New viologen analogs: 1,4-bis[2-(pyridin-4-yl)ethenyl]benzene quaternary salts

Alkylation of 1,4-bis[2-(pyridin-4-yl)ethenyl]benzene with alkyl p-toluenesulfonates and dimethyl sulfate gave new viologen analogs, 1-alkyl-4-(2-{4-[2-(1-alkylpyridinium-4-yl)ethenyl]phenyl}ethenyl)-pyridinium bis(p-toluenesulfonates) and sulfate. Their derivatives with tetrafluoroborate and tetraphenylborate ions were also obtained. Spectral properties of the synthesized compounds were examined, and their structure was determined by X-ray analysis.     

Electrochemical and spectral properties of thienylene-polyparaphenylenevinylene derivative stereoisomers

Four new compounds: 1,4-dimetoxy-2,5-bis[2-(tien-2-yl)ethenyl]benzene), 1,4-dietoxy-2,5-bis[2-(tien-2-yl)ethenyl]benzene), 1,4-isopropyloxy-2,5-bis[2-(tien-2-yl)ethenyl]benzene) and 1,4-dietoksy-2,5-bis[2-(5-methylthiophen-2-yl)ethenyl]benzene are synthesized. Three steroisomers ZZ, EZ and EE are isolated from the reaction mixture for the first two of them. Third compound is fully converted to the most stable EE form. Polymerization of all isomers leads to identical polymeric product. Mechanism of polymerization is recognized by using model molecule with methyl substituents blocking α-, α′-sites. All seven stereoisomers have photoluminescent properties. Detailed spectral and electrochemical studies reveal isomerization phenomena during oxidation or at light exposure. Published in Russian in Elektrekhimiya, 2006, Vol. 42, No. 12, pp. 1401–1408. Based on the report delivered at the 8th International Frumkin Symposium “Kinetics of the Electrode Processes.” October 18–22, 2005, Moscow. The text was submitted by the authors in English.     

Extended dipolar nonlinear optical chromophores based on trans-bis[1,2-phenylenebis(dimethylarsine)]chlororuthenium(II) centers

Four new complex salts trans[RuIICl(pdma)2LA][PF6]n [pdma = 1,2-phenylenebis(dimethylarsine); LA = 1,4-bis[E-2-(4-pyridyl)ethenyl]benzene (bpvb), n = 1, 1; LA = N-methyl-1,4-bis(E-2-(4-pyridyl)ethenyl)benzene (Mebpvb+), n = 2, 2; LA = N-phenyl-1,4-bis(E-2-(4-pyridyl)ethenyl)benzene (Phbpvb+), n = 2, 3; LA = N-(2-pyrimidyl)-1,4-bis(E-2-(4-pyridyl)ethenyl)benzene (Pymbpvb+), n = 2, 4] have been prepared. The electronic absorption spectra of 1-4 display intense, visible metal-to-ligand charge-transfer (MLCT) bands, with lambda(max) values in the range 432-474 nm in acetonitrile. Intense intraligand charge-transfer (ILCT) bands due to LA are also observed, with lambda(max) values in the range 350-416 nm. Cyclic voltammetric studies in acetonitrile reveal reversible RuIII/II waves with E(1/2) values of ca. 1.05 V vs Ag/AgCl, together with LA-based reduction processes that are irreversible with the exception of 1. Salts 1-4 have been investigated by using Stark (electroabsorption) spectroscopy in butyronitrile glasses at 77 K. These studies have afforded dipole moment changes, Deltamu12, for the MLCT and ILCT transitions which have been used to calculate molecular static first hyperpolarizabilities, Beta0, according to the two-state equation Beta0 = 3Deltamu12(mu12)2/(Emax)2 (mu12 = transition dipole moment, Emax = MLCT/ILCT energy). In contrast with related RuII ammine complexes, replacement of a central E-ethylene bond with a 1,4-phenylene unit does not appear to be an especially effective strategy for combating the NLO transparency-efficiency tradeoff in these pdma complexes. Single-crystal X-ray studies with the complex salts 2 and 3 and also with the pro-ligand salt [Phbpvb+] PF6.0.5HPF6 show that these materials all adopt centrosymmetric packing structures.     

Singlet Oxygen Quenching by Resveratrol Derivatives†

We investigated the singlet oxygen quenching ability of several derivatives of trans-resveratrol which have been reported to have significant antioxidant ability, including photoprotective activity. We measured the total rate constants of singlet oxygen removal (k_T) by the methylated resveratrol derivative 1,3-dimethoxy-5-[(E)-2-(4-methoxyphenyl)ethenyl]benzene, and the partially methylated resveratrol derivatives 4-((E)-2-(3,5-dimethoxyphenyl)ethenyl)phenol (pterostilbene), 5-[(E)-2-(4-methoxyphenyl)ethenyl]benzene-1,3-diol and (2R,3R)-3,5,7-trihydroxy-2-(3,4,5-trihydroxyphenyl)-2,3-dihydrochromen-4-one (dihydromyricetin). A protic solvent system results in higher k_T values, except for the completely methylated derivative. We also investigated the ability of trans-resveratrol to directly act as a photosensitizer (rather than via secondary photoproducts resulting from other primary photochemical reactions) for the production of singlet oxygen but found that neither resveratrol nor any of its derivatives are able to do so. We then studied the chemical reactions of the methylated derivative with singlet oxygen. The main pathway consists of a [4 + 2] cycloaddition reaction involving the trans-double bond and the para-substituted benzene ring similar to what has been observed for trans-resveratrol. Unlike trans-resveratrol, the primary singlet oxygen product undergoes a second [4 + 2] cycloaddition with singlet oxygen leading to the formation of diendoperoxides. A second reactivity pathway for both trans-resveratrol and the methylated derivative leads to the formation of aldehydes via cleavage of a transient dioxetane.     

Heck Synthesis of New Organosilicon Oligo(arylenevinylenes)

Russian Journal of Organic Chemistry - Two alternative synthetic approaches to new silicon-containing oligo(arylenevinylenes), 1,4-bis-{(E)-2-[4-(trimethylsilyl)phenyl]ethenyl}benzene and...     

Surface interaction and self-assembly of cyclodextrins with organic dyes

The interaction of seven novel substituted merocyanine dyes, i.e. 1-methyl-4-[2-(3-methoxy-4-hydroxyphenyl)ethenyl)]pyridinium iodide, 1-methyl-4-[2-(3,5-dimethoxy-4-hydroxyphenyl)ethenyl)]pyridinium iodide, 1-methyl-4-[2-(4-dimethylaminophenyl)ethenyl)]pyridinium iodide, their quinoide forms as well as 1-methyl-4-[2-(3-methoxy-4-oxocyclohexadienilydene)ethylidene]-1,4-dihydropyridine, 1-methyl-4-[2-(3,5-dimethoxy-4-oxocyclohexadienilydene)ethylidene]-1,4-dihydropyridine, with α-CD, γ-CD as well as functionalized γ-cyclodextrin phosphate sodium salt is studied by the methods such as UV–Vis and fluorescence spectroscopy, linear-polarized infrared (IR-LD) spectroscopy of oriented colloids in nematic host, ¹H- and ¹³C-NMR spectroscopy, HPLC ESI tandem mass spectrometry, scanning electron and tunneling microscopy, powder X-ray diffraction as well as thermal methods. A formation of the 1D and 2D “supramolecular polymers” with nanosizes is found. The dyes are adsorbed on the CDs surface and form a hexagonal microcrystalline sub-structures. Remarkable fluorescence properties depending of the type of the substituent in the dyes, in solid-state are observed.     

Conformational polymorphism of (E,E)‐N,N′‐bis(4‐nitrobenzylidene)benzene‐1,4‐diamine

Two polymorphs of (E,E)‐N,N′‐bis(4‐nitrobenzylidene)benzene‐1,4‐diamine, C₂₀H₁₄N₄O₄, (I), have been identified. In each case, the molecule lies across a crystallographic inversion centre. The supramolecular structure of the first polymorph, (I‐1), features stacking based on π–π interactions assisted by weak hydrogen bonds involving the nitro groups. The second polymorph, (I‐2), displays a perpendicular arrangement of molecules linked via the nitro groups, combined with weak C—H...O hydrogen bonds. Both crystal structures are compared with that of the carbon analogue (E,E)‐1,4‐bis[2‐(4‐nitrophenyl)ethenyl]benzene, (II).     

Synthesis of aromatic polyethers by Scholl reaction. V. Synthesis and polymerization of 1,3-bis[4-(1-naphthoxy) benzoyl]benzene, 1,4-bis[4-(1-naphthoxy)benzoyl]benzene,bis[4-(1-naphthoxy)phenyl]methane, 1,3-bis[4-(1-naphthoxy) phenylmethyl]benzene,and 1,4-bis-[4-(1-naphthoxy)phenylmethyl]benzene

This article describes the synthesis and the cation-radical polymerization (Scholl reaction) of 1,3-bis[4-(1-naphthoxy) benzoyl] benzene ( 6 ) and 1,4-bis[4-(1-naphthoxy) benzoyl]- benzene ( 7 ) initiated by FeCI₃. This polymerization produced poly(ether ether ketone ketone)s (PEEKK) of number average molecular weight (M?_n) up to 5400 g/mol. The synthesis of bis[4-(1-naphthoxy) phenyl] methane ( 8 ), 1,3-bis[4-(1-napthoxy) phenylmethyl] benzene ( 9 ), and 1,4-bis[4-(1-naphthoxy) phenylmethyl] benzene ( 10 ) are also described. Polyethers of M?_n up to 15400 g/mol at a FeCl₃/monomer molar ratio of 2/1 were obtained. An increased polymerizability of the monomers 9 and 10 containing two CH₂ groups versus that of the corresponding monomers containing two carbonyl groups ( 6 and 7 ) was observed. This enhanced polymerizability was explained based on the increased nucleophilicity of monomers 9 and 10 .     

Methyl and Phenylmethyl 2-Acetyl-3-{[2-(dimethylamino)-1-(methoxycarbonyl)ethenyl]amino}prop-2-enoate in the Synthesis of heterocyclic systems: Preparation of 3-amino-4H-pyrido-[1,2-a]pyrimidin-4-ones

Methyl 2-acetyl-3-{[2-(dimethylamino)-1-(methoxycarbonyl)ethenyl]amino}prop-2-enoate ( 4 ) and phenyl-methyl 2-acetyl-3-{[2-(dimethylamino)-1(methoxycarbonyl)ethenyl]amino}prop-2-enoate ( 5 ) were prepared in three steps from the corresponding acetoacetic esters, and used as reagents for the preparation of N³-protected 3-amino-4H-pyrido[1,2-a]pyrimidin-4-ones 10 – 12 , 5H-thiazolo[3,2-a]pyrimidin-5-one 13 , 4H-pyrido[1,2-a]-pyridin-4-one 19 and 2H-1-benzopyran-2-ones 20 – 23 . Free 3-amino-4H-pyrido[1,2-a]pyrimidin-4-ones 24 – 26 were prepared from 10 – 12 by removal of the 2-(methoxycarbonyl)-3-oxobut-1-enyl or 3-oxo-2-[(phenyl-methoxy)carbonyl]but-1-envl as N-protecting group by various methods.     

超高效合相色谱法快速检测纺织品中的8种荧光增白剂

建立了同时检测纺织品中1,2-双(5-甲基-2-苯并恶唑基)-乙烯(PF)、7-二乙氨基-4-甲基香豆素(SWN)、2,2'-(2,5-二苯基硫代)双[5-(1,1-二甲基乙基)]苯并恶唑(OB)、2-[4-[2-[4-(2-苯并恶唑基)苯基]乙烯基]苯基]-5-甲基苯并恶唑(KSN)、1,4-双(2-氰基苯乙烯基)苯(ER-Ⅰ)、1-邻氰苯乙烯基-4-对氰苯乙烯基苯(ER-Ⅱ)、2,2-(1,4-亚萘基)双(苯并恶唑)(KCB)和4,4'-双[2-(2-甲氧基苯基)亚乙基]-1,1'-联苯(FP)8种荧光增白剂的超高效合相色谱(UPC²)检测方法。样品经二甲苯提取、浓缩、定容后,由UPC²进行定性定量分析。以超临界CO₂-甲醇为流动相,梯度洗脱,采用ACQUITY UPC² HSS C18 SB色谱柱(100 mm×3.0 mm,1.8 μm)进行分离。8种荧光增白剂在1.0~20.0 mg/L范围内线性良好(r≥0.9991),定量限(LOQ,S/N=10)在0.70~0.95 mg/L之间。不同添加水平的回收率范围为90.9%~96.5%,相对标准偏差(RSD)为2.8%~4.2%。该方法简单、准确度高、分析时间短,可用于快速检测纺织品中的8种荧光增白剂。     

Reaction of the thiolsulfonate group with the aromatic nucleus: A new ring closure

The double ring closure of N,N-bis[2- (alkyl- or arylsulfonylthio)ethyl]anilines to form 2,3,5,6-tetrahydro[1,4]thiazino[4,3,2-de][1,4]benzothiazines, a new ring system, is reported. The effects of various benzene ring substituents upon the ring closure are described.     

Synthesis and characterization of poly[(4-vinylphenyl)dimethyl- silane]-b-polybutadiene-b-poly[(4-vinylphenyl)dimethylsilane] (PVPDMS-b-PBd-b-PVPDMS)

The novel functionalized triblock copolymers,poly[(4-vinylphenyl)dimethylsilane]-b-polybutadiene-b-poly[(4-vinylphenyl)-dimethylsilane] (PVPDMS-b-PBd-b-PVPDMS),were synthesized by anionic polymerization method using high vacuum technique. The hydrocarbon-soluble dilithium initiator synthesized from l,3-di[l-(methylphenyl)ethenyl]benzene(MPEB) was used to synthesize polybutadiene(PBd) precursors and the triblock copolymers in the presence of sec-BuOLi.The precursors and copolymers were characterized by size exclusion chromatography(SEC),~1HNMR and DSC techniques.     

Elucidation of the Reaction Products of Acetonitrile with Phosphorus Pentachloride

Abstract

The reaction of acetonitrile with PCl, results in the ionic compounds (1) to (4) containing the trichloro[2-chloro-2-[(trichlorophosphoranyli-dene)amino]ethenyl]phosphorus cations and not in the compounds [CH2?C?NPCl₃]PCl₆1 or trichloro[2-chloro-1 -[(trichlorophosphoranyli-dene)amino] ethenyl]phosphorus hexachlorophosphate (5) as assumed from ³¹P-NMR spectra [2, 3]. The crystal structures of the compounds (1) to (4) were determined with X-rays at 95K. As observed for the CI-C(NPCl₃); cation all the cations show cis-trans conformations with respect to their CI-C-X-P torsion angles. The wcl3 groups of the cations have two different orientations with one C?N?P?CI torsion angle of about 0° (cis) as in (1) or about 180° (trans) as in (3) and (4). In the salt (2) there are two formula units in the asymmetric unit with one cation showing the cis and the other showing the tram conformation.     

Methyl 2-[bis(acetyl)ethenyl]aminopropenoate in the synthesis of heterocyclic systems

Methyl 2-[bis(acetyl)ethenyl]aminopropenoate ( 4 ) was prepared in 3 steps from acetylacetone ( 1 ) via 4-(N,N-dimethylamino)-3-acetylbut-3-en-2-one ( 2 ) and methyl N-[2,2-bis(acetyl)ethenyl]glycinate ( 3 ). Compound 4 reacts with N- and C-nucleophiles to give fused heterocyclic systems. Derivatives of pyrido[1,2-a]pyrimidones 14–16 and thiazolo[3,2-a]pyrimidones 17 and 18 were prepared from 2-aminopyridines and 2-aminothiazoles, respectively. With C-nucleophiles derivatives of pyrido[1,2-a]-pyridinone 19 and 2H-1-benzopyran-2-one 20–22 were prepared.     

Flip‐type disorder in 3‐substituted 2,2′:5′,2′′‐terthiophenes

In the crystal structures of four thiophene derivatives, (E)‐3′‐[2‐(anthracen‐9‐yl)ethenyl]‐2,2′:5′,2′′‐terthiophene, C₂₈H₁₈S₃, (E)‐3′‐[2‐(1‐pyrenyl)ethenyl]‐2,2′:5′,2′′‐terthiophene, C₃₀H₁₈S₃, (E)‐3′‐[2‐(3,4‐dimethoxyphenyl)ethenyl]‐2,2′:5′,2′′‐terthiophene, C₂₂H₁₈O₂S₃, and (E,E)‐1,4‐bis[2‐(2,2′:5′,2′′‐terthiophen‐3′‐yl)ethenyl]‐2,5‐dimethoxybenzene, C₃₆H₂₆O₂S₆, at least one of the terminal thiophene rings is disordered and the disorder is of the flip type. The terthiophene fragments are far from being coplanar, contrary to terthiophene itself. The central C—C=C—C fragments are almost planar but the bond lengths suggest slight delocalization within this fragment. The crystal packing is determined by van der Waals interactions and some weak, relatively short, C—H...S and C—H...π directional contacts.     

peri-Naphthylenediamines: XL. Solvatochromism of 1-methyl-4-[2-(1-naphthyl)ethenyl]pyridinium salts, including that containing “proton sponge” residue

A number of 1-methyl-4-[2-(1-naphthyl)ethenyl]pyridinium salts were synthesized by condensation of 1,4-dimethylpyridinium iodide with naphthalene-1-carbaldehydes containing dimethylamino groups in positions 4 and 5. The obtained salts are characterized by negative solvatochromism which is the most pronounced for those possessing 1,8-bis(dimethylamino)naphthalene (“proton sponge”) and 1,2,2,3-tetramethyl-2,3-dihydroperimidine residues.     

Phenylene vinylene oligomers studied by theoretical methods: Joint analysis of computational and x-ray results of the configurational isomers of 1,4-bis[2-(3,4,5-trimethoxyphenyl)ethenyl]benzene

The configurational isomers of 1,4-bis[2-(3,4,5-trimethoxyphenyl)ethenyl]benzene have been investigated by ab initio and MOPAC-AM1 semiempirical methods. The calculations were guided by and compared with single crystal X-ray results of the trans, trans-isomer (taken from the literature) and of the cis,cis-isomer (reported here). Using 4-21G-based ab initio calculations, free state geometries, deviations from coplanarity, and barriers to rotation of the central and peripheral rings were evaluated. Such barriers were also enumerated for the solid state of the cis,cis- and trans,trans-isomers. A single-molecule cluster surrounded by point charges sufficed to rationalize observed solid state properties in the trans,trans-isomer, including the quasi-free rotation of the central ring. A multimolecule cluster, however, was required to rationalize the restricted rotation of the rings in the cis,cis-isomer. MOPAC-AM1 methods were used to calculate geometries and energies of rotameric forms on the singlet photoisomerization path cis,cis → cis,trans → trans,trans. Finally, UV absorption wavelengths and oscillator strengths were calculated and the electronic structure of the states discussed. © 1996 by John Wiley & Sons, Inc.     

Synthesis of new imines and amines containing organosilicon groups

The Peterson olefination reaction of terephthalaldehyde with tris(trimethylsilyl)methyl lithium, (Me₃Si)₃CLi, in THF at 0 °C gives 4-[2,2-bis(trimethylsilyl)ethenyl]benzaldehyde (1) and 4,4-bis[2,2-bis(trimethylsilyl)ethenyl]benzene (2). The new aldehyde (1) reacts with variety of amines in ethanol to afford the corresponding imines (3) containing vinylbis(trimethylsilyl) group. The newly synthesized imines (3) can be completely converted into amines containing vinylbis(trimethylsilyl) group with an excess amount of NaBH₄. In the case of N-[4-(2,2-bis(trimethylsilyl)ethenyl)benzyl]-2,6-dimethylaniline LiAlH₄ was used as a reducing agent in THF.     

Blue luminescent 2-(2'-pyridyl)benzimidazole derivative ligands and their orange luminescent mononuclear and polynuclear organoplatinum(II) complexes

Five new 2-(2'-pyridyl)benzimidazole derivative ligands, 1,4-bis[2-(2'-pyridyl)benzimidazolyl]benzene (1,4-bmb), 4,4'-bis[2-(2'-pyridyl)benzimidazolyl]biphenyl (bmbp), 1-bromo-4-[2-(2'-pyridyl)benzimidazolyl]benzene (Brmb), 1,3-bis[2-(2'-pyridyl)benzimidazolyl]benzene (1,3-bmb), and 1,3,5-tris[2-(2'-pyridyl)benzimidazolyl]benzene (tmb), have been synthesized by Ullmann condensation methods. The corresponding mononuclear and polynuclear PtII complexes, Pt2(1,4-bmb)Ph4 (1), Pt2(bmbp)Ph4 (2), Pt(Brmb)Ph2 (3), Pt2(1,3-bmb)Ph4 (4), and Pt3(tmb)Ph6 (5), have been obtained by the reaction of the appropriate ligand with [PtPh2(SMe2)]n. The structures of the free ligands 1,4-bmb, bmbp, and tmb, as well as the complexes 1-3, were determined by single-crystal X-ray diffraction. All ligands display fluorescent emissions in the purple/blue region of the spectrum at ambient temperature and phosphorescent emissions in the blue/green region at 77 K, which are attributable to ligand-centered pi --> pi* transition. No ligand-based emission was observed for the PtII complexes 1-5. All PtII complexes display orange/red emissions at 77 K in a frozen solution or in the solid state, attributable to metal-to-ligand charge transfers (MLCT). Variable-temperature 1H NMR experiments establish that complexes 1, 4, and 5 exist in isomeric forms in solution at ambient temperature due to the hindered rotation of the square PtC2N2 planes in the complexes.     

Synthesis of the methanesulfonates of α-(4-chlorophenyl)-α-[1-(2-chlorophenyl)emenyl]-1H-1,2,4-triazole-1-ethanol and α-[1-(2-chlorophenyl)ethenyl]-α-(2,4-difluorophenyl)-1H-1,2,4-triazole-1-ethanol,alpha styryl carbinol antifungal agents

The methanesulfonates of (α-(4-chlorophenyl)-α-[1-(2-chlorophenyl)ethenyl]-1H-1,2,4-triazole-1-ethanol and α-[1-(2-chlorophenyl)ethenyl]-α-(2,4-difluorophenyl)-1H-1,2,4-triazole-1-ethanol ( 1a, b ) are orally effective α-styryl carbinol derivatives developed for the treatment and prevention of systemic fungal infections. Practical new processes amenable for the large-scale production of these compounds are described. Of note is the selection of dichlorostyrene as a convenient precursor of the styryl portion, modification of a sensitive Grignard addition into a realistic preparative reaction and the use of 1,2,4-triazole simultaneously as a base transfer agent and nucleophile.