Recent progress in the development of advanced element-block materials

Abstract

An element-block is defined as a minimum functional unit composed of heteroatoms. The concept of 'element-block material' for designing advanced materials was proposed in 2015. In this review, the recent progress in material designs based on this concept is described. From our research, several element-blocks as representative examples are selected, and their roles in each material are explained. Initially, research on the development of 'designable hybrids' by employing polyhedral oligomeric silsesquioxane (POSS) is illustrated. Multiple functions of hybrids composed of modified POSS and the significant roles of POSS in bio-related polymeric materials for solving critical problems in conventional 19 F MR probes and for realizing new sensing technologies are demonstrated. Next, solid-state luminescent materials containing o-carborane and group 13 element-blocks are discussed. The materials' highly efficient emission in the solid state and their origins are explained. Furthermore, stimuliresponsive luminescent chromism is summarized. The sensing mechanisms and the application of these materials as sensors are presented in this study. In the last part, we mention optically active element-blocks containing chiral P-stereogenic phosphorus. In this review, the characteristics originating from each element-block are explained.

Improvement of Solid‐State Excimer Emission of the Aryl–Ethynyl‐o‐Carborane Skeleton by Acridine Introduction

“…Because of the steric structure of the o ‐carborane unit, non‐specific intermolecular interaction can be efficiently disturbed even in the condensed state, followed by highly‐efficient solid‐state luminescent properties. On the basis of these results, we regard o ‐carborane as a conjugated “element‐block”,, which is the minimum functional unit consist of heteroatoms, and designed various aryl‐modified molecules to obtain optical materials . So far, the series of unique luminescent materials have been prepared by the combination of various aromatic rings, such as aggregation‐induced emission,, intense solid‐state luminescence with almost quantitative efficiencies in the visible region,, a highly‐stable near‐infrared luminophore and stimuli‐responsive luminochromic behaviors .…”

Enhancing Light‐Absorption and Luminescent Properties of Non‐Emissive 1,3,4,6,9b‐Pentaazaphenalene through Perturbation of Forbidden Electronic Transition by Boron Complexation

“…Various strategies have been proposed to develop new functional π‐conjugated materials. Among those strategies, we have recently proposed the conceptual idea for designing π‐conjugated material based on element‐blocks, which are functional building blocks containing heteroatoms . By combination, assembly and integration with element‐blocks, unique functions originating from not only heteroatoms themselves but also electronic interaction between π‐conjugation and heteroatoms can be expected.…”

“…Among those strategies, we have recently proposed the conceptual idea for designing πconjugated material based on element-blocks, which are functional building blocks containing heteroatoms. [8,9] By combination, assembly and integration with element-blocks, unique functions originating from not only heteroatoms themselves but also electronic interaction between π-conjugation and heteroatoms can be expected. From this standpoint, we have focused on the effect of heteroatoms onto the optoelectronic properties of π-conjugated system.…”

Modulation of the cis‐ and trans‐Conformations in Bis‐o‐carborane Substituted Benzodithiophenes and Emission Enhancement Effect on Luminescent Efficiency by Solidification

“…One promising platform to overcome the ACQ problem is a class of aggregation-induced emission (AIE)-active boron complexes, which show significant emission not in the dilute state but in aggregation. [22][23][24][25][26][27][28][29][30][31][32][33][34] We have also focused on the arylmodified o-carboranes as a scaffold for constructing luminescent "element-block", [35,36] which is defined as a minimum functional unit composed of heteroatoms. [4] Additionally, based on environment-responsive intensity changes of the AIE-active materials, various types of film-type luminescent materials and sensors can be fabricated.…”