Synthesis of through‐space conjugated polymers containing [2.2]paracyclophane and thieno[3,4‐b]pyrazine in the main chain

We synthesized through‐space conjugated polymers with [2.2]paracyclophane and thieno[3,4‐b]pyrazine units in the main chain by the Sonogashira–Hagihara coupling reaction. The obtained polymers were soluble in common organic solvents, and homogeneous thin films were readily obtained from the polymer solutions by spin‐coating techniques. The polymers exhibited the extension of the conjugation length via the through‐space interaction. The polymers showed orangish‐red emission with peak maxima of around 610 nm in diluted solutions and their thin films, which were derived from the thieno[3,4‐b]pyrazine moieties. The optical and electrochemical behaviors of the polymers containing pseudo‐para‐ and pseudo‐ortho‐linked [2.2]paracyclophane were identical. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009     

Anthracene‐thieno[3,4‐c]pyrrole‐4,6‐dione based donor–acceptor conjugated copolymers for applications in optoelectronic devices

Three novel alternating copolymers of thieno[3,4‐c]pyrrole‐4,6‐dione (TPD) and triisopropylsilylacetylene‐functionalized anthracene were prepared via Suzuki polymerization. Various solubilizing substituents were attached to the TPD moiety in order to ascertain the impact they have upon the optical, electrochemical, and thermal properties of the resulting polymers. All copolymers showed good solubility and thermal stability with decomposition temperatures in excess of 300°C. Optical properties revealed that PTATPD(O), PTATPD(DMO), and PTATPD(BP) displayed optical energy gaps in excess of 2.0 eV. It is speculated that steric repulsion between solubilizing groups on repeat units along polymer chains reduces their planarity and decreases their electronic conjugation. The amorphous nature of the polymers was confirmed with differential scanning calorimetry and powder X‐ray diffraction. The highest occupied molecular orbital levels of the three polymers are unaffected by the different solubilizing chains. However, they exert some influence over the lowest unoccupied molecular orbital (LUMO) levels with PTATPD(BP) and PTATPD(O) displaying the lowest LUMO levels (?3.4 eV). In contrast, PTATPD(DMO) displayed the highest LUMO level (?3.3 eV). © 2015 The Authors. Polymers for Advanced Technologies Published by John Wiley & Sons Ltd.     

A New Four‐Component Reaction for the Synthesis of Spiro[4H‐indeno[1,2‐b]pyridine‐4,3′‐[3H]indoles]

A new four‐component synthesis of spiro[4H‐indeno[1,2‐b]pyridine‐4,3′‐[3H]indoles] and spiro[acenaphthylene‐1(2H),4′‐[4H‐indeno[1,2‐b]pyridines] by the reaction of indane‐1,3‐dione, 1,3‐dicarbonyl compounds, isatins (=1H‐indole‐2,3‐diones) or acenaphthylene‐1,2‐dione, and AcONH₄ in refluxing toluene in the presence of a catalytic amount of pyridine is reported.     

Synthesis and characterization of thieno[3,2‐b]thiophene‐isoindigo‐based copolymers as electron donor and hole transport materials for bulk‐heterojunction polymer solar cells

A novel class of thieno[3,2‐b]thiophene (TT) and isoindigo based copolymers were synthesized and evaluated as electron donor and hole transport materials in bulk‐heterojunction polymer solar cells (BHJ PSCs). These π‐conjugated donor‐acceptor polymers were derived from fused TT and isoindigo structures bridged by thiophene units. The band‐gaps and the highest occupied molecular orbital (HOMO) levels of the polymers were tuned using different conjugating lengths of thiophene units on the main chains, providing band‐gaps from 1.55 to 1.91 eV and HOMO levels from ?5.34 to ?5.71 eV, respectively. The corresponding lowest unoccupied molecular orbital (LUMO) levels were appropriately adjusted with the isoindigo units. Conventional BHJ PSCs (ITO/PEDOT:PSS/active layer/interlayer/Al) with an active layer composed of the polymer and PC₇₁BM were fabricated for evaluation. Power conversion efficiency from a low of 1.25% to a high of 4.69% were achieved with the best performing device provided by the D?π?A polymer with a relatively board absorption spectrum, high absorption coefficient, and more uniform blend morphology. These results demonstrate the potential of this class of thieno[3,2‐b]thiophene‐isoindigo‐based polymers as efficient electron donor and hole transport polymers for BHJ PSCs. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Thieno[3,4‐b]pyrazine‐based low bandgap photovoltaic copolymers: Turning the properties by different aza‐heteroaromatic donors

A new series of low‐bandgap copolymers based on electron‐accepting thieno[3,4‐b]pyrazine (TPZ) and different electron‐donating aza‐heteroaromatic units, such as carbazole (CZ), dithieno[3,2‐b:2′,3′‐d]pyrrole (TPR) and dithieno[3,2‐b:2′,3′‐e]pyridine (TPY), have been synthesized by Suzuki or Stille coupling polymerization. The resulting copolymers were characterized by NMR, elemental analysis, gel permeation chromatography, thermogravimetric analysis, and differential scanning calorimetry. UV–vis absorption and cyclic voltammetry measurements show that TPZ‐based copolymer with TPR has the best absorption due to the strongest intramolecular charge transfer effect and smallest bandgap. The basic electronic structure of D‐A model compounds of these copolymers were also studied by density functional theory (DFT) calculations. The conclusion of calculation agreed also well with the experimental results. The polymer solar cells (PSCs) based on these copolymers were fabricated with a typical structure of ITO/PEDOT:PSS/copolymer:PC₇₁BM/Ca/Al under the illumination of AM 1.5G, 100 mW cm^?2. The performance results showed that TPZ‐based copolymer with TPR donor segments showed highest efficiency of 1.55% due to enhanced short‐circuit current density. The present results indicate that good electronic, optical, and photovoltaic properties of TPZ‐based copolymers can be achieved by just fine‐tuning the structures of aza‐heteroaromatic donor segments for their application in PSCs. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

An Alternating Copolymer Derived from Indolo[3,2‐b]carbazole and 4,7‐Di(thieno[3,2‐b]thien‐2‐yl)‐2,1,3‐benzothiadiazole for Photovoltaic Cells

An alternating narrow bandgap conjugated copolymer (PICZ‐DTBT, E_g = 1.83 eV) derived from 5,11‐di(9‐heptadecanyl)indolo[3,2‐b]carbazole and 4,7‐di(thieno[3,2‐b]thien‐2‐yl)‐2,1,3‐benzothiadiazole (DTBT), was prepared by the palladium‐catalyzed Suzuki coupling reaction. The resultant polymer absorbs light from 350–690 nm, exhibits two absorbance peaks at around 420 and 570 nm and has good solution processibility and thermal stability. The highest occupied molecular orbital (HOMO) energy level and lowest unoccupied molecular orbital (LUMO) level of the copolymer determined by cyclic voltammetry were about −5.18 and −3.35 eV, respectively. Prototype bulk heterojunction photovoltaic cells from solid‐state composite films based on PICZ‐DTBT and [6,6]‐phenyl‐C₇₁ butyric acid methyl ester (PC₇₁BM), show power conversion efficiencies up to 2.4% under 80 mW · cm⁻² illumination (AM1.5) with an open‐circuit voltage of V_oc = 0.75 V, a short current density of J_sc = 6.02 mA · cm⁻², and a fill factor of 42%. This indicates that the copolymer PICZ‐DTBT is a viable electron donor material for polymeric solar cells.

     

1H and 13C NMR assignments of bioactive indeno[1,2‐b]indole‐10‐one derivatives

The complete ¹H and ¹³C assignments of eight bioactive indeno[1,2‐b]indole‐10‐one derivatives were accomplished by the combined use of one‐dimensional and two‐dimensional NMR experiments. Copyright © 2013 John Wiley & Sons, Ltd.     

Diversity‐Oriented Synthesis of Novel 2′‐Aminospiro[11H‐indeno[1,2‐b]quinoxaline‐11,4′‐[4H]pyran] Derivatives via a One‐Pot Four‐Component Reaction

A sequential one‐pot four‐component reaction for the efficient synthesis of novel 2′‐aminospiro[11H‐indeno[1,2‐b]quinoxaline‐11,4′‐[4H]pyran] derivatives 5 in the presence of AcONH₄ as a neutral, inexpensive, and dually activating catalyst is described (Scheme 1). The syntheses are achieved by reacting ninhydrin ( 1 ) with benzene‐1,2‐diamines 2 to give indenoquinoxalines, which are trapped in situ by malono derivatives 2 and various α‐methylenecarbonyl compounds 4 through cyclization, providing the multifunctionalized 2′‐aminospiro[11H‐indeno[1,2‐b]quinoxaline‐11,4′‐[4H]pyran] analogs 5 . This chemistry provides an efficient and promising synthetic way of proceeding for the diversity‐oriented construction of the spiro[indenoquinoxalino‐pyran] skeleton.     

Facile one‐pot synthesis of a series of 7‐aryl‐8H‐benzo[h]indeno[1,2‐b]quinoline‐8‐one derivatives catalyzed by cellulose‐based magnetic nanocomposite

A sulfonated magnetic cellulose‐based nanocomposite was applied as an efficient, inexpensive and green catalyst for the one‐pot three‐component synthesis of 7‐aryl‐8H ‐benzo[h ]indeno[1,2‐b ]quinoline‐8‐ones starting from 1,3‐indanedione, aromatic aldehydes and 1‐naphthylamine under solvent‐free conditions in high yields (79–98%) within short reaction times (2–5 min). The nanobiostructure catalyst can be easily separated from the reaction mixture by using an external magnet and reused several times.     

Selective Synthesis of 1,2‐Diarylpyrrolo[3,4‐b]pyridine‐5,7‐diones via Cyclization Reaction of β‐Enamino Imides with Cinnamaldehydes

The novel 1,2‐diaryl substituted pyrrolo[3,4‐b]pyridine‐5,7‐diones were selectively synthesized in high yields by the base catalyzed cyclization reaction of 3‐arylamino‐1‐methyl‐1H‐pyrrole‐2,5‐diones with cinnamaldehyde and its derivatives in acetonitrile at room temperature. However, when piperidinium trifluoroacetate was employed as catalyst, the reaction afforded a mixture of 1,2‐diaryl and 1,4‐diaryl substituted pyrrolo[3,4‐b]pyridine‐5,7‐diones in comparable yields.     

Synthesis of Newly Substituted Pyrazoles and Substituted Pyrazolo[3,4‐b]Pyridines Based on 5‐Amino‐3‐Methyl‐1‐Phenylpyrazole

The reaction of the aminopyrazole 1 with benzenesulfonyl chloride, arenediazonium salt, chloroacetyl chloride, ethoxy methyleneamlononitrile and with ethyl 2‐cyano‐3‐ethoxyacrylate gave the substituted 3‐methyl‐1‐phenylpyrazole 2–5a,b . Compound 5b was cyclized to 6 and to 7 by treating it with AlCl₃ and with POCl₃, respectively. Compound 6 converted to 7 by boiling it in POCl₃/PCl₅. Compound 10b was produced through reaction of 9 with acetophenone. Reaction of 1 with benzylidinemalononitrile afforded 11 . New methods for preparation of 15 and 16 are described. The reaction of 8 with malononitrile, thiosemicarbazide, phenyl hydrazine and acetophenone afforded compounds 18–21 . The reaction of 21 with malononitrile gave 22 . Compounds 23–26 were produced upon reaction of 10a with malononitrile, phenyl hydrazine, thiosemicarbazide, semicarbazide and with benzaldehyde, respectively.     

One‐pot Combinatorial Synthesis of Benzo[4,5]imidazo‐[1,2‐a]thiopyrano[3,4‐d]pyrimidin‐4(3H)‐one Derivatives

A series of novel fused tetracyclic benzo[4,5]imidazo[1,2‐a]thiopyrano[3,4‐d]pyrimidin‐4(3H)‐one derivatives were synthesized via the reaction of aryl aldehyde, 2H‐thiopyran‐3,5(4H,6H)‐dione, and 1H‐benzo[d]imidazol‐2‐amine in glacial acetic acid. This protocol features mild reaction conditions, high yields and short reaction time.     

Synthesis of Novel 1H‐Imidazol[1,2‐a]Indeno[2,1‐e]Pyridine‐6(5H)‐Ones Derivatives via a One‐Pot Four‐Component Condensation Reaction

1H‐imidazol[1,2‐a]indeno[2,1‐e]pyridine‐6(5H)‐ones derivatives were synthesized in a one‐pot four‐component condensation of corresponding aldehydes, 1,3‐indandione, diamine, and nitro ketene dithioacetal using KAl(SO₄)₂·12H₂O (alum) as nontoxic, reusable, inexpensive and easily available catalyst in good to excellent yields. This green protocol provides a powerful entry into fused polycyclic structures related to bioactive heterocycles.     

Synthesis and characterization of indeno[1,2‐b]fluorene‐based white light‐emitting copolymer

An indenofluorene‐based copolymer containing blue‐, green‐, and red light‐emitting moieties was synthesized by Suzuki polymerization and examined for application in white organic light‐emitting diodes (WOLEDs). Tetraoctylindenofluorene (IF), 2,1,3‐benzothiadiazole (BT), and 4,7‐bis(2‐thienyl)‐2,1,3‐benzothiadiazole (DBT) derivatives were used as the blue‐, green‐, and red‐light emitting structures, respectively. The number‐average molecular weight of the polymer was determined to be 25,900 g/mol with a polydispersity index of 2.02. The polymer was thermally stable (T_d = ～398 °C) and quite soluble in common organic solvents, forming an optical‐quality film by spin casting. The EL characteristics were fine‐tuned from the single copolymer through incomplete fluorescence energy transfer by adjusting the composition of the red/green/blue units in the copolymer. The EL device using the indenofluorene‐based copolymer containing 0.01 mol % BT and 0.02 mol % DBT units ( PIF‐BT01‐DBT02 ) showed a maximum brightness of 4088 cd/m² at 8 V and a maximum current efficiency of 0.36 cd/A with Commission Internationale de L'Eclairage (CIE) coordinates of (0.34, 0.32). The EL emission of PIF‐BT01‐DBT02 was stable with respect to changes in voltage. The color emitted was dependent on the thickness of the active polymer layer; layer (～60 nm) too thin was unsuitable for realizing WOLED via energy transfer. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3467–3479, 2009     

Synthesis of Certain 3-Aminopyrazolo[5,4-b]pyridine and 3,4-Substituted Pyrido[2′,3′：3,4]pyrazolo[5,1-c][1,2,4]triazine Derivatives

2-Thioxo-1,2-dihydropyridine derivatives 2a, 2b were reacted with methyl iodide to give 2-methylthiopyridines 3a, 3b, which were reacted with hydrazine hydrate to produce 3-aminopyrazolo[5,4-b]pyridines 4a, 4b. Compounds 4a, 4b were diazotized to afford the corresponding diazonium salts 5a, 5b, which were reacted with some active methylene compounds 6a-6h to give the corresponding pyrido[2′,3′ ： 3,4]pyrazole[5,1-c][1,2,4]triazines 7-14.     

The Synthesis of Some New 7‐Methyl‐3‐substituted‐1,2,4‐triazolo[3,4‐b]benzothiazoles

New 7‐Methyl‐3‐substituted‐1,2,4‐triazolo[3,4‐b]benzothiazoles were synthesized from p‐methylaniline to 5 with various aromatic carbonic acids. The yielded product 6a‐j was investigated with Elemental analyses, NMR, MS and IR techniques.     

3,6‐Dialkylthieno[3,2‐b]thiophene moiety as a soluble and electron donating unit preserving the coplanarity of photovoltaic low band gap copolymers

It has been shown recently, that the presence of alkyl side chains at the 3‐positions on the thiophene rings placed next to 2,1,3‐benzothiadiazole core in the backbone of several conjugated polymers results in severe steric hindrance and prevents efficient planarity of the thiophene‐2,1,3‐benzothiadiazole‐thiophene (TBzT) segment. Both properties have a strong influence on the optoelectronic properties of the polymer and need to be considered when the polymer is to be used for organic electronics applications. In this work, we modified a previously synthesized oligothiophene copolymer, consisting of two 3,4′‐dialkyl‐2,2′‐bithiophene units attached to a 2,1,3‐benzothiadiazole unit (TBzT segment) and a thieno[3,2‐b]thiophene unit, by optimizing the lateral alkyl side chains following a density functional theory investigation. It is demonstrated that eliminating the alkyl side chains from the 3‐positions of the TBzT segment and anchoring them onto the thieno[3,2‐b]thiophene, using an efficient synthesis of the 3,6‐dihexylthieno[3,2‐b]thiophene unit, allows us to reduce the energy band gap. In addition, the chemical modification leads to a better charge transport and to an enhanced photovoltaic efficiency of polymer/fullerene blends. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis,characterization, and large two‐photon absorption cross‐sections of solid red‐emitting 1,4‐diketo‐3,6‐diphenylpyrrolo [3,4‐c]pyrrole/3,6‐carbazole/terfluorene copolymers

The synthesis, one‐ and two‐photon absorption (TPA) and emission properties of three novel 1,4‐diketo‐3,6‐diphenylpyrrolo[3,4‐c]pyrrole (DPP)/3,6‐carbazole (Cz)/terfluorene (TF) copolymers are reported. The molar ratios of DPP versus TF are 15:85 ( TCP15 ), 25:75 ( TCP25 ), and 50:50 ( TCP50 ) under Cz:(TF + DPP) = 1. Two distinguished one‐photon absorption and emission bands observed in solutions imply that the electronic states of Cz–DPP–Cz and Cz–TF–Cz are not well mixed and the energy transfer from TF segments to DPP units is incomplete. However, in film states, all three copolymers are monochromatic red emitting with the peak wavelengths at 617, 621, and 631 nm for TCP15 , TCP25 , and TCP50 , respectively, indicating that the interchain interactions also have played an important role in the energy transfer. In two‐photon measurement, the copolymer solutions still exhibit two distinguished emission bands but the relative intensities at short‐wavelength region are obviously decreased, implying that Cz–TF–Cz segment is high one‐photon active but low TPA active, whereas Cz–DPP–Cz unit is low one‐photon active but high TPA active. All the copolymers show large δ over the range of measured wavelengths and the δ values of TCP15 , TCP25 , and TCP50 increase with DPP contents and are up to 530, 770, and 850 GM per repeating unit, respectively. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Electrochemical and optical studies of furan and thieno[3,2‐b]thiophene end capped benzotriazole derivatives

Two new 2‐dodecyl benzotriazole (BTz) based donor‐acceptor‐donor (DAD) type polymers were synthesized and characterized in terms of their electrochemical and spectral properties. These DAD type polymers were synthesized electrochemically from furan or thieno[3,2‐b]thiophene (TT) end‐capped BTz monomers. Furan based and thieno[3,2‐b]thiophene based monomers showed monomer oxidations at 1.15 and 1.25 V, respectively, which eased the formation of conducting polymer films without overoxidation. Cyclic voltammetry and spectroelectrochemistry studies showed that both materials are multicolored electrochromic polymers. Results and comparison with properties of other BTz based DAD type polymers are highlighted in detail. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

(3‐Oxo‐[1,2,4]triazolidin‐1‐yl)bis (butane‐1‐sulfonic acid) functionalized magnetic γ‐Fe2O3 nanoparticles: A novel and heterogeneous nanocatalyst for one‐pot and efficient four‐component synthesis of novel spiro[indeno[1,2‐b]quinoxaline derivatives

The efficient synthesis of novel spiro[indeno[1,2‐b]quinoxaline derivatives via the four‐component condensation of amines, ninhydrin, isatoic anhydride, and о‐phenylenediamine derivatives catalyzed by ( 3‐oxo‐[1,2,4]triazolidin‐1‐yl)bis (butane‐1‐sulfonic acid) supported on γ‐Fe₂O₃ as novel heterogenous magnetic nanocatalyst was described. The novel nanocatalyst was characterized by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR), vibrating sample magnetometry (VSM), Field Emission Scanning Electron Microscopy (FE‐SEM), and thermal analysis (TGA‐DTG). The nanoparticles covered by (3‐oxo‐[1,2,4]triazolidin‐1‐yl)bis (butane‐1‐sulfonic acid) showed enhanced catalytic performance in the preparation of spiro[indeno[1,2‐b]quinoxaline derivatives in excellent yields. Moreover, this method showed several advantages such as mild conditions, high yields, easy work‐up, and being environmentally friendly. The catalyst can be easily separated from the reaction mixture by an external magnet, recycled, and reused several times without a noticeable decrease in catalytic activity.