Hf(OTf)4-Catalyzed Three-Component Synthesis of N-Carbamate-Protected ß-Amino Ketones.

Hafnium(IV) triflate (Hf(OTf)4) has been identified as a potent catalyst for the direct three-component synthesis of ß-carbamate ketones. This new method, featuring a low catalyst loading, fast reaction rate, and solvent-free conditions, provided facile access to a diversity of carbamate-protected Mannich bases. A mechanistic investigation indicated that the three-component reaction proceeds via sequential aldol condensation and aza-Michael addition, but not the Mannich-type pathway.

An Improved Approach for Practical Synthesis of 5-Hydroxymethyl-2'-deoxycytidine (5hmdC) Phosphoramidite and Triphosphate.

5-Hydroxymethyl-2'-deoxycytidine (5hmdC) phosphoramidite and triphosphate are important building blocks in 5hmdC-containing DNA synthesis for epigenetic studies. However, efficient and practical methods for the synthesis of these compounds are still limited. The current research provides an intensively improved synthetic method that enables the preparation of commercially available cyanoethyl-protected 5hmdC phosphoramidite with an overall yield of 39% on 5 g scale. On the basis of facile and efficient accesses to cyanoethyl protected-5hmdU and 5hmdC intermediates, two efficient synthetic routes for 5hmdC triphosphate were also developed.

Photo-Switchable Aggregation-Induced Emission of Bisthienylethene-Dipyrimido[2,1-b][1,3]benzothiazole Triad.

A bisthienylethene-dipyrimido[2,1-b][1,3]benzothiazole (BTE-2PBT) triad has been designed and synthesized based on our recent discovery of PBTs as atypical propeller-shaped novel AIEgens. The triad not only maintains the photochromic properties of BTE moiety in solution, film, and solid state but also exhibits remarkable AIE properties. Moreover, the fluorescence of BTE-2PBT PMMA film could be modulated with high contrast by alternate UV and visible light irradiation. Photoerasing, rewriting, and non-destructive readout of fluorescent images on BTE-2PBT PMMA film well demonstrate its potential application as optical memory media.

A long-lifetime iridium(iii) complex for lysosome tracking with high specificity and a large Stokes shift.

Investigating the role of lysosome dysfunction in cancer requires the development of efficient probes for lysosomes. We report herein a cyclometalated iridium(iii) complex (Ir-Ly) as a luminescent probe for visualizing lysosomes in cancer cells. The morpholine and hydroxy moieties within Ir-Ly provide suitable hydrophilicity and responsiveness to pH. Importantly, Ir-Ly exhibits a large Stokes shift, long lifetime and high photostability, which are important advantages for lysosome tracking in living cells.

Significant Enhancement of C2 H2 /C2 H4 Separation by a Photochromic Diarylethene Unit: A Temperature- and Light-Responsive Separation Switch.

A dual temperature- and light-responsive C2 H2 /C2 H4 separation switch in a diarylethene metal-organic framework (MOF) is presented. At 195 K and 100 kPa this MOF shows ultrahigh C2 H2 /C2 H4 selectivity of 47.1, which is almost 21.4 times larger than the corresponding value of 2.2 at 293 K and 100 kPa, or 15.7 times larger than the value of 3.0 for the material under UV at 195 K and 100 kPa. The origin of this unique control in C2 H2 /C2 H4 selectivity, as unveiled by density functional calculations, is due to a guest discriminatory gate-opening effect from the diarylethene unit.

Photoswitching CO2 capture and release in a photochromic diarylethene metal-organic framework.

We demonstrate herein a promising pathway towards low-energy CO2 capture and release triggered by UV and visible light. A photosensitive diarylethene ligand was used to construct a photochromic diarylethene metal-organic framework (DMOF). A local photochromic reaction originating from the framework movement induced by the photoswitchable diarylethene unit resulted in record CO2-desorption capacity of 75% under static irradiation and 76% under dynamic irradiation.

3-(4-{3,3,4,4,5,5-Hexafluoro-2-[5-(3-methoxy-phen-yl)-2-methyl-3-thien-yl]cyclo-pent-1-en-yl}-5-methyl-2-thien-yl)benzonitrile.

The title compound, C(29)H(19)F(6)NOS(2), is a new unsymmetrical photochromic diarylethene derivative with different meta-phenyl substituents. The distance between the two reactive (i.e. can be irradiated to form a new chemical bond) C atoms is 3.501 (4) Å; the dihedral angles between the mean plane of the main central cyclo-pentene ring and the thio-phene rings are 47.7 (5) and 45.1 (2)°, and those between the thio-phene rings and the adjacent benzene rings are 29.4 (2) and 28.4 (3)°. The three C atoms and the F atoms of hexa-fuorocyclo-pentene ring are disordered over two positions, with site-occupancy factors of 0.751 (4) and 0.249 (4).

1,2-Bis[5-(2,2'-dicyano-vinyl)-2-n-pentyl-3-thien-yl]-3,3,4,4,5,5-hexa-fluoro-cyclo-pent-1-ene: a new photochromic diaryl-ethene compound.

The title compound, C(31)H(26)F(6)N(4)S(2), is a new photochromic dithienylethene with dicyano-vinyl subsitituents. In the crystal structure, the mol-ecule adopts a photoactive anti-parallel conformation, with two n-pentyl groups located on opposite sides of the cyclo-pentene ring. The cyclo-pentene ring assumes an envelope conformation. The distance between the two reactive C atoms on the thio-phene rings is 3.834 (7) Å. One of the n-pentyl groups is disordered over two positions; the site occupancy factors are ca 0.7 and 0.3.

[Spectral analysis of the effect of different polymerization potential on electrosynthesized poly (5-nitroindole) films].

High quality poly (5-nitroindole) (PNI) films can be synthesized electrochemically by direct anodic oxidation of 5-nitroindole (NI) in boron trifluoride diethyl etherate (BFEE) at different polymerization potential in the range of 1.23-2.23 V (vs. SCE). To the best of our knowledge, this is the first time that high quality polymer films of nitro group substituted conducting polymers were electrodeposited. The oxidation onset potential of NI was only 1.04 V vs. SCE in this medium. Chronoamperometric response of NI, FTIR and 1H NMR indicated that the polymerization potential had a great effect on the quality of PNI films. Lower potential is helpful for the electrochemical polymerization of NI and the extension of the conjugation length of PNI. On the other hand, a higher potential led to side reactions and poor polymer film quality. The structural characterization of PNI films by FTIR and 1H NMR indicated that the electrochemical polymerization of NI occurred at C2 and C3 positions.

1-(2-Methyl-5-phenyl-3-thienyl)-2-(3-methyl-5-phenyl-2-thienyl)-3,3,4,4,5,5-hexafluorocyclopent-1-ene: a novel photochromic hybrid diarylethene.

The title compound, C27H18F6S2, a novel photochromic hybrid diarylethene derivative containing 2- and 3-thienyl substituents, is one of the most promising photochromic candidates with shorter wavelength for optical storage and other optoelectronic devices. In the crystal structure, the molecule adopts a photoactive antiparallel conformation. The distance between the two reactive C atoms, i.e. the ring C atoms to which the methyl groups are attached, is 3.430 (4) A. The dihedral angles between the thienyl and adjacent phenyl rings are 26.8 (2) and 33.98 (9) degrees.

1,2-Bis[5-(1,3-dioxolan-2-yl)-2-ethyl-3-thienyl]-3,3,4,4,5,5-hexafluorocyclopent-1-ene, a photochromic dithienylethene.

The title compound, C23H22F6O4S2, a photochromic dithienylethene, is a promising material for optical storage and other optoelectrical devices. The molecule adopts a photoactive antiparallel conformation in the crystalline state. The distance between the two reactive C atoms which are involved in potential ring closure is 3.829 (4) A. The dihedral angles between the central cyclopentene ring and the adjacent thiophene rings are 55.38 (7) and 54.81 (9) degrees. The colourless crystals turn magenta when exposed to UV radiation and the process is reversible.

3,3,4,4,5,5-Hexafluoro-1,2-bis(5-hydroxymethyl-2-methyl-3-thienyl)cyclopent-1-ene.

The title compound, C(17)H(14)F(6)O(2)S(2), a photochromic diarylethene, is one of the most promising materials for optical memories and other optoelectronic devices. The hexafluorocyclopentene group and the two thiophene rings are all planar, and the dihedral angles between the cyclopentene ring and the adjacent thiophene rings are 46.4 (1) and 49.5 (1) degrees.