Synthesis and characterisation of some new chalcone liquid crystals

A series of new chalcones with four aromatic rings is synthesised and characterised. The chemical structures of chalcones are evaluated by Fourier transform-infrared spectroscopy, elemental analysis, ¹H and ¹³C nuclear magnetic resonance spectroscopic techniques. The compounds were investigated for liquid crystalline properties using differential scanning calorimetry and polarising optical microscopy with hot stage. The results indicate that the formation of mesophase type is dependent on the alkyl chain length at one end of the molecule. Compounds 9a–d with relatively shorter chains show SmA and nematic mesophases, whereas 9e–g exhibit SmC and SmA mesophases. Compound 9h having a cyano group at one end, exhibit SmA and nematic mesophases.     

Synthesis and chemical characterisation of some new diheteroaryl thienothiophene derivatives

Treatment of 1-(5-acetyl-3,4-dimethythieno[2,3-b]thiophene-2yl)ethanone (1) with dimethylformamide dimethyl acetal afforded enaminone derivative 2, which reacted with amino derivatives to give the corresponding bis-pyrimidine, bis-pyrazole, bis-triazolo-pyrimidine and bis-benzoimidazopyrimidine derivatives.     

Synthesis and characterisation of new ditopic receptors for guanosine

Novel ditopic receptors for guanosine have been prepared and characterised. Their association constants with a lipophilic guanosine derivative are somewhat smaller than the expected values for a guanosine-cytidine base pair, but remain in a useful range for building supramolecular structures.     

Synthesis and characterisation of some new cyanonitrosyl chromium(l) complexes with phenetidines and anisidines

Summary A new series of cyano-substituted nitrosylchromium(I) complexes having octahedral stereochemistry around the metal ion, and of general formula, [CrNO(CN)₂(L)₂(H₂O)] (L =o-,m- andp-phenetidines oro-,m-, andp-anisidines) have been isolated in the solid state by interaction of potassium pentacy-anonitrosylchromate(I) monohydrate with the appropriately substituted aniline. The complexes, which have been characterised by elemental analysis, conductance, molecular weight determination, magnetic measurements, e.s.r. and i.r. spectral studies, contain chromium(I) in a low-spin d⁵-configuration.     

Synthesis and characterisation of two new binaphthyl trisilanes

The synthesis and characterisation of two binaphthyl trisilanes is described. Reaction between 2,2′-dilithio-1,1′-binaphthyl and 1,3-dichlorohexamethyltrisilane gave 3,3,4,4,5,5-hexamethyl-4,5-dihydro-3H-3,4,5-trisilacyclohepta[2,1-a;4,3-a′]binaphthalene (3). Compound 3 was characterised by ¹H, ¹³C and ²⁹Si NMR spectroscopy and a crystal structure analysis. Reaction between 2,2′-dilithio-1,1′-binaphthyl and 1,3-bis(trifluoromethanesulfonyloxy)-1,1,2,3,3-pentamethyltrisilane, generated in situ by treatment of 1,3-diphenyl-1,1,2,3,3-pentamethyltrisilane with trifluormethanesulfonic acid, gave 3,3,4,5,5-pentamethyl-4,5-dihydro-3H-3,4,5-trisilacyclohepta[2,1-a;4,3-a′]binaphthalene (7). Analysis by ¹H, ¹³C and ²⁹Si NMR spectroscopy revealed that 7 had a very similar structure to 3.     

The preparation and characterisation of some new binary fluorides of antimony

Antimony pentafluoride acts as a useful oxidising agent towards many non-metals, giving interesting cations, and in the process is itself reduced. It would be helpful to know what the reduced products are, and under what conditions they are formed. Therefore, SbF₅ and the known SbF₅·SbF₃⁽¹⁾ in AsF₃ solution were reduced by iodine and/or PF₃ giving crystals of the new adduct, (SbF₃)₆(SbF₅)₅ [Monoclinic, a = 11.638(1), b = 8.995(1), c = 16.723(3) ā, β = 106.81(1)°, P2₁/c]; (SbF₃)₅(SbF₅)₃ [Orthorhombic, a = 19.187(9), b = 15.890(2), c = 15.713(3) ā, Pnma] and (SbF₃)₃SbF₅ [Monoclinic, a = 10.895(3), b = 10.941(3), c = 4.772(1) ā, β = 96.66(3)°, P2₁/m]. (SbF₃)₃SbF₅ seemed to be the most reduced adduct, no evidence was obtained for (SbF₃)_n(SbF₅) n > 3, under these conditions. The (SbF₃)₆(SbF₅)₅ adduct has a Raman spectrum identical to that reported by Gillespie⁽²⁾ and coworkers for an adduct of approximate composition SbF₃·SbF₅ and has a very different structure to that of (SbF₃)₆(SbF₆)₅ reported by Edwards.⁽³⁾ The crystal structures of the new adducts will be discussed and the cations they contain compared with those found in SbF₃·SbF₅⁽¹⁾ and (SbF₅)₆(SbF₅)₅⁽³⁾ (Edward's form).     

Synthesis of some new arylindoles

New indole derivatives — 2-ethoxycarbonyl-5(p-acetylphenyl)indole andpara-substituted 2-diphenylindoles —key compounds for synthesis of new bisindoles, were synthesized from 4-acetyl-4-nitrodiphenyl.I. Dzhavakhishvili Tbilisi State University, Tbilisi 380028. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1351–1354, October, 1994. Original article submitted September 15, 1994.     

Synthesis of some new indolizines

The reaction between 4‐dimethylaminopyridine (DMAP) and 2‐bromoacetophenone(s) readily gives 1‐ [2‐(4‐substitutedphenyl)‐2‐oxoethyl]‐4‐(dimethylamino)pyridinium bromide ( 1–14 ). Action of aqueous NaOH on 1–8 generates the corresponding pyridinium ylide ( 15–22 ), which is isolated as a colored stable crystalline solid. Addition of 15–22 to dimethylacetylene dicarboxylate (DMAD) gives dimethyl 3‐(substitutedbenzoyl)‐7‐(dimethylamino)indolizine‐1,2‐dicarboxylate ( 23–30 ) in 46–62% yield.     

Synthesis of some new fluorophenothiazines

The synthesis of various 3-substituted derivatives of 7-fluorophenothiazin-3-ol and their 5-oxides is described. The ir, uv and mass spectral data are also included.     

Synthesis and characterisation of morin-functionalised silica gel for the enrichment of some precious metal ions

Silica gel was firstly functionalised with aminopropyltrimethoxysilane obtaining the aminopropylsilica gel (APSG). The APSG was reacted subsequently with morin yielding morin-bonded silica gel (morin-APSG). The structure was investigated and confirmed by elemental and thermogravimetric analyses, IR and (13)C NMR spectral studies. Morin-APSG was found to be highly stable in common organic solvents, acidic medium (<2molL(-1) HCl, HNO(3)) or alkaline medium up to pH 8. The separation and preconcentration of Ag(I), Au(III), Pd(II), Pt(II) and Rh(III) from aqueous medium using morin-APSG was studied. The optimum pH values for the separation of Ag(I), Au(III), Pd(II), Pt(II) and Rh(III) on the sorbent are 5.7, 2.2, 3.7, 3.7 and 6.8, giving rise to separation efficiencies of 43.9, 85.9, 97.7, 60.9 and 91.0%, respectively, where the activity was found to be >90% in the presence of acetate ion. The ion sorption capacity of morin-APSG towards Cu(II) at pH 5.5 was found to be 0.249mmolg(-1) where the sorption capacities of Ag(I) and Pd(II) were 0.087 and 0.121mmolg(-1) and 0.222 and 0.241mmolg(-1) at pH 2.2 and 5.7, respectively. This indicates a 1:1 and 1:2 morin/metal ratios at pH 2.2 and 5.7, respectively. Complete elution of the sorbed metal ions was carried out using 10mL (0.5molL(-1) HCl+0.01molL(-1) thiourea) in case of Au(III), Pd(II), Pt(II) and Rh(III) and 10mL 0.5molL(-1) HNO(3) in case of Ag(I). Morin-APSG was successfully employed in the separation and preconcentration of the investigated precious metal ions from some spiking water samples yielding 100-folds concentration factor. The relative standard deviation (R.S.D.) and the T-test (|t|(1)) were calculated.     

Synthesis and characterisation of a new helically chiral ruthenium complex

A new helically chiral hexacyclic phosphine, containing one thiophene ring was prepared in good yield via a five-step sequence involving a palladium-catalysed Mizoroki-Heck coupling reaction and classical oxidative photocyclisation. A mononuclear air stable ruthenium complex of this phosphine was also prepared and characterised.     

Synthesis and properties of some new polyazomethine-urethanes

Two new bisazomethine diols were prepared from terephthalaldehyde and aromatic or aliphatic aminoalcohols. The structure of the diols with bisazomethine moieties was confirmed by ¹H-NMR, IR, UV spectroscopy and elemental analysis. Bisazomethine aliphatic diol exhibited a smectic phase that has been identified by means of polarizing microscopy and differential scanning calorimetry. By using these diols as partners in polyaddition reaction between poly(tetramethylene oxide)diol of 2000 average molecular weight, tolylene-2,4-diisocyanate (as 2,4- and 2,6-TDI, 80:20 v/v isomers mixture) and bisazomethine diol (1:3:2 molar ratio), two polyazomethine-urethanes were synthesized. Polyazomethine-urethanes with a higher concentration of poly-Schiff's base units were also obtained by reacting the above bisazomethine diols with the same diisocyanate (1:1 molar ratio). All polymers were characterized by viscometry, elemental analysis, IR, UV, ¹H-NMR spectroscopy and TGA techniques.     

新型吲哚碳菁染料的合成及表征

通过简单而有效的方法合成了14个二碳菁和三碳菁染料,其中大多数是新化合物,同时研究了染料的组成和性质之间的关系。     

苯并噻唑偶氮吡唑和苯并噻唑偶氮嘧啶的合成

2-氨基苯并噻唑重氮盐与丙二腈偶联, 生成2-(苯并噻唑腙基)-丙二腈, 然后分别与水合肼, 苯肼和硝酸胍反应, 形成相应的4'-(苯并噻唑-2-偶氮)-3',5'-二氨基吡唑, 4'-(苯并噻唑-2-偶氮)-3',5'-二氨基-2'-苯并吡唑和5'-(苯并噻唑-2-偶氮)-2',4',6'-三氨基嘧啶.     

The preparation and characterisation of some new CF3Se-derivatives

The preparation and characterisation of CF₃SePF₂, CF₃SeSi(CH₃)₃ and CF₃SeTl(CH₃)₂ are described. The vibrational and n.m.r. spectra of these compounds are presented and discussed.