新型同分异构芘基查尔酮的理论研究和超快三阶非线性光学响应

Theoretical Investigation and Ultrafast Third-Order Nonlinear Optical Response of Novel Isomeric Pyrenyl Chalcones

合成了3个新型同分异构芘基查尔酮:1-(芘-1-基)-3-(吡啶-2-基)-2-丙烯-1-酮(3a)、1-(芘-1-基)-3-(吡啶-3-基)-2-丙烯-1-酮(3b)和1-(芘-1-基)-3-(吡啶-4-基)-2-丙烯-1-酮(3c)。通过核磁共振波谱仪(NMR)、傅里叶变换红外光谱仪(FTIR)和液-质联用仪(LC-MS)等技术手段表征3个化合物的结构、热稳定性和线性光学性质和三阶非线性光学吸收性能。结果表明,在532 nm和180 fs条件下,化合物3a-3c均表现出超快三阶非线性光学响应,化合物3c的非线性吸收系数分别是化合物3b和3a的1.14和2.67倍。运用密度泛函理论方法计算了化合物3a-3c的非线性光学性质及其电子性质,结果表明,化合物3c分子具有最大的静态第一超极化率(β0)(2830.9 a.u.),并具有最小的最高占据分子轨道(HOMO)-最低空分子轨道(LUMO)之间的能隙(3.11 eV)和最小的跃迁能(ΔE)(2.67 eV),这与N原子在吡啶环上的位置有关;分子内部均存在电荷转移现象。3个化合物的紫外-可见光谱在450 nm以上无吸收,有良好的热稳定性,在激光防护方面有应用前景。

Three nevol isomeric pyrenyl chalcone 1-(pyren-1-yl)-3-(pyridin-2-yl)prop-2-en-1-one(3a),1-(pyren-1-yl)-3-(pyridin-3-yl)prop-2-en-1-one(3b)and 1-(pyren-1-yl)-3-(pyridine-4-yl)prop-2-en-1-one(3c)were successfully synthesized and characterized by nuclear magnetic resonance(NMR),Fourier transform infrared spectrometer(FTIR),and liquid chromatography-mass spectrometer(LC-MS).Their thermal stability was measured by differential scanning calorimetry(DSC).The linear optical properties and third-order nonlinear optical(NLO),absorption were studied by ultraviolet visible(UV-Vis)spectrum and Z-scan technique,respectively.The experiment shows that compounds 3a-3c are all able to exhibit ultrafast third-order NLO response with 180 fs laser pulses at 532 nm.The nonlinear absorption coefficient of compound 3c is 1.14 and 2.67 times of compounds 3b and 3a,respectively.The non-linear optical properties and the electron transition properties of compounds 3a-3c were calculated by density functional theory method.The results indicate that molecule 3c has the largest static first hyperpolarizability(2830.9 a.u.)and the smallest energy gap(3.11 eV)between highest occupied molecular orbital(HOMO)and lowest unoccupied molecular orbital(LUMO),and also has the smallest transition energy(ΔE)(2.67 eV),which is related to the position of N atom on the pyridine ring.There are charge transfer phenomena inside the molecules of 3a-3c.Three compounds have no absorption at more than 450 nm but show good thermal stability implying potential application in the laser protection.