Effect Of Phenyl Substitution Research Articles

Catalyst-Free Synthesis of Novel 4-(Benzofuran-2-yl)-N-phenylthiazol-2(3H)-imines, Crystal Structure Elucidation, and the Effect of Phenyl Substitution on Crystal Packing

A one-pot reaction of an equimolar mixture of 4-methoxyaniline, phenyl isothiocyanate, and 2-bromoacetylbenzofuran in absolute ethanol in the absence of any catalysts afforded 4-(benzofuran-2-yl)-3-(4-methoxyphenyl)-N-phenylthiazol-2(3H)-imine with an 83% yield. Under similar conditions, 4-flouroaniline provided a mixture of the expected 4-(benzofuran-2-yl)-3-(4-fluorophenyl)-N-phenylthiazol-2(3H)-imine and unexpected 4-(benzofuran-2-yl)-N-(4-fluorophenyl)-3-phenylthiazol-2(3H)-imine at an overall 73% yield. The structures of the synthesized heterocycles were confirmed using NMR spectroscopy. The products were recrystallized from dimethylformamide to afford samples suitable for structural determination via single-crystal diffraction. The molecules of the products share a common backbone and have similar conformations. They also display some common intermolecular interactions, including C–H···X (X = N, O, π) and π···π contacts. The molecules differ due to the methoxy and fluoro substituents on their phenyl rings, resulting in variations in the extended network in the crystals. Electron density maps and Hirshfeld surfaces have been used to rationalize the intermolecular contacts.

Multi-stimuli responsive carbazole-imidazole derivatives: Effect of phenyl substitution and UV light-oxygen induced photochemical transformation

New carbazole-imidazole derivatives, (3-(4,5-diphenyl-1H-imidazole-2-yl)-9-(3-methoxyphenyl)-9H-carbazole (Cz-DPIM)) and 9-(3-methoxyphenyl)-3-(1,4,5-triphenyl-1H-imidazole-2-yl)-9H-carbazole (Cz-TPIM) are synthesized and investigated the effect of phenyl substitution on the fluorescence and stimuli-induced fluorescence properties. Cz-DPIM exhibited relatively strong fluorescence in solution compared to Cz-TPIM (Quantum yield (Φf, compared to quinine sulphate standard) = 0.28 (Cz-DPIM) and 0.09 (Cz-TPIM)). In contrast, Cz-DPIM is weakly fluorescence in solid-state but Cz-TPIM showed strong fluorescence (Φf = 1.3% (Cz-DPIM) and 18.2% (Cz-TPIM)). Cz-TPIM displayed mechanoresponsive reversible fluorescence switching upon crushing and solvent fuming. Both Cz-DPIM and Cz-TPIM exhibited reversible halofluorochromsim upon exposure of trifluoroacetic acid (TFA) and ammonia (NH3). Interestingly, Cz-DPIM and Cz-TPIM exhibited photocleavage upon UV light irradiation in presence of oxygen in CH3CN and produced green emissive fluorescence product. The controlled studies revealed that the presence of oxygen is important for exhibiting photocleavage by UV light exposure and suggest potential use for oxygen sensing application. The UV light and oxygen induced photocleavage of Cz-DPIM and Cz-TPIM also demonstrated in thin films.

Ferrocene appended 1,8-naphthalimide chromophores: Synthesis, theoretical, the effect of phenyl substitution on aggregation-induced enhanced emission and second-order nonlinear optical studies

A new ferrocene appended linear donor-π-acceptor (D-π-A) type 1,8-naphthalimide chromophores [FcPhNap-n-butyl (1) and Fc(Ph)2Nap-n-butyl (2)] have been synthesized and characterized using various analytical and spectroscopic techniques. The chromophores 1 and 2 show the one-electron transfer process, which was examined through cyclic voltammetric (CV) method. The solvatochromic studies show red shift by increasing the solvent polarity from non-polar to polar for both the chromophores 1 and 2, due to the better stabilization of the more polarized excited state than the ground state in the polar solvent. The fluorescence studies show low fluorescence emission, which was enhanced by aggregation in THF/water mixture when the water ratio is increased upto 60%, due to the restricted intramolecular rotation (RIR) process in the aggregated state. Also, the quantum yield increases 3.4 (1) and 6.8 (2) times in the aggregation induced enhanced emission (AIEE) state than THF solution for both the chromophores [THF/AIEE = 0.05/0.17 for 1 and 0.03/0.22 for 2]. The second-order non-linear optical properties of the chromophores 1 and 2 were studied using Kurtz and Perry powder technique, chromophore 2 shows 1.2 times higher SHG efficiency than 1, owing to the presence of additional phenyl group in 2, which further supports the effective charge transfer process from donor to acceptor. Furthermore, optical and non-linear optical properties of chromophores 1 and 2 were analyzed by DFT/TD-DFT calculations using different functionals (B3LYP, long-range corrected CAM-B3LYP and LC-BLYP) with 6–31+G** level of theory. The B3LYP functional shows higher hyperpolarizability values [β0 = 109.2 × 10-30 esu (1), 299.7 × 10-30 esu (2)], due to the overestimation of the dipole moment, polarizability and hyperpolarizabilities between the donor–π–acceptor systems in B3LYP-hybrid functional, which leads to incorrect long-range charge transfer.

Molecular stacking character and charge transport properties of tetrabenzoheptacenes derivatives: the effects of nitrogen doping and phenyl substitution.

The nitrogen doping and phenyl substitution effects on the geometries, molecular stacking character, electronic, and charge transport properties of tetrabenzoheptacene (TTBH) have been investigated by means of density functional theory (DFT) calculation and incoherent charge hopping model. Our results indicate that the nitrogen doping (TTH) at the 6,8,15,17 positions improves its stability in air and the ability of electron injection and in the meantime slightly changes the molecular stacking due to the C-H···N interaction. For both TTBH and TTH, large hole transport mobility (μh) and electron transport mobility (μe), which are on the same order of magnitude, are given rise by their dense displaced π-stacking in crystal. Comparatively, the phenyl substitution (Ph-TTBH) at the 6,8,15,17 positions adopts a non-planar conformation, adverse to close packing and therefore leads to smaller electron/hole transport mobility (μ) than those of TTBH and TTH. The calculations suggest TTBH and TTH are promising candidates for excellent ambipolar OFET materials.

The effect of phenyl substitution on the fluorescence characteristics of fluorescein derivatives via intramolecular photoinduced electron transfer

UV-vis absorption, steady state fluorescence emission, time-correlated single photon counting and laser flash photolysis methods were employed to examine the excited state properties of fluorescein derivatives to understand the mechanism that controls their fluorescence efficiency. The fluorescein derivatives contain amino, t-butyl, carboxyl or nitro on their phenyl moieties, respectively. These substituents are not directly connected to the fluorophore but still showed a very remarkable effect on the fluorescence properties. Compared to fluorescein, the introduction of nitro, a strong electron withdrawing group, or amino, a strong electron donating group, caused a substantial quenching of both the fluorescence quantum yield and lifetime. The presence of a t-butyl or carboxyl, on the other hand, caused a smaller decrease. The mechanism for the substituent effect is due to the involvement of an additional de-excitation process, i.e. intramolecular photoinduced electron transfer (PET). The thermodynamics and kinetics of PET were analyzed. Depending on the nature of the substituent, the xanthenic ring acts as an electron acceptor (or donor), while the phenyl moiety is the corresponding electron donor (or acceptor) in PET. The rate constant of PET for the amino case is larger than 4.79 x 10(9) s(-1), while for nitro substitution it is 0.67 x 10(9) s(-1). Both values are much larger than the radiation rate constant of 0.20 x 10(9) s(-1), meaning that PET plays important roles in the deactivation of S(1) for the two dyes. The charge transfer state generated by PET was observed by laser flash photolysis.

The phenyl substitution effects on the 2,4,6-triphenoxy-1,3,5-triazines

The phenyl substitution effects on the 2,4,6-triphenoxy-1,3,5-triazines

Methyl and Phenyl Substitution Effects on the Proton Affinities of Hydrides of First and Second Row Elements and Substituent Effects on the Proton Affinities of Ring Carbons in Benzene: A DFT Study

Theoretical calculations using B3LYP density functional theory (DFT) with the 6-311++G(d,p) basis set have been performed to determine proton affinities (PAs) of a series of H-X compounds and the corresponding methyl- (H(3)C-X) and phenyl- (Ph-X) substituted derivatives with a variety of proton acceptor atoms, such as C, O, N, F, Si, P, S, Cl, etc. Our results illustrate an interesting substituent effect on PAs. The PAs of ring carbon atoms for a series of monosubstituted benzene molecules (Y-C(6)H(5); Y = F, Cl, CH(3), OCH(3), NH(2), PH(2), OH, SH, SiH(3), CN, CF(3), and NO(2)) have also been estimated. Correlations between proton affinities of H-X, H(3)C-X, and Ph-X and substituent effects on the PAs of the ring carbon atoms for a series of monosubstituted benzene molecules have been studied. It has been observed that substituent effects on the PAs of the ring carbon atoms follow a good Hammett-type correlation.

Regioselective phenyl-substitution effects on the solvatochromism of 2-phenylimidazo[1,2- a]pyrazin-3(7 H)-one derivatives: expansion of the color variation range of a visible indicator for the proton donor ability of solvents

Phenyl-substitution to the C8 position of an imidazopyrazinone ring resulted in the significant bathochromic shift of the lowest energy band, while the substitution to the C6 position does not produce such a shift. This provides evidence that a color variation range of the solvatochromism of 2-phenylimidazopyrazinone derivatives depends strongly on the position of phenyl-substitution. Results indicated that an imidazopyrazinone with the phenyl groups at the C2 and C8 positions acts as a potential indicator of the proton donor ability of solvents.

Amine Donors in Nonlinear Optical Molecules: Methyl and Phenyl Substitution Effects on the First Hyperpolarizability

The effects of amine donors (a:NH 2 , b:NMe 2 , c:NMePh, d:NPh 2 ) and conjugation length on the molecular hyperpolarizabilities of a series of dipolar molecules have been theoretically investigated by using CPHF/6-31G method. The first hyperpolarizabilities (β) of p-nitrobenzene derivatives increase with the donor in the order, NH 2 < NMe 2 < NMePh < NPh 2 , whereas slightly different order is observed in more conjugated derivatives, i.e., NH 2 < NPh 2 < NΜe 2 < NMePh. The result has been attributed to the extent of charge transfer and torsion angle. Moreover, the results show that non-traditional π-conjugation effect exists in small compounds and decreases as the conjugation length between donor and acceptor increases.

The Effect of Phenyl Substitution on the Thermochemistry of Gas-Phase Ions and Their Neutral Counterparts

The available data for the heats of formation of phenyl-substituted organics have been critically evaluated. Phenyl substitution is always thermochemically destabilizing in that Δ fH0[R–C6H5] – Δ fH0[R–H] is a positive quantity. The magnitude of the effect in neutrals depends on the substitution site, e.g. from + 79 kJ mol−1 for HCOR or HCCR to + 155 kJ mol−1 for RCO2H. Multiple phenyl substitution (where possible) at the same site is generally simply additive. For the corresponding cationic species, the first phenyl substitution is stabilizing when the ionization energy of the substrate is lowered thereby and for even-electron ions resonance-stabilization energies may also come into play. Additional phenyl substitution at the same site is, however, always destabilizing. Phenyl substitutions were compared with vinyl substitution: for neutral species the effects are similar, whereas for even-electron ions, multiple vinyl substitution is only weakly stabilizing or destabilizing.

Incorporation of phenyl-substituted pentadienyl ligands in (pentamethylcyclopentadienyl)ruthenium complexes †

The reactions of the [Ru(C5Me5)Cl]4 tetramer with 2,4-diphenylpenta-1,3-diene or 3-phenyl- or 1,5-diphenyl-substituted pentadienyl anions lead to the incorporation of the expected phenyl-substituted pentadienyl ligands into the respective symmetric Ru(C5Me5)(Pdl) products (Pdl = 2,4-Ph2C5H5; 3-PhC5H6; 1,5-Ph2C5H5). The reaction of the tetramer with a mixture of 2-methyl-4-phenylpenta(-1,3- or -2,4-)dienes led to the Pdl = 2-Me-4-PhC5H5 complex. In contrast, the reaction of the tetramer with 3-phenylpenta-1,3-diene led to simple incorporation of the η4-diene ligand. Structural confirmation of the formulations of the four η5-pentadienyl complexes has been achieved, allowing for a number of comparisons to be made regarding the structural effects of phenyl substitution on the (1,5), (2,4) and 3 positions of the open dienyl ligand.

Phenyl substitution effects on rate acceleration of cation radical deazetation of 2,3-diazabicyclo[2.2.2]oct-2-enes

Under the 9,10-dicyanoanthracene (DCA)-photosensitized electron-transfer conditions 1-phenyl-2,3-diazabicyclo[2.2.2]oct-2-ene ( 1b) and 1,4-diphenyl-2,3-diazabicyclo[2.2.2]oct-2-ene ( 1c) were deazetized with rate constants, k -N2, of ca. 8.4 × 10 7 and 6.6 × 10 10 s −1, respectively, whereas the parent 2,3-diazabicyclo[2.2.2]oct-2-ene ( 1a) was not reactive, showing remarkable rate acceleration by the σ (CN)-π (Ph) orbital interaction due to the phenyl substitution.

Effects of Phenyl Substitution on the Fragmentation of Sterically Congested Di-tert-butylstilbene Radical Cations

The characteristic mass spectrometric fragmentation patterns of sterically congested stilbenes, phenyl-substituted 2,2,5,5-tetramethyl-3,4-diphenylhex-3-enes, are described. In contrast to stilbene, these sterically congested stilbenes show facile loss of tert-butyl and/or isobutene and phenyl, ultimately leading to ions with the constitution of disubstituted acetylenes. The isobutene/tert-butyl ratio increases as substituents attached to the phenyl ring become more electronegative.

Effect of phenyl substitution on bonding in η3-benzyl complexes of platinum

Reaction of the platinum(0) styrene complexes [Pt(η2-CH2CHC6H4X){But2P(CH2)3PBut2}]1a–1f(X = Br-3, Br-4, Me-4, F-4, F-3 or MeO-4) with HBF4 in diethyl ether afforded the η3-methylbenzyl complexes [Pt(η3-MeCHC6H4X){But2P(CH2)3PBut2}][BF4]2a–2f. The effect of phenyl substitution on the asymmetry of the η3-methylbenzyl interaction was measured by 31P-{1H} NMR spectroscopy and it was found that, in general, the more electron releasing the substituent, X, the more asymmetric is the bonding. Complexes 2a–2f lose styrene reversibly to form the hydride-bridged dinuclear platinum complex [Pt2(µ-H)2{But2P(CH2)3PBut2}2][BF4]2. Displacement of styrenes from 2a–2f by ethene and bicyclo[2.2.1]hept-2-ene affords known complexes stabilized by a three-centre, two-electron (agostic) bond.

ChemInform Abstract: Directing Effects of Phenyl Substitution in the Reaction of OH Radical with Aromatics: The Radiolytic Hydroxylation of Biphenyl

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Directing effects of phenyl substitution in the reaction of hydroxyl radical with aromatics: the radiolytic hydroxylation of biphenyl

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDirecting effects of phenyl substitution in the reaction of hydroxyl radical with aromatics: the radiolytic hydroxylation of biphenylXiaofeng Chen and Robert H. SchulerCite this: J. Phys. Chem. 1993, 97, 2, 421–425Publication Date (Print):January 1, 1993Publication History Published online1 May 2002Published inissue 1 January 1993https://doi.org/10.1021/j100104a025RIGHTS & PERMISSIONSArticle Views190Altmetric-Citations29LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (545 KB) Get e-Alerts

The effect of phenyl substitution on the structure of benzylic anions

The structures of 9-sodio-9-phenyl-and-9-sodio-9-(4′-cyanophenyl)-9,10-dihydroanthracene are examined by 13C NMR, and by AM1 semiempirical molecular orbital calculations on the corresponding anions. Evidence is presented for a aryl substituent coplanar with the anionic center in the p-cyano case.

ChemInform Abstract: UV Laser Photochemistry of Azoalkanes: Surprising Effects of Phenyl Substitution on the Lifetimes of 1,3‐Cyclopentanediyl and 1,4‐Cyclohexanediyl Triplet Diradicals.

AbstractThe direct and semitized (Ph2CO) photolysis of azoalkanes (I) leads to biradicals 3(II).

UV-laser photochemistry of azoalkanes: surprising effects of phenyl substitution on the lifetimes of 1,3-cyclopentanediyl and 1,4-cyclohexanediyl triplet diradicals

UV-laser photochemistry of azoalkanes: surprising effects of phenyl substitution on the lifetimes of 1,3-cyclopentanediyl and 1,4-cyclohexanediyl triplet diradicals

Elimination and addition reactions. Part 41. Nucleophilic eliminative fission of cyclopropanes: the coiled spring effect of ring strain on nucleofugality and its evaluation

Rates have been measured of sulphonyl-activated eliminative ring fissions of a series of six cyclopropanes in which the leaving group is stabilised by alkoxycarbonyl, cyano, or sulphonyl groups. The measurements allow assignment of ranks (nucleofugalities) to carbon leaving groups in systems in which the connection to the leaving group is strained by incorporation in a cyclopropane ring. The values obtained are compared with those obtained for a unstrained (acyclic) analogues. Rank enhancements of about 9 (log) units are obtained; these enhancements suggest that free energies of activation for leaving-group expulsion are reduced by about 53 kJ mol–1, or about 46% of the excess of enthalpy of the strained ring, notwithstanding the small degree of ring fission in the transition structure. The effect of phenyl substitution at the leaving group suggests that cleavage of the ring is very little advanced in the transition structure, although this is variable with the nature of the leaving-group stabilisation. This is the first direct determination of the effect of strain on nucleofugality.