0000000000542337
AUTHOR
Ri-cheng Yu
Electron crystallography and organic materials with non-linear optical properties
Results of electron microscopic studies of crystal structures of a number of bis-benzylidene cyclohexanones are presented. It is shown that some of these compounds are efficient crystalline non-linear optically active (NLO) chromophores with second harmonic generation (SHG) properties. Appropriately functionalized chromophores of this type can be used as a polycondensation comonomer to produce partly crystalline main-chain NLO-active polymers. Electron diffraction crystal structural data, obtained for very small crystals, allowed us to get reasonable estimations of macroscopic crystal NLO-coefficients, relating quantum-chemically calculated molecular first hyperpolarizability components to …
ChemInform Abstract: Electron Crystallography and Organic Materials with Non-Linear Optical Properties
Results of electron microscopic studies of crystal structures of a number of bis-benzylidene cyclohexanones are presented. It is shown that some of these compounds are efficient crystalline non-linear optically active (NLO) chromophores with second harmonic generation (SHG) properties. Appropriately functionalized chromophores of this type can be used as a polycondensation comonomer to produce partly crystalline main-chain NLO-active polymers. Electron diffraction crystal structural data, obtained for very small crystals, allowed us to get reasonable estimations of macroscopic crystal NLO-coefficients, relating quantum-chemically calculated molecular first hyperpolarizability components to …
Strategies for structure solution and refinement of small organic molecules from electron diffraction data and limitations of the simulation approach
In recent years, a series of non-linear optically active bis(benzylidene) ketones have been synthesized and investigated by electron crystallography. In most cases, structure refinement was possible by combining electron diffraction analysis and quantum-mechanical calculations with maximum-entropy methods. However, when the torsional angles between the phenyl rings and the C=C double bonds are strongly affected by the crystal field, this method fails because packing-energy calculations are not sufficiently sensitive. This problem can be solved by refining the approximate model with SHELXL, if the data set is sufficiently accurate and the model close to the correct structure. Here it is show…