Visualization of the Eigen-structure Updating of Three-Dimensional Random Tensor

This image visualizes the structural relationship between the higher order singular value decomposition (HOSVD) of a three-dimensional random tensor (above) of size 20x15x10 and a partial three-dimensional tensor (below) of size 7x10x5, which is extracted from the original random tensor (above). The relative position of the new tensor within the old tensor is highlighted in yellow. Their higher order singular value decompositions are shown on the right, which consist of core tensors (red and blue), and two sets of loading matrices (shown in colored images). In this research in UIC, we discovered the structural relationship between the HOSVDs of those two tensors, and developed fast updating and downdating algorithms for re-calculating of HOSVDs. These algorithms are applicable to many areas of research involving tensor-form data. Specifically, we applied these algorithms in dynamic updating and downdating of video and motion trajectory databases

External Heavy-Atom Activated Phosphorescence of Organic Luminophores in a Rigid Fluid Matrix

Growing attention has been paid to pure organic room-temperature phosphorescence (RTP). Although an insufficient population and fast nonradiative decay of triplet excitons are avoided in recent endeavors, complicated synthesis and limited universality still hinder its development. Further, fluid RTP materials are more difficult to design because of faster nonradiative relaxation. Herein, a deep eutectic mixture of glucose and choline, a stable supercooled liquid at room temperature, is employed as a matrix. Direct transformation from commercial fluorescent dyes to RTP fluid is realized by doping without modifications. The excited triplet states are generated by an external heavy atom, while the rigid noncovalent network stabilizes them with both functions intrinsic to the liquid matrix. Modulation of matrix components also results in nearly white light emission of a single dye. This study presents a general strategy to design fluid RTP materials starting from the vast library of fluorophores

Controllable Self-Assembling of Gold Nanorods via On and Off Supramolecular Noncovalent Interactions

5,15-Bis­(4-sulfonatophenyl)­porphyrin (<b>DPPS</b>) with a planar conjugated system and two negative charges was found to be able to engender the self-assembling of CTAB-<b>GNR</b>s due to the electrostatic interaction between <b>DPPS</b> and CTAB together with the π–π intermolecular interaction of <b>DPPS</b>, while its bulky supramolecular pseudo[3]­rotaxane included by β-cyclodextrin prevented such self-assembling due to the interruption of the above noncovalent interactions

Multicolor Photoluminescence of a Hybrid Film via the Dual-Emitting Strategy of an Inorganic Fluorescent Au Nanocluster and an Organic Room-Temperature Phosphorescent Copolymer

Achieving multicolor photoluminescence, especially white-light emission, under mild conditions based on hybrid organic–inorganic materials has attracted growing attention. A novel system, via a histidine modified Au nanocluster (AuNC@histidine) with bluish green fluorescence and a 4-bromo-1,8-naphthalic anhydride derivative polymer (poly-BrNpA) with orange room-temperature phosphorescence (RTP) emission, was designed and prepared. White-light emission could be achieved by adjusting the proportions of the two components. The hydrogen bond enhanced the RTP emission of such copolymer systems through suppressing the nonradiative relaxation process by the well-formed and highly cross-linked network. By introducing fluorescence compounds (AuNC@histidine) which were insensitive to environmental humidity, this fluorescence-phosphorescence dual-emitting hybrid system could also be used as a humidity responsive material, since the hydrogen bonds in poly-BrNpA chains could be broken by environmental humidity. The color switching could be well conducted in a poly­(vinyl alcohol) (PVA) matrix, which was good for forming a processable and humidity responsive film

Amorphous 2‑Bromocarbazole Copolymers with Efficient Room-Temperature Phosphorescent Emission and Applications as Encryption Ink

The development of metal-free organic room-temperature phosphorescent (RTP) materials is promising but challenging, because spin–orbit coupling is less efficient without heavy metals such as platinum and palladium. Here, we present a novel amorphous copolymer composed of 2-bromocarbazole phosphor and acrylamide on its side chains, which can engender blue–purple phosphorescence emission with high quantum yield at room temperature. The polymer matrices of acrylamide and the hydrogen bonding in the polymeric chain system can effectively help to inhibit nonradiative transition process and, hence, strengthen the phosphorescent emission. The molar ratio of the 2-bromocarbazole phosphor and acrylamide remarkably influences the RTP emission intensities and quantum yields of the polymers. The high amount of phosphor will weaken the rigidity of the polymers and the shielding effect from oxygen, thus leading to a decrease in their RTP emission, while a low concentration of the phosphor will also weaken their RTP emission intensity. Furthermore, RTP intensity of the amorphous polymer is responsive to humidity, because the hydrogen bonding in the polymeric chain system can be broken by water, which makes it applicable in the area of encryption

A Total Synthesis of the Antifungal Deoxyaminocyclitol Nabscessin B from l‑(+)-Tartaric Acid

Aminocyclitol <b>2</b>, a recently isolated and notable antifungal agent, was prepared from homochiral γ-hydroxycyclohexenone <b>4</b>, which is itself available in six steps from l-(+)-tartaric acid (<b>3</b>). The well-defined rigidifying effect arising from the 1,2-diacetal protecting group associated with compound <b>4</b> and its derivatives allows for high levels of regio- and stereo-chemical control in the manipulation of the cyclitol framework

Total Synthesis of the Marine Alkaloid Discoipyrrole C via the MoOPH-Mediated Oxidation of a 2,3,5-Trisubstituted Pyrrole

A total synthesis of the marine alkaloid discoipyrrole C (<b>3</b>) is described. In the pivotal step, the 2,3,5-trisubstituted pyrrole <b>19</b> was treated with MoOPH in the presence of MeOH, and the resulting methoxylated 1,2-dihydro-3<i>H</i>-pyrrol-3-one <b>20</b> subjected to reaction with potassium carbonate in MeOH then trifluoroacetic acid and H₂O. This gave a mixture of target <b>3</b> and its dehydration product, and the structure of the former compound was confirmed by single-crystal X-ray analysis

Total Synthesis of the Marine Alkaloid Discoipyrrole C via the MoOPH-Mediated Oxidation of a 2,3,5-Trisubstituted Pyrrole

A total synthesis of the marine alkaloid discoipyrrole C (<b>3</b>) is described. In the pivotal step, the 2,3,5-trisubstituted pyrrole <b>19</b> was treated with MoOPH in the presence of MeOH, and the resulting methoxylated 1,2-dihydro-3<i>H</i>-pyrrol-3-one <b>20</b> subjected to reaction with potassium carbonate in MeOH then trifluoroacetic acid and H₂O. This gave a mixture of target <b>3</b> and its dehydration product, and the structure of the former compound was confirmed by single-crystal X-ray analysis

Total Syntheses of the Resorcylic Acid Lactones Paecilomycin F and Cochliomycin C Using an Intramolecular Loh-Type α‑Allylation Reaction for Macrolide Formation

Subjection of the resorcylic ester <b>16</b> to a Nozaki–Hiyama–Kishi reaction afforded the 12-membered lactone <b>17</b>, while treatment of it under the Loh-type α-allylation conditions using indium metal gave the isomeric, 14-membered macrolide <b>18</b>. Compound <b>18</b> was readily elaborated to the resorcylic acid lactone type natural products paecilomycin F and cochliomycin C

Visible-Light-Dependent Photocyclization: Design, Synthesis, and Properties of a Cyanine-Based Dithienylethene

A cyanine-based dithienylethene is developed. Its photoisomerization shows that (1) the irradiation of visible light can induce cyclization while the cycloreversion takes place upon irradiation with UV light and (2) the addition of CN^– can lead to cyclization and cycloreversion upon irradiation of UV light and visible light, respectively