Tuning Second-Order Non-linear (NLO) Optical Response of Organoimido-Substituted Hexamolybdates through Halogens: Quantum Design of Novel Organic-Inorganic Hybrid NLO Materials

Muhammad Ramzan Saeed Ashraf Janjua; Zhong-Min Su; Wei Guan; Chun-Guang Liu; Li-Kai Yan; Ping Song; Gull Maheen

doi:10.1071/CH10094

RESEARCH ARTICLE

Tuning Second-Order Non-linear (NLO) Optical Response of Organoimido-Substituted Hexamolybdates through Halogens: Quantum Design of Novel Organic-Inorganic Hybrid NLO Materials

Muhammad Ramzan Saeed Ashraf Janjua ^A ^C , Zhong-Min Su ^A ^C , Wei Guan ^A , Chun-Guang Liu ^A , Li-Kai Yan ^A , Ping Song ^A and Gull Maheen ^B

+ Author Affiliations

- Author Affiliations

^A Institute of Functional Material Chemistry and Key Laboratory of Polyoxometalate Science of Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, China.

^B State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, China.

^C Corresponding authors. Email: Dr_Janjua2010@yahoo.com; zmsu@nenu.edu.cn

Australian Journal of Chemistry 63(5) 836-844 https://doi.org/10.1071/CH10094
Submitted: 19 February 2010 Accepted: 26 March 2010 Published: 21 May 2010

Abstract

The second-order non-linear optical (NLO) response of organoimido-substituted hexamolybdates has been tuned from 218.61 × 10^–30 to 490.10 × 10^–30 esu. The dipole polarizabilities and second-order nonlinear optical (NLO) properties of organoimido derivatives of hexamolybdates have been investigated by using the time-dependent density functional response theory (TDDFT). The electron withdrawing ability of F (fluorine) has played an important role in tuning the second-order NLO response in this class of organic-inorganic hybrid compounds; particularly system 6 [Mo₆O₁₈(NC₁₆H₈F₂(CF₃)₂I)]^2– with the static second-order polarizability (β_vec ) computed to be 490.10 × 10^–30 esu. Thus, our studied systems have the feasibility to be excellent tuneable second-order NLO materials. The analysis of the major contributions to the β_vec value suggests that the charge transfer (CT) from POM to organic ligand (D-A) along the z-axis has been enhanced with addition of F atoms at the end phenyl ring which directs head (POM) to tail (fluorinated ring) charge transfer. The computed β_vec values have been tuned by incorporation of different halogen atoms at the end phenyl ring of organoimido segment. Furthermore, substitution of two trifluoromethyl (–CF₃) groups sideways along with iodine (I) at the terminus of end phenyl ring in the organoimido ligand has a striking influence on tuning the optical non-linearity, as CT from POM to the organoimido ligand was significantly increased. These systematic small changes in molecular composition by substitution of different halogen groups leads to a tuning the NLO response; the so-called ‘ripple effect’ catches this point nicely. Thus, the present investigation provides thought provoking insight into the tuneable NLO properties of organoimido-substituted hexamolybdates.

Acknowledgements

The authors gratefully acknowledge the financial support from the National Natural Science Foundation of China (Project No. 20971020), Program for Changjiang Scholars and Innovative Research Team in University (IRT0714), Department of Science and Technology of Jilin Province (20082103), the Training Fund of NENU’s Scientific Innovation Project (STC07017), and Science Foundation for Young Teachers of North-east Normal University (20090401). Muhammad Ramzan Saeed Ashraf Janjua acknowledges the Government of Pakistan (Ministry of Education) and China Scholarship Council (CSC) for the award of a PhD scholarship for 2006–2010. Ramzan Saeed Janjua is also thankful to Saira Janjua, Muhammad Sareb Janjua, Rayhan Gul Kashi, and Muhammad Shahbaz Mustafai for their continuous support and encouragement.

References

Tuning Second-Order Non-linear (NLO) Optical Response of Organoimido-Substituted Hexamolybdates through Halogens: Quantum Design of Novel Organic-Inorganic Hybrid NLO Materials

Abstract

Acknowledgements

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