Rational Designs of AIE-Active Molecules and Luminochromic Materials Based on Group 13 Element-Containing Element-Blocks

  • Kazuo TanakaEmail author
  • Yoshiki ChujoEmail author


There are numerous numbers of boron complexes having luminescent properties originating from rigid π-conjugated systems. However, similarly to other commodity chromophores, emissive boron complexes often suffer from aggregation-caused quenching (ACQ) in the applications as a luminescent film or an optical device. This ACQ problem is still a critical issue to be solved for expanding applicability of emissive boron complexes as advanced organic devices, environment sensors, and bioprobes. Recently, the class of boron complexes possessing aggregation-induced emission (AIE) properties has been discovered, and in particular, their environment-responsive luminescent characters have attracted attention as a key phenomenon to construct not only solid-state luminescent dyes but also stimuli-responsive luminochromic materials. In this review, AIE-active boron complexes are introduced mainly from our studies. Initially, the series of o-carboranes which are the boron cluster compound are introduced. Originating from intrinsic electron deficiency at the carbon atoms in the cluster, o-carborane works as a strong electron-accepting unit in the conjugated system. As a result, intense emission with the intramolecular charge transfer character can be observed. It should be noted that these emission properties can be preserved even in the condensed state by disturbing intermolecular interaction because of steric hindrance. Based on these facts, various types of solid-state luminescent materials have been developed with the modified o-carboranes. The mechanism and optical properties are demonstrated. Next, AIE-active boron complexes with β-diketonate derivatives are demonstrated. Transformation from conventional ACQ-presenting luminescent dyes to AIE-active molecules is presented. By using the key structures such as boron ketoiminate and diiminate, luminescent polymers were obtained. As an application, the film-type sensors for bio-significant molecules are shown. Finally, rational design for AIE-active molecules with theoretical calculations from the scratch is illustrated. Based on flexible boron complexes that show large degree of structural relaxation in the excited state, the AIE behaviors were able to be realized. The results are explained in this review.


Boron complex Carborane Solid-state luminescence Luminochromism Element-block 


  1. 1.
    Loudet A, Burgess K (2007) BODIPY dyes and their derivatives: syntheses and spectroscopic properties. Chem Rev 107:4891–4932CrossRefGoogle Scholar
  2. 2.
    Yoshii R, Nagai A, Tanaka K, Chujo YJ (2013) Highly near-infrared emissive boron di(iso)indomethene-based polymer: drastic change from deep-red to near-infrared emission via quantitative polymer reaction. Polym Sci Part A: Polym Chem 51:1726–1733CrossRefGoogle Scholar
  3. 3.
    Yoshii R, Yamane H, Nagai A, Tanaka K, Taka H, Kita H, Chujo Y (2014) π-conjugated polymers composed of BODIPY or Aza-BODIPY derivatives exhibiting high electron mobility and low threshold voltage in electron-only devices. Macromolecules 47:2316–2323CrossRefGoogle Scholar
  4. 4.
    Ulrich G, Ziessel R, Harriman A (2008) The chemistry of fluorescent bodipy dyes: versatility unsurpassed. Angew Chem Int Ed 47:1184–1201CrossRefGoogle Scholar
  5. 5.
    Yamane H, Tanaka K, Chujo Y (2015) Simple and valid strategy for the enhancement of the solid-emissive property of boron dipyrromethene. Tetrahedron Lett 56:6786–6790CrossRefGoogle Scholar
  6. 6.
    Yeo H, Tanaka K, Chujo Y (2013) Effective light-harvesting antennae based on BODIPY-tethered cardo polyfluorenes via rapid energy transferring and low concentration quenching. Macromolecules 46:2599–2605CrossRefGoogle Scholar
  7. 7.
    Kajiwara Y, Nagai A, Tanaka K, Chujo YJ (2013) Efficient simultaneous emission from RGB-emitting organoboron dyes incorporated into organic–inorganic hybrids and preparation of white light-emitting materials. J Mater Chem C 1:4437–4444CrossRefGoogle Scholar
  8. 8.
    Luo J, Xie Z, Lam JWY, Cheng L, Tang BZ, Chen H, Qiu C, Kwok HS, Zhan X, Liu Y, Zhu D, Tang BZ Aggregation-induced emission of 1-methyl-1,2,3,4,5-pentaphenylsilole. Chem Commun. 2001:1740−1741.
  9. 9.
    Mei J, Leung NLC, Kwok RTK, Lam JWY, Tang BZ (2015) Aggregation-induced emission: together we shine, united we soar! Chem Rev 115:11718–11940CrossRefGoogle Scholar
  10. 10.
    Gon M, Tanaka K, Chujo Y (2018) Synthesis, properties and structure of borafluorene-based conjugated polymers with kinetically and thermodynamically stabilized tetracoordinated boron atoms. Polym J 50:197–202. Scholar
  11. 11.
    Chujo Y, Tanaka K (2015) New polymeric materials based on element-blocks. Bull Chem Soc Jpn 88:633–643CrossRefGoogle Scholar
  12. 12.
    Kokado K, Chujo Y (2009) Emission via aggregation of alternating polymers with o-carborane and p-phenylene−ethynylene sequences. Macromolecules 42:1418–1420CrossRefGoogle Scholar
  13. 13.
    Tanaka K, Nishino K, Ito S, Yamane H, Suenaga K, Hashimoto K, Chujo Y (2017) Development of solid-state emissive o-carboranes and theoretical investigation of the mechanism of the aggregation-induced emission behaviors of organoboron “element-blocks”. Faraday Discuss 196:31–42CrossRefGoogle Scholar
  14. 14.
    Nishino K, Yamamoto H, Tanaka K, Chujo Y (2016) Development of solid-state emissive materials based on multifunctional o-carborane–pyrene dyads. Org Lett 18:4064–4067CrossRefGoogle Scholar
  15. 15.
    Naito H, Nishino K, Morisaki Y, Tanaka K, Chujo Y (2017) Solid-state emission of the anthracene-o-carborane dyad from the twisted-intramolecular charge transfer in the crystalline state. Angew Chem Int Ed 56:254–259CrossRefGoogle Scholar
  16. 16.
    Naito H, Nishino K, Morisaki Y, Tanaka K, Chujo YJ (2017) Highly-efficient solid-state emissions of anthracene–o-carborane dyads with various substituents and their thermochromic luminescence properties. J Mater Chem C 4:10047–10054CrossRefGoogle Scholar
  17. 17.
    Naito H, Nishino K, Morisaki Y, Tanaka K, Chujo Y (2017) Luminescence color tuning from blue to near infrared of stable luminescent solid materials based on bis-o-carborane-substituted oligoacenes. Chem Asian J 12:2134–2138CrossRefGoogle Scholar
  18. 18.
    Nishino K, Uemura K, Tanaka K, Chujo Y (2017) Enhancement of aggregation-induced emission by introducing multiple o-carborane substitutions into triphenylamine. Molecules 22:2009–2018CrossRefGoogle Scholar
  19. 19.
    Nishino K, Yamamoto H, Tanaka K, Chujo Y (2017) Solid‐state thermochromic luminescence through twisted intramolecular charge transfer and excimer formation of a carborane−pyrene dyad with an ethynyl spacer. Asian J Org Chem 6:1818–1822CrossRefGoogle Scholar
  20. 20.
    Tanaka K, Chujo Y (2012) Advanced luminescent materials based on organoboron polymers. Macromol Rapid Commun 33:1235–1255CrossRefGoogle Scholar
  21. 21.
    Tanaka K, Chujo Y (2015) Recent progress of optical functional nanomaterials based on organoboron complexes with β-diketonate, ketoiminate and diiminate. NPG Asia Mater 7:e223CrossRefGoogle Scholar
  22. 22.
    Yoshii R, Nagai A, Tanaka K, Chujo Y (2013) Highly emissive boron ketoiminate derivatives as a new class of aggregation-induced emission fluorophores. Chem Eur J 19:4506–4512CrossRefGoogle Scholar
  23. 23.
    Yoshii R, Nagai A, Tanaka K, Chujo Y (2014) Boron‐ketoiminate-based polymers: fine-tuning of the emission color and expression of strong emission both in the solution and film states. Macromol Rapid Commun 35:1315–1319CrossRefGoogle Scholar
  24. 24.
    Yoshii R, Tanaka K, Chujo Y (2014) Conjugated polymers based on tautomeric units: regulation of main-chain conjugation and expression of aggregation induced emission property via boron-complexation. Macromolecules 47:2268–2278CrossRefGoogle Scholar
  25. 25.
    Yoshii R, Hirose A, Tanaka K, Chujo YJ (2014) Functionalization of boron diiminates with unique optical properties: multicolor tuning of crystallization-induced emission and introduction into the main chain of conjugated polymers. Am Chem Soc 136:18131–18139CrossRefGoogle Scholar
  26. 26.
    Hirose A, Tanaka K, Yoshii R, Chujo Y (2015) Film-type chemosensors based on boron diiminate polymers having oxidation-induced emission properties. Polym Chem 6:5590–5595CrossRefGoogle Scholar
  27. 27.
    Ito S, Hirose A, Yamaguchi M, Tanaka K, Chujo YJ (2016) Size-discrimination of volatile organic compounds utilizing gallium diiminate by luminescent chromism of crystallization-induced emission via encapsulation-triggered crystal–crystal transition. J Mater Chem C 3:5564–5571CrossRefGoogle Scholar
  28. 28.
    Yamaguchi M, Ito S, Hirose A, Tanaka K, Chujo Y (2017) Control of aggregation-induced emission versus fluorescence aggregation-caused quenching by bond existence at a single site in boron pyridinoiminate complexes. Mater Chem Front 1:1573–1579CrossRefGoogle Scholar
  29. 29.
    Ohtani S, Gon M, Tanaka K, Chujo Y (2017) A flexible, fused, azomethine–boron complex: thermochromic luminescence and thermosalient behavior in structural transitions between crystalline polymorphs. Chem Eur J 23:11827–11833CrossRefGoogle Scholar

Copyright information

© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Department of Polymer Chemistry, Graduate School of EngineeringKyoto UniversityKyotoJapan

Personalised recommendations