Dione Units Research Articles

Electrostatic Potential Design of Solid Additives for Enhanced Molecular Order of Polymer Donor in Efficient Organic Solar Cells.

Polymeric semiconducting materials struggle to achieve fast charge mobility due to low structural order. In this work, five 1H-indene-1,3(2H)dione-benzene structured halogenated solid additives namely INB-5F, INB-3F, INB-1F, INB-1Cl, and INB-1Br with gradually varied electrostatic potential are designed and utilized to regulate the structural order of polymer donor PM6. Molecular dynamics simulations demonstrate that although the dione unit of these additives tends to adsorb on the backbone of PM6, the reduced electrostatic potential of the halogen-substituted benzene can shift the benzene interacting site from alkyl side chains to the conjugated backbone of PM6, not only leading to enhanced π-π stacking in out-of-plane but also arising new π-π stacking in in-plane together with the appearance of multiple backbone stacking in out-of-plane, consequent to the co-existence of face-on and edge-on molecular orientations. This molecular packing transformation further translates to enhanced charge transport and suppressed carrier recombination in their photovoltaics, with a maximum power conversion efficiency of 19.4% received in PM6/L8-BO layer-by-layer deposited organic solar cells.

Designing and theoretical characterization of benzodithiophene dione based donor molecules for small molecule organic solar cells

A series of novel A1-A2-D-A2-A1 type four small donor molecules named SM1-SM4 have been designed based on a common dual accepting benzodithiophene dione unit. These donor molecules were designed by replacing end-capped (rhodanine) acceptors of already synthesized SBDT-BDD (reference R) molecule with 2-methylenemalononitrile (A1a) forming SM1, methyl 2-cyanoacrylate (A1b) forming SM2, 2-(3-oxo-2,3-dihydro-1H-inden-1-ylidene) malononitrile (A1c) forming SM3 and 1,4-dimethyl-5-methylene-2,6-dioxo-1,2,5,6-tetrahydropyridine-3-carbonitrile (A1d) forming SM4 molecule. The geometry optimization and theoretical characterization were carried out using reliable DFT at hybrid CAM-B3LYP/6–31G (d,p) level of theory. The photophysical, opto-electronic and wavelength dependent parameters of newly structured donors were computed and their resulting charge mobilities, maximum absorptions as well as exciton dynamics have been well addressed with respect to SBDT-BDD reference. Amongst all, SM3 exhibited maximum absorption at 484.2 nm due to its lowest energy bandgap (4.14 eV). It also exhibited lowest values of first singlet transition energy (2.56 eV), oscillator strength (1.01) and exciton binding energy (0.48 eV) because of its functionalization with strong electron withdrawing group (A1c). Moreover, the higher dipole moments, comparable hole and electron mobilities and higher values of Voc of SM1 and SM4 than R indicate the worth of these molecules being utilized as efficient donors in future OSC’s.

Constructing fused bis-isatins from pyrroloindoles using direct oxidation approach and re-visiting indophenine reaction

Two novel electron accepting bis-isatins, having fused bis-lactam rings have been synthesized from corresponding pyrroloindoles 7 and 14 by one-pot direct oxidation approach involving oxidant NBS with or without co-oxidant TBHP in DMF/CHCl3. Synthesized fused bis-isatins 8 and 15 are extensively studied for thermal, photophysical, electrochemical and thin-film morphological properties and are found to have characteristic properties like solid-solid transitions, visible light absorption, lowered FMO energy levels (LUMOs below −4.1 eV and HOMOs below −5.9 eV) as well as oriented packing of molecules in the film state. The famous indophenine reaction is re-visited with fused bis-isatins to form conjugated polymers P-1 and P-2, having quinoidal pyrroloindole dione units. The polymers are studied for thermal, photophysical, electrochemical and thin-film morphological properties indicating sufficiently high thermal stability (up to 200 °C), extended absorptions up to near IR region, lowered FMO energy levels (LUMOs below −4.3 eV and HOMOs below −5.8 eV) and amorphous nature of polymer films.

6-Methyl-1,4-bis[(pyridin-2-yl)methyl]quinoxaline-2,3(1H,4H)-dione

The title compound, C21H18N4O2, crystallizes with one independent molecule in the asymmetric unit. The 6-methylquinoxaline-2,3(1H,4H)-dione unit is essentially planar. The dihedral angles between the mean plane of the 6-methylquinoxaline-2,3(1H,4H)-dione ring and its pendant pyridin-2-yl rings are 85.1 (3) and 73.8 (4)°. The pyridin-2-yl rings are inclined pointing away from the 6-methylquinoxaline-2,3(1H,4H)-dione ring system. In the crystal, molecules are linked by weak C—H...O interactions, forming a three-dimensional network structure.

Enhanced photovoltaic performances of bis(pyrrolo[3,4-c]pyrrole-1,3-dione)-based wide band gap polymer via the incorporation of an appropriate spacer unit between pyrrolo[3,4-c]pyrrole-1,3-dione units

Bis(pyrrolo[3,4-c]pyrrole-1,3(2H,5H)-dione) (BDPPD)-based new electron deficient monomer unit (TTBDPPD) incorporating thieno[3,2-b]thiophene as a connecting spacer unit in between pyrrolo[3,4-c]pyrrole-1,3(2H,5H)-dione units was prepared. The copolymerization of 2D-conjugated benzodithiophene (BDTT) and TTBDPPD derivatives afforded new alternating copolymer P(BDTT-TTBDPPD). The estimated optical band gap and highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) energy levels of P(BDTT-TTBDPPD) were 2.06 eV and −5.42 eV/−3.36 eV, respectively. The organic field effect transistor made form P(BDTT-TTBDPPD) exhibited a hole mobility of 6.21 × 10−4 cm2V−1s−1. The polymer solar cells (PSCs) prepared using P(BDTT-TTBDPPD):PC70BM (1:2 wt%)+3 vol% DIO blend offered a maximum power conversion efficiency (PCE) of 5.37% with an open-circuit voltage (Voc) of 0.90 V, a short-circuit current (Jsc) of 8.94 mA/cm2 and a fill factor (FF) of 67%. This study reveals that the photovoltaic performance of BDPPD-based reported polymer, P(BDTT-TBDPPD), incorporating thiophene spacer unit in between pyrrolo[3,4-c]pyrrole-1,3(2H,5H)-dione units has been greatly improved (over 2%) when thiophene replaced with thieno[3,2-b]thiophene.

Piezochromism, acidochromism, solvent-induced emission changes and cell imaging of D-π-A 1,4-dihydropyridine derivatives with aggregation-induced emission properties

Three D-π-A 1,4-dihydropyridine derivatives with aggregation-induced emission characteristics were synthesized. The molecules comprise of a 4-(dimethylamino)styryl group as the electron donor group and different end groups, dicyanomethylene, vinylcyanoacetate, and 2-methylene-1H-indene-1,3(2H)-dione, as the electron acceptor, respectively. These target compounds display different stimulus-responsive fluorescent properties in the solid state. The original samples with the dicyanomethylene and vinylcyanoacetate groups do not show fluorescence color changes in response to external force stimuli, whereas the compound containing the 2-methylene-1H-indene-1,3(2H)-dione unit exhibits reversible piezochromism and solvent-induced emission changes due to the transformation between the crystalline and amorphous states, which can be ascribed to their different molecular stacking mode in the solid state. Furthermore, these compounds show different acid/base-induced solid-state fluorescence switching properties due to the different sites of the protonation. Additionally, all of the derivatives can be fabricated into biocompatible fluorescent nanoparticles and used for MCF-7 cell imaging.

Incorporation of a 2,3-dihydro-1H-pyrrolo[3,4-d]pyridazine-1,4(6H)-dione unit into a donor–acceptor triad: synthesis and ion recognition features

A novel directly-linked donor–acceptor–donor (D–A–D) type system, which is based on 2,3-dihydro-1H-pyrrolo[3,4-d]pyridazine-1,4(6H)-dione as the A unit and thiophene as the D units, respectively, is designed, synthesized, and characterized by spectroscopic methods. This novel D–A–D system can be used for the fluorogenic detection of Cu2+ among other ions.

Structural properties of charge-transfer complexes of multilayered [3.3]paracyclophanes

In the solid state, multilayered [3.3]paracyclophanes (PCPs) 2–6 and tetracyanoethylene (TCNE) form charge-transfer (CT) complexes with a 1:1 stoichiometry. All the benzene rings overlapped each other. All the [3.3]PCP units and dione units assume chair conformations and the transannular distances are shorter than those of the corresponding free multilayered [3.3]PCP except for the dione unit in the four-layered dione 6. In the crystal-packing diagrams, the PCP and TCNE are located in alternating donor-acceptor stacking in columns, and effective short contacts are observed in the neighboring molecules.

2-(1,3-Dioxoisoindolin-2-yl)acetonitrile

The asymmetric unit of the title compound, C10H6N2O2, contains two independent mol­ecules. The dihedral angles between the acetonitrile and the 1H-isoindole-1,3(2H)-dione units are 69.0 (7)° and 77.0 (5)° in the two mol­ecules. One of the two terminal N atoms is disordered over two positions in a 0.66 (8):0,34 (8) ratio. In the crystal structure, the mol­ecules are linked by inter­molecular C—H⋯O hydrogen bonds.

Synthesis of Multilayered [3.3](3,5)Pyridinophanes

Two- to four-layered [3.3](3,5)pyridinophanes (PyPs) have been synthesized by the (4-tolylsulfonyl)methyl isocyanide (TosMIC) method. The coupling reaction between 3,5-bis[2-iso-cyano-2-(4-tolylsulfonyl)ethyl]pyridine (TosMIC adduct) and bis(chloromethyl) or tetrakis(bromomethyl) compounds in the presence of sodium hydride in N,N-dimethylformamide or sodium hydroxide and tetrabutylammonium iodide under high-dilution conditions gave the two-layered dione or three- and four-layered tetra-ones. Wolff-Kishner reduction of the ketones afforded the desired two- to four-layered [3.3](3,5)PyPs. The structure of the dione units take an anti geometry whereas the cyclophane units take a syn geometry in solution.

Synthesis, Structure, and Transannular π−π Interaction of Three- and Four-Layered [3.3]Paracyclophanes

The synthesis of three- and four-layered [3.3]paracyclophanes ([3.3]PCPs) 3-5 has been accomplished by utilizing the (p-ethylbenzenesulfonyl)methyl isocyanide (EbsMIC) method. The structures of the three- to four-layered [3.3]PCPs 3- 5 and their diones 8, 10, and 11 have been elucidated based on the (1)H NMR spectra and finally by X-ray structural analysis. In the three-layered [3.3]PCP-dione 8, the trimethylene bridges of the [3.3]PCP unit assume a chair conformation similar to that of 2, while the [3.3]PCP-2,11-dione unit assumes a boat conformation different from that of [3.3]PCP-dione 1 with a chair conformation. On the other hand, the two [3.3]PCP units in three-layered [3.3]PCP 3 both assume a boat conformation. In the four-layered [3.3]PCP-dione 10, the two outer [3.3]PCP units assume a boat conformation while the inner dione unit has a chair conformation. The trimethylene bridges in the four-layered [3.3]PCP 4 are highly disordered even at -150 degrees C. All the outer benzene rings are distorted into a boat form while the inner ones are distorted into a twist form. In the electronic spectra, bathochromic shift and hyperchromic effect are observed, but the magnitude decreases with an increase in the number of layers and the spectra become structureless. In the charge-transfer (CT) bands of the three- to four-layered [3.3]PCPs 3- 5 with tetracyanoethylene (TCNE), two absorption maxima (lambda(max)) are observed. The effect of an increase in the layers becomes significant, and the changes in the longest wavelength lambda(max) values from two to three and three to four are ca. 60 and 50 nm, respectively. By comparison of the stereoisomeric four-layered [3.3]PCPs 4 (meso) and 5 (racemic), the helical arrangement of the trimethylene bridges of 5 shows a more efficient transannular pi-electronic interaction. In the three- to four-layered [3.3]PCP-diones, a magnitude of the CT interaction almost comparable to that of [3.3]PCP 2 was observed, and this indicates that the -CH(2)COCH(2)- bridges inhibit the CT interaction and that this tendency is supported by the calculated HOMO energy levels and observed oxidation potentials. Three- and four-layered [3.3]PCPs 3- 5 show reversible redox processes, and 4 and 5 show an electron-donating ability almost comparable to that of [3 6]CP. Very good correlation between the lambda(max) of the CT bands with TCNE and the oxidation potentials is observed.

Porphyrin-Diones and Porphyrin-Tetraones: Reversible Redox Units Being Localized within the Porphyrin Macrocycle and Their Effect on Tautomerism

Porphyrin-2,3-diones and porphyrin-2,3,7,8- and porphyrin-2,3,12,13-tetraones were shown to have a redox-active unit that can function independently of the macrocycle at large. Electroreduction of 5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)porphyrin-2,3-diones [(P-dione)M] and the corresponding -2,3,12,13-tetraones [L-(P-tetraone)M] and -2,3,7,8-tetraones [C-(P-tetraone)M], where M = 2H, CuII, ZnII, NiII, and PdII was investigated and the products were characterized by ESR and thin-layer UV-visible spectroelectrochemistry. Electrochemical and spectroelectrochemical data show that the first two reductions of the porphyrin-diones and the first three reductions of the porphyrin-tetraones occur at the dione units. This was confirmed by ESR spectra of first reduction products which show that the electron spin is totally localized on a semidione unit, independent of the central metal ion and of the number and location of dione units. ESR spectra of the radical anions derived from free-base porphyrin-2,3-dione [(P-dione)2H] and porphyrin-2,3,12,13-tetraone [L-(P-tetraone)2H] confirm the trans-arrangement of the two inner protons and their location on nonsubstituted pyrrolic rings, thereby maintaining an 18-atom 18-pi electron bacteriochlorin-like aromatic delocalization pathway. The redox unit is not similarly isolated in the corner free-base porphyrin-2,3,7,8-tetraone [C-(P-tetraone)2H]. A one-electron reduction of C-(P-tetraone)2H leads to the formation of a tautomer with trans inner hydrogens with one residing on the N of the ring with the reduced unit as the only detectable product. This process is favorable because it creates a more delocalized 18-atom 18-pi electron aromatic pathway. This result is consistent with the measured redox potentials which show the first reduction of C-(P-tetraone)2H to be substantially easier than (P-dione)2H or L-(P-tetraone)2H.

Characterization of the reactive and dissociative behavior of transition metal oxide cluster ions in the gas phase

The reactive and dissociative behavior of molybdenum and tungsten oxide cluster ions has been studied in the gas phase using a triple quadrupole mass spectrometer. Cluster ions (MO 3) − n were formed via a simple thermal desorption/electron capture negative ionization method, and their structures were characterized by collision-activated dissociation (CAD). Typically, the clusters fragment by losses of neutral (MO 3) units. Reactions of the oxide cluster ions with ethylene oxide, cyclohexene oxide, ethylene sulfide, cyclohexene sulfide, 2,3-butanedione, and 2,4-pentanedione were examined, and product ions were characterized by CAD. The clusters react with ethylene oxide by addition of ethylene oxide or net addition of oxygen, whereas the clusters react with ethylene sulfide via net addition of one or two sulfur atoms. Reactions of the clusters with the diones result in addition of one or two dione units, in some cases with dehydration.

Cyclopolymerization of 2,4-toluylene diisocyanate in presence of phosphoric acid amides

The cyclopolymerization of 2,4-toluylene diisocyanate (TDI) in presence of phosphoric acid amides has been studied. It was shown that amidophosphites can catalyse both cyclic polymerization and trimerization of this diisocyanate. By varying the reaction conditions the direction of cyclopolymerization can be changed to either dimerization or to formation of polyisocyanates, cyntaining isocyanurate or urethidine dione units.

Copolymerization of 4‐cyclopentene‐1,3‐dione with styrene

AbstractThe copolymerization of 4‐cyclopentene‐1,3‐dione (D) with styrene (S) is reported. The copolymers were prepared by heating sealed tubes containing the monomer feeds and azobisisobutyronitrile. The copolymers exhibited infrared bands for the phenyl and β‐diketone groups, indicating that copolymerization had occurred. The copolymers were completely insoluble in all solvents. Some swelling was observed in tetrahydrofuran, nitrobenzene, and aqueous sodium hydroxide. From the compositions of the copolymers, as determined from the carbon and hydrogen analyses, it was found that the copolymers were about 40 mole‐% styrene over an appreciable range of feed compositions (0.1–0.6 mole fraction styrene). The results at styrene feeds <0.5 were in general agreement with the equation: d[D]/d[S] = 1 1/2 + (kDD/2kDCK[S]). This equation was derived on the basis of monomer complex (C) participating in the propagation and a penultimate effect preventing the occurrence of a sequence of three dione units.