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Dithienylethenes (DTEs) are a promising class of organic photoswitches that can be used to create crystalline solids with properties controlled by light. However, the ability of DTEs to adopt multiple conformations, only one of which is photoactive, complicates the rational design of these materials. Herein, the synthesis and structural characterization of 19 crystalline solids containing a single DTE molecule are described. A novelD–Danalysis of the molecular geometries obtained from rotational potential energy surface calculations and the ensemble of experimental structures were used to construct a crystal landscape for DTE. Of the 19 crystal structures, 17 contained photoinactive DTE rotamers and only 2 were photoactive. These results highlight the challenges associated with the design of these materials. Overall, theD–Danalysis described herein provides rapid, effective and intuitive means of linking the molecular structure to photoactivity that could be applied more broadly to afford a general strategy for producing photoactive diarylethene-based crystalline solids.

 

We report the first instance of observing the phototriggered isomerization of dmso ligands on a bis sulfoxide complex, [Ru(bpy) 2 (dmso) 2 ], in the crystalline solid state. The solid-state UV-vis spectrum of the crystal demonstrates an increase in optical density around 550 nm after irradiation, which is consistent with the solution isomerization results. Digital images of the crystal before and after irradiation display a notable color change (pale orange to red) and cleavage occurs along planes, (1̄01) and (100), during irradiation. Single crystal X-ray diffraction data also confirms that isomerization is occurring throughout the lattice and a structure that contains a mix of the S , S and O , O / S , O isomer was attained from a crystal irradiated ex situ . In situ irradiation XRD studies reveal that the percentage of the O-bonded isomer increases as a function of 405 nm exposure time. 

The organic salt ( S )-nicotinium 2,6-dihydroxybenzoate undergoes reversible single crystal to single crystal phase transition at 104 K. The phase transition was monitored using temperature dependent single crystal X-ray diffraction and was attributed to symmetry breaking translations and rotations of the crystal components. 

In the title double proton-transfer salt, C 12 H 12 N 2 2+ ·2C 8 H 7 O 4 − , consisting of a 1:2 ratio of 4,4'-(ethene-1,2-diyl)dipyridinium cations ( trans bipyridinium ethylene) to 2-hydroxy-3-methoxybenzoate anions ( o -vanillate), the complete cation is generated by crystallographic inversion symmetry and it is linked to adjacent o -vanillate anions by N—H...O hydrogen bonds, forming trimolecular assemblies. The trimers are linked by C—H...O hydrogen bonds as well as aromatic π–π stacking interactions into a three-dimensional network. The anion features an intramolecular O—H...O hydrogen bond. 

2D molecular entities build next-generation electronic devices, where abundant elements of organic molecules are attractive due to the modern synthetic and stimuli control through chemical, conformational, and electronic modifications in electronics. Despite its promising potential, the insufficient control over charge states and electronic stabilities must be overcome in molecular electronic devices. Here, we show the reversible switching of modulated charge states in an exfoliatable 2D-layered molecular conductor based on bis(ethylenedithio)tetrathiafulvalene molecular dimers. The multiple stimuli application of cooling rate, current, voltage, and laser irradiation in a concurrent manner facilitates the controllable manipulation of charge crystal, glass, liquid, and metal phases. The four orders of magnitude switching of electric resistance are triggered by stimuli-responsive charge distribution among molecular dimers. The tunable charge transport in 2D molecular conductors reveals the kinetic process of charge configurations under stimuli, promising to add electric functions in molecular circuitry.

 

The title triphenylamine derivative, C 24 H 17 Cl 2 N, featuring a 3,5-dichloro-1,1′-biphenyl moiety has been synthesized and structurally characterized. The molecular structure shows rotations of the phenyl rings in the range of 37–40° from the amine plane. In the crystal, the molecules interact by van der Waals interactions.