Synthesis, Structure and Properties of Formamidine‐templated Metal Formate Crystals

Abstract

This work reports the preparation of crystals of two metal organic frameworks [(NH 2 CHNH 2 )][Zn(HCOO) 3 ] (1) and [(NH 2 CHNH 2 ) 2 ][Cu 2 (HCOO) 6 ] (2) by using the solvent evaporation method. Under the same experimental conditions, the obtained crystals show different crystal structures. The complex 1 forms 3D structure geometry with one Zn(Ⅱ) ion in the center of an octahedral coordination environment, which is bridged with six nearest Zn(Ⅱ) ions by the formate ligands. The 3D scaffold of the complex 2 consists of two copper ions (Cu1 and Cu2) in the center of an octahedral coordination environment bridged by formate ligands. Magnetic study shows diamagnetic susceptibility for [NH 2 CHNH 2 ][Zn(HCOO) 3 ] and antiferromagnetic coupling between the Cu(Ⅱ) ions for [(NH 2 CHNH 2 ) 2 ][Cu 2 (HCOO) 6 ].

Raman Spectroscopy of Formamidinium-Based Lead Halide Perovskite Single Crystals

“…30 To provide more specific insight into how changes in the Raman intensity and peak position relate to physical properties, the observed Raman peaks were assigned to specific vibrational modes based on previous Raman and infrared studies on formamidinetemplated Co and Fe formates. 31,32 It is clear that compared with δ-FAPbI 3 , the FA bending as well as the NH 2 bending, torsion, and wagging modes in α-FAPbI 3 show varied intensity. One possible explanation for the increased intensity is due to the higher FA molecular polarizability in the α phase, as the Raman intensities are proportional to the square of the changes of the polarizabilities.…”