Role of C, S, Se and P donor ligands in copper(i) mediated C–N and C–Si bond formation reactions

The first comparative study of C, S, Se and P donor ligands-supported copper(i) complexes for C-N and C-Si bond formation reactions are described. The syntheses and characterization of eight mononuclear copper(i) chalcogenone complexes, two polynuclear copper(i) chalcogenone complexes and one tetranuclear copper(i) phosphine complex are reported. All these new complexes were characterized by CHN analysis, FT-IR, UV-vis, multinuclear NMR and single crystal X-ray diffraction techniques. The single crystal X-ray structures of these complexes depict the existence of a wide range of coordination environments for the copper(i) center. This is the first comparative study of metal-phosphine, metal-NHC and metal-imidazolin-2-chalcogenones in C-N and C-Si bond formation reactions. Among all the catalysts, mononuclear copper(i) thione, mononuclear copper(i) N-heterocyclic carbene and tetranuclear copper(i) phosphine are exceedingly active towards the synthesis of 1,2,3-triazoles as well as for the cross-dehydrogenative coupling of alkynes with silanes. The cross-dehydrogenative coupling of terminal alkynes with silanes represents the first report of a catalytic process mediated by metal-imidazolin-2-chalcogenones

Super bulky Bismuth(III) imidazole selones

Treatment of BiBr3 with super bulky [(IPaul)Se] (L1) ([(IPaul)Se] = 1,3-bis(2,4-methyl-6-diphenyl phenyl)imidazole selone) or IPr*Se (L2) (IPr*Se = 1,3-bis(2,6-diphenylmethylphenyl)imidazole selone) in toluene afforded the dinuclear complex [(L1)BiBr2(µ-Br)]2 (1) and mononuclear complex [(L2)BiBr3] (2), whose structures have been determined by an X-ray crystallographic study. The complexes were characterized by a combination of 1H NMR and 13C{1H} NMR spectroscopy. The thermal stability of 1 and 2 was compared using TGA. The steric controlled super bulky ligand systems allow for the first structural isolation of a novel super bulky dinuclear complex 1 with edge shared octahedral geometry and mononuclear super bulky complex 2 with mono capped seesaw geometry. The sterically more crowded complex 2 showed the long Bi-Se bond distance (3.192(3) Å) compared to 1 (2.902(5) Å)

Hierarchical Ultrathin Layered GO-ZnO@CeO2 Nanohybrids for Highly Efficient Methylene Blue Dye Degradation

Highly efficient interfacial contact between components in nanohybrids is a key to achieving great photocatalytic activity in photocatalysts and degradation of organic model pollutants under visible light irradiation. Herein, we report the synthesis of nano-assembly of graphene oxide, zinc oxide and cerium oxide (GO-ZnO@CeO2) nanohybrids constructed by the hydrothermal method and subsequently annealed at 300 °C for 4 h. The unique graphene oxide sheets, which are anchored with semiconducting materials (ZnO and CeO2 nanoparticles), act with a significant role in realizing sufficient interfacial contact in the new GO-ZnO@CeO2 nanohybrids. Consequently, the nano-assembled structure of GO-ZnO@CeO2 exhibits a greater level (96.66%) of MB dye degradation activity than GO-ZnO nanostructures and CeO2 nanoparticles on their own. This is due to the thin layers of GO-ZnO@CeO2 nanohybrids with interfacial contact, suitable band-gap matching and high surface area, preferred for the improvement of photocatalytic performance. Furthermore, this work offers a facile building and cost-effective construction strategy to synthesize the GO-ZnO@CeO2 nanocatalyst for photocatalytic degradation of organic pollutants with long-term stability and higher efficiency

Rare antimony(iii) imidazole selone complexes: steric controlled structural and bonding aspects

Novel antimony(iii) imidazole selone complexes in a super crowded environment are reported for the first time. The super bulky selone antimony complexes, [{IPr∗Se}(SbCl3)2] (1) and [{IPr∗Se}(SbBr3)2] (2), were isolated from the reactions between IPr∗Se (IPr∗Se = [1,3-bis(2,6-diphenylmethylphenyl)imidazole selone]) and suitable antimony(iii) halides. 1 and 2 are dinuclear complexes with a Sb:Se ratio of 1:0.5 with an unusual coordination mode of selone. The molecules 1 and 2 consist of both Menshutkin-type Sb⋯πaryl interactions and a Sb-Se coordination bond. However, the reaction between antimony(iii) halides and [(IPaul)Se] ([(IPaul)Se] = [1,3-bis(2,4-methyl-6-diphenyl phenyl)imidazole selone]) with a spatially defined steric impact gave the dinuclear complex [{(IPaul)Se}(SbCl3)]2 (3) and the mononuclear complex [{(IPaul)Se}(SbBr3)] (4) without Menshutkin-type interactions. The Sb:Se ratio in 3 and 4 is 1:1. Interestingly, the Menshutkin-type interaction was absent in 3 and 4 due to the efficient coordinating ability of the ligand [(IPaul)Se] with the Sb(iii) center compared to that of the super bulky ligand IPr∗Se. The thermal property of these antimony selone complexes was also investigated. Density functional theory (DFT) calculations were carried out on the model systems [L(SbCl3)2] (1A), [L(SbCl3)] (1B), [L′(SbCl3)2] (1C), and [L′(SbCl3)] (1D), where L = [1,3-bis(2,6-diisopropyl-4-methyl phenyl)imidazole selone] and L′ = [1,3-bis(phenyl)imidazole selone], to understand the nature of orbitals and bonding situations. The computed metrical parameters of 1A are in good agreement with the experimental values. Natural population analysis of the model system reveals that the natural charge and total population of antimony(iii) are comparable. The unequal interaction between selenium and antimony obtained using Wiberg bond indices (WBIs) is fully consistent with the findings of the single-crystal X-ray studies

Thermochemically Stable Liquid-Crystalline Gold(I) Complexes Showing Enhanced Room Temperature Phosphorescence

Gold(I) complexes are some of the most attractive materials for generating aggregation-induced emission (AIE), enabling the realization of novel light-emitting applications such as chemo-sensors, bio-sensors, cell imaging, and organic light-emitting diodes (OLEDs). In this study, we propose a rational design of luminescent gold complexes to achieve both high thermochemical stability and intense room temperature phosphorescence, which are desirable features in practical luminescent applications. Here, a series of gold(I) complexes with ligands of N-heterocyclic carbene (NHC) derivatives and/or acetylide were synthesized. Detailed characterization revealed that the incorporation of NHC ligands could increase the molecular thermochemical stability, as the decomposition temperature was increased to ~300 °C. We demonstrate that incorporation of both NHC and acetylide ligands enables us to generate gold(I) complexes exhibiting both high thermochemical stability and high room-temperature phosphorescence quantum yield (>40%) under ambient conditions. Furthermore, we modified the length of alkoxy chains at ligands, and succeeded in synthesizing a liquid crystalline gold(I) complex while maintaining the relatively high thermochemical stability and quantum yield

Metal–Organic Framework-Derived Fe-Doped Ni₃Se₄/NiSe₂ Heterostructure-Embedded Mesoporous Tubes for Boosting Oxygen Evolution Reaction

It is crucial but challenging to promote sluggish kinetics of oxygen evolution reaction (OER) for water splitting via finely tuning the hierarchical nanoarchitecture and electronic structure of the catalyst. To address such issues, herein we present iron-doped Ni3Se4/NiSe2 heterostructure-embedded metal–organic framework-derived mesoporous tubes (Ni-MOF-Fe-Se-400) realized by an interfacial engineering strategy. Due to the hierarchical nanoarchitecture of conductive two-dimensional nanosheet-constructed MOF-derived mesoporous tubes, coupled with fine tuning of the electronic structure via Fe-doping and interactions between Ni3Se4/NiSe2 heterostructures, the Ni-MOF-Fe-Se-400 catalyst delivers superior OER activity: it requires only a low overpotential of 242 mV to achieve 10 mA cm–2 (Ej=10), surpassing the benchmark RuO2 (Ej=10 = 286 mV) and displays exceptional durability in the chronoamperometric i–t test with a small current decay (6.2%) after 72 h. Furthermore, the water splitting system comprises a Ni-MOF-Fe-Se-400 anode and a Pt/C cathode requires a low cell voltage of 1.576 V to achieve Ej=10 with an excellent Faradic efficiency (∼100%), outperforming the RuO2–Pt/C combination. This work presents a novel interfacial engineering strategy to finely adjust the morphology and electronic structure of the non-noble metal-based OER catalyst via a facile fabrication method