Langmuir–Blodgett Films of Hexamolybdate and Naphthylamine Prepared by Two Different Approaches: Synthesis, Characterization, and Materials Properties

Authors

  • Qian Liu,

    1. Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules and School of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, People's Republic of China, Fax: +86-27-88663043
    2. Institute of Molecular Functional Materials and Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Hong Kong, People's Republic of China, Fax: +852-34117348
    Search for more papers by this author
  • Lei Hu,

    1. Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules and School of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, People's Republic of China, Fax: +86-27-88663043
    Search for more papers by this author
  • Hui Fu,

    1. Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules and School of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, People's Republic of China, Fax: +86-27-88663043
    Search for more papers by this author
  • Jun Yang,

    1. Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules and School of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, People's Republic of China, Fax: +86-27-88663043
    Search for more papers by this author
  • Qiao-Min Fu,

    1. Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules and School of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, People's Republic of China, Fax: +86-27-88663043
    Search for more papers by this author
  • Li Liu,

    1. Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules and School of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, People's Republic of China, Fax: +86-27-88663043
    Search for more papers by this author
  • Shi-Zhong Liu,

    1. Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules and School of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, People's Republic of China, Fax: +86-27-88663043
    Search for more papers by this author
  • Zu-Liang Du,

    1. Key Laboratory of Special Functional Materials, Henan University, Kaifeng 475001, People's Republic of China
    Search for more papers by this author
  • Cheuk-Lam Ho,

    1. Institute of Molecular Functional Materials and Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Hong Kong, People's Republic of China, Fax: +852-34117348
    Search for more papers by this author
  • Feng-Rong Dai,

    1. Institute of Molecular Functional Materials and Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Hong Kong, People's Republic of China, Fax: +852-34117348
    Search for more papers by this author
  • Wai-Yeung Wong

    1. Institute of Molecular Functional Materials and Department of Chemistry and Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Hong Kong, People's Republic of China, Fax: +852-34117348
    Search for more papers by this author

Abstract

Two novel covalently-linked organic-inorganic hybrid compounds [(n-C4H9)4N]2[Mo6O18{≡N–(2-Np)}] (NA–Mo6) and [(n-C4H9)4N]2[Mo6O17{≡N–(1-Np)}2] (NA2–Mo6) (2-Np = 2-naphthyl; 1-Np = 1-naphthyl) have been prepared by the reaction of 2-naphthylamine (2-NpNH2) or 1-naphthylamine (1-NpNH2) with [(n-C4H9)4N]2[Mo6O19] (Mo6) in the presence of N,N′-dicyclohexylcarbodiimide (DCC) in anhydrous acetonitrile, and have been characterized by 1H NMR, IR, UV/Vis, and fluorescence spectra as well as X-ray crystallography. Structural analyses reveal the formation of self-assembled infinite 1-D and 3-D supramolecular frameworks. The UV/Vis spectra of NA–Mo6 and NA2–Mo6 show that the lowest energy electronic transfers occur at 362 and 394 nm, respectively, which are dramatically red-shifted when compared to that of Mo6. The luminescence studies show that Mo6 can notably quench the emission of naphthylamine. Monolayer and multilayer films of NA–Mo6 and NA2–Mo6 were fabricated on different substrates by the Langmuir–Blodgett (LB) technique using H2O as the subphase. For comparison, another two types of organic-inorganic hybrid films composed of noncovalently-linked 1-NpNH2/Mo6 and 2-NpNH2/Mo6 systems were also deposited onto the same substrates under the same conditions by the LB technique using an aqueous solution of Mo6 as the subphase. The as-prepared organic-inorganic hybrid films were characterized by π-A isotherms, UV/Vis absorption spectra, photoluminescence spectra, and scanning tunneling microscopy. The results indicate that stable monolayers can be formed at the air–water interface for NA–Mo6 and NA2–Mo6, and at the air–Mo6 solution interface for 1-NpNH2 and 2-NpNH2. The four LB films containing NA–Mo6, NA2–Mo6, 1-NpNH2/Mo6, and 2-NpNH2/Mo6 display interesting electrical conductivity.

Ancillary