Characterization and Photophysical Properties of a Luminescent Aluminum Hydride Complex Supported by a β-Diketiminate Ligand

Abstract

Aluminum hydrides are versatile compounds utilized as reducing agents, precursors of aluminum complexes, and as catalysts for polymerization reactions. However, their photophysical properties have been overlooked, although several luminescent aluminum complexes have been utilized conventionally for emitting layers in modern light-emitting devices. Herein, we report the synthesis and photophysical properties of a luminescent β-diketiminate dihydride complex through the reaction between lithium aluminum hydride and the corresponding ligand. The obtained compound exhibits crystallization-induced emission (CIE) properties at room temperature and long-lifetime phosphorescence at 80 K. Our experimental and theoretical investigations suggest that low-energy molecular vibration could play an important role in the realization of the CIE property.

Reversible Vapochromic Luminescence Accompanied by Planar Half‐Chair Conformational Change of a Propeller‐Shaped Boron β‐Diketiminate Complex

“…Consequently, this complex is allowed to emit stronger in the aggregated state than in the solution state. [54][55][56] Notably, the A/A 0 decreased at the 99 vol % of the water content, but still higher than those under the conditions with a low concentration of water (< 80 vol %). This decrease may originate from the precipitation of the large aggregates.…”

“…[54,55] This electronic transition should originate from the symmetrically allowed π-π* nature of the first singlet excited state S 1 of the compound. [56] This boron complex exhibited typical aggregation-induced emission (AIE) behavior (Figure 2). The absolute photoluminescence (PL) quantum yields of PPB in its dilute chloroform, THF and hexane/chloroform (99/1, vol/vol) solutions (1.0 × 10 À 5 M) were less than the limit of detection (< 0.01).…”

“…[40,45] In addition to this degree of freedom, these complexes often exhibit luminescent chromism in response to external stimuli, such as mechanical grinding, [40,41,[46][47][48][49][50] heating [51,52] and VOCs. [44] β-Diketiminate complexes would be advantageous concerning their efficient solidstate emission including aggregation-and crystallizationinduced emission, [44,[53][54][55][56] the designability of ligands, and chemical stability. [57][58][59][60] In this report, we hypothesized that such flexible and emissive β-diketiminate boron complexes might afford stimuli-responsive luminescent materials with low-energy recycling ability.…”

Synthesis and Stability of Hydrogen Storage Material Aluminum Hydride

“… is a white nonvolatile hexagonal crystal with a density of 1.477 , the theoretical hydrogen content of 10.08%, insoluble or slightly soluble in ether, soluble in tetrahydrofuran, and inert to hydrazine [ 29 , 30 ]. When exposed to water, the pure hydrolyzes slowly, and takes several hours for complete hydrolyses [ 31 , 32 ].…”

Modulation of the solid-state luminescent properties of conjugated polymers by changing the connecting points of flexible boron element blocks

“…For example, we prepared the diamine complexes with aluminum and gallium which belong to the same group as boron in the periodic table. 69,70 Both complexes show CIE, and gallium diiminate exhibits vapochromic luminescent properties. It should be mentioned that the degree of luminescent chromism was critically depended not on the chemical components of the captured volatile organic compounds but on their radius of gyration.…”