A 13C NMR study of the methylol derivatives of 2,4′‐ and 4,4′‐dihydroxydiphenylmethanes found in resol phenol–formaldehyde resins

A total of 13 of the 16 possible methylol derivatives of 2,4′‐ and 4,4′‐dihydroxydiphenylmethane have been synthesized, isolated, and identified. These compounds are found as intermediates in the cure process of resol phenol–formaldehyde (PF) resins. Analysis of the ¹³C NMR spectra (in acetone‐d₆) of these compounds provided a way to evaluate the seven methylolphenol ring types (methylol derivatives of 2‐hydroxyphenyl and 4‐hydroxyphenyl rings) found in typical resol PF resins using the ipso carbon region from 150 to 160 ppm. A simple diagnostic test was developed using the chemical shift values of the methylol methylene carbon atoms to identify the presence of intermediates containing either a 2‐hydroxyphenyl or a 4‐hydroxyphenyl ring. Using these data it is now possible to analyze the major components in extracted prepreg PF resins. Copyright © 2002 John Wiley & Sons, Ltd.     

键联双(口恶)唑类化合物的研究(Ⅱ)——4,4''''-双[2"-(5"-取代苯基(口恶)唑基)]-1,1''''-联苯及5,5''''-双(二甲苯基)-2,2''''-联(口恶)唑的结构与光性能研究

本文合成了9种4.4'-双[2"(5"-_取代苯基(口恶)唑基)]-1,1'-联苯和3种5,5'-双(二甲苯基)-2,2'-联(口恶)唑,其中8种为未见报道的新化合物.讨论了上述化合物的结构与其电子光谱和激光性能间的关系,并总结出一些有一定意义的规律.     

Synthesis and characterization of tris(heteroleptic) Ru(II) complexes bearing styryl subunits

We have developed and optimized a well-controlled and refined methodology for the synthesis of substituted π-conjugated 4,4'-styryl-2,2'-bipyridine ligands and also adapted the tris(heteroleptic) synthetic approach developed by Mann and co-workers to produce two new representative Ru(II)-based complexes bearing the metal oxide surface-anchoring precursor 4,4'-bis[E-(p-methylcarboxy-styryl)]-2,2'-bipyridine. The two targeted Ru(II) complexes, (4,4'-dimethyl-2,2'-bipyridine)(4,4'-di-tert-butyl-2,2'-bipyridine)(4,4'-bis[E-(p-methylcarboxy-styryl)]-2,2'-bipyridine) ruthenium(II) hexafluorophosphate, [Ru(dmbpy)(dtbbpy)(p-COOMe-styryl-bpy)](PF(6))(2) (1) and (4,4'-dimethyl-2,2'-bipyridine)(4,4'-dinonyl-2,2'-bipyridine)(4,4'-bis[E-(p-methylcarboxy-styryl)]-2,2'-bipyridine) ruthenium(II) hexafluorophosphate, [Ru(dmbpy)(dnbpy)(p-COOMe-styryl-bpy)](PF(6))(2) (2) were obtained as analytically pure compounds in high overall yields (>50% after 5 steps) and were isolated without significant purification effort. In these tris(heteroleptic) molecules, NMR-based structural characterization became nontrivial as the coordinated ligand sets each sense profoundly distinct magnetic environments greatly complicating traditional 1D spectra. However, rational two-dimensional approaches based on both homo- and heteronuclear couplings were readily applied to these structures producing quite definitive analytical characterization and the associated methodology is described in detail. Preliminary photoluminescence and photochemical characterization of 1 and 2 strongly suggests that both molecules are energetically and kinetically suitable to serve as sensitizers in energy-relevant applications.     

Synthesis and Characteristics of Hole-transporting Materials Based on Biphenyl Diamine Derivatives with Carbazole Groups

IntroductionThe development of organic light-emitting diodes(OLEDs)has been the subject of intensive academicand industrial research that is directed toward the fabri-cation of large-area,monocolor and full color flat-paneldisplays[1].Ever since Tanget al…     

Tuning and switching MLCT phosphorescence of [Ru(bpy)3]2+ complexes with triarylboranes and anions

Four new Ru(II) complexes, [Ru(bpy)(2)(4,4'-BP2bpy)][PF(6)](2) (1), [Ru(t-Bu-bpy)(2)(4,4'-BP2bpy)][PF(6)](2) (2), [Ru(bpy)(2)(5,5'-BP2bpy)][PF(6)](2) (3), and [Ru(t-Bu-bpy)(2)(5,5'-BP2bpy)][PF(6)](2) (4) have been synthesized (where 4,4'-BP2bpy = 4,4'-bis(BMes(2)phenyl)-2,2'-bpy; 5,5'-BP2bpy = 5,5'-bis(BMes(2)phenyl)-2,2'-bpy (4,4'-BP2bpy); and t-Bu-bpy = 4,4'-bis(t-butyl)-2,2'-bipyridine). These new complexes have been fully characterized. The crystal structures of 3 and 4 were determined by single-crystal X-ray diffraction analyses. All four complexes display distinct metal-to-ligand charge transfer (MLCT) phosphorescence that has a similar quantum efficiency as that of [Ru(bpy)(3)][PF(6)](2) under air, but is at a much lower energy. The MLCT phosphorescence of these complexes has been found to be highly sensitive toward anions such as fluoride and cyanide, which switch the MLCT band to higher energy when added. The triarylboron groups in these compounds not only introduce this color switching mechanism, but also play a key role in the phosphorescence color of the complexes.     

Revisit of the Dessy-White intramolecular acetylene-acetylene [2 + 2] cycloadditions

In this experiment, a series of thermal reactions of 4,4'-disubstituted 2,2'-bis(phenylethynyl)biphenyls with 2,3,4,5-tetraphenylcyclopenta-2,4-dienone were carried out under neat conditions and in diphenyl ether at temperatures between 260 and 270 degrees C to give rise to 9,10,11,12,13,14-hexaphenylcycloocta[l]phenanthrenes as the adducts in 12-23% yields. We traced these results to the intramolecular [2 + 2] thermal cyclization of 2,2'-bis(phenylethynyl)biphenyls to form 1,2-diphenylcyclobuta[l]phenanthrenes, which were further trapped as bridged-ketone Diels-Alder adducts, followed by thermal decarbonylative ring opening, which gave rise to the products.     

SYNTHESIS AND CRYSTALLIZATION BEHAVIOR OF POLY(ETHER ETHER KETONE ETHER KETONE)(PEEKEK)*

In this paper, the synthesis and crystallization behavior of poly(ether ether ketone ether ketone) (PEEKEK) arereported. PEEKEK was prepared from 4,4'-bis(p-fluorobenzoyl) diphenyl ether (4,4'-FBDE) and hydroquinone along thenucleophilic substitution route. The thermal properties were investigated by using DSC and TGA. The crystallizationbehavior of PEEKEK under several conditions, i.e., crystallization from the molten state (melt crystallization), crystallizationfrom a quenched sample (cold crystallization) and crystallization induced by exposing glassy sample to methylene chloride(solvent-induced crystallization) has also been investigated. The results show that crystallization of PEEKEK could beinduced by the above methods, and no polymorphism was found. The diflierences in the crystallization of PEEKEK inducedby the above methods are seen in their degree of crystallinity.     

NMR assignment in regioisomeric hydroquinones

A set of regioisomeric pairs of tricyclic hydroquinones, analogues of antitumor 9,10-dihydroxy-4,4-dimethyl-5,8-dihydroanthracen-1(4H)-one (1) and other derivatives, were synthesized and their regiochemistry and NMR spectra assigned by using (1)H-detected one-bond (C-H) HMQC and long-range C-H HMBC, in good agreement with theoretical O3LYP/Alhrichs-pVTZ calculations. The 5-hydroxymethyl derivatives (11, 15, 19) showed a (3)J(H, H) coupling constant of methylene protons evidencing the presence of a seven-membered intramolecular hydrogen bonded ring, not observed for the 8-hydroxymethyl isomers.     

Semiconducting organic assemblies prepared from tetraphenylethylene tetracarboxylic acid and bis(pyridine)s via charge-assisted hydrogen bonding

Principles of crystal engineering have been applied toward the construction of supramolecular assemblies between an acid-functionalized tetraphenylethylene derivative and three different bis(pyridine)s [4,4'-bis(pyridyl)ethylene, 4,4'-bis(pyridyl)ethane, and 4,4'-bipyridine]. Each assembly was structurally characterized, and charge transfer interactions within each sample were visually apparent. Quantum chemical calculations were used to determine crystal band structure and band gap magnitude, and electrical properties of the materials were measured using conducting probe atomic force microscopy (CP-AFM). The crystals displayed charge-carrier capability, and the magnitude of semiconductivity varied systematically as a function of conjugation in the bis(pyridine) component. Crystals incorporating 4,4'-bis(pyridyl)ethylene and 4,4'-bipyridine displayed conductivities comparable to those of established organic semiconductors (μ(eff) = 0.38 and 1.7 × 10(-2) cm(2)/V·s, respectively).     

Enhanced rate of arene hydrogenation with imidazolium functionalized bipyridine stabilized rhodium nanoparticle catalysts

The imidazolium functionalized bipyridine compounds, {4,4'-bis[7-(2,3-dimethylimidazolium)heptyl]-2,2'-bipyridine}(2+) ([BIHB](2+)) and {4,4'-bis[(1,2-dimethylimidazolium)methyl]-2,2'-bipyridine}(2+) ([BIMB](2+)), were prepared and used as Rh nanoparticle stabilizers. The dispersed Rh nanoparticles were used as catalysts in the biphasic hydrogenation of various arene substrates. The catalytic activity was strongly influenced by the stabilizer employed and followed the trend [BIHB](2+) > bipy > [BIMB](2+). The steric and electronic characteristics of the imidazolium functionalized bipyridine ligands were assessed via the synthesis of rhenium carbonyl complexes, which facilitated the rationalization of the catalytic properties of the nanoparticles.     

Crystal and molecular structures of four model compounds for liquid crystal dimers with a methylene spacer of various lengths

The crystal and molecular structures of four model compounds for liquid crystal dimers namely, 4,4-[octyl]bis-acetophenone (B(AcP)8), 4,4-[heptyl]bis-acetophenone (B(AcP)7), 4,4-[hexyl]bis-acetophenone (B(AcP)6), and 1,1-(1,6-hexyldion)bis-benzene (DP6D), have been determined in order to gain an insight into observed differences in the textures of liquid crystalline phases of compounds with odd and even methylene spacers. All four compounds exhibit extended conformations with an all-trans conformation of the methylene chain but a twist between phenyl rings of about 125°, except DP6D for which the benzene groups lie in plane with the methylene chain. Half a molecule is necessary to represent the asymmetric unit of compounds with even numbers n of methylene groups in the spacer and belong to centrosymmetric space groups. The model compound with an odd value of n is non-centrosymmetric and shows another type of packing arrangement which may cause different textures and behaviour for dimesogenic compounds in the liquid crystalline state.     

Synthesis of 2,2'-Bis(3,6,9-triazanonyl)-4,4'-bithiazole and related compounds as new DNA cleavage agents

Two new bithiazole derivatives, 2,2'-bis(3,6,9-triazanonyl)- and 2,2'-bis(3,7,11-triazaundecyl)-4,4'-bithiazoles (3a, b), were readily synthesized in six steps using the corresponding dialkylenetriamine as starting materials. Under physiological conditions, 5.0 microM 3a exhibited significant DNA cleavage activity in the presence of Co(II), whereas even at 50 micriM, 3b exhibited no DNA cleavage activity. Furthermore, it was demonstrated that 3a forms a 1 : 2 complex with Co(II) ions, whereas 3b does not. These conclusions were based on measurements of stoichiometries of the bithiazole-cobalt complexes obtained by the Job continuous variation method. In contrast, 3a, which contains diethylenetriamine moieties, showed decreased affinity for Calf Thymus (CT) DNA compared with that of 3b, which contains dipropylenetriamine moieties. These findings indicate that the structure of the two aminoalkyl side chains attached at the 2- and 2'-positions of the 4,4'-bithiazole ring significantly influence the formation of cobalt complexes, and affects the compound's ability to cleave DNA as well as its affinity for double-stranded DNA.     

Amphiphilic ruthenium sensitizers and their applications in dye-sensitized solar cells

Amphiphilic ligands 4,4'-bis(1-adamantyl-aminocarbonyl)-2,2'-bipyridine (L(1)), 4,4'-bis[5-[N-[2-(3beta-cholest-5-en-3-ylcarbamate-N-yl)ethyl]aminocarbonyl]]-2,2'-bipyridine (L(2)), 4,4'-bis[5-[N-[2-(3beta-cholest-5-en-3-ylcarbamate-N-yl)propyl]aminocarbonyl]]-2,2'-bipyridine (L(3)), and 4,4'-bis(dodecan-12-ol)-2,2'-bipyridine (L(4)) and their heteroleptic ruthenium(II) complexes of the type [Ru(II)LL(1)(NCS)(2)] (5), [Ru(II)LL(2)(NCS)(2)] (6), [Ru(II)LL(3)(NCS)(2)] (7), and [Ru(II)LL(4)(NCS)(2)] (8) (where L = 4,4'-bis(carboxylic acid)-2,2'-bipyridine) have been synthesized starting from dichloro(p-cymene)ruthenium(II) dimer. All the ligands and the complexes were characterized by analytical, spectroscopic, and electrochemical techniques. The performance of these complexes as charge-transfer photosensitizers in nanocrystalline TiO(2)-based solar cells was studied. When complexes 5-8 anchored onto a 12 + 4 microm thick nanocrystalline TiO(2) films, very efficient sensitization was achieved (85 +/- 5% incident photon-to-current efficiencies in the visible region, using an electrolyte consisting of 0.6 M butylmethylimidazolium iodide, 0.05 M I(2), 0.1 M LiI, and 0.5 M tert-butyl pyridine in 1:1 acetonitrile + valeronitrile). Under standard AM 1.5 sunlight, the complex 8 yielded a short-circuit photocurrent density of 17 +/- 0.5 mA/cm(2), the open-circuit voltage was 720 +/- 50 mV, and the fill factor was 0.72 +/- 0.05, corresponding to an overall conversion efficiency of 8.8 +/- 0.5%.     

Reversed-phase high-performance liquid chromatography on porous copolymers of different chemical structure

The influence of chemical structure of porous polymers on the chromatographic properties of high-performance liquid chromatography columns was studied. Columns were packed with four different porous copolymers: di(methacryloyloxymethyl)naphthalene-divinylbenzene containing ester functional groups, 4,4'-bis(maleimido)diphenylmethane-divinylbenzene with imide groups, di(4,4'-dimethacrylphenyl)sulfone-divinylbenzene which contains sulphonyl groups, and styrenedivinylbenzene with any functional groups. Using the alkyl aryl ketone scale, the retention indices of five homologous series (alkylbenzenes, alkyl aryl ketones, N-alkylanilines, alkyl aryl ethers, alkylbenzoates) and column test compounds (toluene, nitrobenzene, p-cresol, 2-phenylethanol, N-methylaniline) were calculated. Their values were used for comparison of the selectivities of the studied polymeric packings.     

Ring transformations of heterocyclic compounds. XIII. Bis(2,4,6-triarylphenyl) substituted bispyridinium salts from methyl derivatives by double pyrylium and thiopyrylium ring transformations

The synthesis of hitherto unknown 4,4′-bis(2,4,6-triarylphenyl) substituted bispyridinium diperchlorates 3 , in which the N-atoms are linked by a carbon chain, a heteroatom containing a carbon chain or a bis(methylene) substituted aromatic/heteroaromatic ring, from 4,4′-dimethylbispyridinium derivatives 2 by a double 2,6-[C₅+C] ring transformation of 2,4,6-triarylpyrylium and 2,4,6-triarylthiopyrylium salts 1/4 is reported. Spectroscopic data of the bispyridinium diperchlorates 3 and their mode of formation are discussed.     

Bidirectional racemic synthesis of the biologically active quinone cardinalin 3

Readily available 2,2',6,6'-tetramethoxy-1,1'-biphenyl was transformed in 14 synthetic steps into the natural product cardinalin 3 using a bidirectional approach. One of the key steps was the formation of the cis-1,3-dimethylnaphtho[2,3-c]pyran ring. (+/-)-1,1'-[6,6'-Diallyl-5,5'-bis(benzyloxy)-1,1',3,3'-tetramethoxy-2,2'-binaphthalene-7,7'-diyl]diethanol was treated with O(2) in the presence of CuCl(2) and catalytic PdCl(2) to afford 5,5'-bis(benzyloxy)-7,7',9,9'-tetramethoxy-1,1',3,3'-tetramethyl-1H,1'H-8,8'-bibenzo[g]isochromene. Hydrogenation of this compound afforded 7,7',9,9'-tetramethoxy-cis-1,3-cis-1',3'-tetramethyl-3,3',4,4'-tetrahydro-1H,1'H-8,8'-bibenzo[g]isochromene-5,5'-diol in quantitative yield, which was converted in 3 steps to cardinalin 3.     

4,4'-(多苯基三联苯)双(有机硅烷)的合成

本文研究了以4,4'-双(三苯基环戊二烯酮基)苯为双烯体,含乙烯基或苯乙炔基有机硅烷为双亲烯体,通过成环反应合成了六个新的4,4'-(多苯基三联苯)双(有机硅烷),产率60%～85%,并用元素分析,IR和'HNM表征了它们的结构。     

Synthesis and Photoinitiated Isomerizations of 3-(4-Nitrophenyl)-and 3-(4-Aminophenyl)bicyclo[2.2.1]hepta-2,5-diene-2-carbaldehyde and -2-carboxylic acid Derivatives

3-(4-Nitrophenyl)bicyclo[2.2.1]hepta-2,5-diene-2-carbaldehyde and its derivatives at the formyl group were synthesized. By reduction of the nitro group the corresponding 3-(4-aminophenyl)-substituted compounds were obtained, as well as 4,4'-bis(bicyclo[2.2.1]hepta-2,5-dien-2-yl)azobenzenes. Irradiation of the resulting norbornadiene derivatives in the region of their absorption maxima resulted in valence isomerization with formation of the corresponding quadricyclanes. The reverse transformations are promoted by molybdenum(VI) oxide as heterogeneous catalyst. 4,4'-Bis(bicyclo[2.2.1]hepta-2,5-dien-2-yl)azobenzenes undergo reversible (on heating) photochemical EZ/ isomerization at the NÍN bond.     

Preparation of large macrocyclic tetra-amines consisting of a methylene backbone and a cyclophane type skeleton

Efficient synthetic routes to 1,10,19,28-tetraazacyclohexatriacontane, a 36-membered ring compound with a methylene backbone, and bis(N,N-octamethylene-4,4′-diaminodiphenylmethane), a 38-membered tetra-amine with a cyclophane skeleton, have been developed via reduction of tetralactam and via a double condensation reaction, respectively. Overall yields are 51% with 5 steps for the former, and 46% with 6 steps for the latter, while the corresponding 2 + 2 cyclization gave the cyclic compounds in poor yields, 9% and 4%, respectively, for the 36-membered tetra-aza ring and for the 38-membered cyclophane derivative.     

Templated assembly of a pseudorotaxane of gold rectangles

A nanoscopic pseudorotaxane (1)2 subset2 composed of the gold rectangle [Au4(mu-PAnP)2(mu-bipy)2](OTf)4 and the linear template 4,4'-bis(9'-anthryl)biphenyl was assembled (PAnP = 9,10-bis(diphenylphosphino)anthracene); bipy = 4,4'-bipyridine).