The first fully heterocyclic circulene very recently isolated, C(16)S(8), was studied by means of high accurate methods, allowing reliable predictions and interpretations of the structural and electronic properties of organic molecules bearing sulfur and selenium atoms. The changes induced by the oxidation process and the S/Se substitution on some of its properties and the infrared (IR) spectra were analyzed, allowing a comprehensive assignment of the bands observed in the case of C(16)S(8). The results confirmed the planarity and a large surface area of C(16)S(8), which remain in C(16)S(4)Se(4) and C(16)Se(4) derivatives, favoring their use for H(2) adsorption. The molecules were shown to have a strong aromatic character, while the IR spectrum of C(16)S(8) was elucidated, toward its possible application for a better understanding of the new class of materials; the IR signal associated to the asymmetric stretching of the CC bonds can be used as a structural signature to identify the neutral from the radical forms whose structural planarity was found to resist against the oxidation process. Some of the electronic and physical properties characterizing good electron-donating (ED) and charge-transporting (CT) capacity such as the frontier molecular orbital energies (E(HOMO), E(LUMO)), the ionization potential (IP), and the reorganization energy (lambda(h)/lambda(e) for hole/electron) were calculated and the influence of the cyclic structure of C(16)S(8) on them discussed. C(16)S(8), C(16)S(4)Se(4), and C(16)Se(4) were found to display a comparable/much lower lambda(h) and higher IP and E(LUMO) than those for some of the already well-known field-effect transistors (FET) materials such as pentacene, anthracene, and DT-TTF; further investigation for this issue is strongly recommended.

Metal–organic frameworks (MOFs) and MOF-based composites as luminescent sensors with excellent economic practicability and handy operability have attracted much attention. Herein, we designed and fabricated a porous Zn-based MOF, [Zn­(OBA)2(L1)·2DMA] n [1; H2OBA = 4,4′-oxybis­(benzoic acid), L1 = 2,4,6-tris­(4-pyridyl)­pyridine, and DMA = N,N-dimethylacetamide], with mixed nodes under solvothermal conditions, and the pore size of 5.9 Å was calculated from N2 adsorption isotherms by using a density functional theory model. The as-synthesized compound 1 is stable in different boiling organic solvents and water solutions with a wide pH range of 2–12 and exhibits intense luminescence emission at 360 nm under excitation of 290 nm. Significantly, compound 1 shows high selective detection of Fe3+, CrO4 2–, and Cr2O7 2– in aqueous solution even under the interference of other ions. Compound 1 can quickly sense these ions in a short time and has a striking sensitivity toward Fe3+ with an ultralow limit of detection (LOD) of 1.06 μM. The relatively low LODs for CrO4 2– and Cr2O7 2– are 3.87 and 2.37 μM, respectively, compared to the reported works. Meanwhile, compound 1 can be reused to detect Fe3+, CrO4 2–, and Cr2O7 2– six times by simple regeneration. Considering the practicability, a mixed-matrix membrane (MMM) incorporated compound 1 and poly­(methyl methacrylate) has been constructed. This MMM displays quick detection of Fe3+, CrO4 2–, and Cr2O7 2– and prompt regeneration by lifting from the analyte. This useful MMM shows a comparable LOD below 4.35 μM for these ions. This work presents a cost-effective Zn-based MOF as a functional platform for simple but useful sensing of Fe3+, CrO4 2–, and Cr2O7 2– in aqueous solution.

A quantum chemical investigation is made on the recently synthesized octathio[8]circulene (C16S8), an exotic molecule, the first fully heterocyclic circulene, from the structural and electronic properties and some charge-transport parameters viewpoints. Since the molecule consists of eight thiophene rings fused together, we have chosen to compare it with the acyclic (octathienoacene) analogue and to some relatives thereof, in which the sulfur atoms are substituted by Se, NH, CH2 and O. C16S8, C16Se8 and C16S4Se4 are found to show a low reorganization energy comparable or lower than that for already well known field-effect transistor (FET) materials, a promising property which, combined to some others revealed by this study, makes these compounds potential candidates for FET use. In addition, the twist angle is found to be tightly linked to the peripheral bonds lengths, the least twisted structures showing the most interesting properties for organic FET use.

Theoretical investigations have been performed to explore the optical properties of {[3,5-(CF3)(2)Pz]Cu}3 in monomeric and dimeric forms using TD-DFT approaches. The emission of all complexes originates from the lowest triplet excited-states (T1), and the corresponding emissive states are assigned as the mixture of the metal-centered charge transfer and ligand-to-metal charge transfer. The features of the emission spectrum are clarified in detail. The bulk emission spectrum of complex is mainly determined by the stacked dimers rather than the individual monomers. The predicted maximum emission wavelength (lambda(em)) are in good agreement with experimental values, indicating that the phosphorescence bands can be assigned to two different conformations for the neighboring stacked dimers sharing the same monomer in the complex. Energy transfer from T1 of one stacked dimer to the neighboring one is responsible for the disappearance of the shoulder, leaving only the main peak upon heating. With the aim to reveal the conformational dependence for the triplet excited-state emission spectrum, the optical properties of various stacked dimers with different conformations are investigated by varying the relative arrangements through changing inter-monomer distance or rotational angles for the dimer which is responsible for the main peak emission. Calculation results suggest that the shortest intermolecular Cu...Cu distance plays an important role in the emission spectra of the vertical- and tilting-movement dimers, which is ascribed to the variation of the energy gap for the frontier molecular orbitals involved in the main emitting transition. The blue shift of lambda(em) in parallel-movement and rotational dimers can be traced back to the variation of the mutual spatial orientation. Therefore, the modulation of the extent of movement or rotational angles for stacked dimers by external perturbations creates new possibilities for the design of molecular light-emitting devices.

Equilibrium geometry configurations of the "CH"/N substituted Alq3 and Gaq3 derivatives are calculated by density functional theory (B3LYP/6-31G). The frontier molecular orbital and gap energy calculations for all complexes have been performed at the HF/6-31G level. It was shown that, compared to the pristine molecules, the HOMO and LUMO are stabilized, the net effect being however an increasing/decreasing of the gap (Eg) depending on the position of the substituted group. On the basis of the equilibrium geometries, the effect of the substitution on the absorption and emission spectra was evaluated using TDB3LYP/3-21G. It was shown that the change of "CH"/N substituted position on 8-hydroxyquinoline ligand is a powerful approach for the tuning of emitting color. An important blue shift was predicted for 5-substituted 8-hydroxyquinoline derivatives, an important red one being observed for 4-substituted ones. Interestingly, relatively significant blue and red shifts were also predicted for the 7- and 2-substituted derivatives. In this work, the correlation between the spectrum shifts and the metal-ligand bonding is also discussed.

Physical properties of intercalated porous material can be modulated by intercalation of small molecules, as this was demonstrated through the iodine (I2) intercalation into tris(o-phenylenedioxy)cyclotriphosphazene (TPP) crystals. This work describes in depth theoretical considerations of TPP derivatives. The core ring [(NP)3] substitution by [(CO)3], [(CNH)3], and [(CS)3], as well as the side group modification in size and composition (containing tetrathiafulvalene-like fragments), is well described from the most important aspects as their geometry optimization, their highest occupied molecular orbital (HOMO)−lowest unoccupied molecular orbital (LUMO) consideration together with ionization potentials (IP), and their charged forms. On the basis of PBE0/6-31G(d,p) calculations, the neutral forms of the [(CO)3], [(CNH)3], and [(CS)3] containing derivatives are predicted in a distorted caplike conformation. In the first two series, planar (or nearly planar) conformations are predicted upon oxidation, while IP and HOMO energy calculation revealed an electron-donor strength better or comparable to that of the known tetrathiafulvalene (TTF)-like superconductors. Within the [(NP)3] based derivatives, the results show that the geometry of the central part may be influenced by the structure of the side fragment. Among the most interesting results, a number of derivatives are predicted to show a good electron-donor strength compared to the commonly used TTF-like donors. More interestingly, a larger number of [(NP)3] containing derivatives, especially the O/“NH”-substituted series, are found to combine the good electron-donor capacity and the “paddle wheel” molecular shape, making them good candidates for organic superconductors with the ease of modulating their conducting properties by intercalation of suitable acceptors.

Tris(o-phenylenedioxy)cyclotriphosphazene (TPP) became a compound of choice to investigate the structural features of organic zeolite and their potential applications. Different TPP-like materials are studied in this Letter from the electron-donor (E-D) capacity viewpoint, since this was reported as a stabilizing parameter of the TPP-Lewis acid inclusion compound up to high temperatures. On the basis of DFT-PBE0/6-31G(d,p) calculations, the results reported herein show a tight dependence of the E-D of the entire molecule on that of the side group. It was shown that both the O/NH substitution and the extension of the phenylenedioxyl group with an aromatic ring significantly enhance the E-D. As a result, the corresponding clathrates, including some reported ones, may also be exploited for the same issue, with an even wider range of operating temperatures when trapping compounds of Lewis acidity character comparable to that of I2. Furthermore, it was concluded that these two strategies may significantly enhance the E-D capacity without altering the tolerance of TPP-like host materials to the guest molecules.

Table S1 Selected optimized ground-state parameters of 1 and 2 in gas phase and CH 2 Cl 2 media at B3LYP/LANL2DZ level 1 2 gas CH 2 Cl 2 media gas CH 2 Cl 2 media Bond Length/Å