Synthesis of terphenyl oligomers as molecular electronic device candidates

Six functionalized bis(phenylene ethynylene)-p,p-terphenyls (BPETs) have been synthesized as potential molecular electronic devices. The molecules containing mono- and dinitro terphenyl cores, were rationally designed based on the electronic properties recently found in oligo(phenylene ethynylene)s (OPEs). From our understanding of the conductance properties in OPEs, improvement of electronic properties may be possible by using BPETs due to a higher rotational barrier between the central aromatic rings of the compounds prepared here. BPETs cores were functionalized with nitro groups and with different metallic adhesion moieties (alligator clips) to provide new compounds for testing in the nanopore and planar testbed structures.     

Synthesis of ladder polyaromatics as new molecular device candidates

In order to investigate one of the proposed molecular electronics switching mechanisms, we synthesized several molecules whose cores are unable to undergo conformational rotation. Preparation of these molecules, all of which are terminated with the thioacetyl moiety, takes advantage of an improved synthesis of 2,7-dibromophenanthrene, use of the reduced form of phenanthrenequinone as a protecting group, and various Sonogashira and halogen to Li to S conversions.     

Synthesis of tetracyanoethylene‐substituted ferrocene and its device properties

Small organic molecules are promising candidates for cheaper, flexible and good‐performance sources for organic solar cells (OSCs) due to their easy fabrication, low cost and slightly cheaper processing. However, the lower power conversion efficiency of OSCs is the main problem for their applications. Ferrocene structures could be the best candidates for the active layers of OSCs due to their unique properties such as thermal and chemical stability. The electrochemical, electro‐optical and solar cell performances of 2,5‐dicyano‐3‐ferrocenyl‐4‐ferrocenylethynylhexa‐2,4‐dienedinitrile (DiCN‐Fc) structures were investigated. First, the electrochemical and electro‐optical properties were examined for finding the highest occupied and lowest unoccupied molecular orbital values and bandgap of DiCN‐Fc. The best photovoltaic performance was obtained with 7 wt% of DiCN‐Fc loading, with a power conversion efficiency of about 4.27%. In the light of our investigations, ferrocenyl‐substituted small organic molecules could contribute to the development of organic photovoltaic devices.     

Synthesis and X-ray crystallographic analysis of chiral pyridyl substituted carbocyclic molecular clefts

Ditopic symmetrical bis(pyridyl) ligands incorporating the chiral dibenzobicyclo[b,f][3.3.1]nona-5a,6a-diene-6,12-dione cleft have been synthesised and characterised by NMR spectroscopy, mass spectrometry and X-ray crystallography. The ligands, which incorporate pyridyl groups directly connected to the carbocyclic cleft core or via alkyne or phenyl linkers were accessed from palladium-catalysed coupling reactions of 2,8-dibromodibenzobicyclo[b,f][3.3.1]nona-5a,6a-diene-6,12-dione. X-ray crystal analyses show the interplanar angles between the two cleft aromatic rings in these molecules, which range from 97.80(3) to 109.80(4)°.     

Synthesis of substituted pteridines

Conclusions The cyclocondensation of 2,5,6-triamino-4-oxo-3,4-dihydropyrimidine and tetraaminopyrimidine with butylthioacetone and 2-butylthiopropanal gives 7-methylpteridines, while the reaction of these pyrimidine derivatives with 2-phthalimidopropanal, 1,1-dibutoxyacetone, 1,1-dichloroacetone, and 1,1-dibromoacetone gives mixtures of 6- and 7-methylpteridines.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 452–455, February, 1986.     

取代邻苯二腈的合成

在室温条件下合成了一系列芳氧基邻苯二腈化合物,应用无素分析、1HNMR、IR确定了它们的结构,讨论了不同取代基对反应的影响.结果表明,酚的芳环上有推电子基时反应容易进行;酚的芳环上有拉电子基时反应慢或不反应.     

Synthesis of substituted hydroxypyrazines

Conclusions A new method was developed for the synthesis of substituted hydroxypyrazine derivatives by reacting the hydrochlorides of-amino ketones with the acid chlorides of N-phthaloyl--amino acids in acetone in the presence of diethylaniline, and subsequent treatment of the intermediate N-(N-phthaloyl--aminoacyl)--amino ketones with aqueous sodium acetate solution at 100°.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2417–2421, October, 1978.     

Synthesis of substituted thienothiazoles

The action of sulfur monochloride on 2-amino-3-carboxy-5-phenylthiophene or 2-amino5-phenylthiophene hydrochloride gave 5-phenylthieno[2,3-d]-2-thioniathiazole chloride, which is converted to the corresponding hydrate on treatment with water. Heating of the thionium salt or its hydrate with carbon disulfide in an aqueous alcohol solution of aklaki gave 2-mercapto-5-phenylthieno[2,3-d]thiazole, which under the influence of dialkyl sulfates or on oxidation with potassium permanganate in alkaline media is converted, respectively, to S-alkyl derivatives or a 5-phenylthieno[2,3-d]thiazole-2-sulfonic acid salt. 2-Sulfo-3-alkylthieno[2,3-d]thiazolium betaines are obtained by heating the latter with alkylating agents. 2-Hydroxy-thieno[2,3-d]thiazoles were synthesized by hydrolysis of thienothiazole-2-sulfonic acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 477–480, April, 1979.     

Synthesis of substituted N-aminoisomaleinimides

,-Disubstituted monohydrazides of maleic acid form stable aminoisomaleinimides on treatment with acetic anhydride in the presence of anhydrous sodium acetate. The structure of the products was confirmed by IR and PMR spectroscopy and by chemical methods.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 443–445, April, 1973.     

Synthesis of substituted thiabicyclanes

A simple preparative method for the synthesis of cis-1-thiahydrindan and cis-2-thiabicyclo[3, 3, 1]nonane has been developed. The method can be used to obtain substituted thiabicyclanes by a general method starting from 3-chloromethylcyclohexene. In the cyclization of 3 (-mercaptoethyl)cyclohexane both by an ionic and by a radical mechanism, a mixture of cis-1-thiahydrindan and cis-2-thiabicyclo [3,3,1] nonane in approximately equal amounts is formed.     

Synthesis of trityl radical-conjugated disulfide biradicals for measurement of thiol concentration

Measurement of thiol concentrations is of great importance for characterizing their critical role in normal metabolism and disease. Low-frequency electron paramagnetic resonance (EPR) spectroscopy and imaging, coupled with the use of exogenous paramagnetic probes, have been indispensable techniques for the in vivo measurement of various physiological parameters owing to the specificity, noninvasiveness and good depth of magnetic field penetration in animal tissues. However, in vivo detection of thiol levels by EPR spectroscopy and imaging is limited due to the need for improved probes. We report the first synthesis of trityl radical-conjugated disulfide biradicals (TSSN and TSST) as paramagnetic thiol probes. The use of trityl radicals in the construction of these biradicals greatly facilitates thiol measurement by EPR spectroscopy since trityls have extraordinary stability in living tissues with a single narrow EPR line that enables high sensitivity and resolution for in vivo EPR spectroscopy and imaging. Both biradicals exhibit broad characteristic EPR spectra at room temperature because of their intramolecular spin-spin interaction. Reaction of these biradicals with thiol compounds such as glutathione (GSH) and cysteine results in the formation of trityl monoradicals which exhibit high spectral sensitivity to oxygen. The moderately slow reaction between the biradicals and GSH (k(2) ～ 0.3 M(-1) s(-1) for TSSN and 0.2 M(-1) s(-1) for TSST) allows for in vivo measurement of GSH concentration without altering the redox environment in biological systems. The GSH concentration in rat liver was determined to be 3.49 ± 0.14 mM by TSSN and 3.67 ± 0.24 mM by TSST, consistent with the value (3.71 ± 0.09 mM) determined by the Ellman's reagent. Thus, these trityl-based thiol probes exhibit unique properties enabling measurement of thiols in biological systems and should be of great value for monitoring redox metabolism.     

Synthesis of some substituted cyclopropylmethanols

Conclusions The acetal and ester groups were used as protective agents to synthesize some difficultly available cyclopropylmethanol derivatives.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2381–2383, October, 1979.     

Synthesis of multisulfur-containing substituted dibenzothiophenes

New substituted dibenzothiophenes have been prepared and characterized. Selective functionalizations utilized substitutions of lithiodibenzothiophenes available from established methodology. New dibenzothiophenes prepared include 2-(bromomethyl)dibenzothiophene (5) , 2-(thiomethyl)dibenzothiophene (6) , 2-S-phenylthiomethyldibenzothiophene (24) , 2-S-(2′-dibenzothiophenylmethyl)thiomethyldibenzothiophene (25) , 2-S-methyldibenzothiophene (30) , 2-S-(p-bromophenyl)dibenzothiophene (31) , and 2-S-benzyldibenzothiophene (33). Dibenzothiophenes prepared from 4-lithiodibenzothiophene include 4-(bromomethyl)dibenzothiophene (13) , 4-(thiomethyl)dibenzothiophene (14) , 4-S-(4′-dibenzothiophenylmethyl)thiomethyldibenzothiophene (26) , 4-S-(p-tolyl)dibenzothiophene (34) , 4-S-methyldibenzothiophene (35) , 4-S-benzyldibenzothiophene (37) , and 4-S-(p-bromophenyl)dibenzothiophene (36). Similarly new 2,8-disubstituted dibenzothiophenes prepared include 2,8-bis(thiomethyl)dibenzothiophene (19) , 2,8-bis(S-benzyl)dibenzothiophene (27) , 2,8-bis(S-p-tolyl)dibenzothiophene (28) and 2,8-bis(S-methyl)dibenzothiophene (29). The cmr chemical shift data for these dibenzothiophenes are also included.     

Synthesis of functionally substituted benzaldehydes

A new method of synthesis of functionally substituted benzaldehydes by catalytic debromometoxylation of dibromomethylarenes with benzaldehyde dimethyl acetal has been suggested. Anhydrous zinc chloride has been used as a catalyst. Being soft Lewis acid, it formed no strong complex with aldehyde group and other functional groups. The initial acetal has been readily recovered by the treatment of benzaldehyde isolated from the reaction mixture with trimethyl orthoformate.     

Synthesis of substituted γ-pyrones

Substituted -pyrones were synthesized by the acylation of phenylacetaldehyde and its enol acetate with acetic and propionic anhydrides in the presence of 70% HClO₄. The mechanism of the reaction is examined, and the IR and PMR spectra of the synthesized -pyrones are presented. Some of their transformations were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 152–154, February, 1972.