Luminescence, magnetic and vibrational properties of novel heterometallic niccolites [(CH3)2NH2][CrIIIMII(HCOO)6] (MII=Zn, Ni, Cu) and [(CH3)2NH2][AlIIIZnII(HCOO)6]:Cr3

• Published in: Journal of solid state chemistry 2016-01, Vol.233, p.455-462
• Main Authors: Mączka, Mirosław, Pietraszko, Adam, Pikul, Adam, Hermanowicz, Krzysztof
• Format: Article
• Language: English
• Subjects: Infrared; Luminescence; Magnetization; Metal organic framework; Raman
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2015.11.027

We report synthesis of three novel heterometallic MOFs, [(CH3)2NH2][CrIIIMII(HCOO)6] with M=Zn (DMCrZn), Ni (DMCrNi) and Cu (DMCrCu), crystallizing in the niccolite type structure. We also successfully synthesized [(CH3)2NH2][AlCu(HCOO)6] (DMAlCu) and [(CH3)2NH2][AlZn(HCOO)6] doped with 5.8mol% of Cr3+ (DMAlZn: Cr). X-ray diffraction shows that DMCrZn, DMCrNi and DMAlZn: Cr3+ crystallize in the trigonal structure (space group P3¯1c) while DMCrCu and DMAlCu crystallize in the monoclinic structure (space group C2/c). Magnetic investigation of the chromium-based niccolites reveals no magnetic order in DMCrZn and ferromagnetic order in DMCrNi and DMCrCu below 23 and 11K, respectively. Optical studies show that DMCrZn and DMAlZn: Cr samples exhibit efficient emission typical for chromium ions located at sites of strong crystal field with the Dq/B values 2.62 and 2.67, respectively. We also discuss role of geometrical parameters in stability of the perovskite and niccolite structures. View of the [(CH3)2NH2][CrZn(HCOO)6] crystal structure along the c-axis [Display omitted] •Novel chromium- and aluminum-based MOF compounds have been synthesized.•These heterometallic compounds crystallize in niccolite-type architecture.•Magnetization measurement revealed ferromagnetic ordering at low temperatures.•IR and Raman spectra were measured and assignment of modes has been proposed.•The compounds exhibit efficient chromium-based luminescence.