New anisopleural spindle-like nonlinear optic (NLO) chromophores with a D-D′-π-A′-A or D-A′-π-D′-A structure: interesting optical behavior and DFT calculation results

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2016-01, Vol.4 (36), p.8392-8398
• Main Authors: Li, Chuangyang, Li, Ming, Li, Yao, Shi, Zuosen, Li, Zong-Jun, Wang, Xibin, Sun, Jian, Sun, Jingwen, Zhang, Daming, Cui, Zhanchen
• Format: Article
• Language: English
• Subjects: Absorption; Acceptors (electronic); Charge transfer; Chromophores; Donors (electronic); Mathematical analysis; Nonlinear optics; Wavelengths
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/c6tc02016j

A new series of anisopleural spindle-like chromophores which have both auxiliary donors and acceptors on their conjugated bridge has been designed and synthesized for the first time. The auxiliary donors and acceptors were introduced close to the donors and acceptors respectively and formed D-D′-π-A′-A structure chromophores termed S-chromophores. The opposite D-A′-π-D′-A structure chromophores are termed F-chromophores. The structure-properties relationship based on these anisopleural spindle-like chromophores has been investigated via 1 H-NMR, UV-vis characterization and DFT theoretical calculations. S-Chromophores displayed varied chemical shifts of the double-bond proton and a red-shifted maximum absorption wavelength ( λ max ) as well as a larger absorption intensity ( ) compared to the F-chromophores, indicating that the intermolecular charge transfer has been influenced by the structures. Moreover, the red-shifted λ max and larger indicate a more efficient intermolecular charge transfer which should in turn lead to an increased hyperpolarizability ( β ) for a given class structure of chromophores. The theoretical calculation β values of the S-chromophores showing an increase further rationalize the experimental results. In this way, the structure-properties relationship has been investigated and established. S-Chromophores showed larger DFT calculation μβ and red-shifted λ max which indicated more effective intermolecular charge transfer.