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Synthesis of a nano tetraimine Pd(0) catalyst system using an N,N-bisimine ligand and its catalytic applications in the Heck–Mizoroki reaction in water is described.

Fossil fuel alternatives, such as solar energy, are moving to the forefront in a variety of research fields. Polymer solar cells (PSCs) hold promise for their potential to be used as low-cost and efficient solar energy converters. PSCs have been commonly made from bicontinuous polymer:fullerene composites or so-called bulk heterojunctions. The conjugated polymer donors and the fullerene derivative acceptors are the key materials for high performance PSCs. In the present study, we have performed density functional theory calculations to investigate the electronic structures and magnetic properties of several representative C60 fullerene derivatives, seeking ways to improve their efficiency as acceptors of photovoltaic devices. In our survey, we have successfully correlated the LUMO energy level as well as chemical hardness, hyper-hardness, nucleus-independent chemical shift, and static dipole polarizability of PC60BM-like fullerene derivative acceptors with the experimental open circuit voltage of the photovoltaic device based on the P3HT:fullerene blend. The obtained structure-property correlations allow finding the best fullerene acceptor match for the P3HT donor. For this purpose, four new fullerene derivatives are proposed and the output parameters for the corresponding P3HT-based devices are predicted. It is found that the proposed fullerene derivatives exhibit better photovoltaic properties than the traditional PC60BM acceptor. The present study opens the way for manipulating fullerene derivatives and developing promising acceptors for solar cell applications.

Presently, many researches are directed toward the design of novel superatoms with high nonlinear optical responses. Inspired by a fascinating finding of superatoms which were designed by bonding superhalogen (Al nanocluster) with superalkalis (MO, M = Na and K), we suggest an effective strategy to form a series of typical donor-acceptor frameworks with high nonlinear optical responses via bonding the superalkalis MO (LiO, NaO, KO, LiNaO, LiKO, NaLiO, NaKO, KLiO, KNaO, and LiNaKO) with low ionization potential to the superhalogen Al with large electron affinity. The ionization potential, electronic spatial extent, electric field gradient tensors of O nuclei, and natural bond orbital charge values of the superalkalis MO were also calculated. We found that the M ligands have the remarkable effect on the ionization potential as well as O nuclear quadrupole resonance parameters of the superalkalis MO. Our results also represented that the bonding superalkalis can efficiently narrow wide HOMO-LUMO gap and considerably enhance first hyperpolarizability of the pristine Al, due to electron transfer in this type of superatom. Also, the effect of oriented external electric fields on the nonlinear optical responses of the superatoms MO-Al has been systematically explored. We found that the first hyperpolarizability of the superatom compounds can be gradually increased by increasing the imposed oriented external electric field from zero to the critical external electric field along the charge transfer direction (MO → Al). In this respect, this work reveals an effective approach to gradually enhance the nonlinear optical responses of the superatoms through applying oriented external electric fields.

Optical and electronic properties are evaluated for infinite periodic boron nitride nanotubes (BNNTs) within density functional theory framework. Specifically, the static dipole polarizability and the band gap of the single-walled zigzag and armchair tubes as well as the double-walled zigzag nanotubes are calculated. Four density functional methods of different categories, namely, PBE, TPSS, VSXC, and HSE have been considered for our purpose. Our results allow promising application of the HSE functional in predicting band gap of infinite periodic nanotubes and similar compounds. The behaviors of DFT methods we obtained for single-walled boron nitride nanotubes are also preserved for predicting the band gap and shielding efficiency of double-walled BNNTs. In double-walled coaxial tubes, the interwall interaction is found to reduce the band gap distinctly and to have only minor effects on the polarizabilities of constituent tubes. In contrast with multiwalled carbon nanotubes, where the inner tube is almost completely shielded by the outer tube, in the studied double-walled BNNTs the inner tube is only partially shielded by the outer shell. This study has implication for nanoelectronics and specifically suggests a new route to efficiently design novel nanodevices with tunable gaps.

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