AIST Nanocharactarization Facility (National Institute of Advanced Industrial Science and Technology)

Abstract

We investigated the spectral properties of electromagnetic (EM) enhancement of one-dimensional hotspots (1D HSs) generated between silver nanowire (NW) dimers.The EM enhancement spectra were directly derived by dividing the spectra of ultrafast surface-enhanced fluorescence (UFSEF) from single NW dimers with UFSEF obtained from large nanoparticle aggregates, which aggregate-by-aggregate variations in the UFSEF spectra were averaged out. Some NW dimers were found to exhibit EM enhancement spectra that deviated from the plasmon resonance Rayleigh scattering spectra, indicating that their EM enhancement was not generated by superradiant plasmons. These experimental results were examined by numerical calculation based on the EM mechanism by varying the morphology of the NW dimers. The calculations reproduced the spectral deviations as the NW diameter dependence of EM enhancement.Phase analysis of the enhanced EM near fields along the 1D HSs revealed that the dipole-quadrupole coupled plasmon, which is a subradiant mode, mainly generates EM enhancement for dimers with NW diameters larger than ~80 nm, which was consistent with scanning electron microscopic measurements.

A method for increasing the solubility of industrial azo pigments for 13C and 1H NMR spectra and the assignments of their 13C and 1H NMR peaks

“…According to the HSQC correlations, the carbon resonance at δ C 119.6 was assigned to C‐4′. According to the literature, [ 11 ] the chemical shift of the hydrazo‐substituted carbon and the nitro‐substituted carbon are roughly at δ C 152 and 146. In the HMBC spectrum, the nonprotonated carbon at δ C 153.9 correlated with the protons at δ H 7.60 (H‐3′) and 2.75 (H‐7′), the nonprotonated carbon at δ C 141.8 correlated with the protons at δ H 8.42 (H‐6′) and 2.75 (H‐7′) and the nonprotonated carbon at δ C 146.9 correlated with the aromatic protons at δ H 8.42 (H‐6′) and 7.60 (H‐3′).…”

Spectroscopically tracing the reactions of octahydridosilsesquioxane (H8Si8O12) with organic molecules

“…This result is consistent with the disappearance of the ν(Si H) peak (2,294 cm −1 ) of T 8 Figure 5a, the 13 C NMR signals from the reaction product of T 8 H 8 and n-propanol appear at 10.3, 25.3, and 66.6 ppm, which are assignable to Si OCH 2 CH 2 CH 3 . [20,21] The formation of Si OC 3 H 7 is a possible origin for the Q 3 signal observed in Figure 4a.…”

“…Formation of Si OCH(CH 3 ) 2 meets the requirements of two types of carbon atoms and the observed chemical shifts. [20,21] In the case of allyl alcohol, the 29 Si spectral pattern is different from that of n-propanol, although both compounds possess an OH functional group. In Figure 4c, the relatively strong signal around −85 ppm reflects abundant (SiO) 3 Si H groups present in the reaction product, which is consistent with the infrared result showing the strongest residual Si H stretching intensity at 2,260 cm −1 in the three reaction cases (Figure 4).…”

“…In the acetone case (Figure 4b), the resultant product has two predominant 29 Si chemical shifts of Q 3 and Q 4 . In 13 C NMR (Figure 5b), no 13 C signal around 206 ppm for the carbonyl of acetone is observed, [20] indicating that the C O group is the active site reacting with T 8 H 8 and there are just two signals at 30.0 and 58.5 ppm, presumably due to an organic component with two different carbon bonding environments. Formation of Si OCH(CH 3 ) 2 meets the requirements of two types of carbon atoms and the observed chemical shifts.…”

“…Formation of this group is evidenced by the chemical shifts of 63.9, 116.1, and 135.6 ppm. [19][20][21] The additional, broad shift at~32.4 ppm Figure 5c cannot be attributed to Si OCH 2 CH 2 CH 3 and Si OCH 2 CH CH 2 ; therefore, organic moieties other than OCH 2 CH CH 2 may also be present in the reaction product of allyl alcohol. In the literature, the 13 C chemical shifts for the secondary carbons of [SiCH 2 (CH 2 ) 4 CH 2 Cl] have been reported to be in the range of 22.6-32.5 ppm.…”