A novel blue-emitting indium(III) complex: Synthesis, crystal structure, and effect of solvents and temperature on the luminescent properties

•A novel indium complex was synthesized by the tetradentate Schiff base ligand.•Complex 1 exhibits blue emitting with the millisecond lifetime.•The effect of deuterated reagent and temperature on luminescent properties is discussed.

A novel indium complex {[InL(NO3)(OH)] · NO3 · CH3OH}2 (1) is isolated from the refluxing reaction of a tetradentate Schiff base ligand, N,N′-bis(2-pyridinylmethylene)cyclohexane-1,2-diamine (L), and In(III) nitrate hydrate. The room temperature (298 K) and cryogenic temperature (77 K) emission spectra of 1 are recorded in solid state and different solvents (CH3OH, CHCl3, CH3CN and DMSO). Complex 1 exhibits a pronounced bathochromic shift in emission spectra as solvent polarity increases (polarity order: DMSO > CH3CN > CHCl3), indicating a change in dipole moment of 1 upon excitation. Further bathochromic shift exists in CH3OH (467 nm) solution. An extended work is developed to discuss on maximum emission and lunminescent lifetime of 1 dispersed in the deuterated reagents (CD3OD, CDCl3, CD3CN and DMSO-d6). The results exhibit that the similar emission also exists in deuterated reagents and the longer lifetime is observed due to the scarcity of OH, NH, and CH oscillators. The quantum yield of 1 decreases with increasing polarity of solvent within the region of 7.8–15.4%. Commission Internationale de L'Eclairage (CIE) 1931 demonstrates that the color gamut of 1 is blue.

Graphical abstractOne novel indium complex {[InL(NO3)(OH)] · CH3OH · NO3}2 is obtained. The emission is sensitive to the polarity of the solvent as well as specific solute–solvent interaction such as hydrogen bonding. In addition, the utilization of deuterated solvents can favor to prolong lifetime.Figure optionsDownload full-size imageDownload as PowerPoint slide