Applicability of in situ detectors for radiological assessment of strontium-90 in rivers and lakes

Journal of Radioanalytical and Nuclear Chemistry - An in situ detector for radiological assessments of strontium-90 (90Sr) in river and lake water is developed, based on a CaF2(Eu) scintillator,...     

Molecular Structure,Electronic Properties,Homo–Lumo,MEP and NBO Analysis of (N-Isocyanimino) Triphenylphosphorane (Ph3PNNC): DFT Calculations

Journal of Structural Chemistry - N-isocyaniminotriphenylphosphorane (Ph3PNNC) is a type of iminophosphorane which is an important reagent in synthetic organic chemistry and a ligand in metallic...     

Nido‐Carboranes: Donors for Thermally Activated Delayed Fluorescence

An approach to the design of nido‐carborane‐based luminescent compounds that can exhibit thermally activated delayed fluorescence (TADF) is proposed. 7,8‐Dicarba‐nido‐undecaboranes (nido‐carboranes) having various 8‐R groups (R=H, Me, i‐Pr, Ph) are appended to the meta or para position of the phenyl ring of the dimesitylphenylborane (PhBMes₂) acceptor, forming donor–acceptor compounds (nido‐ m1 – m4 and nido‐ p1 – p4 ). The bulky 8‐R group and meta substitution of the nido‐carborane are essential to attain a highly twisted arrangement between the donor and acceptor moieties, leading to a very small energy splitting between the singlet and triplet excited states (ΔE_ST <0.05 eV for nido‐ m2 , ‐ m3 , and ‐ p3 ). These compounds exhibit efficient TADF with microsecond‐range lifetimes. In particular, nido‐ m2 and ‐ m3 display aggregation‐induced emission (AIE) with TADF properties.     

Density functional theory studies on the dissociation energies of metallic salts: relationship between lattice and dissociation energies

The formation and physicochemical properties of polymer electrolytes strongly depend on the lattice energy of metal salts. An indirect but efficient way to estimate the lattice energy through the relationship between the heterolytic bond dissociation and lattice energies is proposed in this work. The heterolytic bond dissociation energies for alkali metal compounds were calculated theoretically using the Density Functional Theory (DFT) of B3LYP level with 6‐311+G(d,p) and 6‐311+G(2df,p) basis sets. For transition metal compounds, the same method was employed except for using the effective core potential (ECP) of LANL2DZ and SDD on transition metals for 6‐311+G(d,p) and 6‐311+G(2df,p) calculations, respectively. The dissociation energies calculated by 6‐311+G(2df,p) basis set combined with SDD basis set were better correlated with the experimental values with average error of ca. ±1.0% than those by 6‐311+G* combined with the LANL2DZ basis set. The relationship between dissociation and lattice energies was found to be fairly linear (r>0.98). Thus, this method can be used to estimate the lattice energy of an unknown ionic compound with reasonably high accuracy. We also found that the dissociation energies of transition metal salts were relatively larger than those of alkaline metal salts for comparable ionic radii. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 827–834, 2001     

Synthesis of new poly(amide imide)s with (n‐alkyloxy)phenyloxy side branches

Two series of new poly(amide imide)s having (n‐alkyoxy)phenyloxy side branches with various lengths, poly{p‐phenyleneiminoterephthaloylimino‐p‐phenylene[3,6‐di(n‐alkyloxy)phenyloxy]pyromellitimide}s ( PC _m TA s, m = 4, 8, 12) and poly{p‐phenyleneiminosebacoylimino‐p‐phenylene[3,6‐di(n‐alkyloxy)‐phenyloxy]‐ pyromellitimide}s ( PC _m SeA s, m = 4, 8, 12), were prepared by condensation of terephthalamide‐N,N′‐4,4′‐dianiline ( TA ) and sebacamide‐N,N′‐4,4′‐dianiline ( SeA ) with 3,6‐di[4‐(n‐alkyloxy)phenyloxy]pyromellitic dianhydrides , respectively. The inherent viscosities of the polymers were in the 0.82–1.20 dL/g range. The polymers were highly soluble in N‐methylpyrolidinone (NMP), even at room temperature and soluble in other polar aprotic solvents on heating. The PC _m TA s, which have aromatic backbones, were thermally more stable (431–442 °C) than the PC _m SeA s, which have an octamethylene unit in the main chain (407–409 °C). Degradation of weight up to 900 °C corresponded with the loss of side chain contents. The PC _m TA s exhibited no phase transition, whereas two endothermic peaks were observed for each of the PC _m SeA s. Wide‐angle X‐ray diffractometer investigations revealed that both polymers are amorphous and the n‐alkyloxy side chains are present in a layered structure. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3818–3825, 2001     

Liquid‐crystalline organic–inorganic hybrid polymers with functionalized silsesquioxanes

Liquid‐crystalline (LC) hybrid polymers with functionalized silsesquioxanes with various proportions of LC monomer were synthesized by the reaction of polyhedral oligomeric silsesquioxane (POSS) macromonomer with methacrylate monomer having an LC moiety under common free‐radical conditions. The obtained LC hybrid polymers were soluble in common solvents such as tetrahydrofuran, toluene, and chloroform, and their structures were characterized with Fourier transform infrared, ¹H NMR, and ²⁹Si NMR. The thermal stability of the hybrid polymers was increased with an increasing ratio of POSS moieties as the inorganic part. Because of the steric hindrance caused by the bulkiness of the POSS macromonomer, the number‐average molecular weight of the hybrid polymers gradually decreased as the molar percentage of POSS in the feed increased. Their liquid crystallinities were very dependent on the POSS segments of the hybrid polymers behaving as hard, compact components. The hybrid polymer with 90 mol % LC moiety (Cube‐LC90) showed liquid crystallinity, larger glass‐transition temperatures, and better stability with respect to the LC homopolymer. The results of differential scanning calorimetry and optical polarizing microscopy showed that Cube‐LC90 had a smectic‐mesophase‐like fine‐grained texture. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4035–4043, 2001     

Cationic rhodium(I) and iridium(I,III) complexes of cinnamonitrile and their catalytic activities

Summary Reactions of cinnamonitrile (trans-PhCH=CHCN) with [M(ClO₄)(CO)(PPh₃)₂] (M=Rh or Ir) produce hydrogenation oftrans-PhCH=CHCN to PhCH₂CH₂CN at 100°C under 3 atm of hydrogen.     

Surface-enhanced Raman study of organic sulfides adsorbed on silver

The surface-enhanced Raman scatterings of dimethyl sulfide, diethyl sulfide and dimethyl disulfide have been investigated in silver sol. The dimethyl disulfide molecule decomposes on silver to the corresponding mercaptide implying facile cleavage of its S---S bond. The C---S bond in dialkyl monosulfide appears not to cleave on silver. For diethyl sulfide, the C₂ conformation seems to be favorable on silver than other conformations.     

Antioxidant encapsulated porous poly(lactide-co-glycolide) microparticles for developing long acting inhalation system

The purpose of this study was to fabricate porous poly(lactide-co-glycolide) (PLGA) microparticles for efficient pulmonary deposition and increased therapeutic duration of the antioxidant anthocyanin (ATH). These microparticles were prepared by a water-in-oil-in-water (W(1)/O/W(2)) multi-emulsion method with vaporizing ammonium bicarbonate (AB) as a porogen and starch as a viscous additive. High porosity achieved by the decomposition reaction of AB to the base of ammonia, carbon dioxide, and water vapor at 50°C enabled efficient deposition of ATH throughout the entire lung in BALB/c mice. In addition, the porous microparticles incorporating starch showed sustained ATH release characteristics (up to 5 days) and protracted antioxidant activity (up to 5 days) for 2,2-diphenyl-1-pikryl-hydrazyl (DPPH) radicals, which was comparable to that of the porous microparticles without starch which completely released ATH in 2h. Furthermore, these porous microparticles incorporating starch led to longer ATH residence (up to 20 days) in in vivo lung epithelium. We believe that this system has great pharmaceutical potential as a long-acting antioxidant for continuously relieving oxidative stress in pulmonary diseases like chronic obstructive pulmonary disease (COPD).