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Thus far, only a few methods for the asymmetric synthesis of erythritols bearing a trifluoromethyl group have been developed, and these methods present serious disadvantages such as the requirement of multiple steps for the preparation of their starting materials, low stereoselectivity, and the use of highly toxic reagents. Herein, we have developed a highly diastereo- and enantioselective organocatalytic method to synthesise erythritols bearing a trifluoromethyl group using (1) a commercially available organocatalyst to produce unstable trifluoroacetaldehyde in situ from its corresponding hemiacetal, followed by the simultaneous asymmetric carbon–carbon bond-forming reaction of the organocatalyst with an in situ-generated chiral enamine derived from 2,2-dimethyl-1,3-dioxane-5-one to obtain the corresponding aldol product in good yield (65–80%) with high diastereoselectivity (up to 94% de) and excellent enantioselectivity (up to >98% ee), (2) the highly diastereoselective reduction of the ketone moiety in the aldol product (up to 98% de), and (3) the deprotection of the acetal moiety.

(2R,3aR,8bR)- and (2S,3aS,8bS)-2-Methyl indoline dye tetrabutylammonium carboxylates exhibited the highest conversion efficiency among four regio and stereo isomers. These indoline dyes also showed higher conversion efficiency than DN350.

An indoline dye attached with a carboxylated indan-1,3-dione moiety linked with a hexylthiophene ring exhibited the highest conversion efficiency among six analogues and D205. This result comes from the bathochromic UV–vis absorption band, suitable energy levels, good stability for redox process, and sufficiently long excited-state lifetime.

The cinchonine-catalyzed in situ generation of unstable and gaseous trifluoroacetaldehyde from its hemiacetal and successive direct aldol reaction with 2-methoxy-1-phenylethanone proceeded smoothly to give 4,4,4-trifluoro-3-hydroxy-2-methoxy-1-phenylbutan-1-one in good yield with low diastereoselectivity and enantioselectivity.

A novel polyol compound, amdigenol D, produced by the dinoflagellate Amphidinium sp. has been isolated. Its structure was elucidated by NMR spectroscopy and MS/MS analyses. Amdigenol D consists of a C101-linear carbon backbone including two core structures of amphidinol analogs. Amdigenol D is the longest amdigenol analog identified to date.

Anion exchange in a near-infrared-absorbing heptamethinecyanine dye from an iodide to fluorine-containing anions proceeded smoothly at room temperature to give the corresponding heptamethinecyanine dyes carrying bis(trifluoromethanesulfonyl)imide ((CF 3 SO 2 ) 2 N − ), hexafluorophosphate (PF 6 − ) and trifluoromethanesulfonate (CF 3 SO 3 − ) in good yields. Heptamethinecyanine dyes carrying (CF 3 SO 2 ) 2 N − , PF 6 − , and CF 3 SO 3 − showed better thermal stabilities than the dye carrying an iodide as a counter anion.

Two commercially available simple ionic liquids, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate and 1-ethyl-2,3-dimethylimidazolium trifluoromethansulfonate, effectively promote the solvent-free dehydrative carbon–carbon (C–C) bond-forming reaction of a variety of diarylmethanols and triarylmethanols with π-rich heteroaromatics, such as pyrroles, indole, furan, and thiophene without ring-opening and polymerization to give the corresponding not only 2-substituted pyrroles, furan, and thiophene but also 3-substituted indoles in good to excellent yields with moderate to excellent regioselectivities. These dehydrative C–C bond formation reactions of alcohols offer several advantages, such as the use of stoichiometric amounts of π-rich heteroaromatics and ionic liquids, water is the only by-product, there is no need for either organic solvents or expensive metal or strong Bronsted acid catalysts in the reaction, and the diversity of diarylmethylation and triarylmethylation.

Colorless tetrazole thiolate/sulfide redox couples carrying long alkyl groups, such as n-butyl, n-hexyl, and n-octyl groups, were synthesized as electrolytes in iodine/iodide-free dye-sensitized solar cells (DSSCs). Among N719/TiO2-based DSSCs employing these highly soluble redox couples for 3-methoxypropionitrile (3-MPN) and ionic liquid with PEDOT counter electrode, the DSSC with n-hexyl redox analogue gave an optimized η value of 4.32%. An observed respectable quantum efficiency for 400–500 nm light is in sharp contrast to the decreased performance for iodine/iodide systems that originates from the substantial light absorption of iodine. On the other hand, the redox possessing n-octyl group significantly lowered the cell performance, which could be a result of the much increased resistance of electrolyte diffusion in the DSSC.

6-(9-Anthryl)- and 6-(1-naphthyl)-9-(dibutylamino)benzo[a]phenoxazin-5-ones exhibited fluorescence maximum at around 700 nm in the crystalline form. Their fluorescence quantum yields were significantly higher than that of previously reported 6-perfluoro[4-methyl-3-(1-methylethyl)pent-2-en-2-oxy] derivative due to the isolated dimer-type packing.

3-Butoxy-4-(1-butyl-3,3-dimethyl-3H-indol-2-ylidenemethyl)-3-cyclobut-1,2-dione exhibited the most intense florescence at fluorescence maxima 536 and 563 nm with fluorescence quantum yield 0.21 among any indolenine semi-squarylium dyes in the crystalline form due to the isolated dimer-type molecular packing and its suitable melting point. This compound showed aggregation-induced emission enhancement.

Novel fluorescent dyes, thiazole-boron complexes bearing β-ketoiminate ligands, have been synthesized, and their fluorescence properties were investigated. The BF(2) complexes showed a pronounced aggregation-induced emission enhancement effect because of the restriction of C-Ph intramolecular rotation. The BPh(2) complexes showed higher fluorescence quantum yields than the corresponding BF(2) complexes, both in solution and in the solid state.

The effect of N -(2-alkoxyphenyl) group in double rhodanine indoline dye on the performance of zinc oxide dye-sensitized solar cell was examined. Both J sc and V oc were improved by introducing long alkoxy group due to prevention of H-aggregates formation and inhibition of electron recombination from zinc oxide surface to electrolyte.

An N-butyl indolenine squarylium dye could include toluene and p-xylene and exhibited the solid-state fluorescence in near-infrared region (Fmax=761 nm) in crystalline form due to inhibition of π/π-interactions between the fluorophores.

New indoline dye (DN319) having strong electron-withdrawing dicyanovinylidene moiety and octyl group in the terminal rhodanine ring gave higher efficiency than D205, which was known as an excellent organic dye sensitizer. This result is attributed to the bathochromic shift in the UV–vis absorption band and positive shift in the Eox level of DN319.

In this study, we attempted to increase the fluorescence quantum yield of pyrromethene–BF2 complex (BODIPY) in the solid state by introducing bulky groups as substituents at the boron atom. Although the BF2 complex did not exhibit any fluorescence in the solid state (Φf = 0.00), the B(OMe)2, B(OPh)2, and BPh2 complexes did show solid-state fluorescence with quantum yields of 0.02, 0.04, and 0.22, respectively.

The fluorescence properties of novel 6-butyl-2,3-dicyano-7-methyl-6H-1,4-diazepine styryl dyes having mono-, di-, tri-, and tetra(ethyleneglycol) units were examined. The mono(ethylenglycol) derivative was solid at room temperature, whereas the di-, tri-, and tetra(ethylenglycol) derivatives were oily. The monoethyleneglycol derivative showed weak aggregation-induced emission enhancement with fluorescence maximum at 649 nm, which comes from J-aggregates. The fluorescence of oily di-, tri-, and tetra(ethyleneglycol) derivatives in neat form was very weak. No aggregation-induced emission enhancement was observed for the oily derivatives.

Substituited triple rhodanine indoline dyes showed higher performance than known triple rhodanine derivative (D150). A few triple rhodanine indoline derivatives showed comparable conversion efficiency to D149.

Treatment of trifluoroacetaldehyde ethyl hemiacetal with enamines, derived from acetophenone derivatives, at room temperature gave (E)-1,1,1-trifluoro-4-morpholino-4-aryl-but-3-en-2-ols, which are intermediates for preparation of the β-trifluoromethylated aldol products, 4,4,4-trifluoro-3-hydroxy-1-aryl-butan-1-ones. The structure of the intermediate (E)-1,1,1-trifluoro-4-morpholino-4-(4-nitrophenyl)-but-3-en-2-ols could be assigned by 1H, 13C NMR, IR, and X-ray crystallography. Furthermore, hydrogenation and reductive deamination of the intermediate (E)-1,1,1-trifluoro-4-morpholino-4-aryl-but-3-en-2-ols with hydrogen in the presence of a catalytic amount (10 mol %) of palladium on carbon in trifluoroethanol proceeded smoothly at room temperature to give 1,1,1-trifluoro-4-aryl-2-butanols in good to excellent yields.

Recyclable ionic Bronsted acid was prepared in nearly quantitative yield by reacting 1-butylimidazole with an equimolar amount of 1,3-propanesultone, followed by treatment with an equimolar amount of trifluoromethanesulfonic acid. The ionic Bronsted acid-catalyzed direct benzylation, allylation and propargylation of 1,3-dicarbonyl compounds with various alcohols in ionic liquid [N-ethyl-N-methyl imidazolium trifluoromethanesulfonate (EMIOTf)], at 100 °C for 3 h proceeded smoothly to give the corresponding products in good to excellent yields without the use of any hazardous or volatile solvents and without any by-product such as salts. Furthermore, tandem benzylation–cyclization–dehydration of 1,3-dicarbonyl compounds to give functionalized 4H-chromenes was also achieved in this catalytic reaction.

No solid-state fluorescence is observed for 9-(diethylamino)benzo[ a ]phenoxazin-5-one (Nile Red). However, 9-dibutylamino-6-{perfluoro[4-methyl-3-(1-methylethyl)-2-penten]-2-oxy}benzo[ a ]phenoxazin-5-one showed fluorescence maximum at 717 nm in solid state with fluorescence quantum yield 0.024. X-ray crystallographic analysis suggests that prevention of network π−π interactions by the bulky fluorine-containing and dibutylamino groups is essential to show solid-state fluorescence.

2,3-Diaminomaleonitrile (DAMN) was allowed to react with 2,6-heptanedione to produce (2Z)-2-amino-3-[(1E)-3-methylcyclohex-2-enylideneamino]but-2-enedinitrile and (2Z)-2-amino-3-[(1Z)-3-methylcyclohex-2-enylideneamino]but-2-enedinitrile. The reaction of DAMN with 2,7-octanedione yielded trans-5,8a-dimethyl-1,5a,6,7,8,8a-hexahydrocyclopenta[e]-1,4-diazepine-2,3-dicarbonitrile. DAMN reacted with 2,8-nonanedione to afford trans- and cis-5,9a-dimethyl-5a,6,7,8,9,9a-hexahydro-1H-benzo[e]-1,4-diazepine-2,3-dicarbonitrile. These compounds were characterized by X-ray crystallography, NMR spectroscopy, and DFT calculations.

Novel bisboron complexes of bidentate ligands consisting of 1,4-benzoquinone and two pyrrole rings were synthesized by using a simple two-step reaction. In solution, the bisboron complexes showed absorption maxima at ∼620 and 800 nm, which were attributed to the allowed S0 → S2 and forbidden S0 → S1 transitions, respectively. The bisboron complexes did not show any fluorescence, probably because of their highly symmetrical structure which forbids the S0 → S1 transition. Bisboron complexes underwent a two-electron reduction to yield the corresponding aromatic dianion, which showed absorption maxima at ∼410 nm.

A direct, concise, and enantioselective synthesis of 2-substituted 4,4,4-trifluorobutane-1,3-diols based on the organocatalytic asymmetric direct aldol reaction of an ethyl hemiacetal of trifluoroacetaldehyde with various aldehydes was examined. A catalytic amount (30 mol %) of commercially available and inexpensive l-prolinamide is quite effective as an organocatalyst for the catalytic in situ generation of gaseous and unstable trifluoroacetaldehyde from its hemiacetal, and a successive asymmetric direct aldol reaction with various aldehydes in dichloromethane at 0 °C, followed by reduction with sodium borohydride, gives 2-substituted 4,4,4-trifluorobutane-1,3-diols in moderate to good yields (31–84 %) with low diastereoselectivities and good to excellent enantioselectivities (64–97 % ee).

[reaction: see text] Although the reactivity of tropylium ion with aromatic substrates is low, the reaction of azepinium ion with aromatic substrates such as benzene, phenol, furan, and thiophene resulted in the formation of 2-aryl-2H-azepine as a major product. An exceptional result in the formation of ring-contracted product was observed in the reaction with pyrrole.

The solid-state fluorescence of 2-amino-, 2-ethylamino, 2-diethylamino-, and 2,7-bis(diethylamino)perfluorophenazines was examined. They showed their fluorescence maxima in the range of 584–637 nm. The solid-state fluorescence quantum yield of 2-diethylamino derivative was highest among these derivatives, there being 0.22. X-ray crystallographic analysis suggests that the 2-diethylamino derivative has no strong intermolecular interactions among adjacent molecules to show intense fluorescence, whereas the other derivatives have network NH/F hydrogen, π–π, and CH/F interactions to reduce solid-state fluorescence intensity.

Novel near-infrared (NIR)-sensitizing (up to 800 nm) simple asymmetric squaraine dyes (Sq 31 and Sq 33) carrying indoline moieties that did not require the introduction of any linker groups were developed. DSSCs fabricated with Sq 33 exhibited remarkable characteristics in the long-wavelength visible and NIR region (up to 800 nm), such as a conversion efficiency of 3.75% (AM 1.5G) with an incident photon-to-current conversion efficiency of 63% (650 nm), a short-circuit photocurrent density of 13.64 mA, an open-circuit photovoltage of 0.48, and a fill factor of 0.57.

A novel fluorescence dye based on pyrazine-boron complexes bearing a β-iminoketone ligand has been synthesized by using a simple two-step reaction. Synthesized complexes exhibited fluorescence in solution (F(max): 472-604 nm) and in the solid state (F(max): 496-624 nm). These complexes showed a larger Stokes shift (3690-4900 cm(-1)) than well-known boron dipyrromethene dyes (400-600 cm(-1), in most cases).

A fluorescent dye, the pyridomethene-BF(2) complex, has been synthesized. Although pyridomethenes did not exhibit fluorescence, pyridomethene-BF(2) complexes exhibited fluorescence both in solution and in the solid state. The trifluoromethyl-substituted BF(2) complex formed a J-aggregate and showed the highest fluorescence quantum yield in the solid state among all pyridomethene-BF(2) complexes.

Palladium-catalyzed polycondensation of 2-(7-bromo-9,9-dioctyl-9H-fluoren-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1a) with tBu3PPd(Ph)Br (2) via Suzuki−Miyaura coupling reaction was investigated. The polymerization in a mixture of THF and 2 mol/L aqueous solution of Na2CO3 proceeded smoothly at room temperature and afforded well-defined polyfluorenes with narrow molecular weight distributions. MALDI-TOF mass spectroscopy showed that the obtained polymers have a phenyl group at one end. The relationships of conversion to number-average molecular weight (Mn) and feed ratio to Mn were linear. These results demonstrate that this organometallic polycondensation proceeds through a chain-growth polymerization mechanism from an initiator unit derived from the catalyst.

The 13 C NMR spectra for all seventeen methylated tropylium ions have been obtained in acetonitrile- d 3 and the chemical shifts of the Me- and the ring-carbons assigned. The plots of the 13 C shifts of ring-carbons against charge densities calculated by the simple Huckel MO method by the use of the inductive and the heteroatom models afford linear correlations. The 13 C shifts for the Me-carbons and the 1 H shifts for the Me- and the ring-hydrogens are linearly correlated with the 13 C shifts for the ring-carbons to which they are attached, provided the Me groups or the ring-hydrogens residing in similar steric environments are compared. From the slopes of the correlation lines the dependences of the 13 C shifts of Me-carbons and the 1 H shifts of ring and Me-hydrogens on charge densities of ring-carbons have been estimated to be 35–50, 11–16, and 2.9–5.1 ppm, respectively, by assuming 160 ppm for the charge dependence of the 13 C shifts of the ring-carbons.

Nine tropylium ions have been synthesized and the empirical stability parameters (i)–(iv) have been measured along with the parameters of known tropylium and cyclopropenylium ions: (I) the Cr(II)-ion reduction rate constant ( k 2 ) in 10% aqueous hydrochloric acid at 25.0°; (ii) the charge-transfer frequency ( v CT max ) with pyrene in 1,2-dichloroethane; (iii) the reduction peak potential (E red ) in dichloromethane or in acetonitrile; and (iv) the pK R + values in 23% aqueous ethanol, in 50% aqueous ethanol, and in 50% aqueous acetonitrile. When the linear free-energy relationships (LFER) of these and previously reported results were examined (a) between the charge-transfer energy {(E CT)}, 119.5 × v CT max (cm −1 ), kJ mol −1 and the E red {(96.36 × E red (V), kj mol −1 )}; (b) between the log k 2 {(5.70 × log k 2 (1 mol −1 s −1 ), kJ mol −1 )} and the E red ; and (c) between the log k 2 and the E CT , satisfactory interrelations were found. On the basis of these LFER's the electron affinity scales (log k 2 , E CT , and E red ) are interchangeable for each other as the stability parameters for the cyclopropenylium and tropylium ions. When the pK R + values (5.70 × pK R + , kJ mol −1 ) of 15 cyclopropenylium and 21 tropylium ions were compared with the E red values (kJ mol −1 ), not one but eight correlation lines were shown within the range of slopes −0.25 to −1.05 for each of (1) 12 cyclopropenylium ions in 50% aqueous acetonitrile, (2) nine cyclopropenylium ions in 23% aqueous ethanol, (3) five cyclopropyl-substituted tropylium ions in 50% aqueous acetonitrile, (4) four t-butyl-substituted tropylium ions in 50% aqueous acetonitrile, (5) 10 tropylium ions in 23% aqueous ethanol, (6) nine polymethyl tropylium ions and others in 50% aqueous acetonitrile (7) six 1-aryl-8-tropylionaphthalenes in 50% aqueous ethanol, and (8) five bicycloalkanes fused with the tropylium ion in 50% aqueous ethanol. Thus, the pK R + scale, i.e. the water-affinity scale of the cations, is not generally interchangeable with the E red , i.e. an electron-affinity scale of the cations, even though the pK R + values in a single solvent were compared with the E red values (see categories (1),(3),(4) and (6)). The implications of such divergence of the pK R +- E red correlation are discussed.