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A new oxo-bridged chromium-molybdenum heterometallic complex, O-CrMoHC ([Cr4(MoO4)2O2(OAc)4(DMF)4]·2DMF), was synthesized by using a simple solvothermal reaction. In this complex, the octahedrally coordinated Cr(III) and tetrahedrally coordinated Mo(VI) metal centers are bridged by oxo ligands. O-CrMoHC has in-plane π-conjugation systems, which are interconnected by noncoordinating DMF molecules. The crystals show anisotropic conductivity with respect to the crystal planes, and theoretical calculations were used to study their origins. The O-CrMoHC single crystals exhibited that a relatively high electrical conductivity with an average value of 5.37 × 10-7 S/cm was observed along the [01-1] direction, but the current level was very low along the [100] direction. This is the first report of anisotropic conductivity observed in the single crystal of a monomeric heterometallic complex.

Carrier doping in conductive radical crystal systems is one of the most important and challenging issues in employing radicals as charge carriers, i.e., electronic radicals for high-performance organic electronics. Here, we report an experimental demonstration of the increase in the radical population and the corresponding increase in electrical conductivity by water desorption-involved crystal structure change upon mild heating. The electrical conductivity of the dihydrophenazinium radical cation (H₂PNZ·⁺) crystal is enhanced by 4 orders of magnitude with an increase in radical population by 1.5 times according to the electron paramagnetic resonance signal after heating at 333 K. Single-crystal X-ray analyses show that the increase in radical population originates from the phase transformation from dimer-like radical units to monomer-like radical units upon mild heating in a narrow temperature range. The increase in intermolecular distance results in producing more independent radicals and reducing the band gap. Therefore, the electrical conductivity is increased by the synergistic effects of the radical population increase and band gap reduction.

Producing more than one structure from the same set of metal and ligand precursors will grant structural diversity in metal-organic framework (MOF) systems. One of the biggest obstacles of getting structural diversity for the late transition metals is that the coordination mode is pretty much fixed by nature. Herein, we show that two different coordination modes to Cu(II) are possible for flexible ligands containing hydrophilic terminal groups through solvent guidance. It is demonstrated that trans,trans-muconic acid (H2muco) ligands coordinate to Cu(II) to form Cu(II) muconate MOFs having a 1D chain structure and a 2D plane structure in water-rich and DMF-rich water-DMF mixed solvent systems, respectively. It is suggested that the interaction between ligands and solvent is responsible for the selective coordination. A similar result was observed from the attempts using the fumaric acid ligand. Our results provide a new direction to obtain diverse secondary building units for the construction of diverse MOFs.

Solid-state conversion by the spontaneous redox reaction between tetrathiafulvalene (TTF) and ferric ion is employed to obtain morphology-retained TTF mixed valence (MV) salt crystals. Radical spec...

Chiral organic optoelectronics using circularly polarized light (CPL) as the key element in the photonic signal has recently emerged as a next-generation photonic technology. However, it remains challenging to simultaneously achieve high polarization selectivity and superior optoelectronic performance. Supramolecular two-dimensional (2D) chiral organic single crystals may be good candidates for this purpose due to their defect-free nature, molecular diversity, and morphologies. Here, quasi-2D single crystals of chiral perylene diimides with parallelogram and triangle/hexagon morphologies have been selectively fabricated

Chiral self-sorting has great potential for constructing new complex structures and determining chirality-dependent properties in multicomponent mixtures. However, it is still of great challenge to achieve high fidelity chiral self-discrimination. Besides, the researches on the coordination polymers or metal-organic frameworks for micro/nanooptoelectronics are still rare due to their low conductivity and difficulty in developing a rapid and simple scale-up synthetic method. Here, heterochiral supramolecular coordination networks (SCNs) were synthesized by the solvothermal reaction of naphthalene diimide enantiomers and cadmium iodide, using the chirality as a synthetic tuning parameter to control the morphologies. Intriguingly, heterochiral micro/nanocrystals exhibited photochromic and photodetecting properties. Furthermore, we also developed a simple and efficient doping method to enhance the conductivity and photoresponsivity of micro/nanocrystals using hydrazine. From experimental and theoretical studies, the mechanism was suggested as follows: the radicals in the singly occupied molecular orbital level of the ligands provide charge carriers that can undergo "through-space" transport between π-π stacked ligands and the electron transfer from adsorbed hydrazine to the SCNs results in reduction of energy gap, leading to increased conductivity. Our findings demonstrate a simple and powerful strategy for implementing coordination networks with redox ligands for micro/nanooptoelectronic applications.

Electrically conducting cation-charged dihydrophenazinium radical (H2PNZ•+) crystals were formed by a one-pot photoreaction. Furthermore, new secondary crystals were grown directly from the H2PNZ•+ crystal surface through a surface-mediated recrystallization (SMR) process by a secondary photoreaction with water. Depending on the absence or presence of light during the exposure of the H2PNZ•+ single crystal to water, neutral yellow PNZ crystals (SMRY) or densely packed green H2PNZ•+ crystals (SMRG) were formed, respectively, on the surface of the mother H2PNZ•+ crystal. The single-crystal X-ray analysis reveals that the newly obtained SMRG radical crystal exhibits a shorter intercolumnar distance than the original H2PNZ•+ crystal, resulting in increased electrical conductivity.

The role of antisolvent molecular geometry on the determination of the final molecular crystals morphology formed by the reverse antisolvent crystallization (r-ASC) process has been unveiled. Herein, we newly report that the rod-, disk-, and cube-shaped tetra(4-aminophenyl)porphyrin molecular crystals were selectively obtained by employing o-, m-, and p-xylene as an antisolvent during r-ASC process with ethanol employed as a good solvent. The X-ray diffraction results of the crystals provide a clear indication about the correlation between the solute–solvent interactions and the resulting crystal morphologies. The results show that the geometry of xylene has a pivotal effect on the crystal growth direction and morphologies, especially for polyhedrons. This finding would provide opportunities not only for realization of quite rare organic polyhedral crystals but also for in-depth studies about the fundamental crystallization process.

Morphology-retained solid-state photoconversion of anthracene (AN) to 9,10-anthraquinone (PC-ANQ) and dipara-anthracene (PC-DPA) was accomplished by irradiating mercury lamp light to plate-shaped AN single crystal in oxygen and argon atmosphere, respectively. The photoconverted crystals retained the original plate shape morphology of the starting AN crystal, whereas the emission profile and crystal structure were significantly changed. The electrical conductivity of PC-ANQ crystal is 5 orders of magnitude greater than that of the starting AN crystal, whereas the PC-DPA crystal exhibits a decreased conductivity. The AN/PC-ANQ/PC-DPA heterostructures with smooth interface were successfully obtained by inducing the photoconversion only at the desired area.

By changing the rate of evaporation, two kinds of crystalline films composed of redox-active porous coordination networks (1 and 2) were selectively prepared on a gold-patterned substrate using a DMF solution of 2,5,8-tri(4-pyridyl)1,3-diazaphenalene and Cd(NO3)2. We found the highly sensitive humidity sensing ability of film 1. Single crystal structures and infrared spectroscopic analyses before and after hydration of a single crystal of 1 revealed the sensing mechanism: exchange of nitrate ions with water on Cd atoms occurred in hydrated conditions to generate a conductive cationic network.