Synthesis, crystal structure and optical properties of Me(OH)(HCOO) (Me = Al, Ga)

• Published in: CrystEngComm 2018-05, Vol.2 (19), p.2741-2748
• Main Authors: Krasil'nikov, V. N, Tyutyunnik, A. P, Baklanova, I. V, Enyashin, A. N, Berger, I. F, Zubkov, V. G
• Format: Article
• Language: English
• ISSN: 1466-8033
• DOI: 10.1039/c8ce00309b

The formation conditions, crystal structure and luminescence properties of aluminum and gallium hydroxide diformates, Me(OH)(HCOO) 2 , have been established. Both compounds crystallize in a monoclinic lattice (space group C 2, #5 and Z = 8) with parameters: a = 8.8629(2) Å, b = 9.9890(2) Å, c = 10.2411(1) Å, β = 106.223(1)°, and V = 870.56(3) Å 3 (Al) and a = 8.8746(1) Å, b = 10.3291(1) Å, c = 10.27870(9) Å, β = 105.7565(6)°, and V = 906.81(2) Å 3 (Ga). The emission spectra of Me(OH)(HCOO) 2 under UV excitation with wavelength λ = 285 nm exhibit maxima in the range of 440-470 nm. The emission accompanied by light-blue luminescence is greatly enhanced when going from the aluminum to the gallium compound. The origin of intrinsic emission centers responsible for the luminescence properties of Me(OH)(HCOO) 2 is suggested and the higher emission of the gallium hydroxide diformate is substantiated by means of density-functional theory calculations. Aluminium and gallium hydroxide diformates have been synthesized. Both compounds exhibit similar monoclinic lattice, according to the X-ray, neutron diffraction and IR spectroscopy data. Their samples possess a bright light-blue emission under UV excitation. The origin of intrinsic emission is elucidated by means of DFT calculations.