Abstract: Herein, we report the rational design of practical small-molecule organic semiconductors based on a π-electron skeleton of benzothieno[3,2-b]naphtho[2,3-b]thiophene (BTNT) whose layered herringbone (LHB) packing is intentionally modulated by the designated asymmetric substitutions with the phenyl group and normal alkyl chains. The thermal stability of the hybrid BTNT core is high enough, as it lies between those of dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene (DNTT) and benzothieno[3,2-b]benzothiophene (BTBT), although the solvent solubility for the substituted BTNT at ordinary 2,8-substituting positions by the alkyl chain and phenyl group remains extremely low. We show in the BTBT and BTNT derivatives that the tuning of the substituting position works to slightly bend the rodlike organic semiconductor molecules and thus to decrease the cohesive energy of the crystals with retention of the bilayer-type herringbone (b-LHB) packing for the asymmetric rodlike molecules. This modification eventually leads t...

Abstract: In recent years, the crystal engineering library has been enriched with a number of previously unrecognized or unnoticed intermolecular interactions, such as agostic, tetrel, chalcogen, pnicogen bonding and chelate ring stacking – collectively referred to as “unconventional interactions”. Many open questions remain unaddressed regarding their ability to form synthon interactions, specificity, and cooperativity, for example with π–π stacking interactions. In this work, we throw light on the formation of chelate ring stacking in metal–organic assemblies of nicotinohydrazide ligands (N′-(1-(2-pyridyl)ethylidene)nicotinohydrazide (HL) and N′-(phenyl(pyridin-2-yl)methylene)nicotinohydrazide (HL1)) with mercury(II) halide (HgBr2, HgI2) salts. Their reaction produced five compounds, namely [Hg(μ-L)BrHgBr2]n (1), [Hg(μ-L1)Br]n (2), [Hg(L)I2] (3), [Hg(HL1)I2]·(CH3OH) (4), and [Hg(μ-L1)I]n (5). Crystal structure analysis reveals that chelate ring stackings are formed in four of the reported metal–organic compounds, and are common also in the literature precedents. The energies of chelate ring stackings and π–π heterocycle stackings have been computed and analyzed by means of DFT calculations, and the results were verified using Bader's theory of “atoms in molecules”. These results provide a rationale for preferential formation of both unconventional and conventional stackings and allow us to conclude that chelate ring interaction may be considered as a synthon interaction for nicotinohydrazide metal complexes. Interpretations for packing differences imposed by the substituent effect (substitution of methyl group in HL for phenyl group in HL1) were provided based on the Hirshfeld surface analysis and 2D fingerprint plots of the crystal structures reported here.

Abstract: The influence of the nature of the acid/base pairs on the reactivity of geminal frustrated Lewis pairs (FLPs) (Me2 E-CH2 -E'Ph2 ) has been computationally explored within the density functional theory framework. To this end, the dihydrogen-activation reaction, one of the most representative processes in the chemistry of FLPs, has been selected. It is found that the activation barrier of this transformation as well as the geometry of the corresponding transition states strongly depend on the nature of the E/E' atoms (E=Group 15 element, E'=Group 13 element) in the sense that lower barriers are associated with earlier transition states. Our calculations identify the geminal N/Al FLP as the most active system for the activation of dihydrogen. Moreover, the barrier height can be further reduced by replacing the phenyl group attached to the acidic atom by C6 F5 or 3,5-(CF3 )2 C6 H3 (Fxyl) groups. The physical factors controlling the computed reactivity trends are quantitatively described in detail by means of the activation strain model of reactivity combined with the energy decomposition analysis method.

Abstract: Diaryl and dialkyl chalcogenide molecules serve as convenient precursors to silicon–chalcogenide bonds, ≡Si–E–R groups, on silicon surfaces, where E = S, Se, and Te. The 254 nm light, coupled with gentle heating to melt and liquefy the chalcogenide precursors for 15 min, enables formation of the resulting silicon–chalcogenide bonds. R groups analyzed comprise a long alkyl chain, octadecyl, and a phenyl group. Quantification of substitution levels of the silicon-hydride on the starting ≡Si(111)–H surface by an organochalcogen was determined by XPS, using the chalcogenide linker atom as the atomic label, where average substitution levels of ∼15% were found for all ≡Si–E–Ph groups. These measured substitution levels were found to agree with 2-dimensional stochastic simulations assuming kinetically irreversible silicon–chalcogen bond formation. Due to the small bond angle about the chalcogen atom, the phenyl rings in the case of ≡Si–E–Ph effectively block otherwise reactive Si–H bonds, leading to the observed...

Abstract: Benzanthrone derivatives are potential fluorescent probes for various chemical and biological environments. A mechanistic understanding of their photophysical properties is pivotal for designing an efficient fluorescence sensor based on the benzanthrone framework. In this study, we report on the effect of chemical substitution on the photophysical properties of two benzanthrone derivatives, namely, 3-(N′-methyl)-piperazino-7H-benzo[de]anthracen-7-one [Me-PBA] and 3-(N′-phenyl)-piperazino-7H-benzo[de]anthracen-7-one [Ph-PBA] in different solvents and solvent mixtures of varying polarities and proticities. Both benzanthrone derivatives show interesting solvent-dependent photophysical properties. Although both derivatives exhibit strong intramolecular charge transfer (ICT) characteristics in the excited state, the extent of the charge transfer is significantly influenced by the nature of the chemical substitution. Modulation of photophysical parameters as a function of solvent properties led us to propose that ICT is affected by solvent polarity and hydrogen bonding. From the viscosity effect, it is revealed that the weaker emission of Ph-PBA compared to Me-PBA in polar solvents is primarily due to the non-radiative torsional motion of the phenyl group in the former derivative. In protic solvents, intermolecular hydrogen bonding imparts strong non-radiative deactivation to both derivatives, thus rendering a weak fluorescence yield.

Abstract: In this work, we reported two wide band-gap donor–acceptor (D–A) photovoltaic materials based on asymmetric benzodithiophene units with a bare phenyl or alkoxyl chain modified phenyl group as one of the substitutions The optical band-gaps of the two polymers are both identified above 180 eV P2 (with a side chain in the phenyl group) reveals slightly red-shifted film absorption spectra compared to polymer P1 attached with the bare phenyl group, which is partly attributed to the better molecular conformations and intermolecular interactions Polymer solar cells with different acceptor materials are fabricated to systematically evaluate the photovoltaic properties of the two polymers The results show that P2 based fullerene and fullerene-free solar cells both show superior photovoltaic performance over the devices of P1, mainly attributed to the more favorable heterojunction morphologies and more balanced charge transport P2 based PSCs with PC71BM as the acceptor demonstrate an enhanced efficiency (858%) compared to that of P1 (704%) Notably, low boiling point toluene was reported as an effective additive for the first time to optimize the photovoltaic performance of fullerene-free polymer solar cells The best efficiency of the P2/ITIC based devices reached over 9%, with a VOC of 090 V, JSC of 1670 mA cm−2, and FF of 0603, suggesting the great potential of low boiling point solvents as the additive toward efficient fullerene-free polymer solar cells

Abstract: Here we report a series of 1-phenyl-5-substituted 2,6-di(pyrazol-3-yl)pyridine complexes with iron(II) ion found in a high spin state in solids (according to magnetochemistry) and in solution (according to NMR spectroscopy), providing experimental evidence for it being an intramolecular effect induced by the phenyl groups. According to X-ray diffraction, the high spin locking of the metal ion is a result of its highly distorted coordination environment (with a very low ‘twist’ angle atypical of 2,6-di(pyrazol-3-yl)pyridine complexes), which remains this way in complexes with different substituents and counterions, in a diamagnetic zinc(II) analogue and in their solutions. Three possible reasons behind it, including additional coordination with the phenyl group, energy penalty incurred by its rotation or intramolecular stacking interactions, are addressed experimentally.

Abstract: Phosphoric acid ester amides were examined as a new self-extinguishing solvent for Li-ion batteries. The phosphoric acid ester amides used in this study contained two fluorinated alkyl groups and one amino group, (CF3CH2O)2(NR1R2)P═O (PNR1R2). The thermal stability of the highly concentrated electrolyte of lithium bis(fluorosulfonyl) amide (LiFSA) and PNR1R2 with a molar ratio of [LiFSA]/[PNR1R2] = 0.5 under overcharge depended on the modification of the amino substituent. Introduction of a phenyl group (R1 = CH3, R2 = C6H5) was effective for improving thermal stability. The release of gases and heat that typically accompanied reaction of the solvent with the charged graphite anode was greatly suppressed. Density functional theory calculations indicated that PNR1R2 decomposed reductively near 0.5 V vs Li+/Li, suggesting poor Li ion insertion into the graphite. However, the highly concentrated electrolyte using LiFSA and PNR1R2 reduced the reductive potential of PNR1R2 and enabled not only the insertion of...

Abstract: A monoalkoxy phenyl group as a dummy ligand on indolyl(aryl)iodonium imides, which is related to the N-I bonding hypervalent iodine(III) compound, for the copper-catalyzed indole-selective C-N coupling reaction was designed to provide 3-bissulfonimido-indole derivatives in high yields. In particular, the use of indolyl(2-butoxylphenyl)iodonium bissulfonimides indicated the high indole selectivity. Furthermore, this reaction was applied for the one-pot synthesis of 3-bissulfonimido-indole derivatives directly from indoles with bissulfonimides and (diacetoxyiodo)-2-butoxybenzene in the presence of Cu(MeCN)4BF4 catalyst.

Abstract: The present invention provides a compound represented by chemical formula 1, and an organic light-emitting device comprising the same. In the chemical formula 1: Ars are each independently hydrogen, a substituted or unsubstituted aryl group having 6-30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 6-30 carbon atoms, wherein at least one of the two Ars is a phenyl group or a pyridine group; Xs are each independently CR^1 or N, wherein R^1 is hydrogen, halogen, an amino group, a nitrile group, a nitro group, a substituted or unsubstituted alkyl group having 1-30 carbon atoms, a substituted or unsubstituted aryl group having 6-30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 2-30 carbon atoms; and A and B are each independently a substituted or unsubstituted aryl group having 6-30 carbon atoms or a substituted or unsubstituted heteroaryl group having 2-30 carbon atoms.

Abstract: It has been well established that organic-inorganic hybrid molecules can exhibit biological activities that are different from those of either their intramolecular metals in inorganic forms or their organic structures. We have previously reported that organoantimony compound Sb-phenyl-N-methyl-5, 6,7,12-tetrahydrodibenz[c,f][1,5]azastibocine (PMTAS) is nontoxic, but that the compound exhibits cytotoxicity in vascular endothelial cells when the antimony atom is replaced with a bismuth atom. In the present study, we investigated the cytotoxicity and intracellular accumulation of PMTAS and its analogs and found that the cytotoxicity of PMTAS analogs also decrease depending on the electron-withdrawing property of the substituent bound to the intramolecular antimony atom. On the other hand, with the exception of the phenyl group, and depending on the carbon number of hydrocarbon group bound to the intramolecular nitrogen atom, cytotoxicity was enhanced. Furthermore, the cytotoxicity of PMTAS analogs correlated with their intracellular accumulation values. These results suggested that the low cytotoxicity effects of PMTAS on vascular endothelial cells is due to the characteristics of substituents bound to intramolecular antimony and nitrogen atoms.

Abstract: Cesium carbonate-catalyzed oxidation of substituted phenylsilanes (ArSiH3) in N,N-dimethylformamide (DMF) at room temperature for the efficient synthesis of polyhedral oligomeric silsesquioxanes (POSS) was described. This protocol allowed the rapid and selective access to several types of new POSS cages in modest to good yields under nonaqueous conditions. Depending on the bulkiness of the substituents on the phenyl rings, hexa- (T6), octa- (T8), and dodecaphenylsilsesquioxanes (T12) can be selectively obtained. With the more bulky 2-(2′,4′,6′-trimethylphenyl)phenyl group, the cyclic tetrasiloxane (D4) bearing four hydroxyl groups was isolated. Mechanism studies disclosed that the initial step involved the Cs2CO3-catalyzed hydrosilylation of DMF with a hydrosilane to generate a siloxymethylamine intermediate followed by the dehydrocarbonative cross-coupling of the hydrosilane with the siloxymethylamine.

Abstract: Zinc methyl 20-substituted 3 1 -demethyl-bacteriopheophorbides- d were prepared through palladium-catalyzed cross-coupling of chlorophyll- a derivatives. The synthetic zinc 3 1 -hydroxy-13 1 -oxo-chlorins possessing a(n) (un)substituted ethynyl or butadiynyl group at the 20-position were good models for bacteriochlorophylls- c / d found solely in chlorosomes, the main light-harvesting antennas of green photosynthetic bacteria. Similarly as in natural chlorosomes, the synthetic models self-aggregated in an aqueous Triton X-100 solution to form large oligomers with red-shifted and broadened electronic absorption bands. While a phenyl group directly connected with the chlorin π-system at the 20-position disturbed the chlorosomal self-aggregation, the insertion of an ethynylene group between the two functional groups reduced the steric hindrance around the 20-position and was useful for the facile formation of the self-aggregates. A similar substitution effect was observed in the 20-ethynyl to butadiynyl moieties bearing a sterically bulky trimethylsilyl group at the terminal position.

Abstract: Three new series of mesogens have been synthesized by fixing 4-methoxy or 4-butoxy substituted phenyl ring in one side and 4-hydroxy, bromo or amino substituted phenyl group in the other side with ...

Abstract: The influence of the structure of diimine bridge in the Schiff’s bases (derivatives of N,N'-ethylenebissalicylimine) on the rate of the loss of electroactivity of their complexes with nickel in acetonitrile containing 0.1 M of tetraethylammonium tetrafluoroborate (anhydrous and upon addition of 1 wt % of water) has been studied. It has been shown that the presence of bulky yet light methyl groups in the structure of diimine bridge significantly reduced the loss of electroactivity (37% of the initial capacity retained after 50 cycles) as compared to the ligand containing no substituents and containing phenyl group as the substituent (17 and 20%, respectively, of initial capacity retained after 50 cycles).

Abstract: The multistep synthesis of a versatile new 4-substituted 3,5-bis(2-pyridyl)-1,2,4-triazole (Rdpt) ligand, 4-[4-(2-aminomethyl)phenyl]-3,5-bis(2-pyridyl)-4 H-1,2,4-triazole (apdpt), is reported, which features a reactive aminomethyl para-substituent on the phenyl group that points "out of the back" of the triazole. This enables further functionalisation under mild conditions by using a range of esters to form an amide link. Specifically, this proof of principle study demonstrates the synthesis of apdpt successfully appended with gold-binding thioctic acid (tpdpt), graphene-binding/emissive pyrene/propylpyrene (prdpt/pbdpt), and a Langmuir-Blodgett film-forming polyethylene glycol (PEG) tail (pgdpt). These ligands are subsequently reacted with [Fe(pyridine)4 (NCBH3 )2 ] to give the mononuclear iron(II) complexes [Fe(Rdpt)2 (NCBH3 )2 ]⋅solvent, in which Rdpt/solvent is tpdpt/2.5 H2 O (1), prdpt/0.5 CHCl3 ⋅H2 O (2), and pbdpt/0.5 CHCl3 ⋅2 H2 O (3), as red powders. Magnetic studies on these powders indicate that the complexes undergo only very gradual and incomplete spin crossover, from completely or mostly high spin at 300 K, to half or three-quarters high spin at 50 K. Gold nanoparticles are successfully functionalised with the thioctic acid tpdpt ligand to give tpdpt@Au with an average diameter (as determined by TEM) of (3.1±0.7) nm. Preliminary studies on the two pyrene systems in dimethylformamide show that upon excitation at λ=345 nm the blue fluorescence observed for the free ligands is retained, essentially unaffected, in the respective complexes.

Abstract: Ureas, pivalamides, and carbamates are widely used as directing metalation groups (DMGs) due to their good directing ability, low cost, ease of access, and ease of removal. Lithiation of substituted benzenes having such directing metalation groups using various alkyllithiums in anhydrous solvent at low temperature provides the corresponding lithium intermediates, but lithiation may take place at various sites. Reactions of the lithium reagents obtained in situ with various electrophiles give the corresponding derivatives, typically substituted at the site(s) where initial lithiation occurred, often in high yields. However, it is often difficult to predict what reagents and/or conditions might be needed to give specific products or to draw general conclusions about the factors that influence the reactions, especially when the reagents, temperature, and solvents used in reported reactions are not directly comparable. In this review, therefore, we attempt to unravel the various factors that influence the lithiation of various simple aromatic compounds containing urea, pivalamide, and carbamate groups. 1 Introduction 2 Lithiation with DMG Attached Directly to the Phenyl Ring 2.1 Influence of the DMG 2.2 Influence of Substitution on the Phenyl Ring 3 Lithiation with the DMG Separated by a CH2 Group from the Phenyl­ Ring 3.1 Effect of the DMG 3.2 Influence of Substitution on the Phenyl Ring 4 Lithiation with the Phenyl Ring and DMG Separated by Two or More CH2 Groups 4.1 Effect of the DMG and Its Distance from the Phenyl Group 4.2 Effect of Substituents on the Phenyl Ring 5 Conclusions