Acetylene Linker Research Articles

Rational design of novel N-doped polyaromatic hydrocarbons as donors for the perylene based dye-sensitized solar cells

This paper reports designing a series of new D-π-A topology-based metal-free organic dye molecules using ullazine and perylene by DFT methods. This work emphasizes the combination of ullazine analogs as donors and perylene dicarboxylic anhydride as an acceptor along with acetylene linker as π-bridge for DSSC applications. The structural and optoelectronic properties of dyes before and after adsorption on to TiO2 semiconductor have been investigated. The screening of the designed dyes is carried out based on the energy gap (Eg), maximum absorption wavelength (λmax), light-harvesting efficiency (LHE), excited-state lifetime (τ), the free energy of electron injection (ΔGinj) and regeneration (ΔGreg). DFT results reveal that the presence of ullazine analogs as a donor reduces the energy gap (Eg) and leads to red-shift in absorption maximum. Further, two different binding modes of dye molecules with (TiO2)38 cluster have been investigated to unravel the binding associated changes in the electronic structure. The results show that the completely dissociated bidentate bridging (CBB2) mode is more favorable, which contains two carboxylic groups. Findings emphasize the remarkable charge transfer characteristics which favors the fast electron injection from excited dye to the conduction band of TiO2. For the first time, this study provides comprehensive structural and electronic information combined with the Dye-TiO2 interactions for the development of perylene based dyes for DSSC applications. This article demonstrates the rational design of novel N-doped Polyaromatic Hydrocarbons as Donors for the Perylene based Dye-Sensitized Solar Cells using state of the art computational methods. This study results in the relatively efficient new dye molecules for DSSC applications. Complete electronic and structural aspects of anatase-TiO2 interaction with designed dye molecules have been elucidated in detail.

Synthesis and Properties of Blue Fluorescent Dyes Based on Diphenylamine by Introducing an Acetylene Linkage Group with Carbazole and 1,8‐Naphthalimide

Four blue fluorescent dyes based on diphenylamine.

The synthesis of red dyes based on diketo-pyrrolo-pyrrole chromophore to improve heat stability and solubility for colour filter fabrication

To replace the conventional red pigment derived from diketo-pyrrolo-pyrrole by new red dyes prepared in this research, an acetylene linkage was introduced between N-alkyl diketo-pyrrolo-pyrrole and naphthalimidyl moiety. TGA analyses and solubility measurement were carried out to compare those of conventional red pigment, C.I. Pigment Red 254, which has been most popular as a red pixel of color filter. Most of the new red dyes were prepared starting from C.I. Pigment Red 254 by the sequent reactions, N-alkylation, Sonogashira coupling, hydrolysis and further Sonogashira coupling. Chemical structures of all red dyes were confirmed by 1H NMR and mass spectral analysis. TGA was carried out at 300 °C, and solubility measurement was carried out using by several organic solvents which can be used in the color filter fabrications. TGA indicated that the introduction of an acetylene linkage group into the N-alkyl diketo-pyrrolo-pyrrole ring combined by an N-butyl-naphthalimidyl system improved its heat stability. The result of weight reduction 1.4% at 300 °C can be identical to that of C.I. Pigment Red 254. The solubility of red dye prepared was observed around 5 g/L, therefore it can be used in the color filter fabrication process to eliminate the conventional photo-etching process.

A DFT probe on the linear and nonlinear optical characteristics of some star‐shaped DI‐π‐DII‐Atype acetylene‐bridged rigid triazines

AbstractThe density functional theory (DFT) computations of linear and nonlinear optical characteristics of nine star‐shaped DI‐π‐DII‐Atype molecules, which encompass electron‐donating phenyl rings connected by acetylene linkage and an electron‐accepting triazine core, were accomplished in present work. The phenyl rings were augmented with functionalities of diverse electron‐donating and electron‐accepting abilities to inspect the effects of substituents on linear and nonlinear optical properties of molecules. The assessment of the potential nonlinear nature of molecules was carried out by computing their second‐order nonlinearities using DFT methods to find that target molecules possessed superior nonlinear optical characteristics. The influence of various DFT methods and basis sets on optical characteristics was also scrutinized.

Green Phosphors Based on 9,10-bis((4-((3,7-dimethyloctyl)oxy) phenyl) ethynyl) Anthracene for LED.

An anthracene aromatic unit was introduced into the phenylethynyl structure by a rigid acetylene linkage at the C-9 and C-10 positions via Sonogashira coupling reactions, resulting in a planar and straight-backbone molecule (9,10-bis((4-((3,7-dimethyloctyl)oxy) phenyl) ethynyl) anthracene) (BPEA). Thermogravimetric analysis demonstrated the good thermal stability of the BPEA. Photoluminescence analysis showed that a suitable expanded π-conjugation in the BPEA made its excitation band extend into the visible region, and an intense green emission was observed under blue-light excitation. A bright green light-emitting diode with an efficiency of 18.22 lm/w was fabricated by coating the organic phosphor onto a 460 nm-emitting InGaN chip. All the results indicate that BPEA is a useful green-emitting material which is efficiently excited by blue light, and therefore, that it could be applied in many fields without UV radiation.

Pyridinic nitrogen exclusively doped carbon materials as efficient oxygen reduction electrocatalysts for Zn-air batteries

Rational design a metal-free catalyst with well-defined structure as alternative of noble metal is highly desirable but challenging to catalyze oxygen reaction for metal–air batteries. In this report, nitrogen with a specific configuration is selectively doped into the carbon skeleton to prepare a graphdiyne-like carbon material, in which one carbon atom in every benzene ring of graphdiyne (GDY) is substituted by pyridinc N (PyN-GDY). Composed by pyridine ring and acetylenic linkers, the PyN-GDY is prepared through a bottom-up strategy using pentaethynylpyridine as the monomer. The as-synthesized PyN-GDY with “defined” molecular structure is an ideal model for addressing the intrinsic activity of active sites at molecular level. It exhibits excellent performance in both alkaline and acidic media as electrochemical catalyst for oxygen reduction reaction (ORR). The PyN-GDY-based Zn-air battery is demonstrated more active and stable than commercial Pt/C-based battery. Density functional theory calculations are used to analyze and determine the possible active sites of PyN-GDY in ORR. The precise construction of specific nitrogen doped carbon material is an effective method to produce efficient catalysts for electrocatalysis.

Near-Infrared Bioluminescence Imaging with a through-Bond Energy Transfer Cassette.

A coelenterazine (CTZ) analogue emitting near-infrared (NIR) bioluminescence was synthesized for through-bond energy transfer (TBET)-based imaging modalities. The analogue, named Cy5-CTZ, was prepared by conjugating cyanine-5 (Cy5) dye to CTZ through an acetylene linker. This novel derivative is intrinsically fluorescent and emits NIR-shifted luminescence upon reacting with an appropriate luciferase, the Renilla luciferase. This Cy5-CTZ substrate is optically stable in physiological samples and rapidly permeabilize through the plasma membrane into the cytosolic compartment of live cells.

Importance of heteroatom doping site in tuning the electronic structure and magnetic properties of graphdiyne

Abstract Density functional theory calculations are carried out to study the electronic structures and magnetic properties of single X (X = B, N, O, P, S) atom doped graphdiyne (GDY) monolayers. It is found that there are three distinct doped models (one benzene ring site X-b, two acetylene linkage sites X-1, X-2), and the heteroatom (B, N, O, P, S) doping site has a serious effect on the electronic structure and magnetic properties of GDYs. The results of cohesive energies reveal that the B and S atoms prefer to substitute the sp2-hybridized C atom at benzene ring, while N, O, P atoms prefer to substitute the sp-hybridized C atom at acetylene linkage. For B, N, O, S-doped GDYs exhibit metallic character, while P-1, P-2 doped GDYs present semiconductor character. The X-1, X-2 (X = B, O, P, S) GDYs with heteroatom at chain site introduce spin polarization, and are magnetic, whereas the X-b (X = B, O, P, S) doped GDYs are nonmagnetic. The N doping site has no impact on its magnetic properties, and all the N doped GDYs are nonmagnetic. The research results offer a theoretical support that heteroatom doping plays an important role in tuning the electronic structures and magnetic properties of GDYs.

Artificial Thiophdiyne Ultrathin Layer as an Enhanced Solid Electrolyte Interphase for the Aluminum Foil of Dual-Ion Batteries.

In this study, we design a novel carbon-based material containing thiophene and acetylenic linkers as functional groups named thiophdiyne (Thi-Dy) and apply it as an ultrathin artificial protective layer for the commercially available aluminum (Al) foil of dual-ion batteries (DIBs). The Thi-Dy films can be grown easily and directly on the Al foil through a mild Glaser-Hay coupling reaction. The as-proposed thiophene and acetylenic linker functional groups in Thi-Dy layers act as energetic active sites for the effective fabrication of a stable hybrid solid electrolyte interphase (SEI) during the electrochemical process, which is revealed through the ex situ measurement. The Thi-Dy-enhanced SEI layer contributes to offer a more effective and regulated lithium intercalation and diffusion pathway and delay the pulverization and huge volume expansion of the Al-Li alloy during long cycles, which are confirmed by the improvement on the cyclic stability of DIBs. Those studies are expected to provide novel thiophene-containing functional materials and mass-produced surface modification approach for metal anode protection, which will promote the research for the next-generation rechargeable battery.

First principles study on hydrogen storage in yttrium doped graphyne: Role of acetylene linkage in enhancing hydrogen storage

Through Density Functional Theory Simulations we predict that a Ytrrium atom attached on graphyne surface can adsorb up to a maximum of 9 molecular hydrogens (H2), with a uniform binding energy of ∼0.3 eV/H2 and an average desorption temperature of around 400 K (ideal for fuel cell applications), leading to 10 wt% of hydrogen, substantially higher than the requirement by DoE. The higher hydrogen wt% in Y doped graphyne compared to Y doped Single Walled Carbon Nanotubes (SWNT) and graphene is due to the presence of sp hybridized C atoms (in the acetylene linkage) supplying additional in-plane px-py orbitals leading to π (π*) bonding (antibonding) states. Charge transfer from metal to carbon nanostructure results in a redistribution of s, p, d orbitals of the metal leading to a non - spin polarized ground state in Y doped graphyne, due to the presence of the acetylene linkage, whereas Y doped SWNT and graphene remain magnetic like the isolated metal atom. In the non-magnetic graphyne + Y system, the net charge transfer from Y to successive H2 molecules is less than in magnetic Y + graphene and Y + SWNT systems, enabling Y + graphyne to store a larger number of H2 molecules. Furthermore, our ab initio MD simulations show that the system is stable even at room temperature and there is no dissociation of H2 molecules, enabling the system to achieve 100% desorption. So Y doped graphyne is found to be a promising hydrogen storage device with high wt%, 100% recyclability and desirable desorption temperature.

Alkynyl-Functionalized Pyrene-Cored Perylene Diimide Electron Acceptors for Efficient Nonfullerene Organic Solar Cells

Integrating two or more perylene diimide (PDI) monomers through the single bond or ring fusion forming a star-shaped structure is a useful strategy for designing high-efficiency electron acceptors. Herein, we implemented an effectual acetylene-linked method of constructing star-shaped PDI-derivative-based high-efficiency nonfullerene organic solar cells (OSCs). A rigid and conjugated pyrene-cored PDI acceptor, B-4TPDI, has been designed and synthesized. The new acceptor manifests a favorable morphology, effective π-electron delocalization, and complementary absorption when it is paired with the polymer donors PTB7-Th or PBDB-T. It is shown that OSCs based on the PTB7-Th:B-4TPDI blend film achieved a power conversion efficiency (PCE) of 7.71% and an outstanding Jsc of 18.13 mA cm–2. More importantly, after adding a small amount of B-4TPDI into the PTB7-Th:ITIC and PBDB-T:ITIC system, the formed ternary OSCs obtained an optimized PCE of 8.76% and 10.93%, respectively. Our work confirms that acetylene linkage would be a prospective π-spacer for designing conjugated PDI-derivative-based new and excellent nonfullerene acceptors.

Position and conjugation–dependent aggregation–induced emission enhancement properties of naphthalimide–tetraphenylethylene conjugates

A series of position and conjugation–dependent donor–acceptor naphthalimide–tetraphenylethylene isomeric conjugates (NTPEs 1–6), possessing single–bond (C–C), vinyl linkage, and acetylene linkage between naphthalimide and tetraphenylethylene moieties, were designed and synthesized. NTPEs 1–6 were fully characterized by 1H NMR, 13C NMR, and mass spectroscopy. The effects of the position and conjugation in NTPEs 1–6 on the absorption, fluorescence, and aggregation–induced emission enhancement were explored. Among the NTPEs 1–6, the 4–substituted NTPEs show the most prominent electronic communication. Furthermore, the 3–substituted NTPEs and 4–substituted NTPEs with single–bond linkage exhibit aggregation–induced emission enhancement, whereas 4–substituted NTPEs with vinyl linkage, and acetylene linkage show small aggregation–caused quenching. The NTPEs 1–3 and 5 show enhanced fluorescence and long fluorescent lifetimes in aggregated state, exhibiting aggregation induced emission. The nanoaggregates of NTPEs 1–6 formed in tetrahydrofuran/water (1:9, v/v) solutions are observed by scanning electron microscopy (SEM), fluorescence microscopy, and dynamic light scattering (DLS).

Novel Turtle‐Shape Dendrimers Based on a Pyrene Core

AbstractThe design and synthesis of X‐shaped molecules bases on a central pyrene is reported. A Sonogashira cross‐coupling reaction was applied to successfully bond the pyrene core through acetylene linkages to electroactive dendrons moieties such as triphenylamine or carbazole. Dendrons were functionalized with bulky alkyl groups to disrupt π‐π stacking interactions and consequently affording soluble dendrimers. These novel π‐conjugated turtle‐shape dendrimers are organic materials with great potential applications in optoelectronic devices.

Development of xanthene dyes containing arylacetylenes: The role of acetylene linker and substituents on the aryl group

Fluorescent dyes possessing a variety of arylacetylenes at the 9-position of a xanthene skeleton were synthesized and their optical properties were investigated. The π system effectively expanded over the xanthene skeleton and the aryl group through the triple bond. Starting from the emission wavelength (λem) of 9-methyl xanthene 20 in basic DMSO solution at 536 nm, the emission wavelengths gradually shifted to the red region for methylacetylene 17 (λem = 600 nm), phenylacetylene 5 (λem = 636 nm), and p-CF3-phenylacetylene 11 (λem = 660 nm). On the basis of these data, we estimated the substituent effects for the red shift on the emission wavelength and rationally explained the results by DFT calculations. Furthermore, potential applicability of these fluorescent dyes to cell staining was exemplified.

Structural and Electronic Properties of α2-Graphyne Nanotubes: A Density Functional Theory Study

Another form of carbon-based two-dimensional material in the graphene family, named the α2-graphyne sheet, was predicted very recently. The α2-graphyne sheet was created by doubling each acetylenic linker in an α-graphyne sheet. It exhibited semimetallic Dirac point features similar to graphene and α-graphyne sheets. In the present work, single -walled carbon nanotubes based on an α2-graphyne sheet was introduced. The structural and electronic properties of these nanotubes were studied using density functional theory. It was found that armchair α2-graphyne nanotubes showed metallic behavior, while zigzag α2-graphyne nanotubes were found to have semiconducting or metallic properties depending on tube size. The energy band gap of zigzag α2-graphyne nanotubes decreased with increasing tube diameter. The results indicated that the α2-graphyne sheet and its nanotubes can be proper materials for future nanoelectronics.

Structure-Based Optimization Strategies for G Protein-Coupled Receptor (GPCR) Allosteric Modulators: A Case Study from Analyses of New Metabotropic Glutamate Receptor 5 (mGlu5) X-ray Structures.

Two interesting new X-ray structures of negative allosteric modulator (NAM) ligands for the mGlu5 receptor, M-MPEP (3) and fenobam (4), are reported. The new structures show how the binding of the ligands induces different receptor water channel conformations to previously published structures. The structure of fenobam, where a urea replaces the acetylenic linker in M-MPEP and mavoglurant, reveals a binding mode where the ligand is rotated by 180° compared to a previously proposed docking model. The need for multiple ligand structures for accurate GPCR structure-based drug design is demonstrated by the different growing vectors identified for the head groups of M-MPEP and mavoglurant and by the unexpected water-mediated receptor interactions of a new chemotype represented by fenobam. The implications of the new structures for ligand design are discussed, with extensive analysis of the energetics of the water networks of both pseudoapo and bound structures providing a new design strategy for allosteric modulators.

Molecular dynamics investigation of the mechanical behavior of multi-layered graphyne and its family under tensile loading

This paper aims to study the mechanical properties of the multi-layered graphyne and other members of the graphyne family under the uniaxial tensile loading. For this purpose, molecular dynamics simulations are used. The effects of the size and number of layers on the fracture and elastic properties are studied. It is shown that Young’s modulus of the zigzag multi-layered graphyne is slightly larger than armchair one. Comparing the stress-strain curves of the multi-layered graphynes with different number of layers, it is observed that the fracture stress and strain of the nanosheets are inversely related to the number of layers. Investigating the influence of the number of acetylene linkage in the structure of the graphyne-n family on their mechanical properties, it is shown increasing the number of triple bonds leads to weakening the fracture stress and Young’s modulus of the nanosheet.

Long-lived triplet excited state in a platinum(ii) perylene monoimide complex.

We report the synthesis and solution based photophysical properties of a new Pt(ii)-terpyridine complex coupled to a perylene monoimide (PMI) chromophoric unit through an acetylene linkage. This structural arrangement resulted in quantitative quenching of the highly fluorescent PMI chromophore by introducing metal character into the lowest energy singlet state, thereby leading to the formation of a long-lived PMI-ligand localized triplet excited state (τ = 8.4 μs). Even though the phosphorescence from this triplet state was not observed, highly efficient quenching of this excited state by dissolved oxygen and the observation of singlet oxygen photoluminescence in the near-IR at 1270 nm initially pointed towards triplet excited state character. Additionally, the coincidence of the excited state absorbance difference spectra from the sensitized PMI ligand using a triplet donor and the Pt-PMI complex provided strong evidence for this triplet state assignment, which was further supported by TD-DFT calculations.

Architecture and properties of a novel two-dimensional carbon material-graphtetrayne

A novel 2D carbon allotrope-Graphtetrayne (GTY), features four acetylene linkages between the pairs of benzene rings to form 30-C hexagons was synthesized by a facile synthesized route of Sonagashira cross-coupling reaction of hexaethynylbenzene and diiodobutadiyne. This all-carbon material shows a distinct structural feature, rich triple bonds and super large cavities structures, which not only has high chemical activity, but also show the high stability. GTY displays excellent semiconductor property of conductivity of 3 × 10–4S/m at room temperature. GTY films were controlled grown on surface of copper with large areas and controlled thickness, as an efficient Li storage material for the fabrication of high-performance Li-ion batteries. The measured maximum Li storage capacity of GTY reached as high as 947mAh/g, this is due to high chemical activity and super large porous for high efficient ion transport.

Cp-Graphyne: A Low-Energy Graphyne Polymorph with Double Distorted Dirac Points.

In the present investigation, we have proposed a novel form of two-dimensional (2D) carbon allotropes with the aid of first-principle density functional theory-based calculations. The carbon polymorph is mainly composed of carbon pentagons (cp) and acetylenic linkers and hence named cp-graphyne. This 2D material is energetically more preferable than the rest of the semimetals of graphyne family, including graphdiyne monolayer. Close inspection of lattice dynamics and thermal and mechanical properties demonstrates the excellent dynamic, thermal, and mechanical stabilities of cp-graphyne. Interestingly, cp-graphyne exhibits a semimetallic nature and possesses double distorted Dirac points in the electronic band spectrum. The Fermi velocities (vf) of cp-graphyne are highly anisotropic and are predicted to be in the range of 1.50–8.20 × 105 m/s. Furthermore, the analysis of structural and electronic properties of the cp-graphyne bilayer discloses the presence of self-doped Dirac-like points nearer to the Fermi level in the electronic spectrum.