Electron transport and nonlinear optical properties of substituted aryldimesityl boranes: a DFT study

Tuning the Electronic Properties of Bridged Dithienyl-, Difuryl-, Dipyrrolyl-Vinylene as Precursors of Small-Bandgap Conjugated Polymer

Optoelectronic properties of linear π-conjugated polymers/oligomers are of great importance for the fabrication of organic photonic and electronic devices. To this end, the π-conjugated polymers/oligomers need to meet both optoelectronic and key structural properties in order to fulfill their implementation as active components. In particular, they need to possess low bandgap and high thermal, conformational, and photochemical stabilities. So far, several strategies have been developed to attain such requirements including the covalent and non-covalent rigidification concepts of the π-conjugated systems. On the basis of these findings, we describe herein the theoretical studies of novel series of covalently bridged derivatives demonstrating the benefits of the strategy. Comparison of these derivatives with compounds previously described in the literature highlights enhanced optoelectronic properties and behaviors that would be beneficial for the construction and development of new linear π-conjugated polymers.

Optical and electrochemical effects of triarylamine inclusion to alkoxy BODIPY-based derivatives

Three new triphenylamine-BODIPY dyads BDPT1–3 have been designed and synthesized.

A computational study of anisotropic charge transport in air-stable fluorinated benzobisbenzothiophene (FBBBT) derivatives

A computational study of anisotropical charge transport properties of fluorinated benzobisbenzothiohphene derivatives (FBBBT) is presented. The values of IP_adia of all FBBBTs are found in the range of 6.00-6.20 eV inferring the fact that the investigated compounds have ambient air-stability. In addition, the energy levels of FBBBT s are found to be lower than those of benzobisbenzothiophene (BBBT) compound indicating higher charge carrier stability in the former. Hirshfield surface analyses showed that, in all the studied compounds, the principal identifiable interaction were mostly due to F⋯H and H⋯H intermolecular couplings with no contribution from S⋯S bondings. The calculated maximum μ_hole(μ_elec) value of the compounds FBBBT-a and FBBBT-b was found to be 0.483 (0.794) cm²V^- 1s^- 1 and 0.688 (0.542) cm²V^- 1s^- 1 respectively in the direction of transistor channel (Φ = 93.39 ^∘(273.30^∘) for FBBBT-a and Φ = 92.24 ^∘/272.72 ^∘ for FBBBT-b). For FBBBT-c, the maximum μ_elec(μ_hole) value of 0.933 (0.233) cm²V^- 1s^- 1 appeared for Φ = 0 ^∘/179.90 ^∘. In addition, the compounds FBBBT-a and FBBBT-b possess two additional fluorine atoms attached at the X positions in the backbone, which result in an increment in μ_elec values (1.4 times and 0.78 times higher than μ_hole) in these two compounds at a particular crystal direction.

Self-Assembled Nanoscaled Metalloporphyrin for Optical Detection of Dimethylmethylphosphonate

The self-assembly approach has been widely adopted in the effort to design and prepare functional materials. Herein, we report the synthesis and optical properties of metalloporphyrin nanoparticles. Nanoscaled particles of 5,10,15,20-tetraphenylporphyrin manganese (MnTPP) and 5,10,15,20-tetraphenylporphyrin indium (InTPP) were produced in the water/dimethylsulfoxide (DMSO) mixed solution by self-assembly approach. The absorbance intensity at the characteristic peak of the monomeric and nanoscaled metalloporphyrins decreased when they interact with dimethylmethylphosphonate (DMMP). Detection limits of MnTPP and InTPP nanoparticles to DMMP were 10⁻⁹ and 10⁻¹⁰ L/L, respectively, and detection limits of monomeric MnTPP and InTPP to DMMP were 10⁻⁶ and 10⁻⁷ L/L, respectively. Density functional theory (DFT) calculations on MnTPP and InTPP with DMMP as axial ligands had been performed in the B3LYP/6-31g (d) approximation. Their optimized geometries and binding energies were found to depend very strongly on the central metal ion, and InTPP was more sensitive for DMMP detection in contract to MnTPP. All the experimental and theoretical results demonstrated that nanoscaled metalloporphyrin have potential prospects in determination for public safety.

Optical and Electronic Properties of Molecular Systems Derived from Rhodanine

Push-pull functional compounds consisting of dicyanorhodanine derivatives have attracted a lot of interest because their optical, electronic, and charge transport properties make them useful as building blocks for organic photovoltaic implementations. The analysis of the frontier molecular orbitals shows that the vertical transitions of electronic absorption are characterized as intramolecular charge transfer; furthermore, we show that the analyzed compounds exhibit bathochromic displacements when comparing the presence (or absence) of solvent as an interacting medium. In comparison with materials defined by their energy of reorganization of electrons (holes) as electron (hole) transporters, we find a transport hierarchy whereby the molecule ( Z)-2-(1,1-dicyanomethylene)-5-[(4-dimethylamino)benzylidene]-1,3-thiazol-4 is better at transporting holes than molecule ( Z)-2-(1,1-dicyanomethylene)-5-(tetrathiafulvalene-2-ylidene)-1,3-thiazol-4.

Computational Studies on Optoelectronic and Nonlinear Properties of Octaphyrin Derivatives

The electronic and nonlinear optical (NLO) properties of octaphyrin derivatives were studied by employing the DFT/TDFT at CAM-B3LYP/6-311++G (2d, 2p) level of the theory. Thiophene, phenyl, methyl and cyano moieties were substituted on the molecular framework of octaphyrin core, in order to observe the change in optoelectronic and nonlinear response of these systems. The frontier molecular orbital studies and values of electron affinity reveals that the studied compounds are stable against the oxygen and moisture present in air. The calculated ionization energies, adiabatic electron affinity and reorganization energy values indicate that octaphyrin derivatives can be employed as effective n-type material for Organic Light Emitting Diodes (OLEDs). This character shows an enhancement with the introduction of an electron withdrawing group in the octaphyrin framework. The polarizability and hyperpolarizability values of octaphyrin derivatives demonstrate that they are good candidates for NLO devices. The nonlinear response of these systems shows enhancement on the introduction of electron donating groups on octaphyrin moiety. However, these claims needs further experimental verification.

Theoretical study on the photophysical properties of boron-fused double helicenes

Seven boron-fused double helicenes containing different electron-donors or acceptors and their combinations were investigated to shed light on the effective way to enhance the second-order NLO response.

A Computational Study of Structure and Reactivity of N-Substitued-4-Piperidones Curcumin Analogues and Their Radical Anions

In this work, a computational study of a series of N-substitued-4-piperidones curcumin analogues is presented. The molecular structure of the neutral molecules and their radical anions, as well as their reactivity, are investigated. N-substituents include methyl and benzyl groups, while substituents on the aromatic rings cover electron-donor and electron-acceptor groups. Substitutions at the nitrogen atom do not significantly affect the geometry and frontier molecular orbitals (FMO) energies of these molecules. On the other hand, substituents on the aromatic rings modify the distribution of FMO. In addition, they influence the capability of these molecules to attach an additional electron, which was studied through adiabatic (AEA) and vertical electron affinities (VEA), as well as vertical detachment energy (VDE). To study electrophilic properties of these structures, local reactivity indices, such as Fukui (f⁺) and Parr (P⁺) functions, were calculated, and show the influence of the aromatic rings substituents on the reactivity of α,β-unsaturated ketones towards nucleophilic attack. This study has potential implications for the design of curcumin analogues based on a 4-piperidone core with desired reactivity.