Di Bella S, Fragalà I, Ledoux I, Zyss J
Dipartimento di Scienze Chimiche, Università di Catania, Italy.
Chemistry. 2001 Sep 3;7(17):3738-43. doi: 10.1002/1521-3765(20010903)7:17<3738::aid-chem3738>3.0.co;2-i.
The synthesis, characterization, and two-dimensional second-order nonlinear optical (NLO) response of a dipolar NiII donor- acceptor Schiff base complex and the related ligand are reported. Electric-field-induced second-harmonic generation and harmonic light (hyper-Rayleigh) scattering techniques, in combination with INDO/SCI-SOS theoretical calculations, were used to investigate the vector part of the hyperpolarizability tensor and the two-dimensional character of the molecular nonlinearity, respectively. Off-diagonal hyperpolarizability tensors can be related to charge-transfer transitions that are polarized perpendicular to the molecular dipolar axis, while parallel transitions account for the diagonal hyperpolarizability tensor. The role of the metal center in enhancing the two-dimensional NLO response of such molecules is twofold since it acts both as the donor and the bridging moiety of the planar donor-(pi-conjugate-bridge)-acceptor system. These dipolar two-dimensional molecules are interesting candidates from the perspective of polarization-independent NLO materials.
报道了一种偶极NiII供体-受体席夫碱配合物及其相关配体的合成、表征和二维二阶非线性光学（NLO）响应。电场诱导二次谐波产生和谐波光（超瑞利）散射技术，结合INDO/SCI-SOS理论计算，分别用于研究超极化率张量的矢量部分和分子非线性的二维特性。非对角超极化率张量可与垂直于分子偶极轴极化的电荷转移跃迁相关，而平行跃迁则对应于对角超极化率张量。金属中心在增强此类分子的二维NLO响应中的作用是双重的，因为它既作为平面供体-（π共轭桥）-受体体系的供体，又作为桥连部分。从偏振无关NLO材料的角度来看，这些偶极二维分子是有趣的候选物。
