Crystal structures, Hirshfeld surfaces, Infrared, and XRF/XAFS studies of Long-chain 2D Lead-free Hybrid Perovskite NH3(CH2)9NH3MCl4 (M = Mn, Co, Cu)

Abstract

Three 2D hybrid perovskite materials based on long chain diammonium NH3(CH2)9NH3MCl4 (M: Mn, Co, Cu) were prepared and characterized. The single crystal X-ray diffraction analysis showed that the novel compound NH3(CH2)9NH3MnCl4 (denoted C9Mn) crystallized in the monoclinic P21/c (Z=4) with the unit cell parameters a=7.405(3) Å, b=7.102(3) Å, c=29.463(11) Å, V=1538.07Å3. The NH3(CH2)9NH3CoCl4 (C9Co) was found to crystallize in the Triclinic space group P¯1 [Z=2; a = 7.3113(4) Å, b = 10.2373(5) Å, c = 12.4701(9) Å; α = 112.323(2)°, β = 92.441(2)°, γ = 93.452(3)°, V=859.68(9) Å3]. The C9Mn and C9Co layered structures contain alternating organic cations +NH3(CH2)9NH3+ and inorganic anions MCl42- (M: Mn, Co), where M is coordinated by six Cl atoms in the octahedral topology MnCl62−, and by four Cl atoms in the tetrahedral CoCl42− unassociated unit. The NH3(CH2)9NH3CuCl4 (C9Cu) crystal quality is not good to do the single crystal X-ray diffraction analysis on this salt. The Hirshfeld surface analyses are performed to compare the importance of attractive H…Cl/Cl…H and detractive H…H intercontacts in the two hybrid compounds. The vibrational modes of alkylenediammonium group of C9Cu, clearly observed in the infrared spectrum, are compared to that observed in the C9Mn and C9Co spectra, discussed based on theoretical group predictions. Analysis was performed at the X-ray absorption fine structure XAFS/XRF beamline to enhance the structure analysis for the salts C9Mn, C9Co and C9Cu.