Design,Efficient Synthesis,and Anti‐HIV Activity of 4′‐C‐Cyano‐ and 4′‐C‐Ethynyl‐2′‐deoxy Purine Nucleosides

Some 4′‐C‐ethynyl‐2′‐deoxy purine nucleosides showed the most potent anti‐HIV activity among the series of 4′‐C‐substituted 2′‐deoxynucleosides whose 4′‐C‐substituents were methyl, ethyl, ethynyl and so on. Our hypothesis is that the smaller the substituent at the C‐4′ position they have, the more acceptable biological activity they show. Thus, 4′‐C‐cyano‐2′‐deoxy purine nucleosides, whose substituent is smaller than the ethynyl group, will have more potent antiviral activity. To prove our hypothesis, we planned to develop an efficient synthesis of 4′‐C‐cyano‐2′‐deoxy purine nucleosides (4′‐CNdNs) and 4′‐C‐ethynyl‐2′‐deoxy purine nucleosides (4′‐EdNs). Consequently, we succeeded in developing an efficient synthesis of six 2′‐deoxy purine nucleosides bearing either a cyano or an ethynyl group at the C‐4′ position of the sugar moiety from 2′‐deoxyadenosine and 2,6‐diaminopurine 2′‐deoxyriboside. Unfortunately, 4′‐C‐cyano derivatives showed lower activity against HIV‐1, and two 4′‐C‐ethynyl derivatives suggested high toxicity in vivo.     

Increased DNA binding and sequence discrimination of PNA oligomers containing 2,6-diaminopurine.

The synthesis of a diaminopurine PNA monomer, N-[N6-(benzyloxycarbonyl)-2,6-diaminopurine-9-yl] acetyl-N-(2-t-butyloxycarbonylaminoethyl)glycine, and the incorporation of this monomer into PNA oligomers are described. Substitution of adenine by diaminopurine in PNA oligomers increased the T m of duplexes formed with complementary DNA, RNA or PNA by 2.5-6.5 degrees C per diaminopurine. Furthermore, discrimination against mismatches facing the diaminopurine in the hybridizing oligomer is improved. Finally, a homopurine decamer PNA containing six diaminopurines is shown to form a (gel shift) stable strand displacement complex with a target in a 246 bp double-stranded DNA fragment.     

Dependence of Diaminopurine Utilization on the Mutational Site of Purine Auxotrophy in Bacillus subtilis I. Nutritional Experiments

An attempt was made to explain the puzzling observation that in bacteria 2,6-diaminopurine can replace guanine for guanineless mutants and for xanthineless mutants (both of which can make adenosine monophosphate de novo) but not for nonexacting purine auxotrophs (which cannot make adenosine monophosphate de novo). The analogue failed to inhibit the growth of nonexacting purineless Bacillus subtilis MB-1356 growing on guanine. In fact, growth was somewhat stimulated. This eliminated a possible solution involving the inhibition of guanosine monophosphate reductase by a diaminopurine derivative. Sparing of guanine by diaminopurine was matched by an even greater sparing of adenine. Addition of a small amount of adenine to MB-1356 failed to allow unrestricted growth on diaminopurine, thus eliminating a possible solution requiring an adenine derivative for the initial deamination of diaminopurine to guanine. The same degree of sparing of adenine by diaminopurine was observed whether both purines were added together or whether the adenine was added 1 hr after diaminopurine. This eliminated the possibility that diaminopurine was wasted by a "dead-end" conversion in the absence of adenine. Consideration of these nutritional data led to the development of two additional explanations, which are examined by tracer methodology in the following paper.     

Sequential Processing for Organic Photovoltaics: Design Rules for Morphology Control by Tailored Semi‐Orthogonal Solvent Blends

Design rules are presented for significantly expanding sequential processing (SqP) into previously inaccessible polymer:fullerene systems by tailoring binary solvent blends for fullerene deposition. Starting with a base solvent that has high fullerene solubility, 2‐chlorophenol (2‐CP), ellipsometry‐based swelling experiments are used to investigate different co‐solvents for the fullerene‐casting solution. By tuning the Flory‐Huggins χ parameter of the 2‐CP/co‐solvent blend, it is possible to optimally swell the polymer of interest for fullerene interdiffusion without dissolution of the polymer underlayer. In this way solar cell power conversion efficiencies are obtained for the PTB7 (poly[(4,8‐bis[(2‐ethylhexyl)oxy]benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl)(3‐fluoro‐2‐[(2‐ethylhexyl)carbonyl]thieno[3,4‐b]thiophenediyl)]) and PC₆₁BM (phenyl‐C₆₁‐butyric acid methyl ester) materials combination that match those of blend‐cast films. Both semicrystalline (e.g., P3HT (poly(3‐hexylthiophene‐2,5‐diyl)) and entirely amorphous (e.g., PSDTTT (poly[(4,8‐di(2‐butyloxy)benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl)‐alt‐(2,5‐bis(4,4′‐bis(2‐octyl)dithieno[3,2‐b:2′3′‐d]silole‐2,6‐diyl)thiazolo[5,4‐d]thiazole)]) conjugated polymers can be processed into highly efficient photovoltaic devices using the solvent‐blend SqP design rules. Grazing‐incidence wide‐angle x‐ray diffraction experiments confirm that proper choice of the fullerene casting co‐solvent yields well‐ordered interdispersed bulk heterojunction (BHJ) morphologies without the need for subsequent thermal annealing or the use of trace solvent additives (e.g., diiodooctane). The results open SqP to polymer/fullerene systems that are currently incompatible with traditional methods of device fabrication, and make BHJ morphology control a more tractable problem.     

The synthesis of N2,N6-substituted diaminopurine ribosides

A series of new 2,6-substituted diaminopurine riboside derivatives were synthesized by activation of protected xantosine with sulfonyl chlorides followed by treatment with various amines. The relationship between the reactivity of intermediates and the nature of the activating agents was studied.     

The synthesis of <Emphasis Type="Italic">N</Emphasis><Superscript>2</Superscript>,<Emphasis Type="Italic">N</Emphasis><Superscript>6</Superscript>-substituted diaminopurine ribosides

A series of new 2,6-substituted diaminopurine riboside derivatives were synthesized by activation of protected xantosine with sulfonyl chlorides followed by treatment with various amines. The relationship between the reactivity of intermediates and the nature of the activating agents was studied.     

Germanium‐ and Silicon‐Substituted Donor–Acceptor Type Copolymers: Effect of the Bridging Heteroatom on Molecular Packing and Photovoltaic Device Performance

The effects of heteroatom substitution from a silicon atom to a germanium atom in donor‐acceptor type low band gap copolymers, poly[(4,4′‐bis(2‐ethylhexyl)dithieno[3,2‐b:2′,3′‐d]silole)‐2,6‐diyl‐alt‐(2,1,3‐benzothiadiazole)‐4,7‐diyl] (PSiBTBT) and poly[(4,4′‐bis(2‐ethylhexyl)dithieno[3,2‐b:2′,3′‐d]germole)‐2,6‐diyl‐alt‐(2,1,3‐benzothiadiazole)‐4,7‐diyl] (PGeBTBT), are studied. The optoelectronic and charge transport properties of these polymers are investigated with a particular focus on their use for organic photovoltaic (OPV) devices in blends with phenyl‐C₇₀‐butyric acid methyl ester (PC₇₀BM). It is found that the longer C‐Ge bond length, in comparison to C‐Si, modifies the molecular conformation and leads to a more planar chain conformation in PGeBTBT than PSiBTBT. This increase in molecular planarity leads to enhanced crystallinity and an increased preference for a face‐on backbone orientation, thus leading to higher charge carrier mobility in the diode configuration. These results provide important insight into the impact of the heavy atom substitution on the molecular packing and device performance of polymers based on the poly[2,6‐(4,4‐bis‐(2‐ethylhexyl)‐4H‐cyclopenta[2,1‐b;3,4‐b]‐dithiophene)‐alt‐4,7‐(2,1,3‐benzothiadiazole) (PCPDTBT) backbone.     

Eco‐Friendly Solvent‐Processed Fullerene‐Free Polymer Solar Cells with over 9.7% Efficiency and Long‐Term Performance Stability

A wide‐bandgap polymer, (poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b′]dithiophene))‐alt‐(2,5‐(methyl thiophene carboxylate))]) (3MT‐Th), is synthesized to obtain a complementary broad range absorption when harmonized with 3,9‐bis(2‐methylene‐(3‐(1,1‐dicyanomethylene)‐indanone))‐5,5,11,11‐tetrakis(4‐hexylphenyl)‐dithieno[2,3‐d:2′,3′‐d′]‐s‐indaceno[1,2‐b:5,6‐b′]dithiophene (ITIC). The synthesized regiorandom 3MT‐Th polymer shows good solubility in nonhalogenated solvents. A film of 3MT‐Th:ITIC can be employed for forming an active layer in a polymer solar cell (PSC), with the blend solution containing toluene with 0.25% diphenylether as a nonhalogenated additive. The corresponding PSC devices display a power conversion efficiency of 9.73%. Moreover, the 3MT‐Th‐based PSCs exhibit excellent shelf‐life time of over 1000 h and are operationally stable under continuous light illumination. Therefore, methyl thiophene‐3‐carboxylate in 3MT‐Th is a promising new accepting unit for constructing p‐type polymers used for high‐performance nonfullerene‐type PSCs.     

Protection of 2,6-Diaminopurine 2′-Deoxyriboside

Abstract

Protection of both mine moieties of 2, 6-diaminopurine 2′-deoxyriboside as a dimethylformamidine group did not proove feasable, while protection with a phenoxyacetyl group afforded only a mono-protected analogue 5. This analogue can be incorporated into oligonucleotides without difficulties. However, oligonucleotides with diaminopurine substituted for adenine did not yield more stable duplexes for the two sequences tested here.     

Magnetic chitosan beads for covalent immobilization of nucleoside 2′-deoxyribosyltransferase: application in nucleoside analogues synthesis

Cross-linked magnetic chitosan beads were prepared in presence of epichlorohydrin under alkaline conditions, and subsequently incubated with glutaraldehyde in order to obtain an activated support for covalent attachment of nucleoside 2′-deoxyribosyltransferase from Lactobacillus reuteri (LrNDT). Changing the amount of magnetite (Fe₃O₄) and epichlorohydrin (EPI) led to different macroscopic beads to be used as supports for enzyme immobilization, whose morphology and properties were characterized by scanning electron microscopy, spin electron resonance (ESR), and vibrating sample magnetometry (VSM). Once activated with glutaraldehyde, the best support was chosen after evaluation of immobilization yield and product yield in the synthesis of thymidine from 2′-deoxyuridine and thymine. In addition, optimal conditions for highest activity of immobilized LrNDT on magnetic chitosan were determined by response surface methodology (RSM). Immobilized biocatalyst retained 50 % of its maximal activity after 56.3 h at 60 °C, whereas 100 % activity was observed after storage at 40 °C for 144 h. This novel immobilized biocatalyst has been successfully employed in the enzymatic synthesis of 2′-deoxyribonucleoside analogues as well as arabinosyl-nucleosides such as vidarabine (ara-A) and cytarabine (ara-C). Furthermore, this is the first report which describes the enzymatic synthesis of these arabinosyl-nucleosides catalyzed by an immobilized nucleoside 2′-deoxyribosyltransferase. Finally, the attached enzyme to magnetic chitosan beads could be easily recovered and recycled for 30 consecutive batch reactions with negligible loss of catalytic activity in the synthesis of 2,6-diaminopurine-2′-deoxyriboside and 5-trifluorothymidine.     

Dopamine Semiquinone Radical Doped PEDOT:PSS: Enhanced Conductivity,Work Function and Performance in Organic Solar Cells

Poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been is applied as hole transport material in organic electronic devices for more than 20 years. However, the redundant sulfonic acid group of PEDOT:PSS has often been overlooked. Herein, PEDOT:PSS‐DA is prepared via a facile doping of PEDOT:PSS with dopamine hydrochloride (DA·HCl) which reacts with the redundant sulfonic acid of PSS. The PEDOT:PSS‐DA film exhibits enhanced work function and conductivity compared to those of PEDOT:PSS. PEDOT:PSS‐DA‐based devices show a power conversion efficiency of 16.55% which is the highest in organic solar cells (OSCs) with (poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl)‐4‐fluorothiophen‐2‐yl)benzo[1,2‐b:4,5‐b′]dithio‐phene))‐co‐(1,3‐di(5‐thiophene‐2‐yl)‐5,7‐bis(2‐ethylhexyl)‐benzo[1,2‐c:4,5‐c′]dithiophene‐4,8‐dione))] (PM6):(2,2′‐((2Z,2′Z)‐((12,13‐bis(2‐ethylhexyl)‐3,9‐diundecyl‐12,13‐dihydro‐[1,2,5]thiadiazolo[3,4‐e]thieno[2′′,3′:4′,5′]thieno[2′,3′:4,5]pyrrolo[3,2‐g]thieno[2′,3′:4,5]thieno[3,2‐b]indole‐2,10‐diyl)bis(methanylylidene))bis(5,6‐difluoro‐3‐oxo‐2,3‐dihydro‐1H‐indene‐2,1‐diylidene))dimalononitrile) (Y6) as the active layer. Furthermore, PEDOT:PSS‐DA also exhibits enhanced performance in three other donor/acceptor systems, exhibiting high compatibility in OSCs. This work demonstrates that doping PEDOT:PSS with various amino derivatives is a potentially efficient strategy to enhance the performance of PEDOT:PSS in organic electronic devices.     

Thymineless death inLactobacillus acidophilus R-26

Thymineless death (TLD) as well as deoxyribosideless death (DRLD) can be observed inLactobacillus acidophilus R-26 during growth in media lacking thymine or deoxyriboside respectively. Both phenomena exhibit the same interval of lage period (2–3 h) but the rate of inactivation is 2–3 times faster in TLD. Transfer experiments show that inactivation of bacterial reproduction is accelerated immediately if—DR medium is replaced by—T one. In the opposite case the deceleration of the inactivation rate does not appear immediately but after a 1–2 h lag period, in which no changes in the number of viable bacteria can be observed. Our results suggested that the accumulation of deoxyriboside compounds has no causal role in the inactivation of bacterial reproduction. However, the presence of deoxyribosides can accelerate the process of inactivation.     

Efficient production of deoxynucleoside-5′-monophosphates using deoxynucleoside kinase coupled with a GTP-regeneration system

Deoxynucleoside-5′-monophosphates (5′-dNMPs) are the basic components of DNA and are widely used in medicine and as chemical and biochemical reagents. A large amount of effort has been expended to obtain 5′-dNMPs of high quality and at a low cost. However, these procedures are inefficient and inconvenient. In this study, deoxyadenosine-5′-monophosphate (5′-dAMP), 2,6-diaminopurine deoxynucleoside-5′-monophosphate (5′-dDAMP), and deoxycytidine-5′-monophosphate (5′-dCMP) were biosynthesized using recombinant N-deoxyribosyltransferase II (NDT-II), deoxycytidine kinase, and acetate kinase in a one-pot reaction system. The ndt-II gene from Lactobacillus delbrueckii, dck from Bacillus subtilus, and ack from Escherichia coli K12 were overexpressed in E. coli BL21 (DE3). Thymidine was used as the deoxyribose donor; GTP was used as the phosphate donor, and acetyl phosphate was used to regenerate GTP. Under optimized conditions, each 10 mM adenine, 10 mM 2,6-diaminopurine, or 10 mM cytosine were converted into 9.01 mM 5′-dAMP, 8.68 mM 5′-dDAMP, or 6.23 mM 5′-dCMP, respectively. The high yield indicated that this process of biosynthesis of 5′-dAMP, 5′-dDAMP, or 5′-dCMP was efficient and economical, and this one-pot system may also potentially be used for the preparation of other types of 5′-dNMPs.     

Designing 1,5‐Naphthyridine‐2,6‐dione‐Based Conjugated Polymers for Higher Crystallinity and Enhanced Light Absorption to Achieve 9.63% Efficiency Polymer Solar Cells

Highly crystalline conjugated polymers represent a key material for producing high‐performance thick‐active‐layer polymer solar cells (PSCs). However, despite their potential, a limited number of crystalline polymers are used in PSCs because of the lack of highly coplanar acceptor building blocks and insufficient light absorptivity (α < 10⁵) of most donor (D)–acceptor (A)‐type polymers. This study reports a series of novel 3,7‐di(thiophen‐2‐yl)‐1,5‐naphthyridine‐2,6‐dione (NTDT) acceptor‐based conjugated polymers, PNTDT‐2T, PNTDT‐TT, and PNTDT‐2F2T, synthesized with 2,2′‐bithiophene (2T), thieno[3,2‐b]thiophene (TT), and 3,3′‐difluoro‐2,2′‐bithiophene (2F2T) donor units, respectively. PNTDT‐2F2T exhibits superior polymer crystallinity and a much higher absorption coefficient than those of PNTDT‐2T or PNTDT‐TT because of adequate matching between highly coplanar A (NTDT) and D (2F2T) building blocks. A bulk heterojunction solar cell based on PNTDT‐2F2T exhibits a power conversion efficiency of up to 9.63%, with a high short circuit current of 18.80 mA cm^?2 and fill factor of 0.70, when a thick active layer (>200 nm) is used, without postfabrication hot processing. The findings demonstrate that the polymer crystallinity and absorption coefficient can be effectively controlled by selecting appropriate D and A building blocks, and that NTDT is a novel and versatile A building block for highly efficient thick‐active‐layer PSCs.     

Diaminopurine-Resistant Mutants of Cultured, Diploid Human Fibroblasts

Clones of cells resistant to 2,6-diaminopurine were detected in skin fibroblast cultures derived from 13 of 21 normal humans of both sexes from 17 unrelated families. Almost all of the cultures that yielded mutants were chosen for further study from among a total of 83 surveyed because they displayed a slight resistance to low concentrations of diaminopurine. The incidences of mutant colonies ranged between about 10(-5) and 10(-4) per cell surviving prior mutagenic treatment with MNNG. The incidences of spontaneous mutants were about 10(-7) to 10(-5) in three unrelated cultures. Most independent mutants had distinctly reduced activity of adenine phosphoribosyltransferase but some had apparently normal amounts of activity. Two mutants from unrelated boys had little or no detectable enzyme activity and were unable to effectively use exogenous adenine for growth when purine biosynthesis was blocked with azaserine. Most mutants could utilize exogenous adenine, just as most azaguanine-resistant fibroblast mutants can utilize exogenous hypoxanthine, even when their hypoxanthine-guanine phosphoribosyltransferase activity is reduced. Diverse genetic changes conferred diaminopurine resistance but their specific natures are still undefined. Gross numerical or structural chromosome abnormalities were not observed in the mutants examined so far. Since at least one gene responsible for adenine phosphoribosyltransferase activity is on autosome No. 16 our results suggest that at least some of the cultures yielding mutants were heterozygous and that alleles conferring diaminopurine resistance may be frequent enough to comprise a polymorphism.     

Synthesis of Oligoribonucleotides Containing 4‐Thiouridine Using the Convertible Nucleoside Approach and the 1‐(2‐Fluorophenyl)‐4‐Methoxypiperidin‐4‐yl Group

Oligoribonucleotides containing 4‐thiouridine were prepared using the Fpmp group for protection of the 2′‐OH. Two uridine derivatives with the 1,2,4‐triazolyl and the 2‐nitrophenyl groups at position 4 were used to obtain 4‐thiouridine by postsynthetic substitution with sodium hydrogen sulfide. Both uridine derivatives allow the preparation of the desired oligonucleotides in good yields.     

Balancing High Open Circuit Voltage over 1.0 V and High Short Circuit Current in Benzodithiophene‐Based Polymer Solar Cells with Low Energy Loss: A Synergistic Effect of Fluorination and Alkylthiolation

Based on the most recently significant progress within the last one year in organic photovoltaic research from either alkylthiolation or fluorination on benzo[1,2‐b:4,5‐b′]dithiophene moiety for high efficiency polymer solar cells (PSCs), two novel simultaneously fluorinated and alkylthiolated benzo[1,2‐b:4,5‐b′] dithiophene (BDT)‐based donor–acceptor (D–A) polymers, poly(4,8‐bis(5′‐((2″‐ethylhexyl)thio)‐4′‐fluorothiophen‐2′‐yl)benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl)‐alt‐2′‐ethylhexyl‐3‐fluorothieno[3,4‐b]thiophene‐2‐carboxylate (PBDTT‐SF‐TT) and poly(4,8‐bis(5′‐((2″‐ethylhexyl)thio)‐4′‐fluorothiophen‐2′‐yl)benzo[1,2‐b:4,5‐b′]dithiophene‐2,6‐diyl)‐alt‐1,3‐bis(thiophen‐2‐yl)‐5,7‐bis(2‐ethylhexyl)benzo[1,2‐c:4,5‐c′]dithiophene‐4,8‐dione (PBDTT‐SF‐BDD), namely, via an advantageous and synthetically economic route for the key monomer are reported herein. Synergistic effects of fluorination and alkylthiolation on BDT moieties are discussed in detail, which is based on the superior balance between high V_oc and large J_sc when PBDTT‐SF‐TT/PC₇₁BM and PBDTT‐SF‐BDD/PC₇₁BM solar cells present their high V_oc as 1.00 and 0.97 V (associated with their deep highest occupied molecular orbital level of ?5.54 and ?5.61 eV), a moderately high J_sc of 14.79 and 14.70 mA cm^?2, and thus result a high power conversion efficiency of 9.07% and 9.72%, respectively. Meanwhile, for PBDTT‐SF‐TT, a very low energy loss of 0.59 eV is pronounced, leading to the promisingly high voltage, and furthermore performance study and morphological results declare an additive‐free PSC from PBDTT‐SF‐TT, which is beneficial to practical applications.     

Stability of Nonfullerene Organic Solar Cells: from Built‐in Potential and Interfacial Passivation Perspectives

Remarkable progress has been made in the development of high‐efficiency solution‐processable nonfullerene organic solar cells (OSCs). However, the effect of the vertical stratification of bulk heterojunction (BHJ) on the efficiency and stability of nonfullerene OSCs is not fully understood yet. In this work, we report our effort to understand the stability of nonfullerene OSCs, made with the binary blend poly[(2,6‐(4, 8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b′]dithiophene))‐alt‐(5,5‐(1′,3′‐di‐2‐thienyl‐5′,7′‐bis(2‐ethylhexyl)benzo[1′,2′‐c:4′,5′‐c′] dithiophene‐4,8‐dione)] (PBDB‐T):3,9‐ bis(2‐methylene‐(3‐(1,1‐dicyanomethylene)‐indanone))‐5,5,11,11‐tetrakis(4‐hexylphenyl)‐ dithieno[2,3‐d:2′,3′‐d′]‐s‐indaceno[1,2‐b:5,6‐b′] dithiophene (ITIC) system. It shows that a continuous vertical phase separation process occurs, forming a PBDB‐T‐rich top surface and an ITIC‐rich bottom surface in PBDB‐T:ITIC BHJ during the aging period. A gradual decrease in the built‐in potential (V₀) in the regular configuration PBDB‐T:ITIC OSCs, due to the interfacial reaction between the poly(3,4‐ethylenedioxythiophene)‐poly(styrenesulfonate) (PEDOT:PSS) hole transporting layer and ITIC acceptor, is one of the reasons responsible for the performance deterioration. The reduction in V₀, caused by an inevitable reaction at the ITIC/PEDOT:PSS interface in the OSCs, can be suppressed by introducing a MoO₃ interfacial passivation layer. Retaining a stable and high V₀ across the BHJ through interfacial modification and device engineering, e.g., as seen in the inverted PBDB‐T:ITIC OSCs, is a prerequisite for efficient and stable operation of nonfullerene OSCs.     

Photoactive Blend Morphology Engineering through Systematically Tuning Aggregation in All‐Polymer Solar Cells

Polymer aggregation plays a critical role in the miscibility of materials and the performance of all‐polymer solar cells (APSCs). However, many aspects of how polymer texturing and aggregation affect photoactive blend film microstructure and photovoltaic performance are poorly understood. Here the effects of aggregation in donor–acceptor blends are studied, in which the number‐average molecular weights (M_ns) of both an amorphous donor polymer, poly[4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b;4,5‐b′]dithiophene‐2,6‐diyl‐alt‐(4‐(2‐ethylhexyl)‐3‐fluorothieno[3,4‐b]thiophene‐)‐2‐carboxylate‐2‐6‐diyl)] ( PBDTT‐FTTE ) and a semicrystalline acceptor polymer, poly{[N,N′‐bis(2‐octyldodecyl)naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5′‐(2,2′‐bithiophene)} ( P(NDI2OD‐T2) ) are systematically varied. The photovoltaic performance is correlated with active layer microstructural and optoelectronic data acquired by in‐depth transmission electron microscopy, grazing incidence wide‐angle X‐ray scattering, thermal analysis, and optical spectroscopic measurements. Coarse‐grained modeling provides insight into the effects of polymer aggregation on the blend morphology. Notably, the computed average distance between the donor and the acceptor polymers correlates well with solar cell photovoltaic metrics such as short‐circuit current density (J_sc) and represents a useful index for understanding/predicting active layer blend material intermixing trends. Importantly, these results demonstrate that for polymers with different texturing tendencies (amorphous/semicrystalline), the key for optimal APSC performance, photovoltaic blend morphology can be controlled via both donor and acceptor polymer aggregation.     

Fungicidal Properties of Some Novel Trifluoromethylphenyl Amides

Trifluoromethylphenyl amides (TFMPAs) were designed and synthesized as potential pesticides. Thirty‐three structures were evaluated for fungicidal activity against three Colletotrichum species using direct bioautography assays. Active compounds were subsequently tested against C. fragariae, C. gloeosporioides, C. acutatum, Phomopsis obscurans, P. viticola, Botrytis cinerea and Fusarium oxysporum. The study identified 2‐chloro‐N‐[2,6‐dichloro‐4‐(trifluoromethyl)phenyl]acetamide ( 7a ) as showing the strongest antifungal activity, and the broadest activity spectrum in this set against Colletotrichum acutatum (at 48 and 72 h) and Phomopsis viticola (at 144 h). The presence of triethylamine in its complex with N‐[2,6‐dichloro‐4‐(trifluoromethyl)phenyl]‐2,2,3,3,3‐pentafluoropropanamide ( 7b′ ) played an important role in the bioactivity, and depending on the concentration or fungal species it showed higher or lower activity than the parent amide. X‐Ray crystallography has shown that the complex ( 7b′ ) is an ion pair, (C₁₀H₂Cl₂F₈NO)^? (C₆H₁₆N)⁺, where a proton is transferred from the amide nitrogen to the triethylamine nitrogen and then connected by hydrogen bonding to the acyl oxygen (N?H 0.893 Å; H???O 1.850 Å; N???O 2.711 Å; N?H???O 161.2(13)°). Although none of these compounds were better than standards, this work revealed some potential lead structures for further development of active novel compounds.