基于二茂铁的两个查尔酮衍生物的合成及超快三阶非线性光学响应

Synthesis of Two Ferrocene-Based Chalcone Derivatives and Their Ultrafast Third-Order Nonlinear Optical Response

二茂铁是合成新颖有机功能材料的基本单元之一。本文设计并合成了两个基于二茂铁的同分异构查尔酮衍生物:1-二茂铁基-3-(噻吩-2-基)丙烯酮(a)和1-二茂铁基-3-(噻吩-3-基)丙烯酮(b)。采用超快激光Z-扫描技术(脉宽180 fs,波长532 nm)测定了化合物a和b的三阶非线性光学性质。结果表明,化合物a吸收系数β=-2. 1×10^(-12)m/W,折射率n_2=1. 9×10^(-19)m^2/W,分子超极化率γ=5. 37×10^(-32)esu;化合物b:β=-1. 2×10^(-13)m/W,n_2=2. 0×10^(-19)m^2/W,γ=4. 48×10^(-32)esu。说明在飞秒激光激发下,电荷转移能够在化合物a和b分子内部快速进行,二者均具有优异的超快三阶非线性光学响应。在B3LYP/6-311+G(d,p)理论水平下,计算了化合物a和b分子轨道能量、极化率和各基团在前线分子轨道中的占有率。理论计算结果显示,二茂铁基团在化合物a和b前线分子轨道中占有率分别为97%和98%,对两化合物的非线性光学性能起主导作用。

Two ferrocene-based isomeric chalcone derivatives 1-ferrocenly-3-(thiophen-2-yl)prop-2-en-1-one(a)and 1-(ferrocenly)-3-(thiophen-3-yl)prop-2-en-1-one(b)were synthesized.Their third-order nonlinear optical properties were measured by Z-scan technique with ultrafast laser operating at 532 nm laser in 180 fs pulse,respectively.The relevant parameters were given as follows:the nonlinear absorption coefficientβ=-2.1×10-12 m/W,the nonlinear refractive index n2=1.9×10-19 m2/W and the third-order nonlinear hyperpolarizabilityγ=5.37×10-32 esu for compound a;β=-1.2×10-13 m/W,n2=2.0×10-19 m2/W andγ=4.48×10-32 esu for compound b.The results indicate that the excitation of femtosecond laser enables intramolecular charge transfer to occur quickly.Thus two compounds can exhibit ultrafast third-order nonlinear optical response.The orbital energies,polarizabilities and possession ratios of different groups in frontier molecular orbitals of compounds a and b were calculated by B3LYP/6-311+G(d,p)level.The percentage of ferrocene group in the frontier molecular orbitals of compounds a and b is 97%and 98%,respectively,which indicates that ferrocene group plays a leading role in the nonlinear optical properties of two compounds.