Renate Dworczak

Structure-color correlations of penta- and heptamethines: Syntheses with nitriles XCIV

Abstract The synthesis of asymmetric cyanine dyes (penta- and heptamethines), prepared by coupling Fischers base with indandione, benzo[b]thiophene and pyrazole derivatives via a C-1 unit, is described. Three different synthetic strategies for substituted polymethines are presented. Dye characteristics are given and the correlation between the chemical structures and the dye properties are discussed by means of semiempirical PPP calculations.

Cyanoacetophenone as a Synthon for 1,4,5-Substituted Pyrazoles

Summary. An improved synthesis of cyanoacetophenone is described. Cyanoacetophenone was reacted with dimethylformamide-dimethylacetal and diphenylformamidine to give 1-dimethylamino-3-oxo-3-phenyl-1-propene-2-carbonitrile and 1-anilinomethylene-3-oxo-3-phenyl-1-propene-2-carbonitrile. Reaction of 1-dimethylamino-3-oxo-3-phenyl-1-propene-2-carbonitrile with hydrazines gave either 1-substituted 5-amino-4-benzoylpyrazoles or (1-substituted) 4-cyano-5-phenylpyrazoles. Treatment of 1-anilinomethylene-3-oxo-3-phenyl-1-propene-2-carbonitrile with phenylhydrazine also yielded 5-amino-4-benzoyl-1-phenylpyrazole, whereas reaction with unsubstituted hydrazine afforded 4-cyano-5-phenylpyrazole.Zusammenfassung. Eine verbesserte Darstellung von Cyanacetophenon wird beschrieben. Cyanacetophenon reagierte mit Dimethylformamid-dimethylacetal bzw. Diphenylformamidin zu 1-Dimethylamino-3-oxo-3-phenyl-1-propen-2-carbonitril und 1-Anilinomethylen-3-oxo-3-phenyl-1-propen-2-carbonitril. Durch Umsetzung von 1-Dimethylamino-3-oxo-3-phenyl-1-propen-2-carbonitril mit Hydrazinen wurden entweder 1-substituierte 5-Amino-4-benzoylpyrazole oder (1-substituierte) 4-Cyano-5-phenylpyrazole erhalten. Reaktion von 1-Anilinomethylen-3-oxo-3-phenyl-1-propen-2-carbonitril mit Phenylhydrazin ergab ebenfalls 5-Amino-4-benzoyl-1-phenylpyrazol, während unsubstituiertes Hydrazin zu 4-Cyan-5-phenylpyrazol reagierte.

Azomethines with nonlinear optical properties and polyesters covalently functionalized with them. Syntheses with nitriles IC

Abstract Polyesters with covalently bound azomethine and carbonanalogous dye moieties were obtained by polymer analogous reactions. Their nonlinear optical properties were examined by electric field induced second harmonic generation measurements and compared with corresponding monomeric dyes. All of them had maximum absorption wavelengths between 400 and 546 nm. Values for μβ (dipole mement μ, molecular hyperpolarizability β) reached 290×10 −68 Cm 5 /V. Quantum chemical calculations indicate the existence of various conformers of the dyes with large differences in their nonlinear optical properties. Furthermore, the calculations also point to a profound sensitivity of the molecular hyperpolarizability to environmental (solvent) effects amounting to an order of magnitude.

Nonlinear optical properties of diazabutadienes and -hexatrienes; experimental and computational aspects

Donor-acceptor substituted diazabutadienes and -hexatrienes were prepared by straightforward procedures and their linear optical (UV-vis) and nonlinear optical second harmonic generation (SGH) properties investigated in a combined theoretical and experimental study. Theoretical and experimental results were in reasonable agreement. For the compounds in this study, which contained a p-nitrophenyl group as electron acceptor, the p-dimethylaminophenyl group was the most powerful electron-donating group, leading to the highest maximum absorption wavelengths, as well as to the maximum SHG efficiency.

Electric field induced second harmonic generation (EFISH) experiments in the swivel cell: New aspects of an established method

The EFISH technique is well known and widely used to determine the efficiency of the second harmonic generation (SHG) of liquid samples. In the first part of this paper, a simple and convenient experimental setup for EFISH measurements is presented. A standard photometric cell was used and the cell was swiveled during the experiments. The mathematical treatment of the data included corrections for the SHG of the optical cells and the solvent. The second part of the paper deals with the measurements of compounds which showed notable absorption at the SHG wavelength. In addition to the contributions of the solvent and the cell to the SHG signal the molar absorption coefficient of the compound and the refractive indices for the ground and the second harmonic wave of the solution were included in the processing of the EFISH data. Results of these measurements were in good agreement with those which others have obtained by independent methods. Thus the swivel method allowed estimation of the SHG (in terms of μβ where μ is the dipole moment of the molecule and β is the second-order polarizability) of non-absorbing, weakly absorbing and notably strongly absorbing compounds by easy-to-perform EFISH measurements.

Possible Rearrangements During the Synthesesof Di- and Trisubstituted Pyrazoles

Summary. The reaction of ethoxymethylene malononitrile and ethoxymethylene cyanoacetic acid ethylester with substituted hydrazines to substituted 5-aminopyrazoles is described. The influence of different substituents on possible migrations during the ring closure was studied..Zusammenfassung. Die Reaktion von Ethoxymethylenmalodinitril und Ethoxymethylencyanessigsäureethylester mit substituierten Hydrazinen zu substituierten 5-Aminopyrazolen wird beschrieben. Der Einfluß unterschiedlicher Substituenten auf mögliche Wanderungen während des Ringschlusses wurde untersucht..

Synthesen mit Nitrilen, 88. Mitt.: Spiro[indol- und Spiro[inden-pyrano[2,3-c]pyrazole]aus Cyanmethylenderivaten und Pyrazolonen

SummaryThe reactivity of cyanomethylene-indolones (1 a–e) and 2-(dicyanomethylene)-indan-1,3-dione (4) towards 1,5-disubstituted 3-pyrazolones (2 a–c) was investigated. The reactions yield spiro[indene- and spiro[indole-4′- and 6′-pyrano[2,3-c]pyrazoles] (3 a–e,5 a–c). The structures are proven by13C-NMR-spectroscopy. The mechanisms of the reactions are discussed.

Nonlinear Optical Properties of Dicyanomethylene-Derived Heteroaromatic Dyes: Semiempirical Molecular Orbital Calculations and Experimental Investigations

The effect of conformation (E/Z isomerism), nature (donor/acceptor) of substituents, and endgroups (indandione, pyrazolone, pyrazoledione) on the molecular hyperpolarizabilityvec of dicyanomethylene (hetero)aromatic dyes is investigated by means of semiempirical (AM1, ZINDO) molecular orbital calculations. Unless Z isomers are stabilized by intramolecular hydrogen bonding, generally E conformers have largervecs. Replacement of one nitrile group of the dicyanomethylene moiety by p-aminoaryl rather than p-R-arylamino (RD NMe2 ,M eO, H, NO 2 )i s found to be advantageous. Increasing the acceptor strength of 29 by successively replacing the carbonyl with dicyanovinyl groups leads to a maximum ofvec for the derivative with one rather than two C(CN)2 groups. With respect to endgroups, the indandione moiety generally is the least active group. Solvent effects are treated within the framework of the self-consistent reaction field approximation. In most cases gas-phase tendencies are either parallel or even reinforced if solvent effects are taken into account. The calculated results are compared with electric field induced second harmonic generation (EFISH) measurements. c 2000 John Wiley & Sons, Inc. Int J Quantum Chem 79: 253-266, 2000

Fischer's base as an electron donor for new penta- and heptamethines

Abstract Asymmetric cyanine dyes (penta- and heptamethines) prepared by coupling Fischers base or Fischers aldehyde with malononitrile dimer or analogous compounds are described. Dye characteristics are given and structure-color correlations are discussed.

Synthesen mit Nitrilen, 85. Mitt.: Über 4-Dicyanmethylen-und 4-Tricyanpropyliden-homophthalimide

SummaryAddition of tetracyanoethylene to the 1,2,3,4-tetrahydro-isoquinoline-1,3-diones1 a–d yields 4-(dicyanomethylene)-1,2,3,4-tetrahydro-isoquinoline-1,3-diones3 or 4-(2-amino-1,1,3-tricyano-3-propylidene)-1,2,3,4-tetrahydro-1,3-diones4 depending on the substituent in position 2. Spectra of both types of derivatives are discussed.