Copolymerization of alkyl diazoacetates with α,β-unsaturated aldehydes: synthesis and application

Abstract

Copolymerization of alkyl diazoacetates with α,β-unsaturated aldehydes and the product's fluorescence property.

Synthesis and Enhanced Photofluorescence of Pyrazoline‐Ester Copolymers from Bisdiazoacetates and Diacrylates

“…The exploration of efficient copolymerizations of diazo compounds with alkenes have been reported previously, however that of bisdiazo compounds with dialkenes have rarely been recorded so far. In our previous work, we synthesized a series of fluorescent pyrazoline oligomers, showing significant enhancement of fluorescence emission intensity compared with the monomer, which mainly ascribe to the propagating pyrazoline chromophore centers with the conjugated structure NNCCO . In this work, through 1,3‐dipolar cycloaddition reaction in one‐pot procedure, efficient two‐component tandem copolymerizations of bisdiazo compounds with dialkenes were recorded to react smoothly under mildness conditions at room temperature ( Scheme ), producing pyrazoline copolymers with number‐average molecular weights ( M n ) in the range of 6100–17900 g mol −1 in excellent yield (up to 90%).…”

“…The fluorescent properties of P1, P2, P7, and P8 are summarized in Figure b,c. Under UV irradiation at ≈290 nm and visible irradiation at ≈580 nm, the fluorescence emission maxima of the four copolymers are located at UV region of 320–330 nm, exhibiting unique fluorescence characteristics, while that of fluorescence pyrazoline oligomer materials are mainly centered at visible region at present . Meanwhile, the fluorescence intensities show a trend of P8 > P1 > P7 > P2, consisting with the results of the molecular fluorescence emission efficiency (defined as I / N , the maximum emission intensity for a nitrogen atom of 1 mg mL −1 ) (Figure d).…”

Novel Synthesis of Down-/Up-Conversion Fluorescent Oligo(2-pyrazoline)s

“…The peaks from 6.5 to 7.9 ppm are attributed to the protons in the phenyl group. With respect to the 13 C NMR spectrum of PPy-1 (Figure 1b), the peak at 173 ppm is belonging to the resonance of carbonyl group (−COO−). The resonance values appearing at 30, 38, 160 ppm are assigned to the carbon atoms located on the pyrazoline ring backbone (adjacent to the ester group and the phenyl group, and the CN bond, respectively).…”

“…Elemental analysis (EA) data were suggested on Vario EL. 1 H and 13 C NMR spectra were recorded on Mercury VX-300 spectrometers using CDCl 3 as solvent and TMS as the internal standard. Thermogravimetric analysis (TGA) curves were measured with NETZSCH STA 449C thermal analyzer (NETZSCH, Germany).…”

“…This is the first example of fluorescent oligomer constructed by pyrazoline as the backbone. Recently, several researches proved that diazo-contained polymers may have unique optical properties, and they could emit both down-conversion fluorescence excited by visible light and the up-conversion fluorescence excited by near-infrared light, which is a potential field in optical materials. − …”