Thermally Stable Heterocyclic Imines as New Potential Nonlinear Optical Materials

Abstract

In the course of a search for new thermostable acentric nonlinear optical crystalline materials, several heterocyclic imine derivatives were designed, with the general structure D−π−A(D‘). Introduction of a donor amino group (D‘) into the acceptor moiety was expected to bring H-bonds into their crystal structures, and so to elevate their melting points and assist in an acentric molecular packing. Six heterocycle-containing compounds of this type were prepared, single crystals were grown for five of them, and these crystals were characterized by X-ray analysis. A significant melting temperature elevation was found for all of the synthesized compounds. Three of the compounds were also found to crystallize in acentric space groups. One of the acentric compounds is built as a three-dimensional H-bonded molecular network. In the other two compounds, with very similar molecular structure, the molecules form one-dimensional H-bonded head-to-head associates (chains). These chains are parallel in two different crystallographic directions and form very unusual interpenetrating chain patterns in an acentric crystal. Two of the compounds crystallized with centrosymmetric molecular packing.

Condensation of DAMN with Conjugated Aldehydes and Polymerizations of the Corresponding Imines

“…In contrast to methylation, where the first substitution activates additional substitution, Schiff base formation at one nitrogen deactivates the second nitrogen, and only the monoimines form under mild conditions. 3,4 DAMN has also been used to prepare 5,6-dicyanopyrazines, [5][6][7][8][9][10][11][12] purines, 13 and amides. 14,15 The conjugated aldehyde and vinyl group in acrolein lead to reactions that are facile, and often different, from those of other aldehydes.…”

“…(2Z)-2-Amino-3-{[(1E)-2-methylprop-2-en-1-ylidene]amino}but-2-enedinitrile (Methacrodamn) 19 (4). 4 was prepared analogously to 3, using methacrolein in place of crotonaldehyde.…”

“…Reaction between DAMN and aldehydes or ketones can result in Schiff base formation (Scheme ). In contrast to methylation, where the first substitution activates additional substitution, Schiff base formation at one nitrogen deactivates the second nitrogen, and only the monoimines form under mild conditions. , DAMN has also been used to prepare 5,6-dicyanopyrazines, − purines, and amides. , …”

Nonlinear optical co-crystal of analogous polyene chromophores with tailored physical properties

“…In order to overcome this limitation many different approaches have been investigated such as use of molecular asymmetry, chirality, hydrogen bonds, strong Coulomb interactions, non-rod-shaped p-conjugated cores, octupolar compounds and photochromism. 2,3 Another interesting approach for achieving acentric crystals is supramolecular synthetic co-crystallization. It offers more design feasibility as one or both constituent molecules can be modified to fit one another and to acquire the desirable macroscopic properties in the solid state.…”

Studies on the Synthesis, Growth and Characterization of ([Paranitrophenyl]Imino)Benzene NLO Crystal by Sankaranarayanan-Ramasamy Method

“…Recently Unver et al have reported the structural and NLO properties for some imine bridged aromatic compounds [13,19,20]. Volodymr et al have designed thermostable acentric nonlinear optical crystalline imine derivatives [21,22]. Heravic et al have reported a theoretical investigation of the structure electronic properties and second harmonic generation of imine ligands [23].…”