Two possible ways to combine boron and gadolinium for Gd-guided BNCT. A concept

Abstract

Two ways of synthesis of theragnostic compounds for Gd-guided boron neutron capture therapy of cancer are proposed. The first way is based on modification of DO3A ligand, which a capable to form stable complexes with gadolinium, with attachment of boron-containing moieties and additional functional groups which can be used for conjugation with various biomacromolecules. The second way is based on the introduction of additional chelating groups into a boron-containing moiety—carborane-based ligand. It is expected that this will significantly improve the stability of the gadolinium bis(dicarbollide) complexes.     

Non-classical control of solid-state aggregation-induced enhanced circularly polarized luminescence in chiral perylene diimides

Organic fluorescent molecules are gaining importance because of their potential applications in many devices. Optically active N,N′-bis((1R)-1-naphthylethyl)perylene-3,4,9,10-tetracarboxylic diimide [(R,R)-1-BNP] and N,N′-bis((1R)-2-naphthylethyl)perylene-3,4,9,10-tetracarboxylic diimide [(R,R)-2-BNP] and their antipode, [(S,S)-1-BNP and (S,S)-2-BNP], emit aggregation-induced enhanced (AIEnh) circularly polarized luminescence (CPL) on both a solid organic polymer film (poly(methyl methacrylate)) and solid inorganic KBr pellet. An opposite chirality is essential for generating CPL of inverted sign. However, a pair of enantiomeric organic molecules may not always be easy to prepare. Interestingly, the chiral perylene fluorophores synthesized in this study can emit both positive and negative AIEnh-CPL in the solid state, depending on their position on the naphthylene groups. In addition, no CPL was observed in these compounds from their dilute solutions.     

Synthesis of All Stereoisomers of RK460 and Evaluation of Their Activity and Selectivity as Abscisic Acid Receptor Antagonists

The PYR/PYL/RCAR protein families have recently emerged as receptors of the phytohormone abscisic acid (ABA, 1 ), which regulates plant responses to environmental stress. These families have multiple members with different physiological actions, and so selective agonists or antagonists are needed both as tools to elucidate functional differences and as lead compounds for agrochemicals. We previously identified RK460 (rac- 3 a ) as a PYR1-selective antagonist, and showed that it possesses five stereocenters on a 6,5-cis-bicyclo skeleton. Here, we synthesized all the stereoisomers of RK460 and evaluated their activity towards a panel of receptors. Relative stereochemistry as well as absolute stereochemistry was important for selective action.     

Synthesis,Electronic, and Morphological Properties of Tetrahedral Oligothiophenes with n‐Hexyl Terminal Groups

A series of tetrahedral oligothiophenes bearing n‐hexyl groups at the α‐positions of the terminal thiophene rings, (n‐C₆H₁₃(C₄H₂S)_n)₄C (Hex‐TnTM; n=1–4), has been synthesized by Kosugi–Migita–Stille coupling as a key reaction. Thanks to the improved solubility afforded by the terminal n‐hexyl groups, the largest homologue (n=4) was successfully obtained. Whereas the smaller derivatives (n=1, 2) were obtained as liquid substances, the larger derivatives (n=3, 4) were obtained as solids. Hex‐T3 TM partially adopts syn conformations between the adjacent thiophene rings in the crystal, probably owing to the packing force. Hex‐T3 TM not only appeared in the crystalline state but also the amorphous state, which was stable to up to 80 °C. Regardless of the terminal groups, the derivatives of n=2 exhibited a broad fluorescence with large Stokes shifts compared to the corresponding linear analogues, thereby suggesting the presence of intramolecular interactions between the bithiophene moieties. Interactions between terthiophene branches was also suggested in the radical cations of Hex‐T3 TM by cyclic voltammetry measurements.     

Facile Preparation of Organometallic Nanorods from Various Ethynyl-Substituted Molecules

A facile method to prepare one-dimensional (1D) organometallic nanomaterials from various ethynyl-substituted molecules is reported. The reactions of 3-chloro-1-ethynylbenzene, p-tBu-phenylacetylene and 4-ethynylbiphenyl with Cu⁺ ions in acetonitrile yield nanorod-shaped copper acetylides (Cu−C≡C−R) crystals. In the case of linear alkynes, namely, propyne, 1-pentyne and 1-hexyne, it was found that using an aqueous ammonia/ethanol mixed solvent instead of acetonitrile is a better approach to obtain 1D nanostructures. This procedure also enables us to prepare functional 1D nanomaterials. We demonstrate the preparation of a paramagnetic nanorod from the organic radical p-ethynylphenyl nitronyl nitroxide, and fluorescent nanorods from 9-ethynylphenanthrene and 2-ethynyl-9,9′-spirobifluorene.     

Multifunctional Cyclic Carbonates Comprising Hyperbranched Polyacetals: Synthesis and Applications to Polymer Electrolytes and Networked Polymer Materials

Hyperbranched polyacetals (HBPAs) bearing cyclic carbonate (CC) terminals were synthesized from protocatechuric aldehydes bearing bifunctional trimethylolpropane (TMP) or glycerol (Gly) structures and then utilized to design polymer electrolytes and networked polymer materials. Since TMP‐based cyclic acetals (CAs) are thermodynamically more stable than Gly‐derived CSs, the copolymerization of these monomers favors to form HBPAs comprising TMP‐based acetal stems and Gly terminals. Consequently, HBPAs composed of larger amounts of TMP or Gly terminals were separately synthesized by changing monomer feed ratios. Their diol terminals react efficiently with diphenyl carbonate to give HBPAs bearing 5‐ or 6‐membered CC (5‐CC or 6‐CC) terminals. HBPAs bearing 5‐CC terminals were mixed homogeneously with lithium bis(trifluoromethanesulfonyl)imide to form uniform films showing lithium ion conductivity ranging from 8.2 × 10^?9 to 2.1 × 10^?3 S cm^?1 at 23–80 °C, whereas networked polycarbonate and polyhydroxyurethane films were successfully fabricated using HBPAs having CC terminals. These results apparently indicate that HBPAs having CC terminals are useful scaffolds to design functional polymer materials. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2295–2303     

TEMPO-substituted polyacrylamide for an aqueous electrolyte-typed and organic-based rechargeable device

A hydrophilic radical polymer, poly(2,2,6,6-teteramethylpiperidinyloxyl-4-yl acrylamide) (PTAm), was synthesized via oxidation of the corresponding precursor polymer, poly(2,2,6,6-teteramethylpiperidine-4-yl acrylamide). Electrochemical properties of the PTAm layer were characterized in three aqueous electrolytes of sodium chloride (NaCl), sodium tetrafluoroborate (NaBF4), and sodium hexafluorophosphate (NaPF6) to optimize its activity as an organic cathode. The counter anion species significantly affected the capacity and the cycle performance of the PTAm layer. The PTAm layer in the presence of BF4? displayed quantitative redox capacity beyond 1 μm layer thickness and maintained the discharging capacity of 110 mAh g-1 (97% vs. the calculated capacity) even after 1000 cycle charging/discharging, which could be ascribed to its appropriate affinity to the aqueous electrolyte without any dissolution into the electrolyte. A totally organic-based rechargeable cell was fabricated using PTAm and poly(N-4,4’-bipyridinium-N-decamethylene dibromide) as the cathode and the anode, respectively, and the aqueous electrolyte of NaBF4. The cell gave a plateau voltage at 1.2 V both on charging and discharging and an excellent charging/discharging cyclability of >2000 with high coulombic efficiency of >95%.     

Extremal quasimodular forms for low-level congruence subgroups

In this paper, we study “extremal” quasimodular forms of depth 1 for the Hecke subgroups of level 2, 3, and 4, and relations to modular differential equations and Atkin?s orthogonal polynomials.