A photoluminescent dinuclear phenylquinolyl Ir(II)-Ir(II) complex featuring a μ-η1:η2-phenylquinolyl bridge and an end-on dinitrogen ligand

The synthesis, characterization and photoluminescent properties of a dinuclear Ir complex with a μ-η(1):η(2)-phenylquinolyl bridge and an end-on dinitrogen ligand are reported herein. DFT studies on its electronic structure and photophysical properties are also presented.     

Electrical and thermal transport properties of icosahedral and decagonal quasicrystals

Electrical and thermal transport properties of quasicrystals are reviewed on the examples of i-Ag-In-Yb and i-Al-Cu-Fe icosahedral phases and d-Al-Co-Ni decagonal phase. Using samples of single-grain morphology and high structural quality, and performing the measurements along well-defined crystallographic directions, the following basic questions in the context of physical properties of quasicrystals are addressed, both experimentally and theoretically: (1) are the unusual transport properties of quasicrystals introduced by the quasiperiodicity of the structure or are they a consequence of complex local atomic order with no direct relationship to the quasiperiodicity; (2) what is the role of the electronic structure of quasicrystals in their electronic transport properties, especially the pseudogap in the electronic density of states in the vicinity of the Fermi energy; (3) what is the anisotropy of the transport coefficients along different crystallographic directions for icosahedral and decagonal quasicrystals and (4) what are the true intrinsic properties of quasicrystalline phases?     

Ground- and excited-state properties of the mixed-valence complex [(NH3)5Ru(III)NCRu(II)(CN)5]-

A computational study of the ground- and excited-state properties of the mixed-valence complex [(NH 3) 5Ru (III)NCRu (II)(CN) 5] (-) is presented. Employing DFT and TDDFT calculations for the complex in the gas phase and in aqueous solution, we investigate the vibrational and electronic structure of the complex in the electronic ground state as well as the character of the electronically excited states. The relevance of the various excited states for the intervalence metal-metal charge-transfer process in the complex is analyzed based on the change of charge density, spin density, and dipole moment upon photoexcitation as well as by a Mulliken-Hush analysis. Furthermore, those intramolecular modes, which are important for the charge-transfer process, are identified and characterized.     

Photoinduced electron transfer in platinum(II) terpyridinyl acetylide complexes connected to a porphyrin unit

A series of six new dyads consisting of a zinc or magnesium porphyrin appended to a platinum terpyridine acetylide complex via a para-phenylene bisacetylene spacer are described. Different substituents on the 4' position of the terpyridinyl ligand were explored (OC7H15, PO3Et2, and H). The ground-state electronic properties of the dyads are studied by electronic absorption spectroscopy and electrochemistry, and they indicate some electronic interactions between the porphyrin subunit and the platinum complex. The photophysical properties of these dyads were investigated by steady-state, time-resolved, and femtosecond transient absorption spectroscopy in N,N-dimethylformamide solution. Excitation of the porphyrin unit leads to a very rapid electron transfer (2-20 ps) to the nearby platinum complex followed by an ultrafast charge recombination, thus preventing any observation of the charge separated state. The variation in the rate of the photoinduced electron transfer in the series of dyads is consistent with Marcus theory. The results underscore the potential of the para-phenylene bisacetylene bridge to mediate a rapid electron transfer over a long donor-acceptor distance.     

Effect of ancillary ligands on the electronic structures, DNA-binding and spectral properties of [Co(L)2(pip)] (L = phen, bpy, en, tap)

Studies on the electronic structures and related properties of a series of Co(Ш) complexes have been carried out, using the density functional theory (DFT) at the B3LYP/LanL2DZ level. The effect of the ancillary ligands on their electronic structures, DNA-binding affinities and spectra was revealed. The results show that an ancillary ligand has quite important effect on electronic structures and DNA-binding properties of these Co(Ш) complexes. The ancillary ligand possessing a great conjugated structure can effectively improve the DNA-binding affinity of the complex. Meanwhile, introducing a stronger electronegative N atom on the skeleton of ancillary ligand can obviously reduce the LUMO energy of the complex. Based on these findings, a designed complex 4 can be expected to have the greatest K_b value in complexes 1–4. So it may be able to control the interaction between the complex and DNA-base-pairs via varying ancillary ligands. In addition, the electronic absorption spectra of these complexes were calculated and simulated in aqueous solution using the time-dependent DFT (TDDFT) method and the effect of the ancillary ligands on the spectra was also explored. The calculated absorption spectra of these complexes in aqueous solution are in a satisfying agreement with the experimental results, and the properties of experimental absorption bands were theoretically explained in detail.     

ESR SPECTHOSCOPIC STUDY OF ACETONITRILE-Cu(Ⅱ) COMPLEX ON Y-TYPE ZEOLITE

<正> Acetonitrile-Cu(II) complex on Y-type zeolite was studied by ESR and the electronic structural parameters of the complex were calculated.The results are reported here and the bonding properties between the transition metal ion and the ligand, as well as their energy relationships are discussed.     

High‐Quality Three‐Dimensional Nanoporous Graphene

We report three‐dimensional (3D) nanoporous graphene with preserved 2D electronic properties, tunable pore sizes, and high electron mobility for electronic applications. The complex 3D network comprised of interconnected graphene retains a 2D coherent electron system of massless Dirac fermions. The transport properties of the nanoporous graphene show a semiconducting behavior and strong pore‐size dependence, together with unique angular independence. The free‐standing, large‐scale nanoporous graphene with 2D electronic properties and high electron mobility holds great promise for practical applications in 3D electronic devices.     

Hypercoordinate germanium complexes with phenanthrene-9,10-diolate ligands: synthesis,structure, and electronic properties

The synthesis, molecular structure, and electronic properties of sodium tris(phenanthrene-9,10-diolato)germanate(iv) are described. The germanate complex is readily oxidized in air to produce 9,10-phenanthrenequinone, and the resulting quinones and the ligands reveal intermolecular π-stacking interaction in the polymeric association in the solid state. Addition of phenanthroline to the germanate complex leads to a monomeric structure.     

Self-assembly of charged Bodipy dyes to form Cassettes that display intracomplex electronic energy transfer and accrete into liquid crystals

Red- and blue-absorbing boron dipyrromethene dyes, bearing opposite electronic charges, associate in solution to form a 1:2 complex having a stability constant of ca. 10(17) M(-2). The complex can be dismantled by addition of a large excess of tetra-N-butylammonium cations. The same complex displays liquid crystalline properties on heating from rt to above 150 °C, as characterized by various experimental techniques. Highly efficient electronic energy transfer from the red to the blue dye occurs in both the initial complex and the subsequent mesomorphic state.     

A Floating Gaussian Orbital calculation on argon hydrochloride (Ar · HCl)

The electronic structure, properties and binding of the argon hydrochloride (Ar-HCl) complex are discussed in connexion with simpleab initio Floating Gaussian Orbital calculations on the system.     

The use of industrial oligomers modified by diisocyanates as adhesive and sealing compositions of different purposes

Methods for effective substitution of the traditional polymer-composite materials (PCM) during mounting of an electronic device by new-generation PCMs, including ones based on epoxyurethane oligomers (EPUR oligomers), are suggested. The processes of production of a complex of EPUR oligomer properties and polymers based on them are investigated.     

Realization of SOMO-HOMO level conversion for a TEMPO-dithiolate ligand by coordination to platinum(II)

We developed a TEMPO-bound dithiolate ligand (= tempodt) and its Pt(diimine)(dithiolate) complex to realize a unique electronic structure with the potential for unprecedented functionalities. The physical properties and electronic structures of tempodt, (tempodt)Pt, and their related compounds were investigated by cyclic voltammetry, UV-visible spectroscopy, electron spin resonance (ESR) spectroscopy, and other techniques. It was revealed that (tempodt)Pt showed an unusual electronic structure in which the HOMO level (= pi-conjugated dithiolate-based orbital) was located above the SOMO level attributed to the TEMPO moiety, and that this situation was achieved via a drastic electronic structure change of SOMO-HOMO level conversion through complex formation. These findings were further supported by an investigation into a one-electron oxidized (tempodt)Pt and related complexes.     

Recent progress of luminescent metal complexes with photochromic units

Photo-responsive molecules have been studied extensively because of their light irradiation abilities that enable modulation of certain physical and chemical properties in emerging molecular electronic and photonic devices. For advanced photonic applications, photochromic metal complexes that have photochromic units as the photo-responsive ligand are highly desirable, as they allow improvement of the photochromic properties and their photo-switching functionality. This article focuses on recent progress in luminescent metal complexes with photochromic units. Luminescence-switching properties of photochromic metal complexes depend on characteristic electronic transitions. The electronic transitions of photochromic metal complexes can be divided into three categories: (1) π–π* transition of the ligand, (2) metal to ligand charge transfer (MLCT) in transition-metal complex, and (3) f–f transition in lanthanide complex. Luminescence modulation using various metal complexes with photochromic units has been studied extensively in recent years, and various applications for future molecular switching devices are expected in the field of advanced photonics. Based on the literature and our studies on luminescent metal complexes with photochromic units, we report on the recent progress of luminescent metal complexes with photochromic units.     

Assessment of intercomponent interaction in phenylene bridged dinuclear ruthenium(II) and osmium(II) polypyridyl complexes

The synthesis and characterisation of [Ru(bipy)(2)(L1)](2+) and the homodinuclear complexes [M(bipy)(2)(L1)M(bipy)(2)](4+)(where M = Ru or Os), employing the ditopic ligand, 1,4-phenylene-bis(1-pyridin-2-ylimidazo[1,5-a]pyridine)(L1), are reported. The complexes are identified by elemental analysis, UV/Vis, emission, resonance Raman, transient resonance Raman and (1)H NMR spectroscopy, mass spectrometry and electrochemistry. The X-ray structure of the complex [Ru(bipy)(2)(L1)(bipy)(2)Ru](PF(6))(4) is also reported. DFT calculations, carried out to model the electronic properties of the compounds, are in good agreement with experiment. Minimal communication between the metal centres is observed. The low level of ground state electronic interaction is rationalized in terms of the poor ability of the phenyl spacer in facilitating superexchange interactions. Using the electronic and electrochemical data a detailed picture of the electronic properties of the RuRu compound is presented.     

Magnetic and Spectral Studies of the Hydrolysis of the Oxopentabisulfatomolybdate(V) [MoO(HSO4)5]2− Complex

The results of magnetic and spectral studies of the hydrolysis of the oxopentabisulfatomolybdate(V) complex are reported. The magnetic properties, electronic spectra and structure of the monomeric [MoO(HSO₄)₅]^2? complex and its dimeric oxygen bridged hydrolysis products are discussed.     

Advances in two-dimensional heterostructures by mono-element intercalation underneath epitaxial graphene

Two-dimensional (2D) materials have displayed many remarkable physical properties, including 2D superconductivity, magnetism, and layer-dependent bandgaps. However, it is difficult for a single 2D material to meet complex practical requirements. Heterostructures obtained by vertically stacking different kinds of 2D materials have extensively attracted researchers’ attention because of their rich electronic features. With heterostructures, the constraints of lattice matching can be overcome. Meanwhile, high application potential has been explored for electronic and optoelectronic devices, including tunneling transistors, flexible electronics, and photodetectors. Specifically, graphene-based van der Waals heterostructures (vdWHs) by intercalation are emerging to realize various functional heterostructures-based electronic devices. Intercalating atoms under epitaxial graphene can efficiently decouple graphene from the substrate, and is expected to realize rich novel electronic properties in graphene. In this study, we systematically review the progress of the mono-element intercalation in graphene-based vdWHs, including the intercalation mechanism, intercalation-modified electronic properties, and the practical applications of 2D intercalated heterostructures. This work would inspire edge-cutting ideas in the scientific frontiers of 2D materials.     

Semiempirical study of the electronic and optical properties of the Er(8-hydroxyquinolinate)3 complex

We use a simple quantum chemical semiempirical procedure to study the electronic properties of organic-lanthanide complexes, taking as a model system Er(8-hydroxyquinolinate)3. Among the problems inherent to such a study is the fact that the lanthanide ion has never been parametrized in any of the standard semiempirical Hamiltonians. To overcome this difficulty, the lanthanide ion is replaced by a different but somewhat similar parametrized ion, or merely by a point charge. Good agreement with experiment, where available, is obtained, particularly in the former case. In fact, the electronic properties of the complex (apart from the emission properties) are seen to be scarcely affected by the nature of the lanthanide ion itself, but the core interactions between the metal ion and the ligand units play a relevant role, also in the calculation of the excitation energies. In particular, the ordering and separation of both singlet and triplet excited states are affected. The main conclusion is that to describe in detail the mechanism of the energy-transfer process occurring in the complex it is essential to take into account the geometry relaxation effects in the excited states.     

A large perturbation on geometry structures, excited state properties, charge-injection and -transporting abilities of Ir(III) complexes by different substituents on ligands: a DFT/TDDFT study

The molecular geometries, electronic structures, photophysical properties, charge-injection and -transporting abilities of a series of Ir(III) complexes with different carrier-transporting substituents, such as carbazole, oxadiazole and dimesitylboryl groups, are investigated theoretically using density functional theory (DFT) and time-dependent DFT (TDDFT) calculations to understand the influence of these substituents on the optical and electronic properties of Ir(III) complexes and to explore how to improve the optoelectronic properties of the complexes. It is found that the introduction of substituents can stabilize both HOMOs and LUMOs and induce variations in the energy gap between HOMO and LUMO. The introduction of hole-transporting carbazole substituent induces the blue-shift of absorption spectrum and improves the hole-injection and -transporting performances of complex. The introduction of electron-transporting oxadiazole substituent and electron-accepting dimesitylboryl substituent induces the red-shift in absorption spectra of complexes, improves their charge transfer abilities and leads to the better balance between the hole- and electron-transporting abilities. Through Lewis acid/base interactions between B atom and F(-), the electronic properties of 4 show dramatic changes in the presence of F(-) and thus 4 can also be used as selective phosphorescent F(-) probe.     

Spectroscopic and theoretical studies on cobalt (II) complex of maleonitriledithiolate and 5-nitro-1,10-phenanthroline

The molecular structure, electronic and infrared spectroscopic properties of the title complex Co(mnt)(5-NO(2)-phen) (mnt(2-) = maleonitriledithiolate, 5-NO(2)-phen = 5-nitro-1,10-phenanthroline) were studied in this paper. With non-empirical density functional theory (DFT) methods, the gaseous molecular geometry of the complex was optimized and corresponding vibrational spectra was obtained. A complete assignment to the IR spectra of such a complicated molecule has been exhibited. And the established scientific method could give a complete and accurate analysis about the vibrational spectra of this complex. An electronic spectra was calculated by ZINDOS/S method. The results showed that the calculated values agreed with the observed ones.