Polymorphism and mechanochromism of N-alkylated 1,4-dihydropyridine derivatives containing different electron-withdrawing end groups

Abstract

A series ofN-alkylated 1,4-dihydropyridine derivatives were reported to exhibit polymorphic and mechanochromic properties.

Tricolor Luminescence Switching by Thermal and Mechanical Stimuli in the Crystal Polymorphs of Pyridyl‐substituted Fluorene

“…[3,4] In recent years, a number of stimuli-responsive organic fluorescent materials have been reported, [5,6] in which switching to the solid luminescent color is achieved by alteringt he mode of molecularly assembled structures upon externals timulus, [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] such as grinding, heating, and exposure to chemicalv apor.T his smart approacht oc hanging the luminescence properties of organic solids is thought to be more promising and easier than switching molecularly chemical structures by chemical reactions. To date, most of the reported examples display ar eversible twocolor luminescence switching, [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] and multicolor switched materials remaine xtremelyl acking due to the un-designability of this kind of smart materials. [41] Recently,w er eported ac lass of fluorenone compounds that exhibit stimuli-responsive solid-state luminescence switching (SLS) properties, [21,22] which derivef rom the reversible phase transformationsb etween p-p stacking-directed packing and hydrogen bond-directed packing.F luorene, the derivatives of which generally possess eminent luminescentp ropert...…”

The Synergistic Effect between Triphenylpyrrole Isomers as Donors, Linking Groups, and Acceptors on the Fluorescence Properties of D–π–A Compounds in the Solid State

“…2-(1-butyl-2,6-dimethylpyridin-4(1H)-ylidene)malononitrile (CN-P), 2-(1-butyl-2,6-dimethylpyridin-4(1H)-ylidene)-1Hindene-1,3(2H)-dione(CO-P), 2-(1-butyl-2,6-2-(2-methyl-4H-chromen-4-ylidene) malononitrile (CN-B) and 2-(2-methyl-4H-chromen-4-ylidene)-1H-indene-1,3(2H)-dione (CO-B) were obtained according to the synthetic methods reported in the previous literature. [46,47] The structures of all products were confirmed by NMR and mass spectra (MS). 1 Hs pectra were obtained using aB ruker ARX400 spectrometer with CDCl 3 as the solvent, and mass spectra were collected by using aF innigan BIFLEX III mass spectrometer.T he UV/Vis absorption spectra were measured on aP ersee TU-1901 UV/Vis spectrophotometer.T he fluorescence spectra were determined on aH itachi F-7000 spectrophotometer.X RD measurements were taken with aB ruker X-ray diffractometer (D8 Advance).…”

Metal‐Free Facile Synthesis of Multisubstituted 1‐Aminoisoquinoline Derivatives with Dual‐State Emissions

“…However, these approaches were difficult to construct multisubstituted 1‐aminoisoquinolines . Recently, our group has been devoted to the construction of 4 H ‐pyran/1,4‐dihydropyridine‐based solid‐state fluorescence stimulus‐responsive materials using 2,6‐dimethyl‐4‐pyrone ( 1 ) as the starting material (Scheme ) . More recently, we were surprised to find that the reaction of 2‐(2,6‐dimethyl‐4 H ‐pyran‐4‐ylidene)‐3‐oxopentanedinitrile ( 2 ) with piperidine afforded to an unexpected multisubstituted 1‐aminoisoquinoline derivative, namely 8‐hydroxy‐3,6‐dimethyl‐1‐(piperidin‐1‐yl)isoquinoline‐7‐carbonitrile ( 3 a ) .…”