Understanding the photophysical properties of chiral dinuclear Re(i) complexes and the role of Re(i) in their complexes. Issue 17 (24th March 2016)

• Record Type: Journal Article
• Authors: Liu, Chunyu; Si, Yanling; Shi, Shaoqing; Yang, Guochun; Pan, Xiumei
• Is Part Of: Dalton transactions. Volume 45:Issue 17(2016)
• Page Start: 7285
• Page End: 7293
• Publication Date: 2016-03-24
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c6dt00089d
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : We have investigated the electronic structure, UV-Vis/CD spectra and the second-order NLO properties of chiral dinuclear Re(i ) complexes and elucidated structure–property relationships with the aid of DFT calculations. Abstract : Chiral transition metal complexes not only have large nonlinear optical (NLO) response but also meet the non-centrosymmetric requirement of second-order NLO materials. Therefore, chiral transition metal complexes become very active in the NLO area. Recently, the second-order NLO response of chiral dinuclear Re(i ) complex2 has been found to be 1.5 times larger than that of KH2 PO4 (KDP) based on experimental measurement. However, its NLO origin has not been determined and a structure–property relationship has not been established at the microscopic level, which are very important to further improve the performance. It is found that charge transfer from metal to ligand is mainly responsible for its NLO origin. Based on complex2, the designed complexes have remarkably large second-order NLO activity. For instance, the designed complex9 has a very large second-order NLO response value (115.81 × 10 −30 esu), which is about 668 times larger than the organic molecule urea. Moreover, time-dependent density functional theory (TDDFT) calculations have been used to investigate their UV-Vis/CD spectra. The simulated circular dichroism (CD) spectra of the complex2 are in good agreement with the experimental ones, which can be used to assign the absolute configurations (ACs) of chiral dinuclear Re(i ) complexes with high confidence. The electronic absorption wavelengths, electron transition properties, and the second-order NLO responses strongly depend on the nature of substituent, different ligands (pyridine and isoquinoline) and their combinations. Based on NBO analysis, the interactions between [Re(CO)3 Cl] fragments and ligands are of n → σ* character.