alexa488 or Cy3 according to the peak location. The error rate of the classification was estimated to be only 0.3%.     

Uniqueness of Solutions on the Whole Time Axis to the Navier-Stokes Equations in Unbounded Domains

We consider the uniqueness of bounded continuous L^{3, ∞}-solutions on the whole time axis to the Navier-Stokes equations in 3-dimensional unbounded domains. Here, L^{p, q} denotes the scale of Lorentz spaces. Thus far, uniqueness of such solutions to the Navier-Stokes equations in unbounded domain, roughly speaking, is known only for a small solution in BC(?; L^{3, ∞}) within the class of solutions which have sufficiently small L^∞(L^{3, ∞})-norm. In this paper, we discuss another type of uniqueness theorem for solutions in BC(?; L^{3, ∞}) using a smallness condition for one solution and a precompact range condition for the other one. The proof is based on the method of dual equations.     

Design and synthesis of a novel fluorescent protein probe for easy and rapid electrophoretic gel staining by using a commonly available UV‐based fluorescent imaging system

A new fluorescent molecular probe, methyl 3‐(3,5‐bis((bis(pyridin‐2‐ylmethyl)amino)‐methyl)‐4‐hydroxyphenyl)‐2‐(5‐(dimethylamino)naphthalene‐1‐sulfonamido) propanoate, dizinc(II) chloride salt (Dansyl‐ 1 ‐Zn(II)), which possesses Zn(II) complexes and a dansyl group, was designed and synthesized to enable the detection of proteins in solution and in high‐throughput electrophoresis by using a UV‐based detection system. Dansyl‐ 1 ‐Zn(II) exhibited weak fluorescence in the absence of proteins and strong green fluorescence at approximately 510 nm in the presence of BSA upon irradiation with light at a wavelength of 345 nm. Compared with conventional protocols for in‐gel SDS‐PAGE protein staining (e.g. silver staining, SYPRO Ruby, and Oriole), the operating times of which range from 90 min to overnight, Dansyl‐ 1 ‐Zn(II) allowed 1‐step protein staining (SDS‐PAGE →Staining →Detection) and shortened the operating time (35 min) with high sensitivity (LOD: 1 ng or less) under 312‐nm or 365‐nm light excitation with orange or red emission filters, respectively. Moreover, Dansyl‐ 1 ‐Zn(II) was successfully applied to protein identification by MS via in‐gel tryptic digestion, Western blotting, and Native‐PAGE. Accordingly, Dansyl‐ 1 ‐Zn(II) may facilitate highly sensitive and high‐throughput protein detection, and it may be widely applicable as a convenient tool in various scientific and medical fields.     

Structure‐Dependent Electronic Nature of Star‐Shaped Oligothiophenes,Probed by Ensemble and Single‐Molecule Spectroscopy

We have investigated the photophysical properties of star‐shaped oligothiophenes with three terthiophene arms (meta to each other, S3 ) or six terthiophene arms (ortho‐, meta‐, and para‐arranged, S6 ) connected to an ethynylbenzene core to elucidate the relationship between their molecular structure and electronic properties by using a combination of ensemble and single‐molecule spectroscopic techniques. We postulate two different conformations for molecules S3 and S6 on the basis of the X‐ray structure of hexakis(5‐hexyl‐2‐thienlyethynyl)benzene and suggest the coexistence of these conformers by using spectroscopic methods. From the steady‐state spectroscopic data of compound S6 , we show that the exciton is delocalized over the core structure, but that the meta‐linkage in compound S3 prevents the electronic communication between the arms. However, in single‐molecule spectroscopic measurements, we observed that some molecules of compound S3 showed long fluorescence lifetimes (about 1.4 ns) in the fluorescence‐intensity trajectories, which indicated that π electrons were delocalized along the meta linker. Based on these observations, we suggest that the delocalized exciton is intensely sensitive towards the dihedral angle between the core and the adjacent thiophene ring, as well as to the substituted position of the terthiophene arms. Our results highlight that the fluorescence lifetimes of compounds S3 and S6 are strongly correlated with the spatial location of their excitons, which is mainly affected by their conformation, that is, whether the innermost thiophene rings are facing each other or not. More interestingly, we observed that the difference between the degrees of ring‐torsional flexibility of compounds S3 and S6 results in their sharply contrasting fluorescence properties, such as a change in fluorescence intensity as a function of temperature.