Asymmetric anionic polymerizations of 7‐(o‐substituted phenyl)‐2,6‐dimethyl‐1,4‐benzoquinone methides: Electrostatic interaction and steric,inductive, and resonance effects of the ortho‐substituent on the optical activity

7‐(o‐Substituted phenyl)‐2,6‐dimethyl‐1,4‐benzoquinone methides which have an electron‐donating methoxy‐(o‐OMe, 2a ) and methyl‐ (o‐Me, 2b ) substituents or an electron‐withdrawing cyano‐ (o‐CN, 2c ) and trifluoromethyl‐ (o‐CF₃, 2d ) substituents at the ortho‐position of the aromatic ring and 7‐(m‐substituted phenyl)‐2,6‐dimethyl‐1,4‐benzoquinone methide with an electron‐withdrawing trifluoromethyl‐ (m‐CF₃, 2e ) substituent at the meta‐position of the aromatic ring were synthesized, and their asymmetric anionic polymerizations using the complex of lithium 4‐isopropylphenoxide with (?)‐sparteine were carried out in toluene at 0 °C. The polymers with negative optical activity were obtained for all of five monomers, and their specific rotation values largely changed depending upon the substituents of the monomers. On the basis of the comparison of various substituents effects, it was found that the specific rotation of obtained polymers is significantly affected by the electronic effects such as inductive and resonance effects rather than the steric and electrostatic effects of the substituent. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 1048–1058     

Mass spectral fragmentation patterns of 3,3-dimethyl-2,3,4,5,10,11-hexahydro-11-(o- and p-R-phenyl)-1H-dibenzo- [b,e][1,4]diazepin-1-ones. II

A study has been made of the fragmentation upon electron impact of 3,3-dimethyl-2,3,4,5,10,11-hexahydro-11-phenyl-1H-dibenzo[b,e][1,4]diazepin-1-one and fifteen of its derivatives containing chloro, bromo, methyl, methoxy, hydroxy, nitro, amino, carboxyl and carboxymethyl substituents on ortho and para positions of the 11-phenyl ring. All the spectra analyzed contain molecular ions and the principal fragmentation routes takes place either from the molecular or from (M⁺-1) ion. There are, however, some deviations from the general fragmentation pattern in the case of 1,4-dibenzodiazepin-1-ones with o-nitro, o-hydroxy and o-carboxyl substituents caused by direct interactions of these groups with the benzodiazepine ring.     

Highly conductive soluble terpolymers of aniline,toluidine, and o‐aminobenzoic acid/m‐aminobenzenesulfonic acid

Two series of terpolymers, one of o‐/m‐toluidine and aniline with o‐aminobenzoic acid and the other of o‐/m‐toluidine and aniline with m‐aminobenzenesulfonic acid, have been synthesized by oxidative polymerization via an emulsion method with ammonium persulfate as the oxidant and HCl as the external dopant. The terpolymers exhibit excellent solubility and retain the high conductivity (∼1 S cm⁻¹) characteristic of the unsubstituted homopolymer, polyaniline. The terpolymers also possess higher thermal stability than polyaniline. This can be attributed to the presence of internal doping groups and substituents, which introduce flexibility to the otherwise rigid polyaniline backbone. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3040–3048, 2005     

Structure–property relationship of phenoxyimine ligands/metal chloride initiating systems for controlled cationic polymerizations of alkyl vinyl ethers

The catalyst structure–property relationships of the phenoxyimine complexes in controlled cationic polymerization of vinyl ethers were investigated based on the Hammett correlation. The correlation analyses of a series of experiments using the phenoxyimine ligands/TiCl₄ initiating systems indicated that the substituents on the N‐aryl phenoxyimine ligands affected the polymerization rate and stereoselectivity. Importantly, a linear correlation was observed between the Hammett substituent constants and the polymerization rates, which indicates that the Lewis acidity of the complex is affected by the electron‐withdrawing and ‐donating effects of the substituents. The tacticity of product polymers correlated to the Hammett substituent constants. Unlike the relationship with the polymerization rates, the σ^– values, which account for the enhanced resonance effects, were more appropriate for the relationship with the tacticity than the normal σ values. In contrast, the polymerization behavior using o‐substituted ligands exhibited a trend different from those using p‐ or m‐substituted ligands. The structural change, which was caused by the rotation of the C? N bonding, most likely triggered the acceleration effect in the case of the o‐substituents. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 2021–2029     

Solid-State Photochromism by Molecular Assembly of Bis-o-carboranyl Siloles

A new type of solid-state photochromism was observed in an AB₂-type molecular assembly comprising a central silole and two peripheral o-carborane units, and in this assembly, depending on the assembling positions of those units at the adjoining benzene ring, two different regioisomers were formed: Si-m-Cb and Si-p-Cb . Each isomer showed different solid-state photochromism depending on its solid-state molecular conformation and was either in the crystalline or amorphous state. The crystals of each meta- or para-isomer, C_Si-m-Cb or C_Si-p-Cb, showed yellow or blue emission, and mechanically grinding those crystals into amorphous powders of A_Si-m-Cb and A_Si-p-Cb, switched their emissions to blue and yellow, respectively. Photophysical studies revealed that the electronic interaction between silole and o-carborane units determined the emission color. The crystal and DFT-optimized structures each account for the crystalline and amorphous structures, respectively, and are correlated well with the electronic interactions in the molecular assembly in the solid state, thus enabling the prediction of the solid-state molecular conformational change.     

Donor–acceptor‐based poly(toluidine‐co‐chloroaniline)s: Synthesis and characterization

A series of poly(o‐/m‐toluidine‐co‐o‐/m‐chloroaniline) copolymers of different compositions were synthesized by an emulsion method with ammonium persulfate as the oxidant. The conductivity of the copolymers was two to five orders of magnitude higher than that of the homopolymers poly(o‐toluidine) and poly(m‐chloroaniline). Among the copolymers, the copolymer of o‐toluidine and m‐chloroaniline exhibited a maximum conductivity of 0.14 S cm^?1. The conductivity of these copolymers was also higher than that of poly(aniline‐co‐chloroaniline). The properties of the copolymers were greatly influenced by the positions of the substituents and the concentrations of the individual monomers in the feed. All the copolymers were completely soluble in polar solvents such as dimethyl sulfoxide and showed higher heat stability as the chloroaniline concentration increased. These effects could be interpreted in terms of extensive hydrogen bonding and interchain linking and, therefore, higher electron delocalization in these copolymers due to the presence of electron‐rich toluidine rings adjacent to electron‐deficient chloroaniline. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1579–1587, 2005     

Synthesis and asymmetric polymerization of a series of methyl‐substituted triphenylmethyl methacrylate

Five novel ortho‐, meta‐, and para‐methyl‐substituted triphenylmethyl methacrylate monomers, such as o‐tolyldiphenylmethyl methacrylate (o‐MeTrMA), di‐o‐tolylphenylmethyl methacrylate (o‐Me₂TrMA), tris‐o‐tolylmethyl methacrylate (o‐Me₃TrMA), tris‐m‐tolylmethyl methacrylate (m‐Me₃TrMA), and tris‐p‐tolylmethyl methacrylate (p‐Me₃TrMA) have been synthesized. The methanolysis rates of these monomers were measured in CDCl₃‐CD₃OD (1:1, v/v) by ¹H NMR spectroscopy at 30 °C. It was found that the order of the methanolysis rates would be TrMA<o‐MeTrMA<o‐Me₂TrMA<o‐Me₃TrMA<m‐Me₃TrMA except p‐Me₃TrMA, which exhibited very good stability to methanolysis. The asymmetric polymerization of these monomers was investigated by chiral anionic complexes as initiators. The results showed that the ability to form a helical chain was effected not only by the types of chiral complex initiators, but also by the position and number of methyl‐substituted groups at the benzene rings of TrMA. The order of the ability of polymerization was o‐MeTrMA >o‐Me₂TrMA>o‐Me₃TrMA and m‐Me₃TrMA> p‐Me₃TrMA>o‐Me₃TrMA. These differences would be attributed to the different sizes and “propeller” steric structures of the bulky side groups. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 430–436, 2001     

Synthesis of orthogonally addressable block copolymers via reversible addition fragmentation chain transfer polymerization and subsequent chemoselective postmodification

This article describes the synthesis of bifunctional block copolymers (BCPs) of type 4 bearing orthogonally reactive backbone substituents such as 1,1,1,3,3,3‐hexafluoroisopropoxycarbonyl groups as active esters and α‐hydroxyalkylphenylketones (2‐hydroxy‐2‐methyl‐1‐phenylpropan‐1‐one) as additional photoactive moieties via reversible addition fragmentation chain transfer (RAFT) polymerization. As monomers 1,1,1,3,3,3‐hexafluoroisopropyl acrylate (HFIPA) and 2‐hydroxy‐2‐methyl‐1‐(4‐vinyl)phenylpropan‐1‐one (HAK) are used. Controlled radical polymerization provides BCPs p(HFIPA)‐b‐p(HAK) with molecular weights (M_n) ranging from 15,000 to 37,000 g mol^?1 and low molecular weight distributions (PDI = 1.2–1.4). The incorporated HFIPA and HAK moieties are used for sequential chemoselective postmodification of 4 . The photoactive block of 4 can be functionalized through a nitroxide photoclick trapping reaction in the presence of functionalized nitroxides and the active ester moieties of the p(HFIPA)‐block are readily thermally amidated using various amines. Chemically modified polymers are characterized by NMR, FTIR, and GPC methods which reveal a high degree of postfunctionalization, typically >95% for both orthogonal processes. The chemically modified polymers feature a narrow molecular weight distribution. The process is successfully applied to the synthesis of a small polymer library and also to the preparation of homo and block polynitroxides using 4‐amino‐TEMPO as amine component in the transamidation reaction. The polynitroxides obtained are characterized by cyclic voltammetry, FTIR, and UV–vis spectroscopy. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 52, 258–266     

A simple one-pot synthesis of hydroxylated and carboxylated aryl alkyl sulfides from various bromobenzenes

A simple one-pot synthesis of aryl alkyl sulfides from various bromobenzenes containing a hydroxy, hydroxymethyl, hydroxyethyl, and carboxylic acid group at -o, -m, and -p positions is reported here. The reaction proceeds through, in sequence, in situ protection of the hydroxy or carboxylic acid group by reaction with a Grignard reagent, lithium-halogen exchange, the formation of lithium thiolates, and the nucleophilic attack of lithium thiolates on various electrophiles without isolation of the thiolates, in one vessel. This procedure required a very short reaction time (1-1.5 h) and gave the corresponding sulfides in 75-97% yields.     

m‐Methoxy Substituents in a Tetraphenylethylene‐Based Hole‐Transport Material for Efficient Perovskite Solar Cells

Three tetrapheynlethylene derivatives (N,N‐di(4‐methoxyphenyl)aminophenyl‐substituted tetraphenylethylene; TPE‐4DPA) with different methoxy positions (pp‐, pm‐, and po‐) have been synthesized and characterized. The methoxy groups can control the oxidation potential of the materials, and the electronic properties of the derivatives were affected by the position of the methoxy substituents. These compounds were synthesized in a facile and cost‐effective way, and were applied as hole‐transport materials in perovskite solar cells. The corresponding cell performances were compared with respect to their structure modifications, and it was found that the derivative with m‐OMe substituents showed the highest power conversion efficiency (PCE) of 15.4 %, with a J_sc value of 20.04 mA cm^?2, a V_oc value of 1.07 V, and a fill factor (FF) value of 0.72, which is higher than the p‐OMe and o‐OMe substituents. Moreover, the PCE of pm‐TPE‐4DPA is comparable with that of the state‐of‐the‐art 2,2′,7,7′‐tetrakis(N,N′‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene under identical conditions.     

Template synthesis and structures of apically functionalized iron(ii) clathrochelates

Template condensation of three nioxime or dichloroglyoxime molecules with monosubstituted boronic acids on an iron(ii) ion matrix afforded apically functionalized tris-nioximate clathrochelates and hexachloride precursors of apically-ribbed functionalized clathratochelates, respectively. The macrobicyclic tris-nioximates containing apical o-dimethoxyphenyl, p-bromophenyl, phenylethynyl, biphenylyl, 6-pyrimidinyl, or tert-butyl substituents and the dibenzothienyl-containing hexachloroglyoximate clathrochelate thus obtained were characterized by elemental analysis and IR, UV-Vis, ¹H and ¹³C NMR, ⁵⁷Fe Mössbauer and PD mass spectroscopies. The structures of o-dimethoxyphenyl- and phenylethynyl-containing iron(ii) tris-nioximates and the dibenzothienyl precursor were established by X-ray diffraction analysis.     

Isotachophoretic determination of mobility and pKa by means of computer simulation : V. Evaluation of mo and pKa of twenty-eight dipeptides and assessment of separability

Isotachophoretic qualitative indices, R_E, for twenty-eight dipeptides were measured in the range pH 7.4–9.6. The absolute mobility, m_o, and pK_a values were evaluated by the use of the least-squares method, utilizing a simulation of the isotachophoretic steady state. The m_o values were newly evaluated and the pK_a values were in good agreement with literature values. By comparison of the evaluated m_o and pK_a values of the dipeptides with those of the constituent amino acids, simple relationships were found which may be used to estimate the m_o and pK_a values of other dipeptides. The separability of the dipeptides was also evaluated by considering the differences between their simulated effective mobilities. It is concluded that isotachophoresis is very convenient for the separation of dipeptides and their constituent amino acids.     

Effect of methoxy position on dynamic mechanical and shape memory properties of methoxyphenol-based polybenzoxazines

Abstract

Two series of benzoxazines were synthesized from o-, m-, and p-methoxyphenols, two polyetheramines with different molecular weights, and formaldehyde. The glass transition temperatures (T _gs) of m-methoxyphenol-based polybenzoxazines are respectively higher than those of o- and p-methoxyphenol-based counterparts. The polybenzoxazines exhibit thermally induced one-way dual-shape memory behavior based on T _g, and the o- and p-methoxyphenol-based polybenzoxazines exhibit higher shape memory performance than m-methoxyphenol-based counterparts under motion constraints.     

Synthesis and activity of aryl benzyl methyl sulfonium salts as cationic initiators: Effect of substituent on aryl group

Benzyl o-, m-, and p-substituted phenyl methyl sulfonium salts ( 2b – 2g ) were synthesized and their activities as cationic initiators were evaluated in the bulk polymerization of phenyl glycidyl ether (PGE). Especially, their activities were estimated with respect to the effect of substituents on the aryl groups. In the polymerizations of PGE with a series of benzyl p-substituted phenyl methyl sulfonium salts, the order of their activities was found to be 2c (CH₃OCOO) > 2b (CH₃COO) > 2d (CH₃O) ～ 2a (HO). In particular, 2c was the most active initiator of all, capable of initiating the polymerization of PGE even at room temperature. In the polymerizations with 2a, 2e (m-Cl), 2f (o-CH₃), and 2g (m-CH₃), the activity of 2e was the highest of all while those of 2a, 2f , and 2g were almost the same. These results strongly suggested that the electron-withdrawing group placed on the aryl group undoubtedly enhanced the activity of the sulfonium salts as the cationic initiators.     

Synthesis of end‐functionalized poly(phenylacetylene)s with well‐characterized palladium catalysts

End‐functionalized poly(phenylacetylene)s were synthesized by the polymerization of phenylacetylene (PA) using the well‐defined palladium catalysts represented as [(dppf)PdBr(R)] {dppf = 1,1′‐bis(diphenylphosphino)ferrocene}. The Pd catalysts having a series of R groups such as o‐tolyl, mesityl, C(Ph)?CPh₂, C₆H₄‐o‐CH₂OH, C₆H₄‐p‐CN, and C₆H₄‐p‐NO₂ in conjunction with silver triflate polymerized PA to give end‐functionalized poly(PA)s bearing the corresponding R groups in high yields. The results of IR and NMR spectroscopies and MALDI‐TOF mass analyses proved the introduction of these R groups at one end of each polymer chain. The poly(PA) bearing a hydroxy end group was applied as a macroinitiator to the synthesis of a block copolymer composed of poly(PA) and poly(β‐propiolactone) moieties. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Syntheses totales et etudes de lignanes biologiquement actifs—I : Application de la reaction d'ullmann a la synthese de biaryles precurseurs de lignanes bisbenzocyclooctadienes

Several biaryls bearing various substituents on both rings were synthesized in a preparative fashion, and in yields up to 88% by a technical improvement on the classical Ullmann reaction. All these biaryls bear reactive functional groups (i.e. formyl, methoxycarbonyl, dimethoxycarbonylpropyl and butanolidylmethyl) in both the o and o′ positions. The biaryls 9, 13, 21 and 26–33 are plausible synthons for bisbenzocyclooctadiene lignans such as schizandrin and steganacin.     

Solvent effects on the proton magnetic resonance spectra of p-substituted phenyltin chlorides

A PMR study of solvent effects on some p-substituted phenyltin chlorides (substituents = CH₃, (CH₃)₃C, CH₃O) is reported. Co-ordination of solvent molecules to the tin atom leads to an unusual low field shift of the o-ring protons. The results for p-tolytin trichloride have been compared with those for p-tolylsilyl trichloride and discussed. In o-, m- and p-tolyltin trichlorides long range spin-spin couplings between the ring methyl protons and the tin atom have been observed. The order of magnitude is o- > p- > m-methyl protons.     

The mass spectra of 1-arylanthra-9,10-quinones

The mass spectra of 1-phenylanthra-9,10-quinone and 20 substituted l-phenylanthraquinones having alkyl methoxyl, nitro and halogen substituents in the o-, m- and p-positions of the phenyl ring have been measured. The spectra are discussed with particular reference to the loss from the molecular ion of a hydrogen atom and of the substituent.     

Exploring Supramolecular Self‐Assembly of Tetraarylporphyrins by Halogen Bonding: Crystal Engineering with Diversely Functionalized Six‐Coordinate Tin(L)2–Porphyrin Tectons

This study targets the construction of porphyrin assemblies directed by halogen bonds, by utilizing a series of purposely synthesized Sn(axial ligand)₂–(5,10,15,20‐tetraarylporphyrin) [Sn(L)₂‐TArP] complexes as building units. The porphyrin moiety and the axial ligands in these compounds contain different combinations of complimentary molecular recognition functions. The former bears p‐iodophenyl, p‐bromophenyl, 4′‐pyridyl, or 3′‐pyridyl substituents at the meso positions of the porphyrin ring. The latter comprises either a carboxylate or hydroxy anchor for attachment to the porphyrin‐inserted tin ion and a pyridyl‐, benzotriazole‐, or halophenyl‐type aromatic residue as the potential binding site. The various complexes were structurally analyzed by single‐crystal X‐ray diffraction, accompanied by computational modeling evaluations. Halogen‐bonding interactions between the lateral aryl substituents of one unit of the porphyrin complex and the axial ligands of neighboring moieties was successfully expressed in several of the resulting samples. Their occurrence is affected by structural (for example, specific geometry of the six‐coordinate complexes) and electronic effects (for example, charge densities and electrostatic potentials). The shortest intermolecular I???N halogen‐bonding distance of 2.991 Å was observed between iodophenyl (porphyrin) and benzotriazole (axial ligand) moieties. Manifestation of halogen bonds in these relatively bulky compounds without further activation of the halophenyl donor groups by electron‐withdrawing substituents is particularly remarkable.     

Synthesis of hetero‐telechelic polymers by self‐polyaddition of monomers containing both oxetanyl and carboxyl groups

The synthesis and self‐polyaddition of new monomers, o‐, m‐, and p‐[(3‐ethyloxetane‐3‐yl)methoxyethyl]benzoic acid (o‐EOMB, m‐EOMB, and p‐EOMB) containing both oxetanyl groups and carboxyl groups were examined. The reactions of o‐EOMB, m‐EOMB, and p‐EOMB in the presence of tetraphenylphosphonium bromide as a catalyst in o‐dichlorobenzene at 150–170 °C resulted in self‐polyaddition to give the corresponding hetero‐telechelic polymers poly(o‐EOMB), poly(m‐EOMB), and poly(p‐EOMB) with M_ns = 14,500–33,400 in satisfactory yields. The M_n of poly(o‐EOMB) decreased at higher reaction temperatures than 150 °C, unlike those of poly(m‐EOMB) and poly(p‐EOMB), possibly due to inter‐ or intraester exchange side reactions. It was also found that the thermal properties and solubilities of these polymers were supposed with the proposed structures. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7835–7842, 2008