Molecular Design of Anionic Phthalocyanines with π–π Stacking Columnar Arrangement. Crystal Structures, Optical, and Magnetic Properties of Salts with the Iron(I) Hexadecachlorophthalocyanine Anions
Citations Over TimeTop 15% of 2013 papers
Abstract
Ionic compounds containing iron(I) hexadecachlorophthalocyanine anions have been obtained for the first time as single crystals: (PPN+){[Fe(I)Cl16Pc(−2)]−} (1), (Ph3MeP+)2{[Fe(I)Cl16Pc(−2)]−}(Br–)·C6H4Cl2 (2), and (PPN+)2[Fe(I, II)Cl16Pc(−2)]3(2−)·4C6H4Cl2 (3), where PPN+ is the cation of bis(triphenylphosphoranylidene)ammonium and Ph3MeP+ is the triphenylmethylphosphonium cation. The [Fe(I)Cl16Pc(−2)]− anions form closely packed π–π stacking columns in 1–3. Salts 1 and 2 with integer −1 charge on iron phthalocyanines have uniform and weakly dimerized columns, respectively. Salt 3 has two cations per three iron phthalocyanine molecules which are arranged in trimers within the columns. Different shift of phthalocyanines at the same interplanar distances of 3.33–3.38 Å provides essentially shorter Fe···Fe distances in 3 (3.62–3.84 Å) than those in 1 and 2 (5.07–5.45 Å). Calculations show a strong LUMO–LUMO overlapping between [Fe(I)Cl16Pc(−2)]− in 1–3 with the overlap integrals of 4.1–7.6 × 10–3. Weak signals attributed to the [Fe(II)Cl16Pc(−3)]− species with the delocalization of electron on the phthalocyanine macrocycles are observed in the EPR spectra of 1–3. The content of this admixture is less than 1% in all salts. Nevertheless, static magnetic susceptibility measurements for 3 detected significant magnetization. The effective magnetic moment is 4.05 μB per formula unit at 300 K. It can originate from the spins localized on the iron atoms of [Fe(I)Cl16Pc(−2)]−. The Weiss temperature of −53 K in the 60–300 K range indicates a strong antiferromagnetic interaction of spins which results in the decreases of magnetic moment of 3 with temperature below 220 K down to 2.72 μB at 6 K. Optical spectra of 1–3 show bands ascribed to [Fe(I)Cl16Pc(−2)]− at 339–349, 538–548, 685–691, and 805–821 nm. The bands in the NIR range at 1740–1810 nm were attributed to charge transfer excitations within phthalocyanine columns associated with the unpaired electrons on the iron atoms.
Related Papers
- → First-principles investigations of Zn (Cd) doping effects on the electronic structure and magnetic properties of CoFe2O4(2011)20 cited
- → Computational discovery of the novel half-metallic full-Heusler alloys Mn2LiAs and Mn2LiSb(2020)9 cited
- → First-principles Studies on Electronic and Magnetic Properties of I A –III A and I A –IV A Compounds with Zinc-Blende and Wurtzite Structures(2014)4 cited
- → The electronic, magnetic and half-metallic predictions of Mx (M = Ag, Cd, Y, Zr, Nb, and x = 0, 0.125, 0.25, 1)W1-xSn alloys(2022)3 cited
- → Effect of Ca doping on the Pr magnetic moment in Pr0.75Ca0.25MnO3(2017)