Byeong Hyo Kim

Ion-selective electrodes based on molecular tweezer-type neutral carriers

Potentiometric properties of cholic and deoxycholic acid derivatives substituted with various ion-recognizing moieties, such as dithiocarbamate, bipyridyl, glycolic and malonic diamides, urea and thiourea, and trifluoroacetophenons (TFAP), have been studied using solvent polymeric membranes. The dithiocarbamate and bipyridyl group containing ionophores exhibit high silver ion selectivity. The cholic acid derivatized with glycolic diamides exhibited high calcium selectivity, but its complex formulation constant was 10(5) times smaller than that of ETH 1001. The reduced calcium binding ability of the glycolic diamide-substituted ionophore was advantageous for eliminating anionic interference. The bi- or tripodal malonic diamide-substituted ionophores exhibited substantially increased magnesium selectivity. Anion-selective ionophores have been designed by substituting urea and thiourea group containing chains to the hydroxyl linkers of chenodeoxycholic acid frames; their selectivity closely followed the sequence of Hoffmeister series, except the unusually large response of the thiourea-substituted ionophore to sulfate. The most successful examples of cholic or deoxycholic acid frame-based ionophores are those functionalized with two carbonate-selective TFAP groups: bipodal TFAP groups behaves like a tweezers for the incoming carbonate, and exhibit analytically interference free and quantitative responses to the carbonate in serum and seawater samples.

Indium-mediated one-pot reductive conversion of nitroarenes to N-arylacetamides

N-Arylacetamides were prepared in excellent yields from nitroarenes in the presence of acetic anhydride, acetic acid and indium by a one-pot procedure.

Solution processable single layer organic light-emitting devices with a single small molecular ionic iridium compound

We herein report on the occurrence of bright and efficient electrophosphorescence from a simple organic light-emitting diode (OLED) with a single organic layer comprised of a small molecular ionic iridium compound, formed using a solution process. The studied small molecular ionic iridium compound is [Ir(dfppy)2(bpy)]+PF6−, which exhibits excellent film-forming properties, bright green photoluminescence, and efficient bipolar carrier transport with balanced electron and hole mobilities of about 10−5 cm2/(V s). A high performance of the device was achieved by using a phosphorescent OLED (PHOLED) that was fabricated using the [Ir(dfppy)2(bpy)]+PF6− compound, with a peak brightness of about 18 000 cd/m2 and a peak current efficiency of 12 cd/A. A peak power efficiency of 2.5 lm/W was measured at 2800 cd/m2. These results suggest that the small molecular ionic iridium compound is a promising material for bright and efficient PHOLEDs manufactured using a simple solution process.

Silver(I) ion selective ionophores containing dithiocarbamoyl moieties on steroid backbone

Tweezer-type and non-tweezer-type ionophores containing dithiocarbamoyl groups on a 7-deoxycholic amide or cholane derivatives were designed and synthesized. Potentiometric evaluation of the poly(vinyl chloride) (PVC) membranes containing those deoxycholic amides/cholanes linked with tweezer-type dithiocarbamoyl moieties showed excellent affinity and selectivity to silver(I) ion over alkali, alkaline earth and other transition metal cations. On the other hand, deoxycholic amides/cholanes substituted with one dithiocarbamoyl group, i.e., non-tweezer-type ionophores, resulted in relatively poor potentiometric sensitivity and detection limits. The enhanced potentiometric properties of newly synthesized tweezer-type dithiocarbamoyl containing ionophores have been further improved by employing silver ion complexing reagent in the internal reference solution, which resulted in greatly reduced detection limit ( approximately 100ppt) for the electrodes based on them.

Indium mediated reductive heterocyclization of 2-nitroacylbenzenes or 2-nitroiminobenzenes toward 2,1-benzisoxazoles in aqueous media

2-Nitro-substituted acylbenzenes or iminobenzenes such as 2-nitrobenzaldehydes, 2′-nitroacetophenone, and N-(2-nitrobenzylidene)anilines were cyclized toward 2,1-benzisoxazoles in the presence of 2-bromo-2-nitropropane and indium in an MeOH/H2O solution in excellent yields.

Incorporation of electroluminescence and electrochemiluminescence in one organic light-emitting device

The incorporation of electroluminescence and electrochemiluminescence in one light-emitting device with the configuration of indium tin oxide (ITO)/[Ru(bpy)2(dimbpy)](PF6)2∕Alq3(30nm)∕NPB(45nm)∕Ag(60nm) is investigated. When the ITO and Ag electrodes are negatively and positively biased respectively, the color of the emission changes from green to light yellow-white within 100 s. So there is only one recombination zone in the bulk of the Alq3 at the initial stage of the operation, followed by the formation of another recombination zone in the bulk of the [Ru(bpy)2(dimbpy)](PF6)2. This directly indicates the existence of unipolar injection (electron injection) process in the ruthenium complex layer. The external quantum efficiency of the device is 1.4% compared with 0.45% of the ITO∕[Ru(bpy)2(dimbpy)](PF6)2∕Ag device, improved by twofold. Furthermore, this hybrid device provides a feasible way to control the emission of a wide spectrum of colors including red, green, yellow, and white.

Reductive heterocyclizations via indium–iodine-promoted conversion of 2-nitroaryl imines or 2-nitroarenes to 2,3-diaryl-substituted indazoles

While N-(2-nitrobenzylidene)anilines produced mixtures of 2,1-benzisoxazoles and 3-anilino-2-aryl-2H-indazoles in the presence of indium and iodine in MeOH, N-(2-nitrobenzylidene)anilines were transformed into 3-anilino-2-aryl-2H-indazoles as the predominant major product through the change of the solvent from protic MeOH to aprotic THF. In an indium-mediated one-pot reductive reaction, 2-benzaldehydes and anilines in THF were also successfully transformed into the corresponding indazoles.

Asymmetric Allylation of Aldimines with Indium and (+)‐Cinchonine

Abstract By applying indium and allyl bromide, aldimines were converted into homoallyl amines with excellent yields. The addition of (+)‐cinchonine to the reaction mixture yielded enantioselective allylation with 22–44% ee.

Reductive cyclization of o-nitrophenylazobenzenes to 2-aryl-2H-benzotriazoles by SmI2

Abstract In a mild reaction with SmI2, ortho-nitro substituted phenylazobenzenes have been converted into 2-aryl-2H-benzotriazoles.

INDIUM MEDIATED REDUCTIVE ACYLATIONS OF NITROARENES TOWARDS N,O-DIACYLATED N-ARYLHYDROXYLAMINES*

By applying indium, Ac2O, MeOH, and catalytic amount of InCl3 in CHCl3 solution, nitroarenes were transformed into N,O-diacylated N-arylhydroxylamines in moderate to excellent yields. *Dedicated to Professor Jack W. Timberlake on the occasion of his 60th Birthday.