N,N-Diarylthiazol-5-amines: Structure-Specific Mechanofluorochromism and White Light Emission in the Solid State

Abstract

A range of N,N-diarylthiazol-5-amines having a 4-pyridyl group on a thiazole ring were developed, and their photophysical properties were elucidated. Their synthesis was achieved by applying our methods to the combination of N-arylmethyl secondary thioamides and N,N-diarylthioformamides. This enabled us to obtain amines with different types of aromatic groups on the nitrogen atom. Their absorption and emission spectra in solution were examined. The 4-pyridyl group gives higher polarity to the amines. The solid-state emissions of the amines were also evaluated. Several amines showed mechanofluorochromism (MFC). A 4-pyridyl group on a thiazole ring was a requisite for the expression of MFC properties. Although N-(5-thiazolyl) N,N-di(2-naphthyl)amines did not exhibit MFC by grinding of the pristine powder, white-light emission was observed when the ground powder was fumed with acetone vapor.

5-N-Arylaminothiazoles with pyridyl groups and their first-row transition metal complexes: synthesis, photophysical properties, and Zn sensing

“…Addition of thioformamides 2 and iodine to the reaction mixture gave 5-aminothiazolines 3 as major products. 44 Further oxidation of 5-aminothiazolines 3 with 2 equivalents of iodine resulted in the formation of the corresponding 5-aminothiazole ligand 4 in low to good yields. Following this reaction, a wide range of substituents possessing electron-donating and -withdrawing properties could be introduced to the 2-, 4-, and 5- positions of the thiazole ring.…”

“…ESI-mass analysis suggested that the zinc atom is coordinated to two bidentate thiazole ligands to form 2 : 1 metal complexes [Zn(L 2 )X 2 ]. 44 …”

“…The emission color of the isolated 5- N -arylaminothiazoles varied with the solution polarity exhibited a tunable emission wavelength in the range of 397–505 nm. 44 The emission maxima of 4f strongly depended on the solvent polarity, and thus their peak emissions were greatly affected. Large red shifts in the emission maxima ( Fig.…”

Recent Advances in Mechanochromic Luminescence of Organic Crystalline Compounds

“…61,62 In 2020, Murai and coworkers demonstrated the whitelight emission from multi-stimuli-responsive N,N-diarylthiazole-5-amine derivative 30 (Figure 7h). 63 Although only a slight change in the emission properties was observed by grinding pristine orange-emissive solid of 30, the emission color of the ground sample significantly changed to white (CIE coordinate: 0.32, 0.33) upon fuming with acetone. In the emission spectrum of fumed 30, a major peak was observed at 475 nm with a shoulder peak around 600 nm, which resulted in the observation of white light.…”

Primary Phosphines and Phosphine Oxides with a Stereogenic Carbon Center Adjacent to the Phosphorus Atom: Synthesis and Anti-Markovnikov Radical Addition to Alkenes

“…The stereochemistry on a phosphorus atom has not received much attention, despite the fact that the introduction of at least three different substituents to the phosphorus atom gives rise to the stereogenic center on the phosphorus atom. During the course of our studies on main group chemistry [39,40], we have intensively studied the synthesis and applications studies on main group chemistry [39,40], we have intensively studied the synthesis and applications of organophosphorus compounds with a binaphthyl group [41][42][43][44][45] and recently reported that the deprotonation and alkylation of phosphonoselenoates and phosphonates with a binaphthyl group creates stereogenic secondary and tertiary carbon centers adjacent to the phosphorus atom with high diastereoselectivity (Scheme 1a,b) [46]. The resulting products are potentially available as precursors of primary phosphines since phosphorus-oxygen bonds are readily reduced to P-H bonds.…”