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 adsorption selectivity in a diarylethene-azobenzene MOF.

The first MOF (metal-organic framework) built on both diarylethene and azobenzene photochromic units is reported here and displays distinct photoresponses for different guest molecules, thus creating an easy-to-use pathway to modulate the adsorption selectivity of MOF materials.

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.

(E)-3-[4-(Diphenyl-amino)-phen-yl]-1-(pyridin-2-yl)prop-2-en-1-one.

The title compound, C(26)H(20)N(2)O, belongs to a new family of organic two-photon absorption materials with triphenyl-amine and pyridine units. In the mol-ecule, the three benzene rings are arranged in a propeller-like fashion; the dihedral angles between the rings are 80.01 (14), 75.68 (13) and 56.93 (14)°. The pyridine ring is oriented at dihedral angles of 56.24 (14), 48.92 (15) and 22.02 (13)° with respect to the three benzene rings. Weak inter-molecular C-H⋯O hydrogen bonding is present in the crystal structure.

4-{2-[5-(3,5-Difluoro-phen-yl)-2-methyl-thio-phen-3-yl]-3,3,4,4,5,5-hexa-fluoro-cyclo-pent-1-en-1-yl}-1,5-dimethyl-pyrrole-2-carbonitrile.

In the title compound, C(23)H(14)F(8)N(2)S, the dihedral angles between the pyrrole and thio-phene groups and the almost planar C-C=C-C unit of the cyclo-pentene ring (r.m.s. deviation = 0.4193 Å) are 43.6 (5) and 50.1 (2)°, respectively. The distance of 3.612 (3) Šbetween the potentially reactive C atoms of the two heteroaryl substituents is short enough to enable a photocyclization reaction.

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(2-methyl-5-phenyl-3-thien-yl)benzene.

In the mol-ecule of the title compound, C(28)H(22)S(2), the two thio-phene rings are twisted with respect to the central benzene ring, making dihedral angles of 71.59 (12) and 50.71 (12)°. The two terminal benzene rings are oriented at dihedral angles of 37.59 (11) and 20.12 (11)° to their bonded thio-phene rings.

(R)-N-{2-tert-Butyl-2-[(R)-tert-butyl-sulfonamido]ethylidene}-tert-butane-sulfonamide.

The title compound, C(14)H(30)N(2)O(2)S(2), is the product of the monoaddition reaction of tert-butyl magnesium chloride with bis-[(R)-N-tert-butanesulfinyl]ethanediimine. There are two almost identical mol-ecules in the asymmetric unit, the mol-ecular conformation of which is stabilized by an intra-molecular N-H⋯N hydrogen bond.

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.