We report the synthesis, crystal structure, phonons and luminescence properties of three novel heterometallic metal organic frameworks (MOFs) with perovskite-like topology of the following formulas: [C3H5N2]Na0.5Cr0.5(HCOO)3 (ImNaCr), [C3H5N2]Na0.
View Article and Find Full Text PDFWe report a continuous-wave (CW) and pulse electron paramagnetic resonance (EPR) as well as pulse electron nuclear double resonance (ENDOR) study of Cu doped [(CH)NH][Zn(HCOO)] hybrid perovskite which exhibits a structural phase transition. The multifrequency (X, Q and W-band) CW EPR measurements allow the temperature evolution of the Cu ion local environment to be studied. The spectrum of the ordered (low-temperature) phase reveals an axially distorted octahedral Cu site confirming the successful replacement of the Zn ions and formation of the CuO octahedra.
View Article and Find Full Text PDFWe report the synthesis, crystal structure, and dielectric, vibrational and emission spectra of two novel heterometallic perovskite-type metal-organic frameworks (MOFs) of the following formula: [(CH)NH][KCr(HCOO)] (DMAKCr) and [CHNH][KCr(HCOO)] (EtAKCr). DMAKCr crystallizes in a trigonal structure (R3[combining macron] space group) and undergoes an order-disorder phase transition to the monoclinic system (P1[combining macron] space group) at about 190 K. The dielectric studies confirm the presence of first-order relaxor-like structural transformation.
View Article and Find Full Text PDFWe report the synthesis, X-ray diffraction, thermal, magnetic, Raman and IR studies of three heterometallic MOFs, [(CH3)2NH2][Fe(III)M(II)(HCOO)6] with M = Zn (DMFeZn), Ni (DMFeNi) and Cu (DMFeCu), crystallizing in the niccolite type structure. DMFeZn and DMFeNi crystallize in the trigonal structure (space group P3[combining macron]1c) while DMFeCu crystallizes in the monoclinic structure (space group C2/c). Magnetic investigation shows that DMFeZn remains paramagnetic down to the lowest temperature obtained in our experiment while DMFeNi and DMFeCu exhibit ferromagnetic order below 42 and 28.
View Article and Find Full Text PDFNovel heterometallic formate [(CH3)2NH2][Fe(III)Mg(II)(HCOO)6] (DMFeMg) was prepared and characterized by single crystal X-ray diffraction, DSC, dielectric, magnetic susceptibility, Raman and IR methods. We also report thermal, Raman and IR studies of the known compound [(CH3)2NH2][Fe(III)Fe(II)(HCOO)6] (DMFeFe). DMFeMg crystallizes in the niccolite structure (P3[combining macron]1c space group).
View Article and Find Full Text PDFWe report the synthesis, crystal structure, and thermal, dielectric, phonon, and magnetic properties of [NH2-CH(+)-NH2][Mn(HCOO)3] (FMDMn). The anionic framework of [(Mn(HCOO)3(-)] is counterbalanced by formamidinium (FMD(+)) cations located in the cavities of the framework. These cations form extensive N-H···O hydrogen bonding with the framework.
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