Themed collection Solid-State Photochemistry

Welcome to this CrystEngComm themed issue entitled “Solid-State Photochemistry”.

In this highlight, we review the present status of acentric core structures for highly efficient nonlinear optical organic crystals and discuss their distinctive supramolecular interactions and THz wave generation and detection applications.

Incorporation of photo-reversible azo dyes into molecular assemblies provides a new family of advanced optical and photo-mechanical materials that enable the direct transformation of light energy into mechanical motion.

A ‘recover before destroy’ approach to minimise photoproduct build-up in solid state enables ultrafast studies of chemical reactions.

Crystals of 4-methoxyazobenzene move on water surface. The liquefied cis isomer acts as a fuel and light activates/deactivates the fuel.

A photochromic phenyl-substituted viologen based derivative that is embedded in a layered zinc–carboxylate framework is shown to have a fast photoswitching behavior. A favorable geometry for intermolecular electron transfer is established by the sandwich-type π–π stacking structure between the photoactive host and guest components.

Ball milling of blue-emitting crystal 1B of gold(I) isocyanide complex 1 induces a phase transition to yellow-emitting powder 1Y_G, which has the same solid structure as the previously reported 1Y obtained upon photoirradiation of 1B.

A phenanthrene-based diarylethene linker with linear pyridyl connectivity, 4,4′-(9,10-bis(2,5-dimethylthiophen-3-yl)phenanthrene-2,7-diyl)dipyridine linker (TPDPy) was prepared and used to synthesize an air-stable metal–organic framework, UBMOF-3, (Zn₃(BDC)₃(TPDPy)₁(DMF)_1.5).

Solid-state photodimerisation of o-ethoxy-trans-cinnamic acid at 343 K (α′ polymorph) proceeds to 100% conversion via a unique two-stage mechanism, both “Schmidt like” and “Kaupp like”.

2,6,10-Trisubstituted triazatriangulene cation (TATA⁺) derivatives were synthesized, which showed a significantly red-shifted fluorescence band in the solid state.

Singlet fission (SF), the conversion of one singlet exciton into two triplet excitons, may increase the efficiency of organic photovoltaics by generating two carriers from one photon. Based on first-principles simulations, the monoclinic form of rubrene is expected to exhibit higher SF efficiency than the orthorhombic form.

An olefin-containing pyridinium-based metal organic complex underwent solid-state [2 + 2] photocycloaddition in 100% yield, and endowed the cyclobutane compound with an unusual rcct-configuration by recrystallization.

NMR crystallography is used to determine the crystal structure of a meta-stable intermediate in a photomechanical transformation.

A new crystal engineering technique for growing large-area organic electro-optic crystals in a confined geometry with a desired thickness, optimal for THz photonics, is developed and the correlations between THz generation characteristics and crystal characteristics are investigated.

Metal–organic networks have become very popular in view of various chemical and physico-chemical applications. Here, a new approach to explore their potentialities as linear optical materials is discussed.

The lifetime of colored species of photochromic derivatives significantly changed after the photoisomerization of the 2-cyanoethyl group.

Photoinduced topographical changes were observed above T_g of their open-ring isomers.

A series of eight closely related N-salicylidene-4-amino-1,2,4-triazole compounds has been prepared. Their crystal structures were elucidated by single-crystal X-ray diffraction and optical properties were examined by diffuse reflectance spectroscopy. Noncovalent interactions detected in these compounds were, for the first time, analyzed by means of Hirshfeld surface analysis.

We report on a first-principle theoretical investigation of the optical absorption and emission spectra of poly(3-hexylthiophene) (P3HT) aggregates by means of a multiscale all-atom hybrid approach, which combines molecular dynamics simulations, quantum-chemical calculations, and solving of a Frenkel–Holstein model.

Narrow plate-like microcrystals of a stilbene-type compound substituted with anthracene and indanone groups bend upon irradiation with ultraviolet light.

Photochromic diarylethene derivatives having benzo[b]thiophene S,S-dioxide groups underwent turn-on mode fluorescence photoswitching in the single-crystalline phase.

The effect of thermal strain on the rate of photoisomerization is qualitatively different from the effect of strain generated by elastic loading.

Ultrafast photoswitching in spin-crossover crystals induces lattice expansion, which drives cooperative and self-amplified spin-state transformation.

Multiple light-induced metastable NO linkage isomers are detected in the dinitrosyl compound [Ru(NO)₂(PCy₃)₂Cl](BF₄) by a combined photocrystallographic and infrared analysis.

A new type of photomechanical motion of photochromic diarylethene crystals has been presented.

Red crystals of N,N′-bis(3-methoxysalicylidene)-1,5-diiminonaphthalene were obtained after Schiff base condensation in ethanol. Recrystallization from acetone afforded yellow crystals, a process which is reversible and reproducible.