Publisher Summary Over the past 15–20 years, the non-linear optical (NLO) response of organic molecules has been of wide interest to organic and physical chemists, as well as physicists and chemical engineers. This interest arises from the possible use of such organic materials. In principle, photonics or the hybrid technology optoelectronics, both based on non-linear optical phenomena, can supersede electronics in communication technology. These technologies allow many operations that are currently effected with electron conduction to be replaced by operations based on light conduction. Many problems are encountered when it comes to the translation of a molecular property into a bulk property. It has transpired that some of these problems are not easy to solve with classical NLO-phores that mostly belong chemically to the class of merocyanine dyes. New design strategies for organic molecules and their respective bulk structures, crystals or oriented composite materials like polymers, are needed. Only a more fundamental understanding of these issues will allow rational optimization of molecular and bulk properties. This chapter surveys second-order molecular polarizabilities of organic molecules. Emphasis is given to the underlying of physical principles of non-linear optics (e.g. molecular topology), and to the establishment of structure–property relationships.

Organic Materials for Second-Order Non-Linear Optics

Activation parameters for the interconversion of conformers IA and IB of neopentylbenzylnitrosamine and of rotamers IIA and IIB of N,2,4,6-tetramethyl-N-benzylbenzamide were determined by two techniques: Equilibration of pure IB (or IIA, respectively) and subsequent measurement of 1H-NMR line shapes with the same sample. Ea- and k0-values obtained by the two methods agree well within error limits, thus confirming the accuracy of rate determinations using NMR line shapes. Chemical shifts Δν, line widths bE, and equilibrium constants K were extrapolated to those temperatures at which they could not be measured directly. Line shape parameters were used for the evaluation of spectra. This method is shown to be preferable to the complete line shape analysis if the line broadening by field inhomogeneities is not taken into account by a convolution.

Protonenresonanz-Untersuchungen zur inneren Rotation 6: The conformers of a nitrosamine and a carboxamide: Comparison of NMR line shape and equilibration methods

The identification of some intermediates of the reactions between β-aminoenones and malononitrile to give 2(1H)-pyridinones has allowed us to obtain valuable information concerning its mechanism. T...

Regioselective Synthesis of 2(1H)-Pyridinones from β-Aminoenones and Malononitrile. Reaction Mechanism

The known flemingins A− C( 1−3) and nine new chalcones, named flemingins G− O( 4−12), along with deoxyhomoflemingin (13) and emodin (14) were isolated from a leaf extract of Flemingia grahamiana. The isolated chalcones were found to have a geranyl substituent modified into a chromene ring possessing a residual chain, as shown by spectroscopic methods. The leaf extract showed an IC50 value of 5.9 μg/mL in a DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay. The chalcones flemingins A, B, C, G, and H were active in the DPPH radical scavenging assay (ED50 4.4−8.9 μM), while flemingins A and C showed cytotoxicity against MCF-7 human breast cancer cells (IC50 8.9 and 7.6 μM, respectively).

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Flemingins G-O, cytotoxic and antioxidant constituents of the leaves of Flemingia grahamiana.

Static and Dynamic Stereochemistry of Push‐Pull and Strained Ethylenes

A relatively fast rotation around the α,β carbon–carbon double bond at the equilibrium of geometrical isomers and a comparatively slow rotation around the carbon-nitrogen single bond in compounds of the type 






(X1, X2 are electron-attracting substituents) were detected and investigated by the NMR technique. The relationships between the free energies of activation for these rotational processes and the character of the substituents, the number of double bonds, solvents and concentration were studied.

NMR spectroscopic study of rotation around CC and CN bonds in diene δ‐aminocarbonyl compounds

Conjugated ω-dimethylamino β-diketones with two to five double bonds and trimethylidyneand pentamethylidyneoxanine salts are formed in the condensation of aminals of conjugated β-dimethylamino aldehydes with indandione.

Reaction of aminals of conjugated ω-dimethylamino aldehydes with indandione

The conversion of dienic δ-monoalkylaminoketo esters into 1-alkyl-3-acetyl-2-pyridones and 1,3-bis[3-(1-alkyl-2-pyridonyl)]-2-buten-1-ones was studied. Heterocyclic analogs of chalcone were synthesized from 1-alkyl-3-acetyl-2-pyridones.

Synthesis of derivatives of N-substitut ed pyridones from dienic monoa lkylaminoketo esters

1.

A study was made of the reaction of enaminocarbonyl compounds (ketones, aldehydes, and esters) with nitroacetic ester.




2.

Some new methods were proposed for the synthesis of substituted isoxazoline and 3-nitro-2-pyridone N-oxides.

Reaction of enaminocarbonyl compounds with nitroacetic ester

1.

The reaction of 1,1,3-trimethoxy-3-dimethylaminopropane with ketones was studied.




2.

A new method was proposed for the synthesis of dienic δ-dimethylaminoketones and symmetrical bis-(δ-dimethylaminoalkadienyl)ketones, including cyclic ketones.




3.

The configuration of the synthesized ketones was established employing NMR.




4.

The protonation of unsaturated δ-aminoketones was studied and it was shown that O-protonation predominates in these compounds.

E. P. Prokof'ev

Papers

NMR spectroscopic study of rotation around CC and CN bonds in diene δ‐aminocarbonyl compounds

Reaction of aminals of conjugated ω-dimethylamino aldehydes with indandione

Synthesis of derivatives of N-substitut ed pyridones from dienic monoa lkylaminoketo esters

Reaction of enaminocarbonyl compounds with nitroacetic ester

Synthesis, stereochemistry, and protonation of unsaturated δ-aminoketones